Experimental investigation for DC filter capacitor that has operated for many years in HVDC transmission system

to explore their remainder predicts life. Three test processes are designed

the first is aging properties test for capacitors and its dielectric

the second is accelerated life test for elements groups

and the third is withstand voltage test for elements. The test results show that the capacitor properties have declined seriously and their dielectrics have been in aging state. According to the accelerated life test results

it is estimated that this type of capacitor is approaching its end of life. Due to that the capacitors have been running for more than 10 years

some of them had been failure

the quality and the running experience between samples are different

the discreteness of the capacitor’s dielectric properties is larger

it is more difficult to discover the influence of temperature on the capacitor’s lifetime

the research method needs to be improved also. The results of this study can be used for reference to the users and manufacturers of DC filter capacitors.