Stable status zero-sequence current increase and assistance device and method

Abstract

The invention discloses a steady-state zero-sequence current increase-support apparatus and method. It has solved the shortcoming that the system fault electric amplitude of its own is small and difficult to detect, which occurs in the exsiting method of using the steady-state component in route selection and positioning. It has advantages such as transient amplification of the fault signal steady-state component after the single-phase ground fault occurs in the power network, which allows the route selection and positioning device based on the single-phase ground fault steady-state quantity, to accurate position, so at to achieve the purpose of positioning and route selection. Its structure is that: it includes a protected bus of the distribution system, and a steady-state zero-sequence current increase-support apparatus installed on the bus, which is connected to a voltage transformer, while the voltage transformer is connected to the bus; the increase-support apparatus is composed of a power capacitor group, on-off switches and a control device which monitors whether the single-phase ground fault occurs in the distribution system, while the power capacitor group help to increase the ground current, and the control device controls the on-off state of the power switch control group through the on-off switches.

Description

technical field [0001] The invention relates to a grounding fault detection technology in a power system, in particular to a steady-state zero-sequence current boosting device and method for a neutral point ungrounded or arc suppression coil grounded system. Background technique [0002] At present, for the power distribution system in operation, since the neutral point of the system is not grounded or grounded through the arc suppression coil, no short-circuit loop will be formed after a single-phase ground fault occurs, and only a small zero-sequence current caused by the distributed capacitance of the system. Various devices for finding single-phase ground faults at home and abroad are based on these relatively small quantities as the judgment basis, and the misjudgment rate is relatively large. In this regard, there is no accurate and reliable microcomputer line selection device that can act on tripping at present. [0003] Universities and manufacturers at home and abr...

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Problems solved by technology

[0004] The purpose of the present invention is to solve the defect that the fault electrical quantity amplitude of the system itself is too small and difficult to detect in the current method for line selection and positioning using the steady-state component of the fault signal, and to provide a method that can instantly Amplify the steady-state component of the fault signal, make the line selection and positioning device based on the single-phase ground fault steady-state quantity operate accurately, and achieve the purpose of positioning and line selection, etc. The steady-state zero-sequence current boosting device and method

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