Single-phase grounding-fault arc extinguishing system and method of small-current grounding system

Abstract

The invention discloses a single-phase grounding-fault arc extinguishing system of a small-current grounding system. The single-phase grounding-fault arc extinguishing system comprises a grounding line selection device, a boosting transformer and a voltage source. Bus three-phase voltage, zero sequence voltage and branch zero sequence currents are input to the input end of the grounding line selection device, and the output end of the grounding line selection device sends out control signals; the voltage source receives the control signals to output specific voltage vectors, and the output endof the voltage source is connected to the low voltage side of the boosting transformer; one end of the high voltage side of the boosting transformer is connected with the neutral point of the small-current grounding system while the high voltage side of the same is grounded. The invention further discloses an arc extinguishing method of the system. fault phase voltage is consistent with the ground, grounding fault can be eliminated rapidly, the situations that grounded cables are burned by arc light and electric shock casualties are avoided, the system does not have to trip immediately and continuous to operate safety for a period of time after single-phase grounding fault, and reliability and security of the system are greatly improved.

Description

technical field [0001] The invention relates to a single-phase grounding fault arc suppression system and method for a small current grounding system, belonging to the field of relay protection of electric power systems. Background technique [0002] In the 3kV-66kV small current grounding system, single-phase grounding is a relatively common fault type. When a single-phase grounding occurs in a low-current grounding system, the fault phase-to-ground voltage decreases, the non-fault phase-to-ground voltage rises, and the line voltage is still symmetrical. In this state, due to the small grounding current, in order to ensure the reliability of power supply, it is allowed to run 1- 2h. However, due to the non-fault phase arc overvoltage, it is easy to cause breakdown of weak insulation parts, voltage transformer iron core saturation, system overvoltage, and the fault phase arc burns the cable, which is easy to cause personal electric shock and casualty accidents. Therefore, a...

AI Technical Summary

Problems solved by technology

However, due to the non-fault phase arc overvoltage, it is easy to cause breakdown of weak insulation parts, voltage transformer iron core saturation, system overvoltage, and the fault phase arc burns the cable, which is easy to cause personal electric shock and casualty accidents. Therefore, after single-phase grounding It is necessary to isolate the single-phase ground fault of the fault phase in time to ensure the safe and stable operation of the system and the reliability of power supply

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