Short-circuit impedance calculation method of transformer

Abstract

The invention discloses a short-circuit impedance calculation method of a transformer. The method comprises the following steps of: measuring controlled silicon commutation time, a mean value of direct current voltage, and direct current in a controlled silicon three-phase full-control rectifier bridge or an inverter bridge; calculating angles, wherein alpha is a controlled silicon trigger angle with a unit rad, and gamma is controlled silicon commutation overlapping angle with a unit rad; calculating leakage inductance of the transformer; and calculating the short-circuit impedance of the transformer according to the calculated leakage inductance of the transformer. The calculation method can be used for calculating the short-circuit impedance of the transformer under the condition of rated current or approximate rated current in the situation that the three-phase full-control rectifier bridge or inverter bridge is not shut down, and a wiring cable of the transformer is not unlocked, thereby reducing the test workload on the short-circuit impedance of the transformer, and improving the test precision of the short-circuit impedance of the transformer.

Description

technical field [0001] The invention belongs to the technical fields of electromechanical and power electronics, and in particular relates to a method for calculating the short-circuit impedance of a transformer in a thyristor three-phase fully-controlled rectifier bridge (or inverter bridge). Background technique [0002] Transformer short-circuit impedance is also called transformer impedance voltage, and its standard value is expressed as a percentage, which is used to indicate the size of the internal impedance of the transformer. Short-circuit impedance is an important technical index of the transformer, which has important significance for the stability of the power supply system and the quality of power supply to the load. The transformer short-circuit impedance is an important basis for judging whether the transformer winding is deformed, and it is a common method for calculating the transformer capacity in engineering. [0003] The standard test method for short-ci...

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Problems solved by technology

This method of using the short-circuit impedance measured at a small current to replace the short-circuit impedance at the rated current has a large experimental error

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