Study on Electrical Aging Characteristics of Fiber Sheath Materials in Power Transformer Oil

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ORIGINAL ARTICLE

Study on Electrical Aging Characteristics of Fiber Sheath Materials in Power Transformer Oil Lu Sun1 · Xiaozhou Fan2 · Shuo Jiang2 · Bowen Wang2 · Yunpeng Liu2 · Shuguo Gao1 · Lingming Meng1 Received: 29 March 2018 / Revised: 2 July 2018 / Accepted: 7 September 2018 / Published online: 15 January 2019 © The Korean Institute of Electrical Engineers 2019

Abstract Optical fiber has great potential in the development of online monitoring for trans-formers. In this paper, the electrical aging test of fiber sheath material based on a gradual voltage-rising method was performed and the influence of thermal aging on electrical aging was determined. Compared to the oil-paper insulation performance of traditional transformers, it was found that ethylene tetrafluoroethylene (ETFE), polytetrafluoroethylene (PTFE) and Polyamide 12 (PA 12) were better than oil-paper. Statistical analysis of the ETFE material and oil-paper test data was conducted using double-parameter Weibull distribution. The inverse power and exponential functions were used to fit the experimental data and voltage tolerance coefficients of the ETFE material were obtained. Experimental results show the parameters of the ETFE model in the inverse power function and exponential function model are better than those of the oil paper insulation, and the sheathed fiber is ETFE that can be stably operated in the transformer. Keywords  Fiber sheath · Electrical aging · Lifetime model

1 Introduction Power transformers are essential equipment in power systems to maintain the safe operation of transformers for safe and reliable operations of power grids. Online monitoring of power transformers is a major link in the development of intelligent power grids [1–3]. Due to superior anti-interference and measurement performance, fiber sensors are a hot area for research and applications in online monitoring of power transformers. Fiber optics is capable of a wide range of measurements including physical quantities [4, 5], such as temperature, pressure, strain, vibration and ultrasound, and chemical quantities such as gas components and pH value. At present, fluorescence fiber sensors, fiber Bragg grating sensors and Farby–Perot (F–P) fiber sensors are used in power transformers, overhead transmission lines, submarine cables and other electric apparatuses [6–9]. The * Shuo Jiang [email protected] 1



Hebei Electric Power Research Institute, State Grid Corporation of China, Shijiazhuang, China



State Key Laboratory of New Energy and Electric Power Systems, North China Electric Power University, Baoding, China

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measurement performance of fiber sensors meets the requirement of online monitoring of power transformer and fiber optics made of fiberglass has excellent insulation properties, high mechanical strength gradually deteriorates [10], and the products of which may threaten the security and stability of transformers. Premature degradation may occur to the fiber sheath material and so studies focusing on the stability of fiber sheath materials in p