主设备保护中功率方向元件的接线方式和内角整定研究

针对当前现场主设备保护中相间功率方向元件接线混乱的现状，利用对称分量法和相量图分析法 ，从方向保护作为线路后备和变压器后备2方面系统地分析了方向元件采用异侧各种电压时的接线方式和对应的内角整定。通过分析得出了作为2种后备时变压器高低压侧功率方向元件在同相位的异侧有无电源2种情况下满足继电保护要求的最佳接线方式和内角整定值。最后针对数字式保护的特点，采用与中、高压侧相间电压满足同相位关系的低压侧相间电压差作为方向元件的电压量的接线方式，提出了一种更好的、使内角整定计算更为方便的功率方向元件的接线方式。

Study on connection and interior angle setting of power directional element in main equipment protection

As the connection for power directional element in main equipment protection is in confusions,the connection and interior angle setting of power directional relay used as back up protections of both line and transformer are analyzed with symmetrical component method and vector diagram.The directional element selects another side voltages.The optimal connection and interior angle setting are given for the power directional elements at high and middle voltage sides.It meets the requirements of power system for protection under both conditions of the another side with and without power supply.A better connection for digital protection is also proposed,which takes the inter phase voltage as the input of the directional element at low voltage side and make interior angle setting easier.