Short-circuit test device for three-phase current containing direct-current component

Abstract

The invention relates to the technical field of electric power test devices, in particular to a short-circuit test device for three-phase current containing direct-current component. The device comprises a three-phase power supply input circuit, a three-phase synchronous signal circuit, an initial short-circuit angle adjusting circuit, a three-phase transformer, a three-phase transformer control circuit, a short-circuit characteristic time constant adjusting circuit and a short-circuit signal output circuit, wherein the three-phase power supply input circuit comprises a power supply main switch, a power supply indication element and an overcurrent protection element of the short-circuit test device, the three-phase synchronous signal circuit determines one of three phases A, B and C as a calculation initial short-circuit angle of a short-circuit output signal through a selection switch, and the initial short-circuit angle adjusting circuit determines the number of short-circuit angles through a selection switch. According to the invention, a composite signal of a three-phase short-circuit current with an additional nonlinear direct-current characteristic component and an adjustable short-circuit initial angle can be output, and verification of actual short-circuit effect simulation are provided for various protection devices in electric power system protection application.

Description

technical field [0001] The invention relates to the technical field of electric power test devices, in particular to a short-circuit test device with a three-phase current containing a DC component. Background technique [0002] With the continuous development of the power system, the level of short-circuit current in the power grid at all levels continues to increase. If a short-circuit fault occurs, it will cause serious consequences. Therefore, in addition to being able to quickly identify short-circuit faults, various short-circuit protection equipment must Predict the zero-crossing point of the short-circuit current, so that the breaking element can break the short-circuit fault current at the zero-crossing point of the maximum short-circuit current, which will greatly improve the breaking short-circuit current capability of the breaking element (switch or vacuum tube) and prolong the service life, but there is no countermeasure yet. This type of protective device is an...

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Problems solved by technology

[0002] With the continuous development of the power system, the level of short-circuit current in the power grid at all levels continues to increase. If a short-circuit fault occurs, it will cause serious consequences. Therefore, in addition to being able to quickly identify short-circuit faults, various short-circuit protection equipment must Predict the zero-crossing point of the short-circuit current, so that the breaking element can break the short-circuit fault current at the zero-crossing point of the maximum short-circuit current, which will greatly improve the breaking short-circuit current capability of the breaking element (switch or vacuum tube) and prolong the service life, but there is no countermeasure yet. Test device for effective verification of this type of protective device

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