# Introduction eliability is concerned with the system capability of survival. In the past twenty years, customer expectations have been increasing in response to evolving new technologies. As part of these evolution, they are demanding from their suppliers: a) Constant improvement in the quality of the products. b) Minimization of the cost. c) Be flexible and responsive to the customers' requirement. Previously the criteria and techniques used for reliability assessment were all deterministically based. The essential weakness was that they did not account for the probabilistic or stochastic nature of system behaviour and component failures. However, the Author : Assistant Professor, EEE, SETGOI, Durgapur, West Bengal. E-mail : tana_lakshman@yahoo.co.in probability theory alone cannot predict either the reliability or safety of the equipment. It is only a tool available to the engineer in order to transform his knowledge of the system for the prediction of future behaviour of the system. # II. # Objectives So basic Objective is to calculate EENS value of loads connected to the system with Skm's PTW 6.5 . # III. # Methods The RBTS is a 6 bus system composed of two generator buses, 5 load buses, 9 transmission lines and 11 generating units. The total installed capacity is 240 MW and the system peak load is 185 MW. ear 2012 Y Products with higher quality, low initial cost, improved customer support and products those are easy and inexpensive to maintain. For a supplier to survive, succeed and be profitable in today's market, it must do the following: a) Rbts Data Table 1 : Bus Data for RBTS system b) Generation Data Table 2 : Generator data for RBTS system c) Rbts-Transmission Data The relevant reliability data for the nine 110 kV lines in Fig. 1 in terms of the permanent and transient failure rates and the permanent outage repair times are given in [11]. The outage duration of a transient outage is considered to be less than one minute. Outages of substation components which are not switched as a part of a line are not included in the line data. A nonrepairable chance failure refers to a random basin curve. Obviously, it corresponds to a constant failure rate and therefore can be modeled using an exponential distribution. fatal failure in the normal operating stage of the life. A nonrepairable wear out failure refers to a random fatal failure in the normal operating stage of the life basin curve. Obviously, it corresponds to a increasing failure rate and therefore can be modeled using an exponential distribution. ? ? ? )))) 1 t ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ( ? ? Time(hr) ? =0.5 ? =1.0 ? =1. # Results & Discussion From the Reliabilty analysis we get the life basin curve by plotting EENS value with time for ? =0.5, ? =1.0, ? =1.5. # V. Discussion And Conclusions to calculate reliability of composite system by calculating probability and frequency of failure of system under different conditions. This area of composite power system reliability evaluation is least developed and also one of the most complicated but in view of environmental, ecological, societal and economic constraints faced by most of power utilities, this area is developing and getting attention in international market. 1![Figure 1 : Single Line Diagram of RBTS system](image-2.png "Figure 1 :") 25![Figure 2 : One line diagram of RBTS system in SKM's PTW 6.5 for aging of Tx's f) Case 3a : Non repairable aging failure for =0.5A nonrepairable aging failure for =0.5 refers to a random fatal failure in the normal operating stage of the life basin curve. Obviously, it corresponds to a decreasing failure rate and therefore can be modeled using an exponential distribution.](image-3.png "Figure 2 : 5 A") ![/year) Value for Aging of Tx's for ? =0.](image-4.png "") 3Reliability Evaluation of Composite System with Aging FailuireF © 2012 Global Journals Inc. (US) 4 5: Load Reliability Data 6e) Aging Repair Rate The Value ofis calculated from the followingRepair Rate Calculation Formula =formula: = 1000000/(Failure Rate*EXP(GAMMALN(1+1/Shape ParameterWhere = Scale parameter = Shape parameter 75 8=0.5 9??Time(hr)Reliability Analysis EENS(Kwh/year) Value for Aging of Tx's for ? =1L2L3L4L5L608855688.94 820.60 2065266.86 81867494.3995477314.3918855688.94 820.60 2065266.86 81867494.3995477314.3958855688.94 820.60 2065266.86 81867494.3995477314.39108855688.94 820.60 2065266.86 81867494.3995477314.39158855688.94 820.60 2065266.86 81867494.3995477314.39208855688.94 820.60 2065266.86 81867494.3995477314.39258855688.94 820.60 2065266.86 81867494.3995477314.39308855688.94 820.60 2065266.86 81867494.3995477314.39358855688.94 820.60 2065266.86 81867494.3995477314.39408855688.94 820.60 2065266.86 81867494.3995477314.39 10=1.5 * Application of Reliability Analysis In Expansion Of Transmission System AKMehta DipakRay KesabBhattacharya May, 2009 Academy Publisher 1 * Application of Reliability Analysis In Expansion Of Transmission System AKMehta DipakRay KesabBhattacharya May, 2009 Academy Publisher 1 * Maintenance Management In Power Systems-Matti Lehtonen July 2007 Helsinki Univeristy Of Technology Kungliga Tekniska Hogs kolan * Verification Of The Transmission System Model Rbts Using Monte Carlo Simulation Methods-KTH, The Royal Institute Of Technology School Of Electrical Engineering 2008 * Power System Reliabilityassessment Using The Weibull-Markov Model-Jasper Van Casteren 2001 Chalmers University Of Technology * Optimization And Implementation Of Maintenance Schedules Of Power-Yang Fan 2011 National University Of Singapore * Incorporating Station Related Maintenance And Aging Outages In Composite System Reliability Evaluation-Hua Yang 2005 University Of Saskatchewan * Bulk System Reliability Evaluation In A Deregulated Power Industry-Yifeng Li 2003 University Of Saskatchewan * Incorporating Substation And Switching Station Related Outages In Composite System Reliability Evaluation-Rajesh 2003 U Nighot-University Of Saskatchewan * Test Systems For Reliability And Adequacy Assessment Of Electric Power Systems-Roy Billinton 2010 Dange Huang University Of Saskatchewan * Reliability Analysis And Economic Equipment Replacement Appraisal For Substation And Sub * Development of Test System for Distribution System Reliability Analysis, Integration of Electric Vehicl into the Distribution System-Pramod Bangalore 2011 Sweden Chalmers University Of Technology Goteborg * Reliability Assessment of Complex Power Systems and the Use of NEPLAN Tool-Shima Mousavi Gargari-Royal Institute of Technology, KTH 2006 * Adequacy Assessment Of Composite Generation And Transmission Systems Incorporating Wind Energy Conversion Systems 2010 Yi Gao-University Of Saskatchewan