大型发变组保护CT极性及保护方向自动检测技术研究

准确无误的电流互感器(CT)极性和保护方向是确保继电保护安全可靠运行的基础,大型发变组保护采用主后一体化的双重化配置模式,需要接入的CT电流回路较多,且部分CT电流回路同时供主保护、后备保护和异常运行保护共同使用,CT极性必须同时满足主保护、后备保护、异常运行保护的要求。由于大型发变组保护的配置及其二次回路的复杂性,导致CT极性和保护方向错误而引发的发变组保护误动或拒动的事情时有发生,严重影响了电网的安全稳定运行。根据传统人工带负荷检测CT极性和保护方向的"六角图理论",在发变组保护装置内构建了CT极性和保护方向自动检测的判据和功能,进一步提升了发变组保护的安全性和可靠性,具有很高的工程实用价值。

Research on CT polarity and protection direction automatic detection technology for large generator transformer unit

Accurate current transformer (CT) polarity and protection direction is to ensure the safe and reliable relay operation of the foundation, large transformer unit protection generally use the main protection and backup protection integration, duplex configuration mode, need to access the CT current loop more, And part of the CT current loop for protection within the main protection, backup protection and abnormal operation protect the common use, CT polarity must also meet the main protection, backup protection, abnormal operation protection requirements. Due to the protection of large transmission unit and the complexity of its secondary circuit, resulting in CT polarity and protection of the wrong direction caused by the protection of the group to prevent malpractice or refusal to happen when things have seriously affected the safety and stability of the grid run. According to the "hexagonal graph theory" of detecting CT polarity and protection direction with traditional artificial load, the criterion and function of CT polarity and automatic detection of protection direction are constructed in the protection device of the transformer group, and the protection group Safety and reliability, with high engineering practical value.