Abstract

A monitoring system based on a digital converter station includes a first monitoring terminal deployed at a first-level monitoring side, a second monitoring terminal deployed at a second-level monitoring side, and a third monitoring terminal deployed at a third-level monitoring side; the monitoring terminal at each level includes a communication module, a human-machine interaction module, a device status monitoring module, a device alarm management module, a video fusion processing module, and a data transmission adjustment and control module.

IPC Classes  ?

• G06V 10/80 - Fusion, i.e. combining data from various sources at the sensor level, preprocessing level, feature extraction level or classification level
• G06V 20/52 - Surveillance or monitoring of activities, e.g. for recognising suspicious objects
• H04L 43/0829 - Packet loss
• H04L 43/0864 - Round trip delays

Abstract

A modular multi-level converter, a converter valve system and a sub-module networking method. Communication optical fibers between sub-modules in a group and valve controllers are simplified, by means of optical switches, from the original multi-receiving multi-transmitting mode to a one-receiving one-transmitting mode, such that the control and monitoring of the sub-modules can be completed using a relatively small number of optical fibers between converter valve controllers and the sub-modules, which can save on costs and reduce the difficulty in laying on the basis of ensuring control synchronization. By means of arranging the optical switches, it is also possible to bypass a faulty sub-module in a timely manner, thereby avoiding the impact on information transmission during uplink or downlink communication. Sub-modules directly forward an instruction when receiving the instruction, thereby ensuring instruction reception synchronization. The mode of uploading information of the sub-modules themselves involves time-sharing delivery in the same direction, such that serial delivery without congestion can be realized.

IPC Classes  ?

• H02M 7/483 - Converters with outputs that each can have more than two voltage levels

Abstract

An energy dissipation apparatus and a switch-in control method therefor, which belong to the technical field of energy dissipation apparatuses. The method comprises: when an energy dissipation apparatus is allowed to be switched in and a received energy dissipation apparatus switch-in instruction is valid, issuing a closing command to control switches of all phases in the energy dissipation apparatus, such that the control switches execute a closing action, wherein the energy dissipation apparatus being allowed to be switched in indicates that the energy dissipation apparatus meets a switch-in condition; and when closed-position states fed back by the control switches of all the phases are received within a required time, determining that the control switches of all the phases are closed successfully, thereby completing the switch-in of the energy dissipation apparatus. The whole method has simple logic, but is highly practical; facilitates the engineering implementation of an energy dissipation apparatus; effectively solves the problem of overvoltage of an alternating-current bus; and improves the power delivery capacity of a direct-current line.

IPC Classes  ?

• H02H 9/04 - Emergency protective circuit arrangements for limiting excess current or voltage without disconnection responsive to excess voltage

Abstract

The present application discloses a monitoring system and method based on a digital converter station. The monitoring system comprises a first monitoring terminal deployed at a first-level monitoring side, a second monitoring terminal deployed at a second-level monitoring side, and a third monitoring terminal deployed at a third-level monitoring side. The monitoring terminal at each level comprises a communication module, a human-computer interaction module, a device state monitoring module, a device alarm management module, a video fusion processing module, and a data transmission regulation and control module. The video fusion processing modules are respectively deployed at the monitoring terminals at all levels, so that the monitoring terminals at all levels can locally respond to monitoring retrieval requests of users at all levels; a station end does not need to completely respond to the monitoring retrieval requests of the users at all the levels, a user can directly view a video fusion picture from the local and does not need to retrieve the video fusion picture from a remote end, and therefore, when network bandwidth resources are limited, network delay can be effectively reduced, the real-time performance of video picture display is improved, and the use effect of a video fusion application and user experience are improved.

IPC Classes  ?

• H04N 7/18 - Closed-circuit television [CCTV] systems, i.e. systems in which the video signal is not broadcast

Abstract

Provided is a method for performing impedance amplitude-frequency characteristic scanning for an RTDS model based on positive and negative zero domains. The method comprises: constructing a power grid model in a real-time digital simulation system (RTDS) (S110); creating a functional block for generating a harmonic voltage signal; creating a script, performing stepped modification on the frequency of a harmonic voltage within a specific frequency range, and enabling a single round of harmonic voltage injection for every time modification is performed (S120); injecting a harmonic wave into a specified port of the power grid model, executing the script, measuring a voltage and a current output by the specified port, and storing a voltage and current data file by the functional block (S130); reading the voltage and current data file using MATLAB, and calculating impedance amplitudes and phase angles at different frequencies (S140). Due to a Fourier transform step being omitted in RTDS real-time simulation, impedance scanning time is greatly shortened, a harmonic signal of a single frequency point can be injected in one round of harmonic injection, and impedance scanning precision is ensured.

IPC Classes  ?

• G01R 27/02 - Measuring real or complex resistance, reactance, impedance, or other two-pole characteristics derived therefrom, e.g. time constant

Abstract

The present invention relates to a low-cost supercapacitor charging circuit and system suitable for a single-phase electricity meter. The charging circuit is used for charging a supercapacitor, and the voltage output from a charging voltage output end is adjusted by means of an output voltage adjustment module connected between a charging voltage input end and the charging voltage output end, such that the voltage at two ends of a supercapacitor to be charged is reduced, and the overall life service index of a single-phase intelligent electricity meter is improved. According to the technical solution provided in the present invention, the current consumed by the charging circuit per se is relatively low, the circuit working state of the charging circuit is stable, the device structure is simple, and the cost is low.

IPC Classes  ?

• H02J 7/00 - Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
• G06F 1/30 - Means for acting in the event of power-supply failure or interruption, e.g. power-supply fluctuations

Abstract

A virtual hardware test acceleration method and apparatus for a software function of an electricity meter. The method comprises the following steps: on the basis of a virtual hardware system, generating a preset number of input signals according to a preset input signal rule (S200); obtaining an input signal amount of the virtual hardware system to be tested (S300); and analyzing and comparing the preset number of input signals with the input signal amount of the virtual hardware system to obtain the running status of software to be tested (S400). A virtual hardware apparatus is used to simulate an electricity meter to be tested so as to quickly generate a large number of cases, product function testing is quickly performed on the virtual hardware apparatus, full coverage of trigger signal input is implemented, and a test speed can be accelerated by using the virtual hardware apparatus, so that the present invention can be applied to automated testing of electricity meters and can also be applied to embedded product testing, and has broad application prospects.

IPC Classes  ?

• G06F 11/36 - Prevention of errors by analysis, debugging or testing of software

Abstract

A direct-current metering voltage sampling device for an electric energy meter, the device comprising a first voltage-division module, an optocoupler processing module, a signal amplification module, a second voltage-division module and a sampling signal switching module, which are sequentially connected in series, wherein an input end of the first voltage-division module is respectively connected to a positive electrode and a negative electrode of a voltage sampling terminal of an electric energy meter to be subjected to measurement; the optocoupler processing module performs linear amplification and isolation on a sampling signal which is subjected to voltage division by means of the first voltage-division module, and an output end of the optocoupler processing module automatically adjusts, according to a connection situation of the positive electrode and the negative electrode of the voltage sampling terminal of said electric energy meter, a reference point of an output voltage; the signal amplification module amplifies the sampling signal output by the optocoupler processing module, and outputs the amplified sampling signal to the sampling signal switching module after passing through the second voltage-division module; and the sampling signal switching module performs, according to a preset frequency value, differential processing on a single-path voltage signal output by the second voltage-division module, so as to obtain an equal-amplitude differential signal and output same to a metering chip voltage channel for metering. The device may allow an input signal of a voltage sampling loop to be either a positive signal or a negative signal; and by means of using the isolation characteristic of a linear optocoupler, a short circuit between the voltage sampling loop and a current sampling loop is avoided, such that two situations where the current sampling of a direct-current electric energy meter is connected to a positive electrode or a negative electrode of a power source to be subjected to measurement are compatible.

IPC Classes  ?

• G01R 19/25 - Arrangements for measuring currents or voltages or for indicating presence or sign thereof using digital measurement techniques

Abstract

Disclosed in the present invention are a method and system for improving the reliability of valve-controlled serial communication. The method comprises: sampling several-point data of different phases; and parsing a sampling value, and outputting parsed data by means of any data frame that is verified to be correct. The system comprises: a sampling apparatus, which is used for sampling multi-point data of different phases; and a parsing apparatus, which is used for parsing a sampling value, and outputting parsed data by means of any data frame that is verified to be correct. Provided in the present invention are a method and system for improving the reliability of valve-controlled serial communication. An error prevention and error correction method within a single communication cycle is provided. By means of the method, a bit value in a serial data frame is sampled in a three-point sampling parallel parsing manner, such that single-bit data is collected more reliably, so as to prevent the phenomenon of data packet loss caused by collection interference of single-bit data in a data frame, thereby improving the reliability of communication of a communication link layer.

IPC Classes  ?

• H03M 1/54 - Input signal sampled and held with linear return to datum
• H04L 29/06 - Communication control; Communication processing characterised by a protocol

Abstract

Disclosed are a multi-master-switch-type high-speed interconnection backplane bus, a control method therefor, and a processing system thereof. The multi-master-switch-type high-speed interconnection backplane bus comprises: a programmable bus protocol controller. The programmable bus protocol controller is electrically connected to several processors of the processing system and several peripheral modules respectively. The programmable bus protocol controller receives control instructions of the several processors, and converts several processed one-to-one, one-to-many or many-to-one concurrent bus access into a virtual end-to-end connection by means of virtual address translation of the several peripheral modules corresponding to the control instructions, so as to improve the data transmission efficiency of the backplane bus. By using a star structure in which the programmable bus protocol controller is connected to the processors and the peripheral modules, the problem of bus resource limitation of concurrent access of multiple processors is solved, the data package collision rate is reduced, multiple processors are allowed to initiate bus access simultaneously or a single processor is allowed to initiate access of multiple peripheral devices simultaneously, and the multi-master access of the backplane bus achieves aggregation of multi-processor computing power.

IPC Classes  ?

• G06F 13/42 - Bus transfer protocol, e.g. handshakeSynchronisation

Abstract

The present invention relates to a rapid restarting apparatus for a charging controller, and a charging pile control system using the rapid restarting apparatus. A switching power source module, an alternating current power supply module, a power supply on/off module, and a power supply control module are arranged; the power supply control module controls, according to a restart control instruction outputted by a charging controller, the power supply on/off module to disconnect the alternating current power supply module and the switching power source module, and after a predetermined time period, connect the alternating current power supply module and the switching power source module, so that the switching power source module is powered on at a predetermined time after being powered off, and therefore, the remote restart of the charging controller is achieved. The present invention achieves the remote power-off and restart of the charging pile control system by means of the rapid restarting apparatus for the charging controller, thereby being capable of rapidly solving some of the faults, improving the intelligent operation and maintenance levels of a charging pile, relieving the operation and maintenance pressure of a large number of charging facilities that are increased in a burst mode, and promoting the healthy development of the charging facility industry.

IPC Classes  ?

• H02J 7/02 - Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries for charging batteries from AC mains by converters

Abstract

Disclosed are a method and apparatus for processing transmission data of a line-protection fiber channel, the method comprising: acquiring a numerical value of a data frame format in a communication message sent by an opposite side; when the numerical value is a first preset numerical value, apparatuses on both sides of a fiber channel periodically sending sampling data and switch quantity data after sampling is interrupted; when the numerical value is a second preset numerical value, sending, to the opposite side, sampling data of the previous frame that has been checked to be abnormal, a sampling sequence number, and the sampling data of the current frame; when the numerical value is a third preset numerical value, performing phasor calculation on the sampling data of a 1/4 cycle before an abnormal frame, sending a real part and an imaginary part of a three-phase current and a corresponding sampling sequence number to the opposite side, and using a current phasor of a local side and a current phasor of the 1/4 cycle of the opposite side to synthesize a differential current and a braking current that are used for differential protection. Sampling data is sent after sampling is interrupted, and when consecutive two data abnormalities are detected, a phasor is calculated using a current sampling value of a 1/4 cycle and is transferred to an opposite side, thereby reducing the influence of an accidental communication abnormality of a fiber channel on differential protection.

IPC Classes  ?

• H02H 7/26 - Sectionalised protection of cable or line systems, e.g. for disconnecting a section on which a short-circuit, earth fault, or arc discharge has occurred
• H02H 1/00 - Details of emergency protective circuit arrangements
• H04B 10/032 - Arrangements for fault recovery using working and protection systems
• H04B 10/25 - Arrangements specific to fibre transmission
• H04L 1/00 - Arrangements for detecting or preventing errors in the information received

Abstract

Disclosed are an IGCT-based controllable reactive power compensation device topology and a control method therefor. Said device topology comprises: a capacitor module, an inductor and a controllable module; the inductor is connected to the capacitor module in series; the capacitor module comprises a fixed capacitor unit and a controllable capacitor unit connected in series, the controllable capacitor unit being connected to the controllable module in parallel; and the controllable module bypasses the controllable capacitor unit when a line voltage is reduced due to a failure of an alternating current power transmission line, so as to increase the reactive power compensation capacity of the compensation device and further stabilize the line voltage, and after the failure of the alternating current power transmission line disappears and the line voltage recovers to a preset voltage upper limit value, the controllable capacitor unit is put into use again, so as to reduce the reactive power compensation capacity of the compensation device. By using the full-control characteristic of an IGCT, both turning-on and turning-off thereof can be controlled, and the precise moments of put-into-use and removal of a capacitor can be controlled in real time, so as to compensate for the reactive power requirement of a grid system in real time and stabilize an alternating current bus voltage.

IPC Classes  ?

• H02J 3/18 - Arrangements for adjusting, eliminating or compensating reactive power in networks

Abstract

An ordered charging control system and method for an alternating-current charging pile. The device comprises a power supply end and an in-vehicle end. Switches S4 and S5 are added between a charging connection confirmation cable (CC) and a grounding cable (PE). The ordered charging control method comprises a connection confirmation stage, a preparation and readying stage, a waiting to start stage, a starting to charge stage, a charging stage, a charge ending stage, and a charge settlement stage. The device and method make improvements and optimizations on the basis of an existing charging process and a standard protocol, implement the function of an ordered charging control process on the alternating-current charging pile, and standardize an ordered charging process.

IPC Classes  ?

• B60L 53/16 - Connectors, e.g. plugs or sockets, specially adapted for charging electric vehicles

Abstract

The present invention relates to a BMS cooperative control system and method for an electrochemical energy storage power station. A communication network is provided for a BMS of each energy storage cabin, and BMSs of different energy storage cabins are interconnected and intercommunicate, so that battery SOC sharing of each energy storage cabin is realized, and the BMS of each energy storage cabin can acquire data such as a battery SOC of BMSs in all the other cabins. The BMS of each energy storage cabin determines, by synthesizing the SOC thereof and the SOC of other cabins, whether the battery of the present cabin needs to be charged and discharged to keep the SOC thereof be at the same level as the SOC of other cabins, and the inter-cabin SOC equalization facilitates the overall efficient operation of the energy storage power station. By means of holographic data analysis, two-way interaction with an EMS and a PCS is further performed, and BMS cooperative control of the whole station is realized.

IPC Classes  ?

• H02J 7/00 - Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
• H01M 10/44 - Methods for charging or discharging

Abstract

A smart management system for a dry-type transformer. A control module (2) is respectively in communication connection with a collection module (1), a display unit (3) and a communication unit (5); and a power supply unit (4) is respectively electrically connected to the control module (2), the display unit (3) and the communication unit (5). The collection module (1) comprises several sensor units arranged on a dry-type transformer and collects detection data of the dry-type transformer. The control module (2) acquires the detection data, performs determination on the detection data according to a pre-stored detection data threshold, and sends an alarm signal when a detection data value exceeds the threshold, and transmits the alarm signal to a remote server by means of the communication unit (5). The display unit (3) receives the detection data transmitted by the control module (2). The smart management system for a dry-type transformer detects the operation state of the dry-type transformer in real time and analyzes detection data, so as to obtain power data and start/stop control state data of the dry-type transformer, determines whether the data exceeds a threshold, and sends an alarm signal, thereby improving the monitoring level of the operation state of the dry-type transformer and realizing visualization of the detection data.

IPC Classes  ?

• G01R 31/00 - Arrangements for testing electric propertiesArrangements for locating electric faultsArrangements for electrical testing characterised by what is being tested not provided for elsewhere
• G08C 17/02 - Arrangements for transmitting signals characterised by the use of a wireless electrical link using a radio link

Abstract

A method and system for frequency modulation control of a new energy power station containing energy storage. The method comprises: a primary frequency modulation system of a new energy device obtaining the current frequency of a power grid in real time, and determining a frequency modulation range to which the current frequency belongs; when the current frequency is within a primary frequency modulation range, determining an own power regulation target according to the current frequency of the power grid, and performing primary frequency modulation according to the determined power regulation target; when the current frequency is within a rapid frequency modulation range, performing rapid frequency modulation according to a power regulation target issued by a station-level rapid frequency modulation system; and when the current frequency is within a normal frequency range, performing normal frequency regulation according to an AGC instruction value issued by an in-station AGC system. According to the method, by means of mutual cooperation of the new energy device body, the station-level rapid frequency modulation system and the in-station AGC system, the safety level of the frequency of a power system, especially the frequency of a sending-end power grid, is improved.

IPC Classes  ?

• H02J 3/24 - Arrangements for preventing or reducing oscillations of power in networks
• H02J 3/28 - Arrangements for balancing the load in a network by storage of energy
• H02J 3/46 - Controlling the sharing of output between the generators, converters, or transformers

Abstract

A virtual and real combined panoramic visualization method and device for a substation communication network. Said method comprises: determining, according to an SPCD file, a correlation between device names and port capability information of a substation, determining, according to an SCD file, a correlation between the device names and virtual circuit service subscription relationships, determining, according to a CSD file of a switch, a correlation between the virtual circuit service subscription relationships and switch information, the switch information including switch name information and corresponding port information; and establishing a correlation between the device names, the port capability information, the virtual circuit service subscription relationships, and the switch information, and generating a display file. The method and device achieve real-time tight coupling of a physical topology and a virtual circuit topology of the substation, achieve panoramic visualization of a service data network of the substation, simplify the management work, enrich monitoring and fault location means, and improve the operating and maintenance level of the substation.

IPC Classes  ?

• H04L 12/24 - Arrangements for maintenance or administration

Abstract

dcrefdcLCCdcLCCdcLCC and the final LCC direct-current voltage reference value, inputting same into a PI controller for adjustment, and outputting a cosine value of a trigger angle; and by means of inverse cosine calculation, outputting a trigger angle of an inverter station. In the method, after a fault in an alternating-current system is cleared, an LCC transient voltage controller appropriately reduces a voltage reference value according to a VSC overvoltage situation and a voltage drop of a direct-current line, such that during a system recovery process, an LCC of an inverter station operates at a low voltage, thereby limiting the overvoltage of a system-pole bus.

IPC Classes  ?

• H02J 3/36 - Arrangements for transfer of electric power between ac networks via a high-tension dc link
• H02J 3/24 - Arrangements for preventing or reducing oscillations of power in networks

Abstract

Disclosed are a circuit for improving clock accuracy and a clock. The circuit comprises an MCU controller, a temperature sensor, and a humidity sensor. An output end of the temperature sensor is connected to the MCU controller. An output end of the humidity sensor is connected to the MCU controller. The MCU controller has a clock function. Calculation is performed according to currently received temperature data and humidity data, as well as preset temperature data, humidity data, and an error curve so as to correct the clock accuracy. A clock using the present circuit has higher output accuracy, higher stability, higher product metering accuracy, and reduced costs.

IPC Classes  ?

• G01D 21/02 - Measuring two or more variables by means not covered by a single other subclass
• G04F 10/00 - Apparatus for measuring unknown time intervals by electric means
• G01R 35/04 - Testing or calibrating of apparatus covered by the other groups of this subclass of instruments for measuring time integral of power or current

Abstract

A differential method for current differential protection for a line having mixed use of different types of current transformers, comprising: performing analysis and model construction on a Rogowski coil not having an integral loop, and performing discretization on a transfer function of the model thereof, thereby acquiring a digital transfer model thereof, and constructing a virtual digital Rogowski coil; passing a signal collected by an electromagnetic current transformer through the virtual digital Rogowski coil to perform equivalent transfer processing; and using a near-side current collected by the Rogowski coil and the opposite-side current collected by the electromagnetic current transformer and then passed through the virtual digital Rogowski coil to establish differential protection. Meanwhile, in order to reduce the impact of distributed capacitance current on differential protection, voltage signals on the two sides undergo processing by the virtual digital Rogowski coil, and then capacitance currents in the mathematical differential fields of both sides are calculated, and said capacitance currents are used to compensate a differential current, thereby improving the precision of differential protection. The method is suitable for lines under a condition of mixed use of different types of current transformers, and reliably acts for internal faults and reliably does not act for external faults.

IPC Classes  ?

• H02H 7/26 - Sectionalised protection of cable or line systems, e.g. for disconnecting a section on which a short-circuit, earth fault, or arc discharge has occurred

Abstract

The present application discloses a method and system for the online evaluation of an electrochemical cell of an energy storage power station. The method comprises: first, a big data processing sub-system processes and stores cell state monitoring data collected in real time; then, data analysis is performed on the basis of real-time data and historical data of a cell; and lastly, evaluation is performed on the cell running state from a short time scale and a long time scale. On the short time scale, a large amount of real-time data, such as the current, voltage, temperature, and so on of a cell stack, a cell module, and a single cell, are analyzed, and the cell consistency and the charge capacity of the overall energy storage power station are evaluated by means of data analysis on characteristic fingerprints, such as temperature, internal resistance, and failure, of cells having different characteristics so as to provide data for the energy storage power station to participate in the optimized control and operation management of a power grid. On the long time scale, the degradation of cell capacity and the service life of a cell are evaluated on the basis of big data analysis on historic data of the full service life cycles of cells under different working conditions so as to serve as reference for the daily operation and maintenance management of cells and the echelon utilization of cells.

IPC Classes  ?

• H01M 10/42 - Methods or arrangements for servicing or maintenance of secondary cells or secondary half-cells
• G01R 31/367 - Software therefor, e.g. for battery testing using modelling or look-up tables

Abstract

The present application discloses an offshore wind power DC transmission system employing two connected transformers, and a control method therefor. The system comprises a plurality of wind farm booster stations. The wind farm booster stations are divided into groups and connected to AC switch stations, then are connected using two transformers connected in parallel, and are finally connected to a DC system. When any of the connected transformers experiences a failure and stops operating, a surplus power of the other connected transformer is quickly calculated, and is compared with output powers of the wind farm booster stations to determine a disconnected wind farm booster station, thereby controlling offshore wind farms and preventing large-scale disconnections thereof, and accordingly improving the stability and reliability of DC transmission of the offshore wind farms.

IPC Classes  ?

• H02J 3/00 - Circuit arrangements for ac mains or ac distribution networks

Abstract

An electric energy meter service life prediction method and apparatus (700), and a storage medium. The method comprises: determining an impact factor corresponding to each fault mode; acquiring historical failure data of each fault mode, and historical failure data corresponding to each impact factor in each fault mode; according to the historical failure data of the fault mode, obtaining a Weibull distribution model of the fault mode; according to the historical failure data corresponding to each impact factor in the fault mode, respectively obtaining a Weibull distribution model of each impact factor in the fault mode; then obtaining an impact coefficient of each impact factor; and according to the impact coefficient of each impact factor, modifying the Weibull distribution model of the fault mode, and then modifying a prediction failure rate, and predicting the batch service life of an electric energy meter according to the prediction failure rate. According to the method, the impact of the impact factors on the fault distribution is truly reflected, and a more accurate Weibull distribution model of each fault mode is obtained, thereby more accurately predicting the batch service life of the electric energy meter.

IPC Classes  ?

• G01R 35/04 - Testing or calibrating of apparatus covered by the other groups of this subclass of instruments for measuring time integral of power or current

Abstract

A measurement method and measurement apparatus (700) for the remaining service life of a dry-type transformer, and a storage medium. The measurement steps of the measurement method comprise: collecting the intrinsic temperature of the dry-type transformer, and the temperature of an environment in which the dry-type transformer is located; according to the intrinsic temperature and the environmental temperature, calculating the service life of the dry-type transformer at the intrinsic temperature; and determining the remaining service life of the dry-type transformer according to the current sampling period, the amount of the service life already used before the current sampling period, and the calculated service life. According to the measurement method for the remaining service life of a dry-type transformer, the remaining service life of the dry-type transformer within the current sampling period can be calculated in real time simply by collecting the intrinsic temperature of the dry-type transformer and the environmental temperature thereof, and therefore, an accurate reference time can be better provided for a maintenance worker and other operation personnel.

IPC Classes  ?

• G01R 31/00 - Arrangements for testing electric propertiesArrangements for locating electric faultsArrangements for electrical testing characterised by what is being tested not provided for elsewhere

Abstract

A database security protection method and device, wherein the method comprises: a database updating module updats a database, and backing up the updated database, at the same time, calculating an abstract of the updated database, encrypting and storing the abstract, and storing a decryption key to a database inspection module (101); in the program running process, the database inspection module uses an encryption abstract and a decryption key to periodicaly check whether the database is tampered or not, if so, replacing the tampered database with the backup database (102). The device comprises a processor and a memory, wherein the memory stores computer programs for implementing a security protection method of the above database. The database security protection method and device can prevent the database from malicious tampering, and improve the security of the database.

IPC Classes  ?

• G06F 16/23 - Updating

Abstract

Disclosed are a control authority switching system and method for a parallel multi-terminal high-voltage direct current converter station. The method comprises: when a first high-voltage direct current converter station needs to switch the control authority, it is determined whether a permission condition of a control authority switching request is met, wherein the permission condition of the control authority switching request at least comprises: the communication status between the first high-voltage direct current converter station and other high-voltage direct current converter station at least one terminal is normal; if the permission condition of the control authority switching request is met, the first high-voltage direct current converter station communicates with specific high-voltage direct current converter stations at other terminals to achieve the control authority switching, the specific high-voltage direct current converter station referring to a high-voltage direct current converter station having a normal communication status with the first high-voltage direct current converter station.

IPC Classes  ?

• H02J 3/36 - Arrangements for transfer of electric power between ac networks via a high-tension dc link

Abstract

An electric vehicle wireless charging phase detection circuit for realizing frequency tracking, comprising: a sampling circuit, a sampling conditioning circuit, a multiplexer and a low-pass filter, wherein the sampling circuit is used for collecting an inversion current signal of an inversion main circuit of a wireless charging transmitting end of an electric vehicle, the sampling conditioning circuit is used for respectively carrying out forward amplification and reverse amplification on the inverter current signal to obtain two output signals with a phase difference of 180 degrees as two input signals of the multiplexer, and the multiplexer is used for selecting one of the two input signals as an output signal according to a channel selection signal. The channel selection signal is obtained by means of delaying a driving signal of a leading bridge arm of the inverter main circuit by 90 degrees, and the low-pass filter is used for carrying out low-pass filtering on the output signal of the multiplexer to obtain a phase detection signal. The phase detection circuit is simple in structure and low in cost.

IPC Classes  ?

• G01R 25/00 - Arrangements for measuring phase angle between a voltage and a current or between voltages or currents

Abstract

The present application relates to a voltage control method for a power distribution network circuit containing distributed power supplies and a device, pertaining to the field of power distribution network control. The method comprises: acquiring a node voltage of an access node of each distributed power supply in a distribution network circuit, selecting an access node that has a highest node voltage exceeding a normal range as a guide node, and reducing, if the voltage of the guide node is in a warning state, a reactive power value of the distributed power supply at the guide node; and if the reduction of the reactive power value of the distributed power supply at the guide node to a minimum adjustable reactive power value is unable to enable the voltage of the guide node to reach a value within the normal range, reducing a reactive power value of a distributed power supply for the remaining distributed power supplies one by one in an ascending order of distances between the distributed power supplies and the guide node. The present application regulates the voltage of the guide node to be within the normal range by using only a few distributed power supplies, such that all nodes on the power distribution network circuit that are overvoltage are all restored to the normal range, thereby improving power supply reliability and stability of the power distribution network circuit.

IPC Classes  ?

• H02J 3/16 - Circuit arrangements for ac mains or ac distribution networks for adjusting voltage in ac networks by changing a characteristic of the network load by adjustment of reactive power
• H02J 3/38 - Arrangements for parallelly feeding a single network by two or more generators, converters or transformers

Abstract

An intelligent meter, comprising a carrier module. The carrier module comprises a module box (2) and a light guide element (3) disposed on the module box (2). The light guide element (3) comprises columnar light guide bodies (1, 34) and a connector (32) that is fixedly connected to more than two columnar light guide bodies (1, 34). A positioning groove (33) or a positioning protrusion is disposed on the light guide element (3). The module box (2) is provided with an adaptive protrusion (21) or an adaptive groove that is adapted to the positioning groove (33) or the positioning protrusion on the light guide element (3). The positioning groove (33) or the positioning protrusion is disposed on the light guide element (3), and the adaptive protrusion (21) or the adaptive groove is disposed on the module box (2) so that the groove (33) and the protrusion (21) cooperate with each other to achieve positioning, thereby reducing the area of a positioning surface. Therefore, positioning accuracy is increased, and the situation in which positioning is difficult due to the area of the positioning surface of the light guide element (3) being large is avoided such that the plug-in installation of the light guide element (3) is relatively simple.

IPC Classes  ?

• G01R 11/04 - HousingsSupporting racksArrangements of terminals

Abstract

Provided is an on-site fault diagnosis instrument for an intelligent single-phase electric energy meter. When a user does not use electricity or when a current signal collected by a current clamp is almost zero, the fault diagnosis instrument can automatically enable a magnetic latching relay (S1) to close, an output end of an isolation power supply unit generates a virtual load current, and current sampling of the virtual load current can be completed by an intelligent single-phase electric energy meter to be tested and the fault diagnosis instrument. The fault diagnosis instrument can solve the problem of complicated wiring that occurs when a user does not use electricity and an external electric load needs to be connected, and can complete the requirements of on-site fault diagnosis in time, thereby greatly improving the working efficiency of on-site power operation and maintenance personnel.

IPC Classes  ?

• G01R 35/04 - Testing or calibrating of apparatus covered by the other groups of this subclass of instruments for measuring time integral of power or current

Abstract

Provided are a test system and test method for an intelligent electricity meter. The test system is provided with an analog quantity output end and a digital quantity input end, wherein the analog quantity output end is configured to be connected to an input end of a metering chip of an intelligent electricity meter to be tested, and is used for sending pre-stored voltage and current signals corresponding to an actual load to the metering chip of the intelligent electricity meter to be tested; and the digital quantity input end is configured to be connected to an output end of the intelligent electricity meter to be tested, and is used for acquiring metering data of the intelligent electricity meter to be tested. The acquired metering data is compared with metering data corresponding to the pre-stored voltage and current signals to obtain the metering accuracy of the intelligent electricity meter to be tested. By means of pre-storing voltage and current signals corresponding to an actual load, when a test is performed, actual on-site voltage and current signals can be used for testing an intelligent electricity meter, thereby ensuring the authenticity of test data, and improving the accuracy of a test result.

IPC Classes  ?

• G01R 35/04 - Testing or calibrating of apparatus covered by the other groups of this subclass of instruments for measuring time integral of power or current

Abstract

A power distribution station area load prediction method and an apparatus, in the technical field of power systems. First, acquiring historical load data and associated factor data of a power distribution station area for a set time period, then creating a prediction model comprising historic load data, related factor data, date type weighting, temperature factor effect weighting and power-off time effect weighting, and finally performing prediction of a future load value according to the model. The present method not only considers the effects of temperature and date type, but also considers the effect of power-off time, and the created prediction model can more precisely describe a relationship between load and various factors, improving prediction accuracy; the present solution also does not require complicated data processing, and is simple and easy to implement.

IPC Classes  ?

• G06Q 10/04 - Forecasting or optimisation specially adapted for administrative or management purposes, e.g. linear programming or "cutting stock problem"
• G06Q 50/06 - Energy or water supply

Abstract

The present invention relates to a method and system for protecting a GIL-overhead hybrid line, the GIL-overhead hybrid line consisting of a GIL line segment and overhead line segments disposed at two ends of the GIL line segment. Two sides of the GIL line segment are provided with GIL line protection apparatuses and GIL line far-tripping apparatuses at the same time, and two sides of the entire hybrid line are provided with hybrid line protection apparatuses and hybrid line far-tripping apparatuses at the same time. When a fault occurs on the GIL line segment, the GIL line protection apparatuses send trip signals to the hybrid line far-tripping apparatuses on the corresponding sides by means of the GIL line far-tripping apparatuses on the corresponding sides. When the hybrid line far-tripping apparatuses receive the trip signals, same carry out tripping and send closed-loop reclosing signals to the hybrid line protection apparatuses. Therefore, the described protection means is applied to a GIL-overhead hybrid line, is capable of meeting the requirements of the GIL-overhead hybrid line, and reliably protect the GIL-overhead hybrid line.

IPC Classes  ?

• H02H 7/26 - Sectionalised protection of cable or line systems, e.g. for disconnecting a section on which a short-circuit, earth fault, or arc discharge has occurred

Abstract

The present application relates to the technical field of wireless charging, and relates to a wireless charging device. The wireless charging device comprises a wireless charging coil, which comprises an excitation layer, a first coil annular loop, and a second coil annular loop. The first coil annular loop is disposed on an upper end surface of the excitation layer in parallel. An electromagnetic shielding plate made of a magnetic conductive material is arranged on the periphery of the first coil annular loop. The electromagnetic shielding plate is fixed on the upper end surface of the excitation layer. The height of the electromagnetic shielding plate on the upper end surface of the excitation layer is greater than the height of the first coil annular loop and a third coil annular loop on the upper end surface of the excitation layer. The second coil annular loop surrounds upper and lower end surfaces and both side surfaces of the excitation layer. The side of the second coil annular loop on the upper end surface is provided close to the side of the first coil annular loop. The wireless charging device in the present application can improve the efficiency of wireless charging, can also shield the radiation scattering generated by the charging coil in the process of transmitting an energy, and has a good electromagnetic shielding effect.

IPC Classes  ?

• H01F 38/14 - Inductive couplings

Abstract

A high-voltage direct current power transmission converter valve tower provided with fire monitoring functions, comprising at least two valve layers, a shield cover being provided above above the top-end valve layer, and further comprising a detection module. The detection module comprises a controller, and further comprises at least one gas temperature sensor and/or at least one smoke sensor. The controller is respectively connected to the gas temperature sensor and/or the smoke sensor. The gas temperature sensor and/or the smoke sensor are disposed in the shield cover. The detection module is disposed in the shield cover at the top-end valve layer, may quickly detect changes in temperature by using the natural rising properties of a hot gas flow, and may thereby quickly provide an early warning at an early stage of a fire incident, and improve the real-time performance and reliability of early warning for fires in valve towers.

IPC Classes  ?

• G08B 17/06 - Electric actuation of the alarm, e.g. using a thermally-operated switch

Abstract

A traveling wave ranging method and apparatus using a homologous double-sampling mode, wherein same relates to the technical field of relay protection of power systems. The traveling wave ranging method using a homologous double-sampling mode comprises respectively obtaining first sampled data and second sampled data by means of using two modes to sample homologous traveling wave data, wherein the magnification factor of the first sampled data is smaller than the magnification factor of the second sampled data, and selecting appropriate data according to the magnitude of a mutation quantity value in order to search for the header of a traveling wave; and when the mutation quantity value is large, selecting the first sampled data with the smaller magnification factor to search for the header, thereby reducing incorrect judgment of the traveling wave, and when the mutation quantity value is small, selecting the second sampled data with the larger magnification factor to search for the header, thereby reducing misjudgment of the traveling wave and improving the identification capacity and accuracy of ranging.

IPC Classes  ?

• G01R 31/00 - Arrangements for testing electric propertiesArrangements for locating electric faultsArrangements for electrical testing characterised by what is being tested not provided for elsewhere
• G01R 19/165 - Indicating that current or voltage is either above or below a predetermined value or within or outside a predetermined range of values

Abstract

Provided are a method and device for protecting a DC line of a DC electrical power distribution grid, comprising: according to an electric current and voltage on the present side of a circuit, determining whether a line protection start determination is satisfied; if the line protection start determination is satisfied, then determining whether the following conditions are met: (1) the reverse direction signal of a fault on the opposite side of the line is not received; (2) the electric current on the current side of the line is a set positive direction; the directions of the electric currents of the two sides of the positive line take as their setting the forward direction of the bus bar flowing into the line; the directions of the electric currents of the two sides of the negative line take as their setting the forward direction of the line flowing into the bus bar; (3) the electric current on the current side of the line satisfies the set action conditions; if satisfied, then the DC line protection will act after a set time delay. By means of receiving a fault start signal on the opposite side of the line to preclude a fault from occurring on the opposite side of the line, it can be reliably determined whether a fault has occurred on the present side of the line, thus effectively avoiding the problem of a fault on the opposite side of a line causing the protection of the line to malfunction. Fig. 1 AA Protection input BB Line current-side voltage < current-side low-voltage start designated value Uqd CC Line current-side current < current-side current start designated value Iqd DD Line current-side current reverse direction EE Line opposite-side fault start reverse direction signal FF Protection start GG Current-side fault start reverse direction HH GOOSE signal II Line current-side current forward direction JJ Line current-side current > current-side current action designated value Iset KK Line current-side voltage < current-side voltage action designated value Uset LL Fault memory component MM Start component NN Lock component OO Action component PP DC line RR Protection action

IPC Classes  ?

• H02H 7/26 - Sectionalised protection of cable or line systems, e.g. for disconnecting a section on which a short-circuit, earth fault, or arc discharge has occurred

Abstract

Provided is a handcart circuit breaker and a contact device thereof including a contact arm and a moving contact. Inner walls of a cylindrical contact finger base in axial direction respectively have a contact finger groove with a spring contact finger for plugging the contact arm and a fixed contact; a rear of the contact finger base sleeves with a front of the contact arm having a positioning groove larger than a fitting end of the support pin, the contact finger base has support pins extending into the contact finger base; a diameter of a circle corresponding to the fitting end of each support pin is larger than a diameter of a circle corresponding to a bottom of each positioning groove; the contact finger base connects with the contact arm and an elastic support structure is arranged between the contact arm and the inner wall of the contact finger base.

IPC Classes  ?

• H01H 33/662 - Housings or protective screens
• H01H 1/38 - Plug-and-socket contacts
• H02B 11/167 - Switchgear having carriage withdrawable for isolation with isolation by horizontal withdrawal truck type
• H01H 1/62 - Heating or cooling of contacts

Abstract

An overcurrent protection method, control system and storage medium for bridge arm current of a flexible direct current transmission system. The method comprises: acquiring a bridge arm current (S101); processing the bridge arm current to obtain a current effective value and a current instantaneous value (S102); and protecting the bridge arm current when the current effective value is greater than a first set threshold and the current instantaneous value is greater than a second set threshold (S103).

IPC Classes  ?

• H02H 7/12 - Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for convertersEmergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for rectifiers for static converters or rectifiers

Abstract

A passive control method, device, and storage medium for a bipolar voltage source converter (VSC). The method comprises: controlling one VSC polarity on an inverter side to unlock, performing constant alternating current voltage control thereon, controlling the other VSC polarity on the inverter side to lock phase with an outputted phase of the VSC polarity, and controlling said other VSC polarity to unlock after the phase locking. In this way, the present invention enables stable unlocking of the two VSC polarities, maintains a synchronized voltage phase between the two VSC polarities after the unlocking, and provides stable power supply to a same passive network.

IPC Classes  ?

• H02J 3/36 - Arrangements for transfer of electric power between ac networks via a high-tension dc link

Abstract

A full-bridge modular multilevel converter (MMC) activation control method and system: each phase bridge arm among a three-phase bridge arm comprises at least two sub-bridge arms, and each sub-bridge arm comprises thereon a full-bridge MMC sub-module; the direction of a current which flows through each sub-bridge arm is detected (S301); a working state of an auxiliary circuit breaker on a corresponding sub-bridge arm, which is connected in parallel to a full-bridge MMC sub-module, is determined according to the detected current direction (S302); whether the full-bridge MMC sub-module on the corresponding sub-bridge arm continues to carry out charging is determined by means of the working state of the auxiliary circuit breaker (S303). As such, direct current bus voltage will not experience significant sudden changes during unlocking, greatly reducing impact current during unlocking, and improving the security and reliability of a system.

IPC Classes  ?

• H02M 1/36 - Means for starting or stopping converters

Abstract

A flexible direct-current power distribution network single-pole ground fault recognition method and apparatus, and a computer storage medium. The method comprises: 1) acquiring a current in and a voltage to ground at a positive direct-current bus on an outlet of a converter, a current in and a voltage to ground at a negative direct-current bus, a positive current of a direct-current line connected to the positive direct-current bus and a negative current of a direct-current line connected to the negative direct-current bus (101); and 2) when the absolute value of the sum of the voltage to ground at the positive direct-current bus on the outlet of the converter and the voltage to ground at the negative direct-current bus is greater than a pre-set voltage threshold, and a differential current change rate between the current in the positive direct-current bus on the outlet of the converter and the positive current in a direct-current line connected to the positive direct-current bus, or between the current in the negative direct-current bus and the negative current in a direct-current line connected to the negative direct-current bus is greater than a pre-set current threshold, determining that a corresponding positive direct-current bus or negative direct-current bus has a single-pole ground fault (102).

IPC Classes  ?

• G01R 31/08 - Locating faults in cables, transmission lines, or networks
• H02H 7/26 - Sectionalised protection of cable or line systems, e.g. for disconnecting a section on which a short-circuit, earth fault, or arc discharge has occurred

Abstract

Provided are a method for identifying a single pole ground fault in a VSC-DC power distribution network, and a single pole ground fault protection method for a VSC-DC power distribution network. The method comprises: acquiring voltages to ground (UP, UN) of positive and negative DC lines, acquiring a voltage change rate between the positive and negative DC lines; if an absolute value of the voltage change rate between the positive and negative DC lines is greater than a first comparison threshold (dUdcset), generating a pulse signal and stretching the pulse signal to a preset value (t1), and if an absolute value of a sum of the voltage to ground (UP) of the positive DC line and the voltage to ground (UN) of the negative DC line is greater than a second comparison threshold (Udcunbalset) for a duration exceeding a time threshold (t2), determining that a single pole ground fault has occurred. The method enables quick identification of a single pole ground fault. In the invention, a DC circuit breaker in which a DC line encountering a ground fault is located is skipped, thereby realizing quick isolation of a faulty line, and increasing reliability of power supply of a DC power distribution network.

IPC Classes  ?

• G01R 31/02 - Testing of electric apparatus, lines, or components for short-circuits, discontinuities, leakage, or incorrect line connection
• H02H 7/26 - Sectionalised protection of cable or line systems, e.g. for disconnecting a section on which a short-circuit, earth fault, or arc discharge has occurred

Abstract

A method for taking a converter of a multi-terminal high voltage direct current electric power transmission system into on-line operation comprises: taking a converter at one terminal of an inverter side into operation in a constant voltage control mode; and taking converters at other terminals of the inverter side into operation in a control mode. The invention realizes stable on-line incorporation of a converter without interfering stable operation of other converters.

IPC Classes  ?

• H02J 3/36 - Arrangements for transfer of electric power between ac networks via a high-tension dc link

Abstract

A direct-current fault ride-through method, wherein same is applied to a hybrid multi-terminal high-voltage direct-current transmission system. The hybrid multi-terminal high-voltage direct-current transmission system comprises at least two line commutated converter (LCC) type converter stations and at least one full-bridge modular multilevel converter (FB-MMC) type converter station. The method comprises: when a direct-current fault signal is detected, forcing an LCC type rectifier to perform a phase shift, so as to rapidly inhibit a fault current, with the LCC type rectifier being a converter in the LCC type converter stations for rectification; switching an FB-MMC type converter to a direct-current control mode, the FB-MMC type converter being a converter in the FB-MMC type converter station; after it is detected that the direct-current fault signal disappears, detecting a stable running signal of the LCC type rectifier; and after the stable running signal is detected, switching the FB-MMC type converter to be in an active power mode.

IPC Classes  ?

• H02J 3/36 - Arrangements for transfer of electric power between ac networks via a high-tension dc link

Abstract

Provided are a direct current converter valve cooling water channel and an electrode and a metal electrode body thereof (3). A metal electrode body of an electrode comprises a central column portion (31) installed at an electrode base (1). A helical wrapping portion (32) surrounds the central column portion. The helical wrapping portion (32) has a start section (321) at the top thereof and a tail section (322) at the bottom thereof. The start section of the helical wrapping portion is connected to the top of the central column portion.

IPC Classes  ?

• H01L 23/473 - Arrangements for cooling, heating, ventilating or temperature compensation involving the transfer of heat by flowing fluids by flowing liquids
• H01L 23/13 - Mountings, e.g. non-detachable insulating substrates characterised by the shape
• H02M 1/06 - Circuits specially adapted for rendering non-conductive gas discharge tubes or equivalent semiconductor devices, e.g. thyratrons, thyristors

Abstract

A simulation interface device suitable for a flexible direct current power transmission system comprises a high-speed signal processing unit, fiber optic interfaces (1, 2, 3, 4) connected to the high-speed signal processing unit, a power supply, and an indicator light connected to the high-speed signal processing unit.

IPC Classes  ?

• G06F 13/38 - Information transfer, e.g. on bus

Abstract

The present invention discloses an information sharing method of a smart electricity meter, smart electricity meter and acquisition router. The method comprises: allocating multiple IPv6 addresses to a smart electricity meter; assigning, by the smart electricity meter and according to a type of information, a corresponding IPv6 address to initiate a TCP/IP connection to an acquisition router; and querying, by the acquisition router and according to said IPv6 address, a routing IPv6 address therein matching an IPv6 address rule, and sending the information to a designation address specified in the information via the routing IPv6 address. The technical solution provided in the present invention realizes point-to-point communication and data transmission between each service master station system and each smart electricity meter, thus improving the speed and reliability of information distribution and sharing. Therefore, information processing of each master station system in a power distribution network is more intelligent and reasonable, such that a pre-service module of a power consumption information acquisition master station system is simplified, thus reducing the waste of system resources, increasing the system access capacity, and ensuring stable and highly efficient operation of a smart electric grid.

IPC Classes  ?

• H04L 29/08 - Transmission control procedure, e.g. data link level control procedure

Abstract

Disclosed are a pre-charged high-speed direct-current breaker and a control method therefor, and a computer storage medium. The pre-charged high-speed direct-current breaker comprises a cutout branch and a main electronic switch branch which are connected in parallel, wherein the main electronic switch branch is used for conducting a current in normal operation; the cutout branch comprises a cutout switch and a capacitor (C) which are connected in series, and both ends of the capacitor (C) are used for being connected to a charging power supply (UC); and the main electronic switch branch comprises at least one electronic switch unit, a plurality of electronic switch units are connected in series, and the electronic switch unit is composed of high-power switch devices. The pre-charged high-speed direct-current breaker is short in breaking time and little in loss, and also can decrease a fault current and release an overvoltage.

IPC Classes  ?

• H02H 3/20 - Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition, with or without subsequent reconnection responsive to excess voltage
• H02H 3/087 - Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition, with or without subsequent reconnection responsive to excess current for DC applications

Abstract

Disclosed is a tip regulation control method for increasing minimum clearance for a large-scale wind powered power-generation unit. On the basis of traditional control strategies, a power tip regulation is added, and when the power reaches a certain limit, pitch varying is started in advance, thrust is reduced and minimum clearance is increased. The method control is simple and highly efficient, the effect of minimum clearance increase is marked, loss of generated electricity is very low, and the unit overrun and stopping due to a gust of wind near rated wind speed can also be reduced while increasing the minimum clearance.

IPC Classes  ?

• F03D 7/00 - Controlling wind motors

Abstract

A test system for simulating the direct-current bias of a converter transformer. The test system comprises an RTDS simulation system of a direct-current power transmission system for simulating the direct-current bias operating condition of the converter transformer, wherein the RTDS simulation system is connected to an RTDS real-time digital simulator and a converter transformer protection device; and a bias resistor is connected in series between a neutral point of a star converter transformer of a unipolar and/or bipolar low-end valve group and a direct-current grounding electrode. By connecting the bias resistor in series between the neutral point of the star converter transformer of the unipolar and/or bipolar low-end valve group and the direct-current grounding electrode, the test system introduces a direct current of the grounding electrode to the neutral point of the Vn/V converter transformer to simulate a phenomenon of the direct-current bias of the converter transformer caused by the fact that the direct current invades the converter transformer in an actual direct-current power transmission system. When the system is used to simulate the direct-current bias of the converter transformer, the realization method is simple and reliable, and the realization threshold is relatively low.

IPC Classes  ?

• G01R 31/00 - Arrangements for testing electric propertiesArrangements for locating electric faultsArrangements for electrical testing characterised by what is being tested not provided for elsewhere

Abstract

A method of metal return longitudinal differential protection in a parallel ice-melting mode relates to the field of direct-current protection for ultrahigh voltage direct-current power transmission. For a direct-current power transmission system in a parallel ice-melting mode, a metal return longitudinal differential protection method is provided. In the method, first pole 1 currents and pole 2 currents of a local station and a remote station are collected, and a line total current of the local station and a line total current of the remote station are separately calculated according to the collected currents; a current difference value between the local station and the remote station is then calculated according to the line total current of the local station and the line total current of the remote station; and finally longitudinal differential protection is performed according to a line total current difference value between the two stations. A maloperation of metal return longitudinal differential protection caused by that only a difference value between a metal return current of a local station and a metal return current of a remote station is calculated in existing metal return longitudinal differential protection is overcome, and the method can rapidly and accurately determine a failure, and avoid phase-shift block in a system caused by a maloperation of metal return longitudinal differential protection in a parallel ice-melting mode.

IPC Classes  ?

• H02H 7/22 - Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for distribution gear, e.g. bus-bar systemsEmergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for switching devices

Abstract

An on-line deblocking and blocking control method for extra-high voltage direct current transmission project converter; through control of a firing angle of an SCA shielding pole layer,, a self-calculation trigger angle is outputted, allowing the voltage across two ends of a valve group to be zero; at the same time tracking current of the valve group using a PI regulator, pulling open a bypass breaker BPS after the current in the bypass breaker BPS is reduced to a breaking capacity so as to complete an on-line deblocking process of the valve group. In a blocking process, transfer of direct current is completed by limiting the firing angle outputted by a current control amplifier, and then implementing a by-pass pair and blocking, thus achieving blocking of the valve group online. The method has faster deblocking and blocking speed, a smaller transient state (overvoltage, overcurrent) in a start process, has a smaller reactive power impact on an alternating current system, while also ensuring a smoother change process of voltage, current, active power and reactive power in the deblocking and blocking process, and is simpler in control logic.

IPC Classes  ?

• H02J 3/36 - Arrangements for transfer of electric power between ac networks via a high-tension dc link
• H02J 1/00 - Circuit arrangements for dc mains or dc distribution networks

Abstract

An on-line login and logout control method for a converter of a parallel high-voltage direct-current power transmission system. The method is based on the voltage and current operation control manners of the traditional parallel high-voltage direct-current power transmission, i.e. a rectifier station adopts constant current control, and an inverter station adopts constant voltage control. A current balance controller is particularly added to an inverter side, and operates in the case of unlocking two converters simultaneously for eliminating an unbalance phenomenon which is generated when the two converters conduct voltage control independently.

IPC Classes  ?

• H02J 3/36 - Arrangements for transfer of electric power between ac networks via a high-tension dc link

Abstract

The present invention relates to a smart alarm inference method based on multi-scenario analysis, the method comprising: an alarm server reports alarm signals to a message center; a smart alarm display module, an inference engine and an operation signal module all acquire the alarm signals from the message center; the operation signal module acquires an operation type alarm signal from the alarm signals, and transmits the signal to the inference engine via the message center; the inference engine classifies, organizes and analyzes the received alarm signal to obtain smart alarm information to be transmitted to the message center; the smart alarm display module acquires the smart alarm information from the message center, and displays the smart alarm information. The present invention utilizes multi-scenario analysis technology to analyze an alarm object, realizing detailed segmentation of smart alarms, expanding the application range of smart alarms, improving alarm accuracy, accelerating alarm information processing, eliminating invalid alarms, reducing the monitoring burden of operating personnel, and enabling the operating personnel to timely make a judgment on a malfunction and take corrective action.

IPC Classes  ?

• H02J 13/00 - Circuit arrangements for providing remote indication of network conditions, e.g. an instantaneous record of the open or closed condition of each circuitbreaker in the networkCircuit arrangements for providing remote control of switching means in a power distribution network, e.g. switching in and out of current consumers by using a pulse code signal carried by the network

Abstract

In a wind power plant harmonic suppression method, grid-connection of a wind power generator sets is achieved by using transformers with different phase-shifting angles on a same feeder line, harmonic waves produced by nonlinear currents are counteracted due to the fact that the phase-shifting angles of the transformers are different, and therefore harmonic output on a power grid of a wind power plant is reduced. The wind power generator sets comprise a wind turbine, a power generation system, and a phase-shifting transformer used for connecting the grid. The wind power station comprises at least two wind power generator sets being spatially adjacent and having a same model.

IPC Classes  ?

• H02J 3/01 - Arrangements for reducing harmonics or ripples
• H02J 3/38 - Arrangements for parallelly feeding a single network by two or more generators, converters or transformers
• F03D 9/00 - Adaptations of wind motors for special useCombinations of wind motors with apparatus driven therebyWind motors specially adapted for installation in particular locations

Abstract

A method for detecting a DC component at a neutral-point current of a transformer, comprising the following steps: 1) determining by an experiment: to establish a correlation database of DC components in a saturated state and triple-frequency harmonics when a mutual inductor of an AC current at the neutral-point of a transformer is saturated, and to establish a correlation database of DC components in an unsaturated state and triple-frequency harmonics when the mutual inductor is unsaturated; 2) during practical operation, obtaining the numerical value of the triple-frequency harmonic at the secondary side of the mutual inductor by measurement and calculation; and 3) judging whether the mutual inductor is saturated or not, and respectively querying the correlation database corresponding to the saturated state and the correlation database corresponding to the unsaturated state to determine the numerical value of a DC component of a current. In this method, an AC current transformer is used to measure triple-frequency harmonics and to indirectly obtain a DC component of a current at a neutral-point when a DC current transformer is not arranged at the neutral point of a transformer.

IPC Classes  ?

• G01R 19/00 - Arrangements for measuring currents or voltages or for indicating presence or sign thereof
• G01R 31/00 - Arrangements for testing electric propertiesArrangements for locating electric faultsArrangements for electrical testing characterised by what is being tested not provided for elsewhere

Abstract

A control method for outputting active power through grid-connected electricity generation of a wind power plant, belonging to the technical field of grid-connected control of wind power plants. The present invention comprises: firstly, establishing a relationship between a power PW which may be currently generated by a wind power plant and a fluctuating power PRES which needs to be abandoned to suppress fluctuation, so as to obtain the fluctuating value required to suppress an active power; in accordance with the requirement of a power grid for the fluctuating amplitude of different wind power plants in different time periods, determining a time constant T of a first-order low-pass filter, determining a sampling interval t, and further discretizing same in a time domain to obtain a stabilization parameter α; concluding the single-machine control of the wind power plant as a target-adjustable integral control policy; and obtaining an adjustable active power target value adapted to the power grid. The load can be rationally distributed in accordance with the target value through the coordinated control of the wind power plant. The self-protection of a draught fan is also changed from passive adjustment of an oar or a splitting type to an active preventing type, thereby not only effectively improving the operation efficiency of the draught fan, but also reducing the impact on the power grid and protecting the operation of the draught fan.

IPC Classes  ?

• H02J 3/48 - Controlling the sharing of the in-phase component

Abstract

A method for monitoring an unbalanced current at a stator side after inter-turn short circuit in a hydro-generator rotor. The method adopts a super-long data window technology, and automatically adjusts the length of a data window according to the number of pole-pairs of a generator, thereby achieving an accurate calculation of fractional harmonic of different units. In this method, an effective value of a fault circulating current is calculated accurately, and fundamental waves, third harmonic waves, and fifth harmonic waves in the unbalanced current during normal operation are filtered out effectively, thereby improving the sensitivity of monitoring the inter-turn short circuit fault in generator rotor windings.

IPC Classes  ?

• G01R 31/02 - Testing of electric apparatus, lines, or components for short-circuits, discontinuities, leakage, or incorrect line connection
• G01R 19/00 - Arrangements for measuring currents or voltages or for indicating presence or sign thereof

Abstract

A hermetic evaporative cooling tower for direct-current electricity transmission, a manufacturing method and a rinsing method of same. The cooling tower comprises a cooling coil, and the cooling coil is integrally formed by bending and is made of stainless steel. The fabrication technique for the cooling coil of the cooling tower comprises: first rinsing the surface of a stainless steel plate by using a pickling liquid, then rolling a steel pipe, next continuously bending a rolled steel pipe by using a bending machine, and finally welding the steel pipe and a cooling water inlet/outlet header pipe after the steel pipe undergoes a pressure resistance test. The rinsing method for the cooling tower comprises: first flushing by using tap water, then rinsing by using an acid liquid, and finally treating a welding line of the cooling coil by using a passivation liquid. The cooling coil of the cooling tower is corrosion resistant, and has less internal impurities, thereby reducing pollution caused to pure water as a cooling medium.

IPC Classes  ?

• F28C 1/00 - Direct-contact trickle coolers, e.g. cooling towers
• F28F 25/00 - Component parts of trickle coolers
• C23G 1/08 - Iron or steel

Abstract

A high-voltage switch permanent magnet operating mechanism with an adjustable attractive force characteristic comprises a casing (6), a magnetic shield (3), a coil (2) and a permanent magnet (4). The magnetic shield and the coil are disposed inside the casing. The permanent magnet is disposed between the magnetic shield and the casing. A magnetic yoke (1) and an end cover (5) are installed at the upper end and the lower end of the casing respectively. An irregular movable iron core (7) is disposed inside the casing. A groove or boss is disposed on the outer wall of the irregular movable iron core. The distribution of a magnetic field is changed by changing the shape of the outer wall of the irregular movable iron core, so as to change the attractive force characteristic. The structure is exquisite, practical, easily adjustable and controllable, is applicable to different characteristic demands of high-voltage switches, is convenient to make design optimization, and has desirable universality.

IPC Classes  ?

• H01H 3/28 - Power arrangements internal to the switch for operating the driving mechanism using electromagnet
• H01H 31/02 - Air-break switches for high tension without arc-extinguishing or arc-preventing means Details
• H01H 33/38 - Power arrangements internal to the switch for operating the driving mechanism using electromagnet