Power network controlled reactance and small resistor combination type earthing device

Abstract

The invention relates to a complete set of compound grounding devices of the controllable reactor and the small resistor for the power grid. The invention is characterized in that the invention comprises a grounding transformer (1), a controllable reactor (2), a small resistor (3) and a controller (4); the secondary winding of the grounding transformer (1) is connected with the neutral point (PT) of the power grid and connected with the grounding point (CT) through the controllable reactor (2), and the small resistor (3) is connected in series with a high voltage switch (5), and the small resistor (3) and the high voltage switch (5) are connected in parallel with the controlled reactor (2); the two inputs of the controller (4) are connected with PT and CT respectively, and the control signal output of the controller (4) is connected with the control input of the high voltage switch (5). The invention solves the problems that various prior protection devices for the grounding fault of the power grid are very difficult to be grounded in isolation, and the grounding lines are very difficult to be found. The invention implements the fast removal of the fault without tripping, and is an ideal set of grounding fault protection device for the distribution network.

Description

technical field [0001] The invention relates to a complete set of device for single-phase ground fault protection applied in a distribution network of a power system, in particular to a controllable reactance and small resistance composite ground fault protection complete set in the technical field of electrical equipment. Background technique [0002] At present, there are mainly the following methods for the neutral point grounding point of the distribution network with a voltage level of 35kV and below in the power system: 1. The neutral point is not grounded; 2. The neutral point is grounded through a resistance, and the small resistance grounding method is the main method; 3. Resonant grounding method, the neutral point is grounded through the arc suppression coil. [0003] In the neutral point ungrounded system, when a phase fault occurs, the power supply of the receivers connected to the phase-to-phase voltage has not been damaged, and they can continue to operate, bu...

AI Technical Summary

Problems solved by technology

[0005] The purpose of the present invention is to overcome the difficulty of isolating the grounding line and the difficulty of finding the grounding line in the arc suppressing coil grounding mode, as well as the indiscrimination of instantaneous grounding and permanent grounding faults in the small resistance grounding mode, high tripping rate, The defect of large impact on the system provides a power network controllable single-phase ground fault protection device

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