Abstract: Disclosed are a device and method for detecting defects of a high-voltage cable cross-bonded grounding system. The method comprises: selecting a protective grounding box of a cross-bonded grounding system, respectively connecting a signal excitation coupler to A-phase, B-phase and C-phase coaxial cables of the protective grounding box, selecting a stable signal with a frequency different from a power frequency or a field interference frequency, and testing effective current values and phases responded by the A-phase, B-phase and C-phase coaxial cables when the stable signal with the frequency F1 is injected into the A-phase, B-phase and C-phase coaxial cables of the protective grounding box in a coupled manner; and obtaining resistances and inductances of branch circuits of the cable cross-bonded grounding system by calculation according to measurement data, and determining if the cable cross-bonded grounding system has a connection defect.

Abstract: Disclosed is an electrical topology of an integrated DC charging station and an operation control method. The electrical topology comprises a supply side DC bus, K discrete charging pile units and a mutual aid total DC bus; each charging pile unit comprises an input DC bus, a mutual aid sub-DC bus, an output DC bus, N isolation branches, a non-isolation DC/DC module and an output terminal, the input DC bus is connected to the supply side DC bus, and the mutual aid sub-DC bus of each charging pile unit is connected to the mutual aid total DC bus; the isolation branch comprises an output branch and a mutual aid branch; and when all the output branches of one charging pile, unit are started and the output power cannot meet the required power, the mutual aid branches of other charging pile units are started to meet the required power.

Abstract: A micro-power wireless access method and apparatus for the Internet of things for power transmission and transformation equipment involves a time synchronization process, a traffic channel access process, a control channel configuration information access process, and a control channel burst information access process. In the time synchronization process, an aggregation node determines a delay parameter and other parameters based on a timeslot in which traffic information randomly transmitted by a sensing terminal is located, and the sensing terminal adjusts transmission time of a corresponding frame based on the parameters. The traffic channel access process adopts a mode in which one-way reporting is mainly used, to minimize working time of a sensor. The present disclosure realizes limited two-way communication on a control channel, supports configuration of a sensor cycle, a threshold, and other parameters, and supports a retransmission mechanism on the control channel for important alarm information.

Abstract: The present invention discloses a device for evaluating and demagnetizing residual magnetism quantity of a power transformer. A main circuit comprises a switching power supply the two ends of which are respectively connected with a filter capacitor and a resistor in parallel. A forward end of the switching power supply is connected with a main switch in series. A rear end of the main switch is connected with a series branch of a sixth switch and a first resistor, a series branch of a first switch and a second switch, and a series branch of a third switch and a fourth switch are connected in parallel. A driving circuit is respectively connected with driving ends of the main switch, the sixth, first, second, third and fourth switches. A control circuit is connected with the driving circuit for sending an instruction to the driving circuit.

Abstract: A micro-power wireless access method and apparatus for the Internet of things for power transmission and transformation equipment involves a time synchronization process, a traffic channel access process, a control channel configuration information access process, and a control channel burst information access process. In the time synchronization process, an aggregation node determines a delay parameter and other parameters based on a timeslot in which traffic information randomly transmitted by a sensing terminal is located, and the sensing terminal adjusts transmission time of a corresponding frame based on the parameters. The traffic channel access process adopts a mode in which one-way reporting is mainly used, to minimize working time of a sensor. The present disclosure realizes limited two-way communication on a control channel, supports configuration of a sensor cycle, a threshold, and other parameters, and supports a retransmission mechanism on the control channel for important alarm information.

Abstract: Disclosed is a low-voltage DC power distribution fast switching device. The device includes a positive output terminal electrically connected to a positive pole of a load, and no less than two switching circuits connected in parallel with each other; the switching circuit includes a positive input terminal electrically connected to a positive pole of common negative power supplies, a supplementary diode cluster composed of no less than one diode connected in series, and a thyristor connected between the positive input terminal and the positive output terminal; the positive input terminal is electrically connected to an anode of the supplementary diode cluster and an anode of the thyristor, and the positive output terminal is electrically connected to a cathode of the complementary diode cluster and a cathode of the thyristor.

Abstract: Disclosed is a fault current controller for a direct current power grid, which includes a primary circuit and a controller. The primary circuit includes an inductor, a filter capacitor, a resistor, an IGBT switch, a diode, a contactor and a Hall current sensor. The inductor, a first resistor and a second contactor are connected in series and are connected to a first contactor in parallel. A first branch including a second resistor and a first diode, a second branch including a third resistor and a second diode, and the inductor are connected in parallel; the filter capacitor, the IGBT switch and the first resistor are connected in parallel. The Hall current sensor is arranged in the series circuit. The controller controls the IGBT switch and the two contactors in the primary circuit to form different on-off combinations.

Abstract: The present invention discloses a device for evaluating and demagnetizing residual magnetism quantity of a power transformer. A main circuit comprises a switching power supply the two ends of which are respectively connected with a filter capacitor and a resistor in parallel. A forward end of the switching power supply is connected with a main switch in series. A rear end of the main switch is connected with a series branch of a sixth switch and a first resistor, a series branch of a first switch and a second switch, and a series branch of a third switch and a fourth switch are connected in parallel. A driving circuit is respectively connected with driving ends of the main switch, the sixth, first, second, third and fourth switches. A control circuit is connected with the driving circuit for sending an instruction to the driving circuit.