整流站无接地极运行时接地极保护优化研究

摘要

When rectifier station loses earthing pole,the direct current (DC)power transmission system may still keep long-time bipolar operation by means of instation earthing mode,but in view of security factor,it is needed to carry out necessary optimization on traditional earthing pole protection. Therefore,this paper analyzes optimizing and setting principles of earthing pole protection in no earthing pole operation mode by working out bound of earth current of the instation grounding network that may meet requirements for equipments and safety of person at the time of rectifier station running,and accord-ing to bipolar running characteristic of being without earthing pole operation. It also proposes optimizing and setting scheme and anti-malfunction measures for reducing earthing pole protection of instation earth current under this mode. By real-time digital simulation platform,it checks single-pole blocking earth current of the DC system before and after optimization and proves effectiveness of these optimization measures. This scheme has been verified and applied in engineering practice.%当整流站失去接地极时，直流输电系统通过站内接地的方式仍可维持长时间双极运行，但出于安全因素的考虑，需要对传统的接地极保护保护进行必要的优化。基于此，通过计算得到整流站运行时满足设备和人身安全要求的站内接地网入地电流边界范围，并根据无接地极双极运行特点，分析无接地极运行方式下接地极保护的优化整定原则，提出了该方式下如何降低站内入地电流的接地极保护的优化整定方案及防误动措施。利用实时数字仿真平台对优化前后的直流系统单极闭锁入地电流进行校核，证明了优化措施的有效性。该优化方案已在工程实践中得到验证和应用。