Power distribution network ground fault flexible dispersion arc extinguishing method based on master-slave control

Abstract

The invention relates to a power distribution network ground fault flexible dispersion arc extinguishing method based on master-slave control. A voltage source type master arc extinguishing device and dispersedly installed current source type slave arc extinguishing devices are applied, wherein the slave arc-extinguishing device adopts a flexible current arc-extinguishing method, calculates and tracks a given current value by using a measured zero-sequence voltage, does not need to perform fault phase selection, and can compensate a grounding current nearby; the main arc extinguishing device adopts a flexible improved voltage arc extinguishing method, current is injected into a power distribution network, the neutral point voltage is actively regulated and controlled, and a fault line equivalent power supply voltage value capable of suppressing the voltage of a fault point and with the current being zero is calculated and serves as a given voltage reference value. The main arc-extinguishing device installed in a transformer substation can dynamically compensate the residual compensation amount of the slave arc-extinguishing device, and the arc-extinguishing effect is not affected by line impedance and load current. According to the present invention, the real-time communication is not needed, the autonomous cooperation between the master arc extinguishing device and the slave arc extinguishing device can be achieved, the reliable arc extinguishing of the single-phase earth fault is achieved, and the adaptability to the network structure changes of the power distribution network is high.

Description

technical field [0001] The invention relates to a flexible decentralized arc suppression method for grounding faults in distribution networks based on master-slave control. Background technique [0002] With the continuous extension of the power distribution network and the increase of the line cable ratio, the single-phase ground fault current level increases sharply, and the compensation capacity of a single arc-suppression coil cannot limit it to a lower level. The high grounding residual current limits the self-extinguishing ability of the grounding arc, which in turn causes the arcing grounding overvoltage, which can reach more than 3 to 5 times the phase voltage, and easily breaks down the weak insulation of the equipment along the distribution network. This will lead to phase-to-phase short circuit and large area blackout. If a complete set of arc suppression coils with larger capacity is replaced, the economy is poor, and substations in unplanned new areas often can...

AI Technical Summary

Problems solved by technology

However, the increase of line cable conversion rate not only increases the reactive component of the ground current, but also increases its active component

In addition, the application of a large number of power electronic equipment increases the harmonic component in the ground current

However, the arc suppression coil can only compensate the reactive component of the ground current, and the ground residual current can still reach more than 5A, which cannot realize reliable arc suppression for single-phase ground faults.

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