基于NCIT和IEC61850-9-2的继电保护技术

Protection Scheme Based on NCIT and IEC61850-9-2

一个完整的数字化变电站除了站级通信总线采用IEC61850技术外,还应包括过程级的数字化,使用传统电流电压互感器的数字化变电站,只能算半数字化.传统互感器除存在CT饱合、CVT暂态特性等问题外,对于特高压系统而言还存在体积、价格、绝缘性能等方面面临的挑战.而基于光电效应的非传统互感器（Non Conventional Instrument Transformer,简称NCIT）则具有成本低、安全性高和精度高、测量范围广等优点,因而将成为解决传统问题的方法.IEC61850的颁布和基于数字输入的二次智能设备（Intelligent Electric Device,IED）的推出更为NCIT的使用扫清了道路.近几年的现场试验证明了基于NCIT、IEC61850-9-2的保护方案的稳定性、可靠性和可行性.

A complete digital substation technology should also comprise the digitalization of the process level, in addition to implementing IEC61850 at the station bus level. A digital substation adopting traditional CTs and VTs is just half digitalized. CT Saturation, CVT transient and so on are problems exist in conventional instrument transformer. UHV system brings more challenges such as size, cost, and insulation to conventional ones. On the other hand, Non Conventional Instrument Transformer （NCIT） has advantages say cost reduction, greater safety, high accuracy, wide dynamic range, and thus will be solution for existing problems. The release of IEC61850 and Intelligent Electric Device （IED） based on digital input smoothes away difficulties of application of NCIT. The reliability, stability and feasibility of protection scheme based on NCIT, IEC61850-9-2 has been proved by field test held in recent years.