Online monitoring and adjustment and control method for single phase compensation status of arc-extinction loop system

Abstract

The invention relates to an on-line monitoring and controlling method for single-phase ground compensation state in an arc suppression coil system, which can effectively estimate compensation state of the system according to relative phase relation between negative sequence component I2 of failure current of a failure line and inductance current IL of an arc suppression coil, and can correctly regulate the arc suppression coil, in order to lead the system into a resonance state; through comparing I2 with a threshold value, the resonance state can be effectively estimated and ensure that the electric arc is reliably extinguished. After the system in the resonance, the change of the run mode can be effectively estimated according to the change of zero sequence current IN0 of the failure line under the standard voltage, when IN0 is changed, the run mode is changed, the compensation state can be effectively estimated after the run mode is changed according to the IN0 before changed and the IN0 after changed, and the arc suppression coil can be correctly regulated again to lead the system into a new resonance state. The on-line monitoring and controlling method dose not need to on-line measure earth capacitance of a distribution system, which reduces the regulation of the arc suppression coil during normal operation and contributes to safe operation of the system, and the load symmetry can not affect the effectiveness of the method at the same time.

Description

technical field [0001] The invention relates to a method for on-line monitoring and regulation of a distribution network, which belongs to the technical field of electrical engineering. Background technique [0002] When a single-phase ground fault occurs in the neutral point ungrounded system, the fault current is the sum of the capacitance current of the distribution system to ground. If the capacitance to ground of the distribution system is small, the fault ground current is small, and the fault ground arc will not be maintained. And automatically extinguished, the power distribution system can continue to operate, and the faulty line can continue to supply power to the load. Single-phase ground faults account for 70% of the total system faults, so the neutral point ungrounded system has high power supply reliability. [0003] However, in recent years, due to the continuous expansion of the distribution network scale and the extensive use of cable lines in the power gri...

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Problems solved by technology

But this method is only effective when the load is symmetrical, and usually the load of the power distribution system is asymmetrical

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