Non-invasive Cable PD Testing

Partial Discharge is a not well understood phenomenon that can cause catastrophic failure of electrical assets.  It can exist at initial commissioning or occur only after decades of use.  Testing cables for partial discharge in the field can be divided into online and offline.  Traditionally offline methods require long outages, invasive techniques, and large, expensive test equipment, all of which limit its usefulness as a condition monitoring method.

Online cable partial discharge testing and monitoring has been increasingly deployed over the past 10 years.  This paper highlights the basics of online partial discharge testing in cables and covers the non-invasive online techniques available today.  Both periodic surveying and full- time monitoring are covered.  Case studies of successful detection of partial discharge in cables are presented.