Composite grounding device based on active inverter voltage regulation and small resistance

Abstract

The invention discloses a composite grounding device based on active inverter voltage regulation and small resistance. The composite grounding device comprises a high-resistance grounding fault identification unit, an active inverter voltage regulator, a small-resistance zero-sequence protection device and a coordination controller; the high-resistance grounding fault identification unit is used for realizing accurate identification of a fault feeder line; the active inverter voltage regulator receives an operation instruction sent by the coordination controller and injects regulating voltage into the neutral point; the small-resistance zero-sequence protection device is used for processing a ground fault when the fault current is not lower than a zero-sequence protection threshold value; and the coordination controller is responsible for coordination and cooperation of the active inverter voltage regulator and the low-resistance zero-sequence protection device. Through efficient coordination and cooperation of the active inverter voltage regulator and the low-resistance zero-sequence protection device, the voltage of a fault point can be efficiently suppressed, efficient and reliable processing of instantaneous and permanent grounding faults is realized, and the device can be particularly used for suppressing high-resistance grounding faults and has good feasibility and practical value.

Description

technical field [0001] The invention relates to the technical field of power electronics, in particular to a composite grounding device based on active inverter voltage regulation and small resistance. Background technique [0002] The distribution network is located at the end of the power system and is closely related to users. Therefore, how to improve the safety and reliability of the distribution network in the event of a fault has always been a research hotspot. The resonant grounding system represented by the arc suppression coil is widely used in urban and rural distribution networks because of its simple working principle and ability to maintain the normal operation of faulted feeders under instantaneous ground faults. However, with the continuous development of urban distribution network, the continuous increase of cable lines and nonlinear loads leads to the increasing amplitude of ground fault current. Traditional arc suppression coils are difficult to expand, ...

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Problems solved by technology

[0005] In order to solve the deficiencies mentioned in the above-mentioned background technology, the object of the present invention is to provide a composite grounding device based on active inverter voltage regulation and small resistance, inject the regulated voltage to the neutral point through the active inverter voltage regulator, It can efficiently suppress the fault point voltage and realize fault elimination. Through the efficient coordination and cooperation of the source inverter voltage regulator and the small resistance zero-sequence protection device, it can realize efficient and reliable processing of instantaneous ground faults and permanent ground faults, and solve the problem of High-impedance ground fault identification and suppression are difficult problems

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