Partial Discharge in HVDC Cables

Completed

Other Power and Storage Technologies(Electricity transmission and distribution)

Applied Research and Development

ENGINEERING AND TECHNOLOGY (Electrical and Electronic Engineering)

Not Cross-cutting

Project Contact
Scottish and Southern Energy plc

Network Innovation Allowance

Ofgem

01 August 2018

01 February 2019

ENA months

£50,000

Power

Scotland

Network Innovation Allowance

Project Contact, Scottish and Southern Energy plc

This project proposes a technical method delivered through PhD studies. Knowledge pertinent to partial discharge inception voltage, magnitude and frequency of discharges, pulse characteristics, and frequency domain profile will be established by applying positive and negative DC stresses to polymer samples. AC stresses will also be recorded for reference.The samples to be tested are:1. Spherical voids in epoxy resina. 2 void sampleb. 3 void samplec. 4 void sampled. 5 void sample2. Cylindrical voids in low-density polyethylene (LDPE) and polypropylene (PP) filmsa. Single void samplesb. 2 void samples (voids in parallel)c. 2 void samples (voids in series)3. Cylindrical void in cross-linked polyethylene (XLPE) Cablea. Single voidThe above knowledge will be captured under laboratory conditions using commercial equipment including: Doble PDS200, LeCroy Waverunner 104Xi, Lemke LDIC LDS-6, and HVPD high-frequency current transformer (HFCT). Analysis is performed using Mathworks Matlab and Microsoft Excel.Detection of the above will be attempted at longer distances, by the use of longer cables between the HFCT and measurement devices to investigate the attenuation of these signals. The scope of the project is limited to laboratory experimentation and does not include on-site testing, although cables will be procured from on-site. The project aims to better facilitate the detection of PD under HVDC conditions but does not involve designing a new monitoring method. To determine1. Partial discharge inception voltages, magnitude and frequency of discharges, pulse characteristics, and frequency domain profiles of the samples mentioned above2. To investigate and consider technologies for the detection of partial discharges in longer length (tens of kilometres) HVDC cables by investigating the attenuation of signals in both the time and frequency domains

Partial discharge (PD) is the breakdown of a small part of insulation on equipment that is under high voltage (HV) stress. It is one of the major causes of catastrophic failures in HV equipment. PD mechanisms in HV Alternating Current (AC) systems are well understood and there is a growing body of knowledge around effective detection, monitoring and mitigation techniques under these conditions. However, there is a lack of knowledge and experience in the industry relating to PD under High Voltage Direct Current (HVDC) conditions. SSEN is investing significantly in HVDC cables, a trend replicated by the rest of the GB industry where there is proliferation of interconnectors and connections to offshore renewable sources of energy. To better prepare for the growth in use of HVDC, there is recognition for the imperative to know more about the mechanisms and characteristics of PD under these conditions.

14/12/22