Research on the Equivalent Circuit Modeling of Oil-Paper Insulation of Transformer by Analyzing the Dielectric Spectra

Abstract:

To assess the oil-paper insulation of transformer, it is necessary to establish the equivalent circuit for it regardless of using the time domain methods or frequency domain methods. Based on the principle of dielectric polarization, the extended Debye model is always adopted for the equivalent circuit of oil-paper insulation in transformer in most cases; however, it is usually difficult to determine the number of relaxation mechanisms in the model. This paper presents a method to determine it by the time domain dielectric spectra, namely, conduct differential operation for the depolarizing current of transformer’s oil-paper insulation to obtain the time domain dielectric spectra, and the number of spectrum peaks is equal to that of relaxation mechanisms. Thereby, the extended Debye model of the equivalent circuit of the oil-paper insulation of transformer can be built. This paper describes the analytical procedures of the time domain dielectric spectra method in detail and presents examples to validate its feasibility and rationality in determining the equivalent circuit model of transformer’s oil-paper insulation.

• Periodical: Applied Mechanics and Materials (Volumes 260-261)
• Pages: 408-413
• DOI: https://doi.org/10.4028/www.scientific.net/AMM.260-261.408
• Online since: December 2012
• Authors: Yong Qing Liu, Jin Ding Cai, Yan Xue Guo
• Keywords: Equivalent Circuit, Oil-Paper Insulation, Power Transformer, Time Domain Dielectric Spectra

References

[1] Zhang Tao, Cai Jinding. Parameter identification of the medium response circuit of Oil-paper insulated transformer [J]. New Technology of Electrical Engineering and Energy, 2010, 29 (4): 35-39.

[2] Roongroj Ch., N. Pattanadech, P. Praisuwanna. Equivalent Circuit Approximation of Transformer Insulation by Using PDC Measurement[N]. Proceedings of ECTI-CON, 2008: 925-928.

DOI: 10.1109/ecticon.2008.4600582

[3] Shayegani A. A., O. Hassan, H: Borsi. PDC Measurement Evaluation on Oil-Pressboard Samples[R]. International Conference on Solid Dielerrrics, 2004: 5-9.

DOI: 10.1109/icsd.2004.1350287

[4] Li Jingde, Cao Wanqiang, Li Xiangqian. Time-domain Dielectric Spectrum and Its Application[N]. Physics, 1996, 45 (7) : 1225-1230. ).

[5] Li Jingde, Zheng Feng, Cao Wanqiang et al. Slow polarization dielectric spectrum of the organic liquid [N] Chimica Sinica, 1997, 55: 644-649.

[6] Yang Qiping, Ci Wude, Lan Zhida. Aging evaluation technology of the transformer insulation[J]. Transformers, 2006, 42 (5) : 1-5.

[7] Zhang Tao. Diagnosis of the oil-paper insulation state of the transformer based on reply voltage characteristic[D]. Fuzhou: Electrical Engineering and Automation Institute of Fuzhou University, 2010: 47 -50.