华能玉环电厂自2007年4台机组相继投产以来，在GE发变组保护二次回路接线设计及GE发变组程序逻辑设置方面存在较多问题。对发变组保护启动厂用电快切、线路断面零功率切机、发电机过激磁保护二次回路接线及逻辑设计存在的问题进行分析和改进，使发变组保护功能更加完善，有力地保证了电力系统的安全生产。

There are many problems in the secondary wiring and logic design of GE generator-transformer unit protection since the four units successively putting into operation in Huaneng Yuhuan Power Plant. It is analyzed and improved about the generator-transformer unit protection, such as starting fast cut back of auxiliary power, zero-power triping of the line section, overexcitation protection of generator, secondary circuit wiring and logic design. It is shown that the protection functions are more perfect, effectively ensuring the safety of power system.