Effect of booster shed on ceramic post insulator pollution flashover performance improvement

To prevent substation post insulator from pollution flashover, apart from PRTV (Permanent Room Temperature Vulcanized) coating on insulator surface, booster shed adoption is also a solution for operation maintenance. In this paper, ceramic post insulators installed with silicone rubber sheds in various configuration are tested by pollution flashover experiment, to find out the optimized configuration of booster sheds. Five test specimens are prepared for this work, including 25mm/kV ceramic insulator installed with 0, 2, 4, 6 silicone rubber booster sheds, contaminated with same pollution degree in solid layer method. As well, insulator coating with PRTV material is prepared in same way for comparison. Pollution flashover tests are performed following IEC/TS 60507. Meanwhile, arc shape variation synchronized with voltage and current change are record by high speed camera. In various configuration, flashover voltage, leakage current and arc development shape show significant characteristic separately. Results show that the booster sheds not only provide additional creepage distance, but also create an alternating hydrophobicity distribution on insulator surface, which is more efficient for pollution flashover performance improvement. Booster shed made of silicone rubber alternates hydrophobicity distribution along ceramic insulator. Accordingly it can enhance the pollution flashover voltage greatly.