变压器和电流保护的性能分析

Analysis on the characteristics of sum current protection for transformer

为了解决变压器电源侧相间后备保护灵敏度不满足要求 ,特别是低压侧加装限流电抗器时的后备保护问题 ,拟用变压器高中压侧CT构成的和电流保护 ,其原理、构成、整定与传统过流保护均有不同 ,值得尽快研究、开发、使用。本文认为 ,和电流保护能显著提高灵敏度 ,应该成为标准配置 ,该保护CT应采用三角形接线 ,用微机型装置实现 ,其整定应以单变运行为计算条件。

To solve the problems on sensitivity of phase to phase backup protection on transformer’s power supply side, especially the problems on the backup protection on the conditions of a current limit reactor applied on the LV side, a sum current protection formed by CT on HV and MV sides on transformer is proposed. Its principle, construction and setting way are different from the traditional overcurrent protections. In the author’s view, the sum current protection would improve the sensitivity considerably and should make it be a standard arrangement. Its CT should be delta wired realized by microprocessor based device. Its setting should be done based on single transformer operation.