Using the neutral grounding method by the resistance in 110?kV system, it can limit the voltage sag and short circuit current when one-phase grounding fault occurred, but it will change the sequence of the network str...Using the neutral grounding method by the resistance in 110?kV system, it can limit the voltage sag and short circuit current when one-phase grounding fault occurred, but it will change the sequence of the network structure and parameters. This paper analyzes the size and distribution of zero sequence voltage and current when one-phase grounding fault occurred in the 110 kV resistance grounding system, and puts forward the grounding protection configuration setting principle of this system combining the power supplying characteristics of 110?kV distribution network. In a reforming substation as an example, the grounding protection of 110 kV lines and transformer have been set and calculated.展开更多
作为变压器重要保护之一的零序差动保护灵敏度高,抗干扰能力强,其保护判据的比较对象是三相进线侧相电流和得到的自产零序电流与中性线零序电流。三相进线电流互感器(current transformer,CT)和中性线电流互感器(neutral current transf...作为变压器重要保护之一的零序差动保护灵敏度高,抗干扰能力强,其保护判据的比较对象是三相进线侧相电流和得到的自产零序电流与中性线零序电流。三相进线电流互感器(current transformer,CT)和中性线电流互感器(neutral current transformer,NCT)饱和特性的差异会对零序电流的传变造成误差,传变后的零序电流波形会产生不同程度的畸变,从而导致虚假差流的产生,进而引起零序差动保护的误动作。针对该问题,在分析各种工况下经CT传变后两侧零序电流大小、相位特征的基础上,提出了一种基于Tanimoto相似度的变压器零序差动保护约束方案,并仿真验证了所提约束方案的有效性。展开更多
为了弥补变压器高压侧相过流保护不能完全保护低压系统非金属接地故障问题,合理配置重要配电变压器的零序电流保护功能,分析了低压单相接地故障对高、低压侧系统的影响,零序电流保护的配置及零序电流保护整定方法,比较中性点零序电流互...为了弥补变压器高压侧相过流保护不能完全保护低压系统非金属接地故障问题,合理配置重要配电变压器的零序电流保护功能,分析了低压单相接地故障对高、低压侧系统的影响,零序电流保护的配置及零序电流保护整定方法,比较中性点零序电流互感器的安装位置,确定了合理的零序电流保护配置方案。以某国际项目为例,使用ETAP软件完成了低压系统零序电流保护,并通过时间电流曲线(Time Current Curve,TCC)说明变压器中性点零序电流互感器保护的必要性。推荐在高压侧过流保护不能够有效保护变压器低压侧套管时,在配电变压器中性点设零序电流保护。展开更多
文摘Using the neutral grounding method by the resistance in 110?kV system, it can limit the voltage sag and short circuit current when one-phase grounding fault occurred, but it will change the sequence of the network structure and parameters. This paper analyzes the size and distribution of zero sequence voltage and current when one-phase grounding fault occurred in the 110 kV resistance grounding system, and puts forward the grounding protection configuration setting principle of this system combining the power supplying characteristics of 110?kV distribution network. In a reforming substation as an example, the grounding protection of 110 kV lines and transformer have been set and calculated.
文摘作为变压器重要保护之一的零序差动保护灵敏度高,抗干扰能力强,其保护判据的比较对象是三相进线侧相电流和得到的自产零序电流与中性线零序电流。三相进线电流互感器(current transformer,CT)和中性线电流互感器(neutral current transformer,NCT)饱和特性的差异会对零序电流的传变造成误差,传变后的零序电流波形会产生不同程度的畸变,从而导致虚假差流的产生,进而引起零序差动保护的误动作。针对该问题,在分析各种工况下经CT传变后两侧零序电流大小、相位特征的基础上,提出了一种基于Tanimoto相似度的变压器零序差动保护约束方案,并仿真验证了所提约束方案的有效性。
文摘为了弥补变压器高压侧相过流保护不能完全保护低压系统非金属接地故障问题,合理配置重要配电变压器的零序电流保护功能,分析了低压单相接地故障对高、低压侧系统的影响,零序电流保护的配置及零序电流保护整定方法,比较中性点零序电流互感器的安装位置,确定了合理的零序电流保护配置方案。以某国际项目为例,使用ETAP软件完成了低压系统零序电流保护,并通过时间电流曲线(Time Current Curve,TCC)说明变压器中性点零序电流互感器保护的必要性。推荐在高压侧过流保护不能够有效保护变压器低压侧套管时,在配电变压器中性点设零序电流保护。