High-speed trial wiring strategy for ground fault of electric power system and trial wiring circuit topology

Abstract

The invention relates to a high-speed trial wiring strategy for a ground fault of an electric power system and a trial wiring circuit topology. According to the high-speed trial wiring strategy for the ground fault of the electric power system and the trial wiring circuit topology, a sampling / recording device is arranged on a bus of a transformer substation, or existing secondary lines are adopted to sample the voltage of the bus; the voltage waveforms, existing before and after the circuit is cut off, of the bus in a certain time period is observed or recorded, and whether the bus is a faulty line or not is judged through waveform characteristics; in this way, a mechanical or electronic power switch can be used for disconnecting the line for a set time period, or in the set power-off time period, the faulty line is cut off instantly after judgment is carried out by adopting a microcomputer, or after the power-off time period, a worker observes the recorded waveform to judge whether the bus is the faulty line or not; in this way, the power-off delay time dt can be set to be quite short and can be set as the shortest time allowing the fault to be distinguished; in addition, the electronic power switch is adopted for high-speed trial wiring, and therefore the time of trial wiring is further shortened. Simulation shows that the high-speed trial wiring strategy and the trial wiring circuit topology for the ground fault of the electric power system can remarkably reduce power failure caused by trial wiring, the power failure time is made to be basically shorter than the trip time of an undervoltage tripping device or a no-voltage tripping device, the undervoltage tripping device or the no-voltage tripping device hardly acts, and the problem of power supply delay is basically solved.

Description

technical field [0001] The invention belongs to power electronic switch switching and power system ground fault processing, in particular to power electronic switch switching circuit and ground fault high-speed search. Background technique [0002] In the small current grounding system of the 10kV power grid, single-phase grounding is a common fault, which mostly occurs in wet and rainy weather. After a single-phase grounding occurs, the voltage of the fault relative to the ground decreases, and the phase voltage of the non-faulty two phases increases, but the line voltage is still symmetrical, so it does not affect the continuous power supply to the user. The system can run for 1 to 2 hours, which is also a small current grounding The biggest advantage of the system. However, if the power grid operates for a long time when a single-phase ground fault occurs, the weak link of the insulation may be broken down due to the increase of the non-fault phase voltage, which may dev...

AI Technical Summary

Problems solved by technology

[0008] 2. Traditional test pull leads to unnecessary power outages

[0009] Due to the fact that the small current line selection device of the 10kV system of the substation is not fully covered and the correct rate of line selection of the small current grounding line selection device is not high, the proportion of finding the grounding line is 81.25%, which is 81.25%. It will inevitably lead to the expansion of the scope of power outages, causing unnecessary power outages for some users without faulty lines, especially for some high-risk and important users who have continuous power supply requirements, bringing safety risks and economic losses

[0010] 3. Delay in power supply for users equipped with under-voltage and loss-of-pressure release devices

[0011] The process of single-phase grounding test pull of 10KV system is accompanied by short-term power outage of the line. Due to the time requirements for uploading information in telemetry and remote signaling, the time of line test pull is usually taken into account (if there is no fault in the line, the whole process includes stop, send The process) takes about 1 minute, but due to the existence of the low-voltage side of some users and the existence of the voltage-loss disconnection device, the disconnection is usually activated within about 5 seconds after the power is lost. As a result, when the high-voltage side has been powered, the low-voltage side is still powered off

Coupled with the lack of management of on-duty personnel in user substations, the time of low-voltage power transmission is often delayed

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