大容量高压电动机变频器继电保护对策探讨

在火力发电厂中采用变频技术可以实现设备的节能降耗。随着机组容量的增大，电厂中的电动机容量和电压等级也相应提升，在运行中存在一些问题。介绍了变频技术的节能原理及在百万千瓦机组工程中的应用情况，针对采用变频器后大容量高压电动机高灵敏度继电保护的完善问题进行了深入探讨，分析了目前继保方案存在的问题，并提出了研发工频、变频运行自适应保护装置等解决措施的设想。

Application of Frequency Converters in Relay Protection of Large-capacity and High-voltage Electric Motors

Application of frequency conversion technology in thermal power plants can achieve energy saving and consumption reduction of equipment. With the increase of unit capacity, the capacity of electric motors and voltage levels of power plants have been upgraded accordingly, while some problems have emerged during the operation. This paper introduces the principle of energy-saving of the frequency conversion technology and its application in projects installed with million-kilowatt units. A study is conducted on improvement of relay protection of large-capacity and high-voltage electric motors with high sensitivity after adoption of frequency converters, and the problems with relay protection schemes are analyzed. In the end, some suggestions are proposed on developing an auto-adaptive relay protection system with both working frequency and variable frequency.