A performance testing method of a voltage transformer

Abstract

The invention relates to the field of unit testing of high voltage transformer products, in particular to a performance testing method for the voltage transformer. The performance testing method for the voltage transformer is characterized in that a frequency modulation voltage-controlled power source is used as a testing power source and a frequency-modulated and voltage-controlled voltage signal is output, the requirements for the exciting voltage of a secondary winding of a tested voltage transformer are met through voltage rising of an exciting transformer, the induction voltage of the first winding of the tested voltage transformer is collected by a voltage sampler, and monitoring is conducted on the output voltage, the frequency and the output currents of the frequency-modulation voltage-controlled power source and high-voltage feedback of the voltage transformer. Compared with the prior art, the performance testing method for the voltage transformer has the advantages that a third harmonic generation power source large in size is replaced, conveying cost of testing equipment is reduced, testing quality is improved, voltage waveform is improved, and disturbance of higher harmonics is avoided. During the testing process, the no-load voltage ratio and excitation characteristic testing can be achieved under the power frequency conditions, and the voltage transformer is multifunctional. Over-voltage protection can be set, and the safety of the tested voltage transformer can be ensured. Equipment is low in weight and convenient to carry.

Description

technical field [0001] The invention relates to the field of unit testing of high-voltage voltage transformer products, in particular to a performance testing method of a voltage transformer. Background technique [0002] In the unit test of the high-voltage voltage transformer, it is necessary to carry out the withstand voltage test and the measurement of the transformation ratio and the excitation characteristics. The induction withstand voltage test of the high-voltage voltage transformer usually uses a triple frequency power supply. The test voltage is roughly 2 to 3 times the maximum working phase voltage. Since the iron core of the transformer is close to saturation at the rated frequency and rated voltage, if a test voltage greater than the rated voltage is applied to both ends of the tested transformer winding with a power frequency power supply, the no-load excitation current will increase sharply, reaching an unacceptable level. It can be seen from the relational ...

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Problems solved by technology

Since the iron core of the transformer is close to saturation at the rated frequency and rated voltage, if a test voltage greater than the rated voltage is applied to both ends of the tested transformer winding with a power frequency power supply, the no-load excitation current will increase sharply, reaching an unacceptable level. It can be seen from the relational expression of the induced potential that in order to apply a test voltage greater than the rated voltage without saturating the iron core, the method of increasing the power frequency can be adopted, but the frequency conversion generator set is heavy and inconvenient to transport, and is not suitable for on-site testing. Use, when the capacity is not large, the waveform is not very good

Three single-phase transformers are connected in parallel and connected in series twice to form an open triangle, and a power output of 150HZ can be obtained, but the waveform and capacity will change with the load, and it is very easy to resonate with the tested product, resulting in five The second and seventh harmonics are easy to damage the tested product due to resonance overvoltage

However, the measurement of the ratio performance and excitation characteristics of the voltage transformer needs to be completed with the help of a ratio speed tester and a self-coupling voltage regulator. The test process is cumbersome and the cycle is long.

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