高压直流断路器供能变压器的设计与试验

Design and Test of Power Supply Transformer for HVDC Circuit Breaker

混合式高压直流断路器的负载形式多样且复杂,针对其供能问题,文中提出了一种级联结构的隔离供能变压器设计方案,以满足±535 kV/25 kA混合式高压直流断路器分层次多目标的供能需求。其中最为关键的是对地隔离供能变压器,因此首先介绍对地隔离供能变压器的级联结构,并对电场、温升进行了仿真校核;然后进行了对地隔离供能变压器抗震性能的有限元计算分析,结果表明满足9级烈度地震的强度要求;最后进行了对地隔离供能变压器样机长期直流耐压下温升试验,以及单节隔离变压器高低温试验和输出绕组温升的测定,结果表明在长期直流耐压下,隔离变压器温升约18 K,电阻温升约33 K,电容器温升约12 K,而单节隔离变压器在高低温作用以及高温带载情况下,环氧树脂未发生开裂等问题,且满足绝缘要求,同时测试计算得到输出绕组温升约为26 K,与热仿真结果基本一致,另外通过试验验证了对地隔离供能变压器的绝缘性能满足要求。

The load forms of hybrid HVDC circuit breaker are various and complicated.In view of its power supply,a kind of design scheme of isolated power supply transformer with cascade structure is proposed in this paper in order to meet the hierarchical multi-objective power supply requirement of±535 kV/25 kA hybrid HVDC circuit breaker.The most critical component is ground-isolated power supply transformer.Therefor,the cascade structure of the ground-isolated power supply transformer is introduced firstly.Then,the electric field and temperature rise are simu-lated and verified.After that,the finite element calculation analysis on seismic performance of the ground-isolated power supply transformer is performed.The result shows it fulfills the strength requirements of 9 seismic intensity.Fi-nally,the temperature rise test of the ground-isolated power supply transformer under long-time DC withstanding volt-age,the high and low temperature test and temperature rise measurement of the output winding of the single isolated transformer are performed.The result shows that under the long term DC withstanding voltage,the temperature rise of the isolated transformer,temperature rise of resistor and of capacitor is about 18 K,33 K and 12 K,respectively.While,no such malfunction as cracking of epoxy resin happens in single isolated transformer at high and low temper-ature or with load at high temperature and the dielectric requirement is met.At the same time,the temperature rise of output winding which is obtained by test and calculation is about 26 K and is basically identical to thermal simulation result.Moreover,it is proved by the test that the dielectric performance of the grounded isolated transformer can meet the requirement.