Low-voltage power supply network electric leakage fault protection method based on zero-phase transfer

Abstract

The invention discloses a low-voltage power supply network electric leakage fault protection method based on zero phase transfer, which is applied to guarantee safety when a low-voltage power supply network breaks down. When earth fault occurs to a line, a power supply is additionally arranged between a zero line and the ground, or a voltage regulator or a transformer is additionally arranged between the zero line and the ground to apply a voltage between the zero line and the ground, so that the fault phase voltage is clamped below a safety voltage, the potential safety hazard of a groundingfault is eliminated, and the long-time uninterrupted safe operation requirement of a low-voltage power supply network is met. According to the invention, a power supply or a voltage regulator or a transformer is used to directly reduce a fault phase voltage below a safety voltage; the safety problem of a line fault can be rapidly solved, the safety risk of personal equipment is reduced, line powersupply is not influenced, normal operation of all loads of a power supply network is ensured, the power supply reliability and safety are greatly improved, meanwhile, the design and construction installation cost is low, and wide market prospects are achieved.

Description

technical field [0001] The invention relates to the technical field of grounding fault suppression in electric power systems, in particular to a zero-phase transfer-based leakage fault protection method for a low-voltage power supply network. Background technique [0002] my country's power grid is divided into two parts: transmission network and distribution network. The distribution network is divided into high-voltage distribution network, medium-voltage distribution network and low-voltage power supply network. The low-voltage power supply network is the most closely related to daily life. Grid voltage level. In recent years, the annual death toll of electric shock in my country accounts for 10% of the total death toll in accidents. According to statistics, in 2017, the number of electric shock deaths nationwide reached 8,000, of which 85% occurred in the low-voltage power supply network. It can be seen that the safety status of the low-voltage power supply network is sti...

AI Technical Summary

Problems solved by technology

However, once the protector operates, the load on the line connected behind the protector will be in a power outage state, which will have a great impact on places that require high capacity and quality, such as hospitals, chemical plants, and national defense units.

At the same time, there are many deficiencies in the existing various types of residual current operated protectors

For example, it will still operate under non-fault conditions such as user equipment access, unbalanced three-phase-to-ground capacitance of the line, and lightning strikes, resulting in a large number of false tripping accidents, seriously affecting industrial and agricultural production, national defense construction, and people's normal work and life. , but also increases the work cost of power operation and maintenance personnel

It is understood that in many places, due to the excessive and frequent misoperation of the residual current action protector, the user will directly remove the protector that has been installed in the line. and property safety

Images