10 P63X变压器差动保护.ppt

// MiCOM P631/P632/P633/P634变压器差动保护 PLACE, Date 2004 MiCOM P631/632/633/634变压器差动保护 应用 MiCOM P631/632/633/634变压器差动保护 主要功能 MiCOM P631/632/633/634变压器差动保护 输入输出 MiCOM P631/632/633/634变压器差动保护 MiCOM P631/632/633/634变压器差动保护 MiCOM P631/632/633/634保护功能介绍 MiCOM P631/632/633/634保护功能介绍 MiCOM P631/632/633/634保护功能介绍 MiCOM P631/632/633/634保护功能介绍 MiCOM P631/632/633/634保护功能介绍 MiCOM P631/632/633/634保护功能介绍 MiCOM P631/632/633/634保护功能介绍 MiCOM P631/632/633/634保护功能介绍 MiCOM P631/632/633/634保护功能介绍 MiCOM P631/632/633/634保护功能介绍 Differential CTS - Requirements Conventional CTS Schemes传统CTS方案 Presence of IO without VO　　判断有零序电流无零序电压 Used on many MiCOM devices (P14x, P34x, P44x)　多数MiCOM装置中采用 Relies on suitable VT?’s being available　　需要将PT引入 Persistent IDIFF for a given time delay　　在给定延时内持续有差流 Traditional approach used on busbar protections　用于母线保护的传统方法 Relies on dual algorithm or CT?’s to prevent maloperations until time delay expires 　　　为防止指定延时内保护误动，采用双重算法或双CT。 Differential CTS - Principles (1)差动CTS-原理（1） Ratio of Negative to Positive sequence current is measured at each CT set　 　　各侧CT电流负序与正序电流比 If ratio is zero (or small) either unloaded, balanced load, three phase fault or three phase CT problem 　　此比率是否为零（很小），或者无载，平衡负荷，三相对称故障或三相CT故障 If ratio is non-zero, either asymmetric fault or CT problem 　　此比率是否不为零，或者非对称故障或者CT故障 Ratio calculated at all CT ends 　计算所有侧CT If ratio is non-zero at two (or more ends) simultaneously, it is almost certainly a genuine fault condition unlikely to be a CT problem 如果二侧（或更多侧）同时出现此比率不为零，则不大可能为CT故障。 Differential CTS - Principles (2)差动CTS-原理（2） Ratio of Negative to Positive sequence current cannot distinguish between genuine faults and CT problems 　　存在负序与正序比并不能区分真正故障和CT故障 Additional criteria is positive sequence (load) current, I1 　　附加判据为正序（负荷）电流，I1 Better detection criteria than phase currents 　　优于采用相电流作判据 Considering a situation where the ratio is non-zero at one end only 　　假设单侧存在负序与正序比 If I1 only detected at one end, system is unloaded and therefore