Two-point Calculation Method of Injected Current in Active Arc Suppression of Small Current Grounding Fault

Abstract

A two-point calculation method for controlling the injection current when the fault phase voltage is 0 by using an active inverter after a small current ground fault. According to the fault phase power supply voltage, two different injection currents and their corresponding bus zero-sequence voltages, the algorithm can calculate the fault point transition resistance and the injection current to make the fault phase voltage zero. The algorithm can adapt to the dynamic change of the line structure, and the accuracy is high when the transition resistance is large, which solves the problem that the traditional active arc suppression technology (also known as active compensation technology or flexible grounding technology) cannot reflect the line in real time when calculating the injection current The problem of structural dynamics.

Description

technical field [0001] The invention belongs to the technical field of small current grounding fault self-healing in power systems, relates to the field of arc suppression technology based on active inverters during small current grounding faults, and in particular relates to a method for calculating injected current with active arc suppression technology. Background technique [0002] At this stage, the medium-voltage distribution network in my country widely adopts the low-current grounding method, that is, the neutral point is not grounded and the neutral point is grounded through the arc suppression coil. When a single-phase ground fault occurs, the current at the fault point is small, which is called small current. grounding system. Single-phase ground fault is the main form of distribution network faults, accounting for about 80% of the total faults. When a single-phase ground fault occurs, since the voltage of the three-phase line remains basically unchanged and the c...

AI Technical Summary

Problems solved by technology

However, the existing active arc suppression control methods measure the ground admittance of the system before the fault, and measure the impedance of the neutral point of the system after the fault to calculate the injected current

In the 2 hours allowed to operate with faults after the small current grounding fault occurs, the distribution network line may be switched. At this time, the existing active arc suppression control method is used to calculate and inject the injected current. ground capacitance current, the current at the fault point may still be large

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