Direct current injection type route selecting positioning system and method thereof

Abstract

The invention discloses a DC injection type route selection positioning system and a method thereof, which makes use of neutral-point voltage to ground to provide power supply for the generation of DC signal and inject DC to a fault system, and realizes faulty route selection and position by the detection of circulation of the DC signals. The structure of the invention comprises a grounding transformer, a DC generator, a control device and a fault indicator FD, wherein, the grounding transformer is connected with a system bus and injects the DC to the fault system by the primary coil of the grounding transformer; the DC generator is arranged between the primary-side neutral-point N of the grounding transformer and the ground; the control device is connected with the secondary side of bus-bar potential transformer to monitor whether a power distribution system has single-phase earth fault, control the switching of the DC, measure the injected DC at the same time and adjust the injectedDC according to the measured injected DC; the fault indicator FD is positioned at the outlet of each feeder, and the fault indicator FD is also arranged at the feeder at intervals to detect the injected DC and select faulty line and locate the fault.

Description

technical field [0001] The invention relates to a ground fault detection technology in a distribution network of a power system, in particular to a DC injection type line selection and positioning system and a method thereof for a neutral point ungrounded or arc suppressing coil grounded system. Background technique [0002] In my country, for the distribution network currently in operation, since the neutral point of the system is not grounded or grounded through the arc suppression coil, no short-circuit loop will be formed after a single-phase ground fault occurs, and only a small zero-sequence current caused by the distributed capacitance of the system. Various devices for finding single-phase ground faults at home and abroad are based on these relatively small faults as the judgment basis, and the misjudgment rate is relatively high. When the distribution network is in normal operation, the three-phase voltage is symmetrical, and the voltage between the neutral point an...

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Problems solved by technology

[0004] The purpose of the present invention is to solve the defect that a special signal generating device and a signal detection device need to be added to the injection of AC signals, and the technical requirements for the injection signal detection device are relatively high and are susceptible to interference. In order to solve the problem of line selection and positioning during high transition resistance faults, it provides a method to use the neutral point-to-ground voltage at the time of faults to provide power for the generation of DC signals after a single-phase ground fault occurs in the distribution network. Fault system injects direct current, realizes fault line selection and positioning function by detecting the flow of direct current signal DC injection type line selection and positioning system and its method

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