Neutral point grounding resistor plant for electrical power system

Abstract

The invention provides a neutral point grounding resistor integrated device for a power system, belonging to the field of power system distribution network technology. The integrated device comprises a grounding transformer, an isolation switch, a voltage transformer, a circuit breaker, a controller, a grounding resistor and a current transformer. When the grounding does not occur, the grounding resistor is not accessed and no current passes by the grounding resistor, thus completely solving the ageing problem caused by the temperature increment during the normal running process and greatly prolonging the service life of the equipment; and after the grounding occurs, the grounding resistor is accessed with time delay, thus avoiding the transient grounding. Compared with the prior art, the integrated device can reduce the shutdown time by about a half; after the grounding resistor is accessed, the grounding resistor is cut off after a certain time, thus preventing the grounding resistor from being burned and ensuring the safety of the equipment.

Description

technical field [0001] The invention relates to a device in the technical field of power distribution network, in particular to a complete set of neutral point grounding resistors in a power system. Background technique [0002] The neutral point grounding resistor, referred to as the grounding resistor, refers to the power resistor installed between the neutral point and the grounding point of the power grid, and is a grounding protection device. With the rapid expansion of the scale of urban power grids, a large number of power lines use cable lines. When a ground fault occurs in the cable line, its ground current is relatively large, and it often develops into a permanent ground fault. The advantage of the grounding method through the grounding resistor is that it can limit the arc grounding overvoltage, which is beneficial to quickly and accurately cut off the faulty line. The disadvantage is that it cannot escape the instantaneous grounding, and every time a fault occu...

AI Technical Summary

Problems solved by technology

[0003] After searching the prior art, it is found that the Chinese patent application number 200710108451.7 and the invention patent application with the publication number CN101055301A have recorded a "neutral point grounding resistor monitoring device". The temperature is monitored to determine whether the neutral point grounding resistor is in normal operation. If the current or temperature of the neutral point grounding resistor exceeds the threshold value, it indicates that the resistor is not working normally, and the alarm is given to cut off the resistor. Although this technology The protection of grounding resistors is enhanced, but this technology cannot identify instantaneous faults. Every time a grounding occurs, the faulty line must be cut off, causing power outages for users and affecting the reliability of power consumption; Possible aging problems of resistors due to temperature rise

Images