Partial Discharge (PD) monitoring technology is a tool often used for identifying High Voltage (HV) cable sections that are at risk of failing in the near future. There are two distinct methods of testing for PD:

• Long term monitoring to identify the degradation of the cable which signals the increase in risk of failure

• PD mapping which pinpoints the location of any discharge along the route of the cable.

Developing the technology to apply these methods gives a network operator the evidence required to assist in targeting investment / cable replacement, with a net improvement in network performance. This project will develop a portable PD monitoring product that can be moved around the network, as tool in the prioritisation in cable replacement.

Objectives

This project will develop partial discharge monitoring hardware which will initially be tested on the SP 11kV network with the following aims:

• To develop a suitable portable monitoring solution with the ability to identify any cable sections which are emitting a level of discharge, which could lead to faults in the short term. The portable monitor will allow SPEN to test for a period of a few minutes to many weeks.

• Following initial testing in 10 primary substations, partial discharge mapping of those cable sections, which are registering the highest level of discharge, will be undertaken.

• Based on the PD maps obtained, any areas of concentrated PD activity, which are identified as critical, will be subject to review and selected cable sections will be replaced. The cable/joints removed will then be tested to validate PD test results.

It is planned that the test results will be collated in a database, which, in conjunction with results from the testing carried out by other GB DNOs, will allow for advancements in the knowledge rules for future PD testing technology.