Abrégé

n is greater or equal to a first determined value.

Classes IPC  ?

• F03D 11/00 - Détails, parties constitutives ou accessoires non couverts par les autres groupes de la présente sous-classe ou présentant un intérêt autre que celui visé par ces groupes
• H02J 3/38 - Dispositions pour l’alimentation en parallèle d’un seul réseau, par plusieurs générateurs, convertisseurs ou transformateurs

Abrégé

B) installed in an electrical power system, each Intelligent Electronic Device comprising a counting means, the grading margin comprising a safety margin set by a user, characterized in that it comprises, when a fault occurs which causes a fault current in the electrical power system, a step of providing a warning to the user when the safety margin is infringed upon.

Classes IPC  ?

• G08B 21/00 - Alarmes réagissant à une seule condition particulière, indésirable ou anormale, et non prévues ailleurs
• H02H 7/30 - Déconnexion échelonnée
• H02H 3/00 - Circuits de protection de sécurité pour déconnexion automatique due directement à un changement indésirable des conditions électriques normales de travail avec ou sans reconnexion

Abrégé

The invention concerns a system for controlling a real-time islanding of an electrical power network (203) for mitigating the impact of disturbances which the power network may experience, said power network comprising generator buses (209), load buses (211) and transmission lines (213) interconnecting said buses, said system comprising : - control means (205) for identifying different classes of coherent generator buses, - control means (205) for subdividing the power network into disjoint domains (231a-231d) where each domain is composed of a single generator bus and a corresponding set of load buses, - control means (205) for separating said disjoint domains (231a-231d) into two different groups, a first group consisting of domains (231a, 231b) having coherent generator buses and a second group (231c, 23Id) consisting of domains having all other generator buses, - control means (205) for determining an initial partition boundary (217a) composed of a set of partition lines which correspond to transmission lines connecting first group buses to adjacent second group buses, - control means (205) for transferring one by one load buses which are linked by said partition lines from one group of said first and second groups to the other one of said two groups while updating at each time the elements of both groups and the corresponding set of partition lines until a minimum load-generation imbalance within both updated groups has been reached, - control means (205) for determining a final partition boundary (217) composed of the updated set of partition lines, and - splitting means (207) for splitting the power network into two islands (303a, 303b) according to the final partition boundary.

Classes IPC  ?

• H02J 3/38 - Dispositions pour l’alimentation en parallèle d’un seul réseau, par plusieurs générateurs, convertisseurs ou transformateurs

Abrégé

The invention concerns a method and a system for online ferroresonance detection in a high voltage electrical distribution network. The method includes: -Overflux detection (23),which acts as the start element, overflux being set if the flux is greater than a threshold for specified time duration, -mode verification (26) which is to recognize the modes of the ferroresonance, a fuzzy logic method being used to discriminate the ferroresonance modes.

Classes IPC  ?

• H02H 9/00 - Circuits de protection de sécurité pour limiter l'excès de courant ou de tension sans déconnexion
• H02H 7/05 - Circuits de protection de sécurité spécialement adaptés aux machines ou aux appareils électriques de types particuliers ou pour la protection sectionnelle de systèmes de câble ou de ligne, et effectuant une commutation automatique dans le cas d'un changement indésirable des conditions normales de travail pour transformateurs pour transformateurs de tension capacitifs, p. ex. contre les conditions de résonance

Abrégé

The invention relates to a method of predicting transient stability of a synchronous generator and to a device for implementing such a method, the device comprising measurement means (MS, MP, Q) and calculation means (U) for calculating an information (I) which indicates, before it actually happens, whether the generator slip will be greater than zero or not at the critical phase angle.

Classes IPC  ?

• H02P 9/10 - Commande s'exerçant sur le circuit d'excitation de la génératrice afin de réduire les effets nuisibles de surcharges ou de phénomènes transitoires, p. ex. application, suppression ou changement brutal de la charge

Abrégé

The invention concerns a method for managing access by a user station to a critical device of an industrial control system comprising a security server and a database comprising user's credentials, said method characterized by regularly transferring user's authentication and authorization data from said database to said critical device to allow authentication of a user by said critical if the security server becomes temporarily unavailable.

Classes IPC  ?

• G06F 21/33 - Authentification de l’utilisateur par certificats

Abrégé

The invention concerns a method to ensure safe access to a critical Intelligent Electronic Device (4) connected to an industrial site (24) to perform maintenance operations of said critical IED (4), wherein only few pre-designated persons (22) are allowed to perform said maintenance operations. The method according to the invention comprises the step of providing the pre-designated persons (22) with exclusive authorisation data to maintain the IED (4) in a secure mode for safety of personnel during the maintenance operations and to put the IED (4) in its normal operational state after completion of said maintenance operations.

Classes IPC  ?

• G06F 21/34 - Authentification de l’utilisateur impliquant l’utilisation de dispositifs externes supplémentaires, p. ex. clés électroniques ou cartes à puce intelligentes

Abrégé

The invention relates to a method of initiating the load shedding within an electrical power system comprising an electricity generator with a source impedance ZS and a load impedance ZL, characterized in that the method comprises: - measuring the voltage VL at the terminal of the load impedance, - calculating by means of a computer a voltage operative level VOP such that: VOP = K VC, where K is a number greater than 1 and VC is a critical voltage at the terminals of the load ZL at which the ratio ZL/ZS is equal to 1, VC depending on the difference β between the phase angle φL of the load impedance ZL and the phase angle φS of the source impedance ZS, and - comparing the voltage VL with the voltage operative level VOP so that the load shedding is initiated as soon as VL is equal to VOP.

Classes IPC  ?

• H02J 3/14 - Circuits pour réseaux principaux ou de distribution, à courant alternatif pour règler la tension dans des réseaux à courant alternatif par changement d'une caractéristique de la charge du réseau par interruption, ou mise en circuit, des charges du réseau, p. ex. charge équilibrée progressivement

Abrégé

Method of adjusting a voltage present across terminals of a load, the load being mounted across terminals of a secondary winding of a transformer (T) having a primary winding and a secondary winding, the voltage being adjusted by modifying a position of a tap point along the first winding due to the action of a command signal (d) on a tap changer (1) connected to the primary winding, characterized in that said method comprises a step of determining, by means of a computer (2), a relationship which indicates if a relative increase of the secondary voltage is greater than a relative decrease of the primary voltage or not, the position of the tap point being modified to increase the secondary voltage if a relative increase of the secondary voltage is greater than a relative decrease of the primary voltage, and being blocked or reversed, if not.

Classes IPC  ?

• G05F 1/14 - Régulation de la tension ou de l'intensité là où la variable effectivement régulée par le dispositif de réglage final est du type alternatif utilisant des transformateurs à prises ou des inductances à changement de prises comme dispositifs de réglage final
• H02J 3/24 - Dispositions pour empêcher ou réduire les oscillations de puissance dans les réseaux

Abrégé

A relay (100) for current differential protection of a transmission line, comprising: a first calculator (110) of symmetrical sequence components of currents of each phase of the transmission line at local and remote ends of the transmission line; a second calculator (110) of phase differences φ12 and φ012 between combinations currents i12 and i012 of the symmetrical sequence currents; a fuzzy inference system (112) which outputs a variable y whose value is calculated according to the values of the phase differences φ12 and φ012; a third calculator (120) which outputs a tripping signal for the control of a circuit breaker arranged on the transmission line and associated with the relay, the value of the tripping signal being calculated according to the values of the variable y and the values of the currents of each phase at the local and remote ends of the protected transmission line.

Classes IPC  ?

• H02H 3/30 - Circuits de protection de sécurité pour déconnexion automatique due directement à un changement indésirable des conditions électriques normales de travail avec ou sans reconnexion sensibles à la différence de tensions ou de courantsCircuits de protection de sécurité pour déconnexion automatique due directement à un changement indésirable des conditions électriques normales de travail avec ou sans reconnexion sensibles à un angle de déphasage entre tensions ou courants comprenant la comparaison des valeurs de tension ou de courant des deux portions séparées d'un même système, p. ex. à deux bouts opposés d'une ligne, à la sortie et à l'entrée d'un appareil utilisant des fils pilotes ou autre canal de signalisation
• H02H 3/28 - Circuits de protection de sécurité pour déconnexion automatique due directement à un changement indésirable des conditions électriques normales de travail avec ou sans reconnexion sensibles à la différence de tensions ou de courantsCircuits de protection de sécurité pour déconnexion automatique due directement à un changement indésirable des conditions électriques normales de travail avec ou sans reconnexion sensibles à un angle de déphasage entre tensions ou courants comprenant la comparaison des valeurs de tension ou de courant des deux portions séparées d'un même système, p. ex. à deux bouts opposés d'une ligne, à la sortie et à l'entrée d'un appareil

Abrégé

The invention relates to a method of monitoring the grading margin between at least two time-current characteristics of Intelligent Electronic Devices (IEDA, IEDB) installed in an electrical power system, each Intelligent Electronic Device comprising a counting means, the grading margin comprising a safety margin set by a user, characterized in that it comprises, when a fault occurs which causes a fault current in the electrical power system, a step of providing a warning to the user when the safety margin is infringed upon.

Classes IPC  ?

• H02H 7/30 - Déconnexion échelonnée
• H02H 3/00 - Circuits de protection de sécurité pour déconnexion automatique due directement à un changement indésirable des conditions électriques normales de travail avec ou sans reconnexion

Abrégé

The invention concerns a phase angle drift method for loss of mains/grid protection, wherein the accumulated electrical phase angle drift derived from the difference between the current measured local frequency and the estimated frequency using historical data is compared to a angle threshold with the phase angle draft αn being such that : Formula (3), where : n : Sample index αn : Updated phase angle αn-12 : Previous phase angle ƒnest : Estimated frequency ƒn : Measured frequency T12samples : Time interval between algorithm executions the estimated grid frequency being calculated using the following equation in which the key parameters are the historical delay, D cycles, and the window, W cycles, over which the estimated frequency is calculated : Formula (4), where : ƒn-D-w : Oldest frequency value ƒn-D : Newest frequency TD : Historical time delay Tw : Estimation window wherein the addition/substration of the phase angle increase/decrease calculated for the half cycle in equation (3) is not carried out unless the frequency difference between the estimated frequency ƒnest and the measured frequency ƒn is greater or equal to a first determined value.

Classes IPC  ?

• H02J 3/38 - Dispositions pour l’alimentation en parallèle d’un seul réseau, par plusieurs générateurs, convertisseurs ou transformateurs

Abrégé

The invention concerns a method of impedance groundfault detection for differential protection of an overhead transmission line in a three-phase high voltage electric power transmission system which comprises many lines (1,12) and many protection relays (2,4), which comprises the following steps : 1) in prefault condition : - measuring the differential current (I); - measuring the phase voltage (II) at the relay location; - measuring the phase current (III) the relay location; - calculating the differential admittance (IV), with the following equation : (formula (V)). With (VI) : the positive sequence impedance of the line-protected. 2) In operating condition : - measuring the differential current (VII); - measuring the phase voltage (VIII) at the relay location; - measuring the phase current (IX) at the relay location; calculating the differential admittance (X), with the following equation : (formula (XI)); - detecting a high impedance groundfault detection, if the following formula is verified : (XII) with (XIII); B0 = the total line admittance.

Classes IPC  ?

• H02H 3/30 - Circuits de protection de sécurité pour déconnexion automatique due directement à un changement indésirable des conditions électriques normales de travail avec ou sans reconnexion sensibles à la différence de tensions ou de courantsCircuits de protection de sécurité pour déconnexion automatique due directement à un changement indésirable des conditions électriques normales de travail avec ou sans reconnexion sensibles à un angle de déphasage entre tensions ou courants comprenant la comparaison des valeurs de tension ou de courant des deux portions séparées d'un même système, p. ex. à deux bouts opposés d'une ligne, à la sortie et à l'entrée d'un appareil utilisant des fils pilotes ou autre canal de signalisation
• H02H 3/40 - Circuits de protection de sécurité pour déconnexion automatique due directement à un changement indésirable des conditions électriques normales de travail avec ou sans reconnexion sensibles au rapport de la tension et du courant

Abrégé

An Intelligent Electronic Device (IED) having a faceplate provided with at leastone visual indicator (33) which emits light to indicate a status of the IED to a viewer, the IED having enhancing means for enhancing the visual impact of the light emitted by the indicator. Theenhancing means is an element (46) located to receive the light emitted bythe indicator and to diffuse this light in a region of interest for the viewer.

Classes IPC  ?

• H02H 1/00 - Détails de circuits de protection de sécurité