Investigation of transient and safety issues in gas insulated systems
National Grid Electricity Transmission
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Network Innovation Allowance
The R&D scope of work of this project will focus on a number of key aspects of GIS with emphasis on switching operations, in particular disconnector switching. The investigations will involve the following deliverables:
- Extensive gathering of existing knowledge from published literature regarding transient voltages for GIS switching,
- Study of GIS components, and the development of physical models to determine electric field distribution and circuits models of GIS components. and connected external circuit of air busbars and overhead lines,
- Simulation of earthing systems at GIS sites and establish rigorous mitigation techniques to improve safety,
- Develop measurement techniques to improve quantification of generated surges and potentials at GIS during switching
- Establish solutions to mitigate fast surges and rise of earth potential.
This research and development programme aims to achieve the following main objectives:
- Completion of an extensive review of available literature on state of the art of GIS discharge phenomena and earthing approaches.
- Develop suitable models of the GIS components and system to determine electric field and fast transient surge levels. Furthermore, develop procedures to reduce the magnitude and other effects of such surges.
- Develop models of the earthing system to allow accurate determination of rise of earth potentials, and develop mitigation techniques to ensure safety of GIS earthing system.
- Develop measurement techniques to allow comparison with modelling, improve understanding and allow future monitoring of the above phenomena in GIS.
- Develop mitigation measures for fast surges and rise of earth potential.
The delivery of a successful innovation project is reliant on a number of deliverables to be achieved at the end of the project period. Comprising of the conclusion of a state-of-art review; provision of parametric modelling of switching operations in GIS; a quantification of the earth potential rises in GIS and the production of possible mitigation measures with recommendations; and the validation and verification of theoretical conclusions of the measurement techniques.