The Design And Application Of Series Resonance Test Power

In order to ensure the good insulation performance of power equipment and prevent the menace to the safe operation of power grid owing to insulation problems,the power equipments need to withstand voltage test according to the test procedures before and after being put into operation.This paper proposes a test method which uses series resonance test power to do it based on the traditional methods that contain DC voltage withstand test and power frequency withstand test.The test power can generate high voltage expending less power.It has stable property and is convenient for application in the field.So the series resonance test power is studied and designed in this paper.The main work is as follows:First of all,the current development status of series resonance test power at home and abroad is introduced.And some key technology that series resonance test power needs is introduced,too.Through the analysis of several kinds of modulation principles,the single polarity double frequency SPWM that its harmonic frequency is higher and its harmonic content is less than others is used,and the realization of the modulation principle is introduced,too.Second the overall structure of the test power is designed according to the performance requirements in the paper.It contains rectifier and filter circuit,variable frequency inverter circuit,LC filter circuit,isolate the booster circuit,high voltage resonance circuit,signal detection and control circuit,human-computerinteraction and control circuit.The frequency of high voltage resonance circuit is defined when the voltage is the biggest in the process of finding resonance frequency through the analysis of the principle of resonance.Then based on the system modeling,a dual-loop control which is filtering inductance current inner loop and filtering capacitor voltage outer loop based on load current feed-forward is proposed.This voltage control method can insure that the inverter circuit outputs good waveform when it is finding resonance frequency or withstanding voltage test.Last the performance of the test power is improved gradually through building the test platform and commissioning thetest.Then a single phase oil-immersed phase-shift capacitor and a 12 k V outdoor vacuum circuit breaker are tested.The test results prove that the test power meets the basic design requirements and has some engineering application value.