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Abstract: operational reliability evaluation theory reflects real-time reliability level of power system. The component failure rate varies with operating conditions. The impact of real-time operating conditions such as ambient temperature and transformer MVA (megavolt-ampere) loading on transformer insulation life is studied in this paper. The formula of transformer failure rate based on the winding hottest-spot temperature (HST) is given. Thus the real-time reliability model of transformer based on operating conditions is presented. The work is illustrated using the 1979 IEEE Reliability Test System. The changes of operating conditions are simulated by using hourly load curve and temperature curve, so the curves of real-time reliability indices are obtained by using operational reliability evaluation.

[1] Billinton, R., 1969. Composite system reliability evaluation. IEEE Trans. on PAS, 88(1):276-278.

[2] Billinton, R., Li, W.Y., 1994. Reliability Assessment of Electric Power Systems Using Monte Carlo Methods. Plenum Press, New York and London.

[3] Billinton, R., Allan, R.N., 1996. Reliability Evaluation of Power Systems (2nd Ed.). Plenum Press, New York and London.

[4] Cheng, L., Sun, Y.Z., Zheng, W.Q., 2004. Large-scale composite generation and transmission system adequacy evaluation. Automation of Electric Power Systems, 28(11):75-78.

[5] Cheng, L., He, J., Sun, Y.Z., 2006. Impact of transmission line’s real-time reliability model parameter upon power system operational reliability evaluation. Power System Technology, 30(13):8-13.

[6] Fu, W.H., James, D.M., Vittal, V., 2001. Risk assessment for transformer loading. IEEE Trans. on Power Systems, 16(3):346-353.

[7] Guo, Y.J., 2001. New methodology for lifetime evaluation of medium and small sized power transformer. Automation of Electric Power Systems, 25(21):38-41.

[8] Guo, Y.J., 2003. Power System Reliability Analysis. Tsinghua University Press, Beijing.

[9] He, J., Cheng, L., Sun, Y.Z., 2006. Analysis of Components’ Reliability Modeling Based on Real-time Operating Conditions of Power Systems. 2006 International Conference on Power System Technology, CQ.

[10] IEEE/ANSI C57.115, 1991. IEEE Guide for Loading Mineral-Oil-Immersed Power Transformers Rated in Excess of 100 MVA.

[11] IEEE/ANSI C57.91, 1981. IEEE Guide for Loading Mineral-Oil-Immersed Overhead and Pad-Mounted Distribution Transformers Rated at 500 KVA and Less with 55° or 65° Average Winding Rise.

[12] IEEE/ANSI C57.91, 1995. IEEE Guide for Loading Mineral-Oil-Immersed Transformers.

[13] IEEE/ANSI C57.91-1995/Cor 1, 2002. IEEE Guide for Loading Mineral-Oil-Immersed Transformers.

[14] IEEE/ANSI C57.92, 1981. IEEE Guide for Loading Mineral-Oil-Immersed Power Transformers up to and Including 100 MVA with 55° or 65° Average Winding Rise.

[15] Muthanna, K.T., Sarkar, A., Das, K., Waldner, K., 2006. Transformer insulation life assessment. IEEE Trans. on Power Delivery, 21(1):150-156.

[16] Reliability Test System Task Force, 1979. IEEE reliability test system. IEEE Trans. on PAS, 96(6):2047-2054.

[17] Sun, Y.Z., Cheng, L., Liu, H.T., 2005. Power system operational reliability evaluation based on real-time operating state. Power System Technology, 29(15):6-12.

[18] Swift, G.W., Zocholl, S.E., Bajpai, M., Burger, J.F., Castro, C.H., Chano, S.R., Cobelo, F., de Sa, P., Fennell, E.C., Gilbert, J.G., et al., 2001. Adaptive Transformer Thermal Overload Protection. IEEE Trans. on Power Delivery, 16(4):516-521.

[20] Wong, C.C., 1994. Substation power-transformer-loading analysis and computer simulations of load ability under realistic operating conditions. IEE Proceedings-Generation Transmission and Distribution, 141(5):413-421.

[21] Working Group 09 of Study Committee 12, 1990. Direct measurement of hot-spot temperature of transformers. CIGRE Electra, 129:48-51.

[22] Zhao, Y., Zhou, J.Q., Liu, Y., 2003. Reliability evaluation of composite generation and transmission system using Monte-Carlo simulation and parallel processing. Electric Power, 36(11):19-23.

[23] Zhao, Y., Zhou, N.C., Xie, K.G., Kuang, J., 2005. Sensitivity analysis on reliability assessment of bulk power system. Power System Technology, 29(24):25-30.

[24] Zhou, X.X., 2000. China Electric Power Encyclopedia. In: Zhou, X.X. (Ed.), Power System (2nd Ed.). China Electric Power Press, Beijing (in Chinese).