UHF Partial Discharge Detection and Localization: On-Site Experiences at 110-kV-Cable Terminations

The measurement of partial discharges (PD) has already proven itself for the use at cable systems. PD measurement is particularly relevant in the area of cable accessories, as both the cable joints and the cable terminations are the most frequent cause of faults within the cable system. Among other things, this can be traced back to assembly faults or improper work. Ultra-high Frequency (UHF) PD measurement is becoming more important in the field of cable terminations. This contribution shows how an on-site measurement can be performed on various 110-kV-cable terminations with a self-developed UHF system. The UHF-PD tests were carried out in two substations. In the first substation, the tests were performed under AC operating voltage on a total of six cable terminations. With the UHF system, both corona discharges and surface discharges could be reliably detected. In the second substation, the UHF PD test was performed in combination with a commissioning test with Damped AC-Test Voltage (DAC). During the commissioning test, PD activity was detected on phases L2 and L3, both in the area of the cable termination. The results of the UHF system confirm those of the conventional PD measurement performed in parallel.