新型变压器零序差动保护方案设计

从保护方案设计和保护逻辑两方面详细论述了一种新型的变压器零序差动保护方案。方案设计中引入了外部故障异步区分、方向判据及二次谐波闭锁判据来可靠区分区内、区外故障,并介绍了差动电流、制动电流的选取。经试验证明该方案安全可靠,能够充分发挥零序差动保护对接地故障灵敏度高的优势。目前,该方案已实际应用于某变压器的保护装置中。

Scheme design of transformer zero-sequence differential protection

A zero-sequence differential protection for transformer is discussed in scheme design and protective logic.Asynchronous detection of external fault,direction criterion and the second harmonic blocking criterion are used in scheme design to properly distinguish the external faults from the internal faults.The selection of the differential current and the restraint current is introduced.Experiments prove its security and reliability,bringing the high sensitivity of zero-sequence differential protection to earthing fault into full play.The new scheme has been applied in one transformer protection equipment.