大型汽轮发电机3次谐波电压定子接地保护方案的研究与改进
|
摘要
基于一台300 MW汽轮发电机的参数,对常用的3种3次谐波电压定子接地保护方案进行灵敏度对比分析。分析结果表明大型汽轮发电机采用接地变压器接地方式时,现有的3次谐波电压定子接地保护在定子绕组中部的灵敏度仍然不足。考虑现有3次谐波电压定子接地保护存在误动较多的问题,分析了导致发电机机端、中性点3次谐波电压变化的原因。在此基础上,提出一种改进型3次谐波电压变化量差动原理定子接地保护方案。该方案对机端3次谐波电压变化量进行校正后与中性点3次谐波电压变化量构成差动判据,可有效区分定子接地故障与发电机3次谐波电压的正常波动。该方案还根据高压侧3次谐波电压的变化量增加了浮动的保护启动门槛,避免因高压侧3次谐波电压变化而导致的误动。仿真结果表明所提方案理论正确,灵敏度较高,受机组运行变化状态的影响小。
The sensitivity of three common stator grounding protection schemes based on the third-harmonic voltage is compared and analyzed based on the parameters of a 300 MW turbine generator,which shows that the sensitivity of stator grounding protection schemes may be insufficient in the middle of the stator winding if the turbine generator is connected with the grounding transformer. Considering the frequent maloperation present in the existing stator grounding protection schemes based on the third-harmonic voltage,the causes of third-harmonic voltage variation of the generator terminal and the generator neutral point are analyzed. Based on the above research,an improved stator grounding protection scheme based on third-harmonic voltage variation component differential principle is proposed. The variation of the third-harmonic voltage of the generator terminal are corrected and then adopted to construct the differential criterion with the variation of the third-harmonic voltage of the generator neutral point,which can effectively distinguish the stator grounding faults from the normal change of generators' third-harmonic voltage. In order to avoid false tripping caused by harmonic voltage changes at high voltage side,a floating threshold value is also set according to the variation of the third-harmonic voltage at high voltage side. Simulative results show that the proposed scheme is theoretically correct and slightly affected by the changes of generator operating state with high sensitivity.
The sensitivity of three common stator grounding protection schemes based on the third-harmonic voltage is compared and analyzed based on the parameters of a 300 MW turbine generator,which shows that the sensitivity of stator grounding protection schemes may be insufficient in the middle of the stator winding if the turbine generator is connected with the grounding transformer. Considering the frequent maloperation present in the existing stator grounding protection schemes based on the third-harmonic voltage,the causes of third-harmonic voltage variation of the generator terminal and the generator neutral point are analyzed. Based on the above research,an improved stator grounding protection scheme based on third-harmonic voltage variation component differential principle is proposed. The variation of the third-harmonic voltage of the generator terminal are corrected and then adopted to construct the differential criterion with the variation of the third-harmonic voltage of the generator neutral point,which can effectively distinguish the stator grounding faults from the normal change of generators' third-harmonic voltage. In order to avoid false tripping caused by harmonic voltage changes at high voltage side,a floating threshold value is also set according to the variation of the third-harmonic voltage at high voltage side. Simulative results show that the proposed scheme is theoretically correct and slightly affected by the changes of generator operating state with high sensitivity.
引文
[1]刘亚东,王增平,苏毅,等.注入式定子接地保护的现场试验、整定和分析[J].电力自动化设备,2012,32(10):150-154.LIU Yadong,WANG Zengping,SU Yi,et al.Field test,setting and analysis of injecting source-based stator grounding protection[J].Electric Power Automation Equipment,2012,32(10):150-154.
[2]陈佳胜,张琦雪,陈俊,等.基于分段相角补偿的注入式定子接地保护方法[J].现代电力,2014,31(1):79-84.CHEN Jiasheng,ZHANG Qixue,CHEN Jun,et al.Stator earth fault protection with voltage injection based on multi-stage phase compensation[J].Modern Electric Power,2014,31(1):79-84.
[3]高春如.大型发电机组继电保护整定计算与运行技术[M].2版.北京:中国电力出版社,2010:160-161.
[4]刘亚东.大型发电机保护关键技术研究[D].北京:华北电力大学,2014.LIU Yadong.Study on key technology of large generator’s protection[D].Beijing:North China Electric Power University,2014.
[5]毕大强,王祥琦,桂林.基于零序电压故障暂态分量的发电机定子单相接地保护方案研究[J].中国电机工程学报,2003,23(11):39-44.BI Daqiang,WANG Xiangheng,GUI Lin.Protection scheme based on the fault transient component of zero-sequence voltage under the stator ground fault of generators[J].Proceedings of the CSEE,2003,23(11):39-44.
[6]党晓强,邰能灵,王海田,等.大型汽轮发电机定子单相接地的继电保护评述[J].电力系统保护与控制,2010,38(2):131-135.DANG Xiaoqiang,TAI Nengling,WANG Haitian,et al.A review on single phase to ground protection for huge turbine-generators[J].Power System Protection and Control,2010,38(2):131-135.
[7]王维俭,鲁华富.三次谐波电压式定子接地保护的运行和改进[J].中国电力,1995(11):46-49,53.WANG Weijian,LU Huafu.Operating and improving of third harmonic voltage stator grounding protection[J].Electric Power,1995(11):46-49,53.
[8]卢琪.提高三次谐波电压式定子接地保护动作可靠性的措施[J].电力自动化设备,2008,28(1):119-121.LU Qi.Reliability of stator grounding protection based on 3rd harmonic voltage[J].Electric Power Automation Equipment,2008,28(1):119-121.
[9]黄少锋,孙鹏,王增平,等.基于三次谐波相角突变原理的发电机定子接地保护[J].电网技术,2000,24(12):70-73.HUANG Shaofeng,SUN Peng,WANG Zengping,et al.A generator grounding fault protection based on phase-angle mutation of third harmonic voltage[J].Power System Technology,2000,24(12):70-73.
[10]毕大强,王祥珩,王维俭.基于3次谐波电压故障暂态分量的定子单相接地保护[J].电力系统自动化,2003,27(13):45-49.BI Daqiang,WANG Xiangheng,WANG Weijian.Protection scheme based on fault transient component of third harmonic voltage for stator ground fault of generators[J].Automation of Electric Power Systems,2003,27(13):45-49.
[11]TAI Nengling,JUERGEN S.Differential protection based on zerosequence voltages for generator stator ground fault[J].IEEETransactions on Power Delivery,2007,22(1):116-121.
[12]王维俭.电气主设备继电保护原理与应用[M].2版.北京:中国电力出版社,2002:205-206.
[13]谌争鸣.大型发电机定子接地保护灵敏度分析与整定计算[J].电力系统自动化,2006,30(19):57-60.CHEN Zhengming.Analysis of the sensitivity of large-scale generator stator ground protection and its setting caculation[J].Automation of Electric Power Systems,2006,30(19):57-60.
[14]中国电力企业联合会.大型发电机变压器继电保护整定计算导则:DL/T 684-2012[S].北京:中国电力出版社,2012.
[2]陈佳胜,张琦雪,陈俊,等.基于分段相角补偿的注入式定子接地保护方法[J].现代电力,2014,31(1):79-84.CHEN Jiasheng,ZHANG Qixue,CHEN Jun,et al.Stator earth fault protection with voltage injection based on multi-stage phase compensation[J].Modern Electric Power,2014,31(1):79-84.
[3]高春如.大型发电机组继电保护整定计算与运行技术[M].2版.北京:中国电力出版社,2010:160-161.
[4]刘亚东.大型发电机保护关键技术研究[D].北京:华北电力大学,2014.LIU Yadong.Study on key technology of large generator’s protection[D].Beijing:North China Electric Power University,2014.
[5]毕大强,王祥琦,桂林.基于零序电压故障暂态分量的发电机定子单相接地保护方案研究[J].中国电机工程学报,2003,23(11):39-44.BI Daqiang,WANG Xiangheng,GUI Lin.Protection scheme based on the fault transient component of zero-sequence voltage under the stator ground fault of generators[J].Proceedings of the CSEE,2003,23(11):39-44.
[6]党晓强,邰能灵,王海田,等.大型汽轮发电机定子单相接地的继电保护评述[J].电力系统保护与控制,2010,38(2):131-135.DANG Xiaoqiang,TAI Nengling,WANG Haitian,et al.A review on single phase to ground protection for huge turbine-generators[J].Power System Protection and Control,2010,38(2):131-135.
[7]王维俭,鲁华富.三次谐波电压式定子接地保护的运行和改进[J].中国电力,1995(11):46-49,53.WANG Weijian,LU Huafu.Operating and improving of third harmonic voltage stator grounding protection[J].Electric Power,1995(11):46-49,53.
[8]卢琪.提高三次谐波电压式定子接地保护动作可靠性的措施[J].电力自动化设备,2008,28(1):119-121.LU Qi.Reliability of stator grounding protection based on 3rd harmonic voltage[J].Electric Power Automation Equipment,2008,28(1):119-121.
[9]黄少锋,孙鹏,王增平,等.基于三次谐波相角突变原理的发电机定子接地保护[J].电网技术,2000,24(12):70-73.HUANG Shaofeng,SUN Peng,WANG Zengping,et al.A generator grounding fault protection based on phase-angle mutation of third harmonic voltage[J].Power System Technology,2000,24(12):70-73.
[10]毕大强,王祥珩,王维俭.基于3次谐波电压故障暂态分量的定子单相接地保护[J].电力系统自动化,2003,27(13):45-49.BI Daqiang,WANG Xiangheng,WANG Weijian.Protection scheme based on fault transient component of third harmonic voltage for stator ground fault of generators[J].Automation of Electric Power Systems,2003,27(13):45-49.
[11]TAI Nengling,JUERGEN S.Differential protection based on zerosequence voltages for generator stator ground fault[J].IEEETransactions on Power Delivery,2007,22(1):116-121.
[12]王维俭.电气主设备继电保护原理与应用[M].2版.北京:中国电力出版社,2002:205-206.
[13]谌争鸣.大型发电机定子接地保护灵敏度分析与整定计算[J].电力系统自动化,2006,30(19):57-60.CHEN Zhengming.Analysis of the sensitivity of large-scale generator stator ground protection and its setting caculation[J].Automation of Electric Power Systems,2006,30(19):57-60.
[14]中国电力企业联合会.大型发电机变压器继电保护整定计算导则:DL/T 684-2012[S].北京:中国电力出版社,2012.