System and method for identification and inhibition of ferromagnetic resonance of medium-voltage power distribution network

Abstract

The invention discloses a system and method for identification and inhibition of ferromagnetic resonance of a medium-voltage power distribution network. The method includes the following steps: installing an active inversion device between a neutral point of the medium-voltage power distribution network and the ground; monitoring a bus zero sequence voltage of the medium-voltage power distribution network in a real-time manner and when the zero sequence voltage is larger than 10% of a rated phase voltage, detecting whether ferromagnetic resonance happens in the medium-voltage power distribution network; if the ferromagnetic resonance happens in the medium-voltage power distribution network, the active inversion device injecting zero sequence current signals to the medium-voltage power distribution network and tracking the zero sequence voltage and changing the intensity and direction of zero sequence current in a real-time manner so as to enable the zero sequence voltage to be zero and force the medium-voltage power distribution network to break away from a ferromagnetic resonance state; and then stopping injection of the zero sequence current so as to enable the medium-voltage power distribution network to return to a normal operation state. The system and method inhibit ferromagnetic resonance through short-time injection of the zero sequence current by the active inversion device so that inhibition of low-frequency ferromagnetic resonance, power frequency ferromagnetic resonance and high-frequency ferromagnetic resonance can be realized rapidly and the system and method have the advantages of being rapid and efficient, simple and convenient in operation, practical and economical and zero in effect on normal operation of the medium-voltage power distribution network and the like.

Description

technical field [0001] The invention relates to a system for identifying and suppressing ferromagnetic resonance of a medium-voltage distribution network. The invention also relates to a method for identifying and suppressing ferromagnetic resonance in a medium-voltage distribution network by using the system. Background technique [0002] The medium-voltage distribution network is prone to ferromagnetic resonance. When ferromagnetic resonance occurs, the oversaturation current caused in the electromagnetic voltage transformer (PT) can reach more than a hundred times the rated excitation current, which may easily cause the PT high-voltage fuse fuse Fuse, in severe cases, burn the PT, and even cause the PT to explode. At the same time, the ferromagnetic resonance overvoltage lasts for a long time, which may cause equipment damage or even a large-scale power outage, endangering the safety of the power grid and causing huge economic losses. [0003] The structure of my countr...

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Problems solved by technology

These suppression methods and devices generally have shortcomings such as single function, large suppression blind area, complicated operation, and poor economy.

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