特高压固定串补MOV防爆能力提升方案

Improvement of Explosion-proof Capacity of MOV Used in UHV Fixed Series Compensation

介绍了500kV沽源站串补MOV粉碎性炸裂的案例,通过分析炸裂的MOV解体情况,发现该型MOV防爆能力不足,当MOV电阻片发生击穿放电时,压力释放通道不通畅,导致瓷套粉碎性炸裂。指出该类型超、特高压MOV设备均有类似炸裂风险,提出在超、特高压MOV单元两端加装垫块和铝遮板的改进措施,并指出特高压MOV设备治理现场问题更为突出,以1 000kV特高压南阳站为例,分析特高压MOV设备治理现场遇到的困难,重点说明改造后MOV铝遮板与法兰间存在缝隙,提出现场解决措施及建议,对国内后续超、特高压类似设备的隐患治理具有借鉴意义。

This paper introduces a case of crushing explosion of MOV device used in 500 kV Guyuan power station series compensation.Based on the disassembly analysis of the cracked MOV,it is considered that the explosion-proof capacity design of this type of MOV is insufficient.When the MOV resistors are broken down and discharged,the ceramic insulator will be smashed and burst due to the blocked pressure release channel.Explosion risk exists in all UHV and EHV MOV equipment with this principle.In order to improve the explosion-proof capability of the EHV and UHV MOV unit,it is proposed to install metal blocks and aluminum shutters at both ends.This paper introduces the improved scheme on UHV MOV equipment in 1 000 kV UHV Nanyang substation.Difficulties encountered and the solutions are analyzed.It is highlighted that chinks existence between the MOV aluminum shutter and the flange after its improvement,solutions and suggestions are put forward.It is valuable for the following EHV and UHV MOV equipment’s improvement work in China.