干式空心并联电抗器绕组绝缘状态在线监测方法

On-line Monitoring Method of Insulation State of Dry-type Air-core Shunt Reactor Winding

干式空心并联电抗器用于无功补偿与抑制工频过电压,在电网中的数量和容量日益增加,事故率却高居不下,其中,绕组匝间绝缘故障占比高居首位,亟需有效的绕组绝缘状态在线监测手段。利用有限元软件对干式空心并联电抗器进行“场-路”耦合仿真,通过分析其绕组异匝和同匝股间短路的电、磁、力变化特征,研究绕组匝间短路故障的发展过程、形成机理,探求便于故障监测的敏感状态量,提出了基于有功功率损耗变化率的绕组绝缘状态在线监测方法。研究结果表明:绕组异匝股间短路对电抗器电、磁、力等物理参量的影响大于相同位置同匝股间短路工况,且异匝股间短路发生在电抗器绕组端部的影响最大。有功功率损耗对电抗器绕组绝缘故障发展的过程反应敏感、易于监测,可通过选择合适的绝缘故障预警值和绝缘失效值,基于有功功率损耗变化率进行状态判断,能够实时发现电抗器绕组绝缘故障,便于及时采取措施,阻止故障蔓延。

Dry-type air-core shunt reactors are used for reactive power compensation and suppression of power frequency overvoltage.The number and capacity in the power grid are increasing day by day,but the accident rate is high.Among them,the ratio of interturn insulation faults is the highest,and effective online monitoring means of winding insulation state are urgently needed.The model of dry-type air-core shunt reactor was carried out by using finite element software.By analyzing the characteristics of electrical,magnetic and force changes of short circuit between different turns and the same turn of the winding,the development process and formation mechanism of short circuit between turns of the winding were studied,and the sensitive state variables convenient for fault monitoring were explored,and an on-line monitoring method of winding insulation state based on the change rate of active power loss was proposed.The results show that the effect of the short-circuit between the different turns of the winding on the physical parameters such as electricity,magnetism and force of the reactor is greater than that of the short-circuit condition at the same position with the same turns,and the effect of the short-circuit between the different turns of the winding occurs at the end of the reactor winding is the greatest.Active power loss is sensitive to the process of reactor winding insulation fault development,and it is easy to monitor.By selecting appropriate insulation fault early warning value and insulation failure value,the state can be judged based on the change rate of active power loss,which can find reactor winding insulation fault in real time,facilitate timely measures and prevent the fault from spreading.