A small resistance grounding relay protection device for distribution network

Abstract

The invention discloses a relay protection device for a small resistance grounding distribution network, which includes an acquisition module, a judgment module, a program module and a drive module. connected to collect the electrical signal of the zero-sequence current transformer; the input stage of the judgment module is electrically connected to the output stage of the collection module, and the judgment module controls the drive module according to the collection signal of the collection module; the input stage of the drive module is connected to the output stage of the judgment module Electrical connection, the drive module is used to connect the trip circuit and remove the fault; the program module is stored in the relay protection device of the small resistance grounding distribution network, including the following steps: according to the acquisition signal of the acquisition module, calculate the characteristic value E of the reference line i ;According to the characteristic value E of the reference line i Make a judgment, if E i >γ, it is considered as a non-fault line, start the drive module, and remove the fault; if E i ≤γ, it is considered as a faulty circuit, and the drive module will not be started.

Description

technical field [0001] The invention relates to the field of power system equipment, and more specifically, to a relay protection device for a small-resistance grounding distribution network. Background technique [0002] With the rapid development of the economic level, the number of outgoing lines in the substation is increasing, and the capacitive current when the line fault occurs also increases. The small resistance grounding system can provide a large short-circuit current when a ground fault occurs, which is conducive to the rapid action tripping of the relay protection, and can avoid the breakdown of the weak insulation caused by the rise of the bus voltage, the short circuit between the phases of the cable, and the resonance overvoltage of the voltage transformer. . However, when a high-resistance grounding fault occurs in a small-resistance grounding system, the fault current will often cause the relay protection to fail to operate correctly because the fault curr...

AI Technical Summary

Problems solved by technology

When a high transition resistance ground fault occurs, the zero-sequence current of the fault line will be far lower than the set value, resulting in the failure of the protection to operate correctly, that is, the protection refuses to operate

If the setting value is lowered, the non-fault line will not be able to avoid the capacitive current and cause protection malfunction

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