A protection circuit is disclosed. The protection circuit includes a direct current (DC) blocking component electrically connected between a neutral of the transformer and a ground, and an overvoltage protection device electrically connected in parallel with the DC blocking component. The overvoltage protection device is constructed to repeatably and reliably provide overvoltage protection in response to a voltage at the transformer neutral above a threshold. The DC blocking component has an impedance below a predetermined value, thereby effectively grounding the neutral of the transformer. The DC blocking component is persistently maintained in connection to the transformer neutral.
H02H 7/04 - 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 transformers
H02H 3/52 - 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 the appearance of abnormal wave forms, e.g. AC in DC installations responsive to the appearance of harmonics
2.
SYSTEMS AND METHODS FOR ACTUATING A TRANSFORMER NEUTRAL BLOCKING SYSTEM
A control device for an electrical protection circuit for use in an alternating current system including a transformer is disclosed. An example system includes a first measurement probe, a second measurement probe configured to measure an electrical property within the electrical protection circuit, and a control module, including a processing device. The control module is configured to monitor a measurement from the first measurement probe and transmit a protection activation control signal to the switch assembly based on the measurement from the first measurement probe exceeding a first predetermined threshold. The control module is also configured to monitor a measurement from the second measurement probe and transmit a protection deactivation control signal to the switch assembly based on the measurement from the second measurement probe satisfying a second predetermined threshold.
H02H 3/08 - 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
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 3/50 - 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 the appearance of abnormal wave forms, e.g. AC in DC installations
H02H 5/00 - Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal non-electric working conditions with or without subsequent reconnection
H02H 7/04 - 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 transformers
Methods and devices for shielding electronic equipment within an enclosure are disclosed. One method includes positioning electronic equipment within an interior volume of a shielding enclosure having an opening providing access to the interior volume, the opening surrounded by an enclosure frame. The method further includes closing a door to the shielding enclosure, thereby closing off the opening, and engaging one or more latches to affix the door in a closed position, the door including a shielding curtain positioned across the opening. The method also includes inflating an inflatable member positioned along a perimeter of the door frame, thereby applying a uniform pressure to the shielding curtain toward the enclosure frame to form a seal therebetween.
Electrical protection devices, such as for use with power systems for overvoltage protection, are disclosed. One electrical protection device includes a first electrical connection, a second electrical connection, a first electrical discharge device, and a second electrical discharge device. The first electrical discharge device includes a first conductive bus connected to the first electrical connection and a second conductive bus connected to the second electrical connection. The first electrical discharge device has a first breakdown voltage. The second electrical discharge device includes a third conductive bus connected to the first electrical connection and a fourth conductive bus connected to the second electrical connection. The second electrical discharge device has a second breakdown voltage.
Methods and systems for providing electromagnetic protection of optical equipment are disclosed. One assembly includes an optical device and an electromagnetically shielding enclosure including a plurality of shielding surfaces, the enclosure defining an interior volume containing the optical device. The assembly further includes a waveguide beyond cutoff extending through a shielding surface of the electromagnetically shielding enclosure. The assembly also includes a first lens located on a first side of the shielding surface, and positioned and oriented to focus light through the waveguide beyond cutoff. The assembly further includes a second lens located on a second side of the shielding surface opposite the first side, positioned and oriented to receive light transmitted through the waveguide beyond cutoff.
H05K 9/00 - Screening of apparatus or components against electric or magnetic fields
G02B 6/06 - Light guidesStructural details of arrangements comprising light guides and other optical elements, e.g. couplings formed by bundles of fibres the relative position of the fibres being the same at both ends, e.g. for transporting images
6.
LOW POWER LOCALIZED DISTRIBUTED RADIO FREQUENCY TRANSMITTER
Methods and systems are disclosed for wireless communication, and in particular using a coaxial antenna for distributed wireless transmission. In one example, a wireless transmitter is disclosed that includes a radio frequency signal source and a coaxial cable including a near end and a far end. The near end is electrically connected to the radio frequency signal source and configured to receive signals from the radio frequency signal source. The coaxial cable has an inner conductor and an outer conductor. The wireless transmitter includes a shorting connection at the far end of the coaxial cable, the shorting connection electrically connecting the inner conductor and the outer conductor, and a plurality of openings along the coaxial cable spaced at predetermined locations to output signals generated by the radio frequency signal source. The invention can be used for RF attenuation monitoring and/or testing applications.
H01Q 13/20 - Non-resonant leaky-waveguide or transmission-line antennas Equivalent structures causing radiation along the transmission path of a guided wave
7.
ELECTROMAGNETICALLY SHIELDED CAMERA AND SHIELDED ENCLOSURE FOR IMAGE CAPTURE DEVICES
Camera arrangements that can include electromagnetic protection, such as from EMP/IEMI events, is disclosed. One example camera arrangement includes a camera including a viewfinder having a lens, and an electromagnetically shielded enclosure defining an interior volume containing the camera and configured to include at least one opening aligned with the lens. The camera arrangement includes an electromagnetically dampening barrier disposed across the at least one opening, the barrier configured to shield the interior volume of the enclosure from electromagnetic signals while exposing an optical path between the lens and objects external to the enclosure.
G08B 13/196 - Actuation by interference with heat, light, or radiation of shorter wavelengthActuation by intruding sources of heat, light, or radiation of shorter wavelength using passive radiation detection systems using image scanning and comparing systems using television cameras
A continuous grounding system for use in an alternating current system including a transformer is disclosed. The system includes a switch assembly connected between a transformer neutral of a transformer and a ground, the switch assembly having an open position and a closed position, the open position disrupting the path through the switch assembly between the electrical connection and the transformer neutral, and the closed position establishing a path connecting the electrical connection to the transformer neutral through the switch assembly, wherein in normal operation of the alternating current electrical device the switch assembly remains in a closed position. The system also includes a DC blocking component positioned in parallel with the switch assembly and connected between the transformer neutral and the ground. The system further includes a control circuit configured to control the switch assembly, the control circuit including a sensor configured to actuate the switch assembly to an open position upon detection of a predetermined harmonic signal threshold at one of the transformer phases or a predetermined threshold of DC current between the transformer neutral and ground.
H02H 9/00 - Emergency protective circuit arrangements for limiting excess current or voltage without disconnection
H02H 3/00 - Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition, with or without subsequent reconnection
H02H 3/52 - 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 the appearance of abnormal wave forms, e.g. AC in DC installations responsive to the appearance of harmonics
H02H 7/04 - 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 transformers
9.
SENSING AND CONTROL ELECTRONICS FOR A POWER GRID PROTECTION SYSTEM
Systems and method for detecting potentially harmful harmonic and direct current signals at a transformer are disclosed. One such system includes a plurality of detection components electrically connected to electrical signal lines leading from one or more connection points on a power grid, and a plurality of threshold detectors, each threshold detector configured to compare an incoming signal from a detection component to a predetermined signal having a threshold. The system also includes a controller receiving an output from each of the plurality of threshold detectors and configured to drive at least one external component in response to receiving an indication from at least one of the plurality of threshold detectors of a detected signal above a threshold.
H02H 3/00 - Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition, with or without subsequent reconnection
H02H 3/04 - Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition, with or without subsequent reconnection Details with warning or supervision in addition to disconnection, e.g. for indicating that protective apparatus has functioned
H02H 7/04 - 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 transformers
patents