Topological information based self-adaptive current quick break protection setting method for power distribution network

Abstract

The invention relates to a topological information based self-adaptive current quick break protection setting method for a power distribution network. The technical feature is that the method includessteps of 1, performing tide calculation by utilizing known power distribution network power source equivalent phase potential and load power during normal operation of the power distribution network,obtaining node voltage of each bus, power of each branch circuit and power supplied by a power distribution network equivalent power source; 2, obtaining equivalent impedance of a power distributionnetwork line and load and the power distribution network power source equivalent impedance during normal operation of the power distribution network according to the result obtained in tide calculation in step 1; 3, establishing a Thevenin's circuit at a protection mounting position through calculating open circuit voltage and short circuit current at the protection mounting position, and obtaining an accurate setting value of self-adaptive current quick break protection setting. The method reduces protection setting calculation time after faults occur and ensures protection speed.

Description

technical field [0001] The invention belongs to the technical field of electric power system relay protection, and relates to a setting method for the adaptive current quick-break protection of a distribution network, in particular to a setting method for the adaptive current quick-break protection of the distribution network based on topology information. Background technique [0002] The development status of distribution network relay protection technology has experienced four development stages: electromagnetic type, transistor type, integrated circuit type and computer type. In the 1980s, the concept of distribution network adaptive relay protection was proposed. In 1984, the CIGRE working group listed the application conditions of adaptive protection. In 1989, the US company Aisika proposed that the characteristic of adaptive relay protection is that it can automatically change system parameters according to changes in power network conditions. Adaptive relay protect...

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Problems solved by technology

In addition to the above-mentioned normal operation conditions, various types of faults may also occur in the power system. The fault may be a metallic short circuit or a short circuit through a transition resistance, and may be transient or permanent, so the research can be adapted to the power system The adaptive relay protection technology of distribution lines that can reliably and accurately remove faults is a very difficult task.

[0005] At present, there are two disadvantages in the setting method of adaptive current quick-break protection: First, because a series of voltage and current components are used to calculate the equivalent phase potential of the system side and the equivalent impedance of the system power supply side when a series of protection installations fail, it is necessary to After the fault occurs, these voltage and current components are obtained through sampling and calculation, and then the setting of the protection is performed (usually the sampling calculation of the power frequency quantity needs at least half a power frequency cycle), which greatly affects the quickness of the protection; second, in the calculation When protecting the equivalent phase potential of the system side and the equivalent impedance of the system power supply side at the installation site, the load of the adjacent line is ignored, that is, the influence of the adjacent feeder change on the protection setting of this feeder is not considered, which reduces the accuracy of the protection setting.

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