Partial discharge behaviour under AC and DC conditions including novel manufacture techniques for void-type dielectric samples

Student thesis: Doctoral Thesis

Abstract

The move from centralised electricity generation, near centres of demand, to distributed generation has brought justification for the use of high voltage direct current (HVDC) transmission techniques. One key application is the transmission of power from offshore wind farms, there is a breakeven distance where conventional high voltage alternating current (HVAC) transmission is less cost effective than HVDC transmission.The condition monitoring of HVDC transmission networks will be paramount to minimise any unnecessary system downtime. The primary method to monitor the condition of an insulation system is the measurement of partial discharge (PD). This thesis develops the understanding around sensor installation, sample behaviour under DC conditions and novel manufacture methods for void type dielectric samples.The first area of interest to this thesis was the development of a method to assess the effect of the electromagnetic field emissions from HVDC converter station on the behaviour of high frequency current transformers (HFCT). A range of sensors of different constructions were tested in a controlled electromagnetic field environment. The relative immunity of the sensors to the incident field was derived using the method.The second phase of this work investigated the behaviour of a range of dielectric samples under AC and DC conditions. Existing analysis techniques were explored based on recommendations in IEC 60270 and literature to date. The behaviour of a void type sample was explored further through the variation of test history such as; grounding period, DC polarity and AC/DC variation.The final section of research focused on the development of novel manufacturing techniques and the behaviour of void type samples under AC and DC conditions. The proposed techniques made use of two very different manufacturing approaches; 3D printing and subsurface laser etching (SSLE). In this study, 3D printing was found to be more successful in enabling void type PD behaviour. Initial explorations were made of AC/DC PD behaviour of multiple void samples and thermally aged samples.
Date of Award1 Jan 2017
LanguageEnglish
Awarding Institution
  • University Of Strathclyde
SponsorsEPSRC (Engineering and Physical Sciences Research Council)
SupervisorWah Hoon Siew (Supervisor) & (Supervisor)

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