No-load Test Method for Large Transformer Using Filter Compensation Technology

Abstract

Provided is a large transformer no-load test method adopting a filter compensation technique. According to the method, alternating current test power sources connected in sequence and an intermediate transformer in secondary connection with a tested transformer are included. The large transformer no-load test method adopting the filter compensation technique is characterized in that one or more sets of high voltage filters are connected between the intermediate transformer and the tested transformer in parallel, and each high voltage filter is a higher harmonic RLC series connection filter. The invention provides a large transformer test device based on a compensation filtering composite technology. The contradiction between the requirements on waveform quality and power capacity in current large transformer tests is solved, fundamental waves of test currents can be compensated, the harmonic waves in the test currents can also be filtered out, the test power source capacity is reduced obviously, and the test voltage waveform is improved. The filters work in a loop all the time in a no-load boosting process, high-voltage switching is not needed, transient overvoltages cannot be generated, and the risk factors of the tests are reduced greatly.

Description

technical field [0001] The invention relates to the technical field of large-scale transformer testing, in particular to a large-scale transformer no-load test method using filter compensation technology. Background technique [0002] Large power transformers are one of the most important and expensive equipment in power transmission and transformation systems, and their reliability is directly related to the safe and stable operation of power systems. Before the transformer leaves the factory or is overhauled and put into operation, tests are required to check whether there are defects inside the transformer and whether it can be put into operation safely. The transformer no-load test can find the quality problems of the transformer core and winding, and it is one of the test items that must be done for the transformer. [0003] At present, the typical no-load test circuit of large transformers at home and abroad is composed of test power supply, intermediate transformer, ...

AI Technical Summary

Problems solved by technology

[0008] The high-voltage capacitor has a certain effect on the compensation of the inductive power frequency fundamental component in the no-load current, but it has an amplification effect on the harmonic component in the no-load current, causing greater distortion of the voltage waveform

At the same time, switching the parallel compensation capacitor will generate a transient overvoltage, which can exceed 1.26 times the rated voltage at most, which may cause loop oscillation, and there is a certain risk

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