A Limitation of On-line Partial Discharge Measurement in a Petrochemical Plant

A partial discharge (PD) measurement is one of the inspection techniques that has been widely adopted to monitor the insulation of electrical medium voltage apparatus nowadays. However, using a partial discharge tool is a limitation to users especially technicians or inspectors who take a responsibility to set-up tool and acquires the real-time data. This is not only about user's lack of competency but also a limited resolution of measurement tool which can affect directly during a result interpretation afterward. Therefore, the exact solution and established standard to solve an occurring phenomenon in a measured medium voltage cable, nonetheless, have not yet been completely clarified. The article is written to demonstrate an obstacle faced by a maintenance personnel showing the example of actual cases in an available tool and user's competency as these will impact an improper diagnosis in PD measurement. The tested object is an electrical medium voltage cable which is difficult to measure by the conventional method, then unconventional method is implemented instead. The problem that happened are the measurement through the shield of the cable, the synchronizing signal with PD signal, and the located position of the PD in multi-core current transformer.