绝缘状况原理在大型水轮发电机3次谐波量接地保护中的应用  

Application of Ground Insulation State to Improve Ground Fault Protection Using Third Harmonic Voltage for Huge Hydraulic Generator

作　　者：党晓强[1] 邰能灵[1] 刘俊勇[2] 张力[3] 冯喆 

机构地区：[1]上海交通大学电子信息与电气工程学院,上海市闵行区200240 [2]四川大学电气信息学院,四川省成都市610065 [3]西华大学电气信息学院,四川省成都市610039 [4]二滩水力发电厂,四川省攀枝花市617000

出　　处：《中国电机工程学报》2012年第34期129-134,19,共6页Proceedings of the CSEE

基　　金："流体及动力机械"省部共建教育部重点实验室学术成果培育项目(SBZDPY-11-15);~~

摘　　要：大型水轮发电机对定子绕组单相接地通常装设的双频式100%保护,实践证明其3次谐波电压保护在可靠性、灵敏性和简洁性等方面存在很多问题,因此提出应用基于绝缘状况的保护原理来解决这些问题。针对水轮发电机定子单相接地3次谐波电压保护原理和其在运行方式变化和起停机过程中可能存在的误动情况进行分析,阐述了基于发电机中性点侧对地绝缘状况的保护原理,其保护出发点是将电气量的差值保护判据变为基于绝缘状况的相对阻抗的无量纲比值保护判据。具体结合该原理与水轮发电机定子单相接地故障特点,分析其对已有问题的解决效果,结果表明,该原理在实际应用中具备合理性,有望在实际应用中改善水轮发电机接地保护的动作情况。Huge hydraulic-generators usually install two-frequency 100% protection for single-phase ground short faults,but the reliability,sensitivity and simplicity of its third-order harmonic voltage protection are not ideal in actual application.This paper presented a protection scheme to resolve these problems based on insulation condition principle.The principles of third-order harmonic voltage protection for ground faults were discussed,and its maloperations caused by generator starting,tripping and changes of operation modes were analyzed.The principle based on neutral side insulation condition was introduced and its keystone is to change the protection criterion based on the difference of electrical quantities to the nondimensional impedance ratio protection criterion based on insulation condition.Combining the principle and the characteristics of the ground faults,the effect in solving the existing problems was analyzed and the results indicate that the criterion is feasible and is hopeful in improving the performance of the ground fault protection for hydraulic-generators.

关 键 词：大型水轮发电机 定子单相接地保护 3次谐波电压 对地绝缘状况 保护误动防范 

分 类 号：TM77[电气工程—电力系统及自动化]