Experimental analysis of EMC immunity for field installed intelligent equipment, of intelligent substation

With the construction of intelligent substation, it is a trend that the secondary intelligent devices are field installed. After field installation of intelligent devices, the electromagnetic environment in switch yard is much more serious than which in relay protection room. After the abnormal condition of the 100kV intelligent substation occurred, the EMC experiments are carried out and the structure of merging unit is improved. For quantitatively analyzing the strength of the disturbance signal, the electromagnetic disturbance signals are recorded when the switch operated. Besides, when another 500kV intelligent substation starts, the electromagnetic disturbance signals are also recorded. The amplitude and time-frequency characteristics of the electromagnetic disturbance signals are analyzed. Based on the results of EMC experiments and the amplitude and time-frequency characteristics of disturbance signals, this paper analyzes the applicability of EMC test standard used in China. And it is pointed out that the test standard is not enough to check the field installation secondary intelligent device. Finally, some suggestions to improving the EMC performance of field installation secondary intelligent devices are put forward.