Capacitive current measurement method and device for ungrounded neutral system

Abstract

The invention discloses a capacitive current measurement method and device for an ungrounded neutral system. The method comprises steps: any line voltage US and neutral point voltage E0 under normal operation of the sytem are acquired; detection current is outputted, and detection current It is acquired; neutral point voltage E1 after the detection current It is outputted is acquired, and output of the detection current It is stopped; and the capacitive current Ic of the system is calculated. The device includes a current output unit 1, a control unit 2 and a grounding transformer 3, wherein the control unit 2 comprises a current output control unit 21 and a voltage detection unit 22. According to the capacitive current measurement method and device for the ungrounded neutral system provided by the embodiment of the invention, the calculation is easier and more convenient to implement, realization is easy, and the calculation accuracy is high.

Description

Technical field [0001] This application is suitable for the technical field of capacitance current measurement, and particularly relates to a method and device for measuring capacitance current of a neutral point ungrounded system. Background technique [0002] In power grid systems, especially in low- and medium-voltage distribution grid systems, single-phase ground faults account for the absolute majority of the total number of faults. When the system capacitance current exceeds a certain value, the grounding arc cannot be extinguished by itself when a single-phase grounding fault occurs, resulting in arc overvoltage and other secondary hazards. [0003] When the capacitive current of the system is large, the controllable current source is used to completely compensate the ground current, and the power supply capacity is large, which is difficult to achieve. However, using the controllable current source with the arc suppression coil for full compensation is not only easy to achi...

AI Technical Summary

Problems solved by technology

[0004] This application provides a method and device for measuring capacitive current in a neutral point ungrounded system to solve the problem of inaccurate measurement of capacitive current in an ungrounded neutral point system in the prior art. This method has a high measurement signal strength and ensures measurement accuracy. And the safety is good, easy to realize and engineering application, and based on this method, an independent capacitive current measuring device can be manufactured

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