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: 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.