F.J. Wester

Advanced partial discharge diagnostic of MV power cable system using oscillating wave test system

To obtain a sensitive picture of discharging faults in power cables the PD should be ignited, detected, and located at power frequencies that are comparable to operating conditions at 50 or 60 Hz. In this way, realistic magnitudes in [pC] and reproducible patterns of discharges in a power cable can be obtained. PD measurements during service as well as on-site continuous energizing at 50 (60) Hz of MV cables are not always economically realistic for on-site inspections. Different energizing methods have been introduced and employed during recent years. Therefore, based on the assumption that sensitive detection of critical PD sites occurs by a method mostly similar to 50 Hz energizing conditions, a method as introduced for on-site PD diagnosis of MV cables is discussed: oscillating wave test system (OWTS).

On-site testing and PD diagnosis of high voltage power cables

In addition to after-laying of new-installed high voltage (HV) power cables the use of on-site non-destructive on-site testing and diagnosis of service aged power cables is becoming an important issue to determine the actual condition of the cable systems and to determine the future performances. In this paper based on field experience an overview is presented on on-site testing and partial discharge diagnosis of HV power cables with regard to on-site testing methods: energizing, diagnostic aspects, possibilities and implications for new and service aged power cables.

Detection of Partial Discharges at Different AC Voltage Stresses in Power Cables

In this article, several fundamental aspects of PD detection at different voltage waveshapes on different types of defect are investigated.

Condition assessment of high voltage power cables

In this contribution based on experiences made in the Netherlands, for condition assessment of HV power cables systematic approach has been developed. Based on the assumption that there is not one dominant failure process in HV cable networks, PD in the cable insulation cannot be seen as the only messenger for failures: the complexity of cable systems in HV networks is often higher (e.g. oil-filled, gas-pressurized cable systems) therefore different approaches have been investigated and implemented in the last five years.

PD detection in power cables using oscillating wave test system

This paper discusses the results of partial discharge measurements in XLPE medium voltage power cables using oscillating test voltages. Based on laboratory and on-site tests the usefulness of this PD measuring technique for practical applications is presented. In particular, the sensitivity and the reproducibility of this new method as an after-laying test procedure are discussed.

PD knowledge rules for insulation condition assessment of distribution power cables

This paper discusses practical experiences in the Netherlands with insulation condition assessment of distribution power cable networks by partial discharge diagnosis and database support. In particular, practical steps are discussed in collecting, analysing and processing the diagnostic data for decision support of utility asset management.

Fundamental aspects of on-line PD measurements on distribution power cables

In this paper the fundamental aspects of online partial discharge detection on distribution power cables as a tool for insulation condition assessment are discussed. In particular, based on laboratory and field tests, the online PD diagnostics is presented to be a good PD detection diagnostic.

PD knowledge rules support for CBM of distribution power cables

It is known that condition based maintenance (CBM) can offer a support in meeting requirements of liberalization processes at power utilities. As a result, based on the information about the actual insulation condition of a cable link, the operation, the maintenance and the replacement can be optimally planned. This contribution discusses, based on advanced PD diagnostic at oscillating voltages, different evaluation methods to assess the insulation condition of cable systems. Based on field experiences, important CBM aspects such as knowledge about ageing processes and failure modes as well as methods to determine the interpretation and knowledge are discussed.

Transmission power cables PD detection at damped AC voltages

This contribution presents new method for on-site PD diagnosis on HV transmission power cables. To on-site energize and to ignite partial discharges in transmission power cables, damped AC voltages up to 250 kV are generated. As a result, sensitive partial discharges detection and PD site location is possible. The developed system as well as PD measurements are shown to demonstrate the principles of this on-site diagnosis on HV transmission cables.

PD inception conditions and PD pattern of defects in PILC

A new medium voltage paper-insulated lead cable (PILC) network represents a large investment, and it is from the economic point of view essential to extend the life time of the medium voltage power cables as much as possible. It is known that with increasing age, the number of faults will increase and the power supply quality might deteriorate. Important symptoms of this degradation process can be related to discharging local insulation imperfections or defects which may occur in particular cable sections or cable accessories: joints and terminations. The PILC section may consist of species of different insulation types and multiple defects may occur at the same time. As a result complex partial discharge (PD) pictures may be measured representing the PD information of all these particular elements. In this study we look at the typical PILC insulation related PD induced dielectric failure processes from the physical point of view.