Course Description

Partial Discharge (PD), as its name would suggest, is an electrical discharge that occurs across a portion of the insulation between two conducting electrodes, without completely bridging the gap. PD's are caused when there is a discontinuity in the insulation system and as a general 'rule-of-thumb' PD will occur in systems operating at voltages of 3000V and above (although it should be noted that PD can occur at lower voltages than this). Partial discharges can occur in voids in solid insulation (paper, polymer etc), along the interfaces of multi-layer solid insulation systems, in gas bubbles in liquid insulation or around an electrode in a gas (corona discharge). Partial Discharge activity can initiate under normal working conditions in high voltage equipment where the insulation condition has deteriorated with age, has been aged prematurely by thermal or electrical over-stressing or due to improper installation (this leads to 'infant mortality'). PD can often be observed with the commissioning of new equipment due to improper installation, poor design and/or workmanship (this is seen particularly in cable joints and terminations which are made-up on site). It is known that poor workmanship can lead to 'infant mortality' of MV/HV networks with a disproportionate percentage of insulation failures being observed within the first 1-3 years of service compared to the rest of the service life of the cables/plant

Course Objectives

·         To understand the basics of stator winding insulation systems and why they deteriorate

·         To understand basic PD theory

·         To understand how PD detection devices work

·         To interpret the test data collected and relate the data to specific failure mechanisms, to enable you to plan maintenance

Who Should Attend?

·         Engineers working in HV department, in transmission and distribution

·         Maintenance engineers working in HV equipments

·         Senior technicians working in HV equipments

Program Schedule

DAY 1

·         Introduction to Partial Discharge and Diagnostics for High Voltage Equipment

·         Equipment failure mechanisms

·         Conventional and unconventional test techniques

·         On-line and Off-line methods

·         How to test different items of plant

DAY 2

·         Deployment of PD Testing in Asset Management Programs

·         Ageing population problem

·         Focus plant replacements/avoid unplanned outage

·         Increasing failure rate or problem with a particular plant type

·         Troubleshooting and failure investigations

·         Safety (mostly with cable terminations & sealing ends/outdoor HV plant)

·         Quality Assurance

DAY 3

·         Partial Discharge Testing and Diagnostics for MV and HV Cables

·         Introduction to test methodologies

·         PD Location methods

·         Assessing criticality

·         Case studies

DAY 4

·         PD Testing and Diagnostics for MV Switchgear

·         Introduction to test methodologies

·         PD Location methods

·         Assessing criticality

·         Case studies

DAY 5

·         Partial Discharge Testing and Diagnostics for Motors and Generators

·         Introduction to Online PD Testing of HV Motors & Generators

·         Recognising Phase-Resolved PD (PRPD) Patterns

·         Assessing criticality

·         Case studies