Trends in Applied Sciences Research1819-35792151-7908Science International10.3923/tasr.2012.813.828AlesaadiAlireza GhaediAmir GhaffariAboozar ParvinVahid 102012710Unexpected failures can be prevented in the power system using online condition monitoring of the related apparatus. In high voltage equipments, such as cross linked poly ethylene (XLPE) cables, power transformers, medium voltage switchgears and rotating machines, many of the reported outages arise from insulation failures and deteriorations. Thus, online monitoring of quantities that originate from insulation failures are useful for on time fault recognition and preventive operation performance. When the strength of insulations is decreased, the Partial Discharge (PD) signals occur in primary stages. The extension of such PDs can result an insulation breakdown. As a result, PD signals detection can be used for insulation monitoring of power system equipments. Online PD detection of the power system apparatus is disturbed by the environmental noises which are difficult to be removed from the PD signals. In this study, a new method based on the Bhattacharyya distance, is introduced and used for de-noising of PD signals in power transformers online condition monitoring.]]>Boggs, S.A.,199063339Boggs, S. and J. Densley,2000161318Dong, X., D. Zhu, C. Wang, K. Tan and Y. Liu,19996803813Donoho, D.L. and I.M. Johnstone,199481425455Ghaffarian, M., M. Vakilian, V. Parvin and A. Ghaedi,20082008pp: 16Di Lorenzo del Casale, M., R. Schifani and J.T. Holboll,20007133140Lundgaard, L.E.,199282531Mak, B. and E. Barnard,19961996Ming, Y. and S. Birlasekaran,20022002pp: 913Moore, P.J., I.E. Portugues and I.A. Glover,200621528530Nattrass, D.A.,198841023Niknazar, M., S.R. Mousavi, B.V. Vahdat, M.B. Shamsollahi and M. Sayyah,20102010pp: 15Satish, L. and B. Nazneen,200310354367Stone, G.C.,19917919Wang, X., D. Zhu and F. Li,20012001pp: 111114Zhou, L., W. Li and Z. Chen,20052005pp: 15Zhang, H., T.R. Blackburn, B.T. Phung and D. Sen,200714314Kreuger, F.H.,1964