Research And Design Of An Apparatus Used In AC Voltage Withstand Test And Partial Discharge Test On The Ultra-high Voltage Equipments

With the rapid increase of load, the ultra-high voltage (UHV) grid is eagerly needed for long-distance, large-capacity power delivery. UHV equipments are important parts of grid and it has been proved as an efficient inspection method to apply AC voltage withstand test (ACVWT) and partial discharge test (PDT) on UHV equipments. This paper included study and design of an appliance which can be used in ACVWT and PDT on the UHV equipments, has both academic significance and practical application value.This paper summarized global research status of this kind testing appliance, analyzed characteristics of different type UHV equipments. Referred to the 1000KV-transformer testing data from UHV test-base of Wuhan High Voltage Research Institute, a testing method and a wiring schematic diagram are both proposed, which are applied in ACVWT and PDT on UHV equipments. Based on analysis of UHV GIS equipments characteristics, a method of variable-frequency (VF) series-resonance is shown, used to get high voltage for the test. Designing way of VF source, high-voltage reactor in the whole equipment and applying modern high-power electronics to change frequency of high voltage have been discussed. It indicated that triode-parallel-magnification can produce huge power to satisfy the needs of test. For the special requirements of the testing appliance, a mode of safety-control applied VF source DC protection is proposed, and negative-feedback loop is also adopted to guarantee stability of the testing voltage. Solution methods are given to reduce influence of partial discharge and generating heat of electronic components on the measurement.This paper has proved the rationality of the testing appliance by analyzing the data from ACVWT and PDT on 750KV-UHV equipments, demonstrated its high stability, good security, strong practicability and good potential in application.