A composite fault protection method for disconnection and grounding of distribution network considering transition resistance

Abstract

The invention discloses a disconnection and grounding complex fault protection method of a distribution network considering transition resistance. Firstly, the three-phase current at the outlet of each feeder is collected, and the negative sequence current amplitude at the outlet of each feeder is calculated based on the three-phase current at the outlet of each feeder. and / or zero-sequence current amplitude; compare the negative-sequence current amplitude at the exit of each feeder with the corresponding negative-sequence current setting value, and / or compare the zero-sequence current amplitude at the exit of each feeder with the corresponding zero-sequence current The size of the current setting value, if the comparison result meets the protection action criterion, the fault feeder is determined based on the comparison result and a corresponding trip command and / or alarm signal is issued. The invention solves the problems of small applicable range and insufficient sensitivity of the existing disconnection protection, takes into account the influence of factors such as disconnection fault type, load size and distribution, and fault location, and can reliably identify disconnection and grounding in the entire range of transition resistance Composite failure.

Description

technical field [0001] The invention relates to the field of relay protection of electric power systems, in particular to a method for protection of distribution network disconnection and grounding complex faults considering transition resistance. Background technique [0002] The distribution network plays the role of electric energy distribution in the power system, and its power supply reliability and quality directly affect industrial production and social and economic development, and are also closely related to people's quality of life. Affected by the idea of ​​"emphasizing distribution and despising distribution", the distribution network is relatively lagging behind in terms of investment construction and automation level. In recent years, with the rapid development of the economy and the increasing demand for electricity, it has become an inevitable trend to vigorously develop environmentally friendly and abundant renewable energy. A large number of new energy sou...

AI Technical Summary

Problems solved by technology

[0006] Aiming at the deficiencies of the above-mentioned prior art, the present invention provides a distribution network disconnection and grounding compound fault protection method considering transition resistance, which effectively solves the problem of the small application range and insufficient sensitivity of the distribution network disconnection fault protection in the prior art Reliable identification of disconnection and grounding compound faults can be realized in the full range of transition resistance

Images