智能站合并单元采样方式问题探讨

Study on the Merging Unit Sampling Mode of Smart Substation

智能变电站发展过程中,智能继电保护采样方式主要经历了"电子式互感器+合并单元"、"常规互感器+合并单元"、"常规互感器电缆常规采样"3种方式,其中"常规互感器+合并单元"的采样方式在目前的智能站中大量使用,针对此方式中合并单元的采样延时、插值同步等问题进行了分析探讨,明确了合并单元存在增加继电保护动作时间、同步异常易导致差动保护误动问题。将智能站改进为常规采样方式后,对继电保护可靠性和电网的稳定性均有较大的提升。

During the development of smart substation, modes of ＂electronic transformer＋ merging unit＂, ＂conventional transformer＋merging unit＂and ＂conventional transformer＋ routine cable sampling＂ have been adopted in relay protection sampling. The mode of＂conventional transformer＋ merging unit＂is generally adopted in the smart substation at present. In this paper, in view of this sampling mode, time delay and interpolation-based time synchronization are analyzed. It is cleared that the merging unit is defective in relay protection action time delaying and the differential protection mal-operation if synchronizing abnormally. After the conventional sampling mode is adopted in smart station, the reliability of the relay protection and the stability of the power grid are greatly improved.