Power distribution network boundary protection method

Abstract

The invention discloses a power distribution network boundary protection method. Under the premise that boundary elements are arranged at two ends of the line, a mode voltage is obtained by calculation according to the measured three-phase voltage or two-pole voltage; a protection starting criterion is constructed through a 1-mode voltage break variable, a protection action criterion is constructed through peak time, when the calculated peak time is less than a setting value, it is considered that the fault is an internal fault, when the calculated peak time is greater than the setting value,it is considered that the fault is an external fault, and finally, protection misoperation caused by transient interference is avoided through a low-voltage or overcurrent auxiliary criterion. According to the invention, full-line fault rapid removal is realized only by using single-ended electrical quantity, superior and subordinate cooperation is not needed, communication is not needed, and therequirement of an AC / DC power distribution network for rapid fault removal is met.

Description

technical field [0001] The invention belongs to the technical field of distribution network relay protection, and in particular relates to a distribution network boundary protection method. Background technique [0002] Distributed power supplies, energy storage devices and other equipment with power electronic interfaces are being connected to the distribution network in large quantities. At the same time, for better access of such equipment, the DC distribution network is also developing rapidly, and the form of the distribution network is changing. In the future, It will present a mixed form of AC and DC with multiple converters, and will eventually become a multi-source power supply system with two-way flow of power flow and changeable topology. Affected by the fragility of power electronic devices, the AC short-circuit current is limited, resulting in low sensitivity of the existing protection; affected by the low inertia of power electronics, the DC short-circuit curre...

AI Technical Summary

Problems solved by technology

Affected by the fragility of power electronic devices, the AC short-circuit current is limited, resulting in low sensitivity of the existing protection; affected by the low inertia of power electronics, the DC short-circuit current rises quickly, which puts forward higher requirements for the rapidity of protection; The bidirectional flow of short-circuit current and the flexible and changeable topology make it difficult to cooperate with the existing protection, and the single-ended full-line fast-acting protection based on boundary elements is an important way to solve the protection problem of distribution networks with multiple converters

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