In the early days of protective relaying, it was recognized that communications between substations could improve relaying performance. Schemes such as power line telephony (1920s) and pilot wire relaying (1930s) evolved into digital time division multiplexers (TDMs) (invented in 1960s and used for power system communications in 1970s). TDM allowed audio teleprotection, audio-based relaying, SCADA, and telephony to share a single link …
Imagine this: A new hyper-scale data center is built in rural New Jersey. It has more than 100 25 KV cables. Six months into operation, a cable termination fails catastrophically, and the forensic investigation determines that termination workmanship was lacking. Partial discharge caused tracking, and the cable flashed over. But that’s not the nightmare scenario. The nightmare scenario is that the …
Partial discharge (PD) is a poorly understood phenomenon that can cause catastrophic failure of electrical assets. It can exist at initial commissioning or occur only after decades of use. The dictionary defines partial discharge as: a flashover of part of the insulation system due to a localized electric field greater than the dielectric withstand capability of that part where the …
Most of us started our electrical careers with fairly good knowledge about the practical aspects of our jobs. We understood voltage, current, power, resistance, etc. We mastered the more esoteric areas such as electrical fields and stress control and only revisited these topics if our day-to-day job required it. Partial discharge (PD) is one of those areas where we might …
Partial discharge (PD) testing is becoming common in U.S. industrial systems and is gaining acceptability in U.S. utilities. Testing in the form of periodic surveys can provide valuable insight into asset condition. Beyond periodic surveys, full-time system monitoring is the state of the art in PD detection, offering additional capabilities that: Warn of rapidly evolving PD situations that might go …