Analysis of Variable Frequency Resonant Withstand Voltage Test for 220kV Long Cable On Site Testing

Du Sisi, Cai Ye, Wang Wei, Zhang Xuefeng
HIMALAYAL - SHANGHAI - CHINA    

Abstract: Newly-completed 220kV cable line in the eastern urban area of Jinan city is 7.97km and has large capacity. If we want to carry out withstand voltage test, power source capacity, maximum output total current, weight of needed test equipment must be minimized and easy to install. This is the first time that such high-voltage test has been conducted in Jinan. After comparing all available methods, serial variable frequency resonant withstand voltage test is adopted. Based on theoretical calculation and analysis, reasonable test scheme is put forward and implemented smoothly. Finally, we make discussions combing with test results. Practice has proved that resonant test system is workable and effective and is of important value for variable frequency resonant withstand voltage test for long power cable on site.

Keywords: power cable high voltage testing, power cable on-site testing

I . Introduction    
Conducting effective cable hand-over test on site can reduce the probability of breakdown to largest extent and ensure reliable and safe cable operation. However, the capacity of cable is great, especially long cable, traditional test methods cannot meet the requirement of field test. At present, There is a lack of long and high-voltage cable hand-over test in China.    
1) Super-low frequency (0.1Hz) withstand voltage test is mainly applicable to medium-low voltage XLP insulation cable withstand voltage test.    
2) Power frequency AC withstand voltage test needs large-capacity test equipment. The equipment weighs several tons and huge in size and difficult to assemble. This type of test cannot meet the requirement of field test.