多判据综合的变压器差动保护

针对目前变压器差动保护存在的不足，提出了多判据综合的变压器差动保护方案。由采样值差动判据、虚拟三次谐波制动及二次谐波制动相量差动判据、故障分量虚拟三次谐波制动相量差动和故障分量采样值差动等判据综合构成的变压器差动保护，能使变压器差动保护的性能得到较大提高。动态模拟试验表明，所开发的多判据综合的变压器差动保护装置对绝大多数内部故障，动作时间在6ms、12ms、16ms左右。在最小方式下，轻微匝间短路，能可靠跳闸，发跳闸令时间小于或等于22ms。带匝间故障空投变压器，发跳闸令时间在25ms左右。区外故障及无内部故障时空投变压器，保护不误动。

POWER TRANSFORMER DIFFERENTIAL PROTECTION WITH INTEGRATION OF MULTI-CRITERIA

Due to the disadvantages of the existingtransformer differential protection, the thought of transformer differential protection based on the integration of multi-criteria is proposed. On this basis the transformer differential protection constituted by the combination of sampled valuedifferential criterion, virtual 3rd and 2nd harmonic restraintphasor differential criteria, fault component based virtual 3rd harmonic restraint phasor differential and sampled valuedifferential criteria can improve the protection performance to a great extent. The results of dynamic simulation of thedeveloped protection device based on the above mentionedthought show: (1) for most internal faults, the tripping time is about 6ms, 12ms or 16ms after fault inception. (2) under the minimum operation mode, the protection can reliably operate at about 22ms even for light turn-to-turn faults. (3) When switching on an internal fault, the device generates trippingcommand at 25ms. (4) For external faults and switchingtransformer with no fault, the device can definitely remain not operating.