Single-point grounding fault detection and positioning method for cascaded H-bridge battery energy storage system

Abstract

The invention provides a single-point grounding fault detection and positioning method for a cascaded H-bridge battery energy storage system. The method aims at a cascaded H-bridge battery energy storage system in a central point ungrounded power grid, and comprises the steps of: S1, obtaining the AC side voltage and phase of each energy storage unit of the cascaded H-bridge battery energy storage system; S2, measuring the voltage to ground of the central point of the cascaded H-bridge battery energy storage system and the phase of the voltage to ground; S3, judging whether a single-point grounding fault occurs or not, and if the single-point grounding fault occurs, entering S4; and otherwise, determining that there is no single-point grounding fault, and skipping to S1; S4, judging the phase of the single-point grounding fault; and S5, judging the electrical position of the single-point grounding fault in the fault phase. According to the method, the single-point grounding fault of the CHB-BESS in the neutral point ungrounded power grid can be effectively detected, the electrical position where the grounding fault occurs can be positioned, and fault overhaul and maintenance of the CHB-BESS are greatly facilitated.

Description

Technical field [0001] The present invention relates to the field of battery energy storage systems, and more particularly to a single-point ground fault detection and positioning method of cascaded H-bridge battery energy storage system operating in a neutral point in-plane grid. Background technique [0002] The battery energy storage system mainly implements energy storage and release, and can solve the power quality problem of wind energy, solar energy, and maintain the power balance of grid. In a large-capacity battery energy storage system, the cascading H bridge energy system has a wide range of application prospects due to its advantages such as strong extension, large capacity, high voltage, and output voltage current harmonic content. The battery energy storage system has a wide area, and as it is promoted, the ground fault is increasingly prominent. [0003] At present, the grounding failure of China and foreign affiliates H-bridge battery energy storage system has not...

AI Technical Summary

Problems solved by technology

These researches on the fault detection of cascaded H-bridge battery energy storage systems are mainly aimed at the open circuit or short-circuit faults of switching devices and distribution network faults, which are not directly related to the internal ground faults of cascaded H-bridge battery energy storage systems.

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