With rising global electricity demand and increasing penetration of intermittent renewable energy sources, monitoring and protection of power networks is increasingly important for transmission and distribution network operators. It is, therefore, desirable to increase the coverage of, and reduce the cost per unit of monitoring systems. Fibre optic based transducers present a low cost, multiplex-able alternative to conventional methods of current and voltage measurement for monitoring and protection of power networks, however, prior to adoption by industry, it is desirable to characterise and improve sensor accuracy as much as possible. This thesis presents an investigation of several factors affecting the accuracy of piezoelectric stack and fibre Bragg grating based low voltage sensors in particular, with a focus on piezoelectric behaviour in the immediate aftermath of a grid fault, with the aim of developing engineering solutions to maximise sensor accuracy. Fiber [sic] Bragg grating technology is introduced and applications are highlighted. Conventional and proposed voltage and current sensors are described and the advantages of fibre Bragg grating based voltage and current sensors elucidated. The phenomena of piezoelectric ageing, creep and fatigue are reviewed. The effects of piezoelectric degradation on the measurement accuracy of optical fibre and piezoelectric stack based low voltage transducers(LVTs) were experimentally investigated. An accelerated life test to determine the most fatigue resistant bonding method for connecting fibre Bragg gratings to the piezoelectric transducer is discussed. Finally, the proposed protection circuitry for the prototype LVT is revised, based on experimental and theoretical considerations.
|Date of Award||1 Sep 2017|
- University Of Strathclyde
|Sponsors||University of Strathclyde|
|Supervisor||Pawel Niewczas (Supervisor) & Graeme Burt (Supervisor)|