Study On Parallel Operation Of Portable Resonant Voltage Withstand Device

AC withstand voltage test is a very important electrical test of AC electrical equipment(hereinafter referred to as electrical equipment).Whether the electrical equipment can be put into operation and whether it can operate normally after being put into operation is closely related to whether it can pass the AC withstand voltage test smoothly.At present,the AC voltage withstand test of capacitive test objects(hereinafter referred to as test objects)is mainly divided into power frequency voltage withstand test and resonance voltage withstand test.Power frequency voltage withstand test is generally used for small capacitance and low voltage withstand test objects,while resonance voltage withstand test is generally used for large capacity or high voltage withstand test objects.With the continuous improvement of the capacity and voltage of electrical equipment,its capacitance and withstand voltage value are also increasing synchronously.Therefore,more and more AC withstand voltage tests of electrical equipment have to use large resonance withstand voltage device,which leads to the use of crane and other hoisting machinery to hoist the test equipment in the test,increasing the safety risks.At the same time,the construction of electrical equipment in the city is also in conflict with the urban land: in order to meet the less and less urban land,more and more electrical equipment have to reduce the land area,or use underground layout to meet the increasingly serious urban land problem.These reasons make it more difficult to install the test equipment in the narrow space,and even have to use some unconventional methods,such as demolishing some buildings or erecting ultra long high voltage test lines,to increase the test cost or safety risks,to carry out the withstand voltage test on the tested objects.Therefore,it is necessary to further study the resonant voltage withstand device in order to further increase its applicability in narrow space.In this paper,the series compensation resonant circuit,which is rarely used in resonant voltage withstand test,is studied.The results show that when the same resonant voltage withstand device carries out resonant voltage withstand test on the same test object,whether the series compensation resonant circuit or the series resonant circuit is used,their resonant frequency and active power are approximately equal.Based on this conclusion,a series compensation resonant circuit is proposed The simplified algorithm of complementary resonant circuit.Then,the relationship between AC resistance,DC resistance and frequency of core reactor is studied,and the empirical formula for calculating core reactor before saturation is proposed,which solves some calculation problems when using portable resonant withstand voltage device for resonant withstand voltage test.Finally,based on the portable resonant voltage withstand device,combined with the series compensated resonant circuit,the feasibility of using multiple groups of portable resonant voltage withstand devices for large capacity and high voltage withstand test objects with different parallel operation schemes is demonstrated,and some suggestions are put forward for the portable resonant voltage withstand device,and the best parallel scheme is demonstrated.