Distribution System Reliability Analysis using ETAP

International Journal of Advanced Research in Electrical and Electronics Engineering Volume: 2 Issue: 1 08-Mar-2014,ISSN_NO: 2321-4775 Distribution System Reliability Analysis using ETAP Prem Prakash1, Vivek Anand Verma2, R.C. Jha3 Asst. Professor, Dept. of EEE, BIT Mesra, RanchiIndia1 Student, Dept. of EEE, BIT Mesra, Ranchi, India2 Professor, Dept. of EEE, BIT Mesra, Ranchi, India3 pprakash@bitmesra.ac.in1, verma.vivekanand@live.in2, rcjha@bitmesra.ac.in3 ABSTRACT— With recent advents in technology, efficient utilization of resources is now a need for secure and reliable electrical power distribution system. For the concern of both customers and power utilities, reliability is a major issue for power distribution system. In this paper, reliability of distribution side is assessed using ETAP software with various scenarios viz. consideration of lateral distributor protection and passive failure rate of components and large impact of distributed generations. The improvement in reliability in various cases has been evaluated on the basis of various reliability indices such as load point indices and system indices. The variation of indices has been followed with various different cases. The usefulness of this work is analysis of reliability, security and efficient operation of electrical distribution system. The analysis is performed on Roy Billinton Test System (RBTS) using Electrical Transient Analyzer Program (ETAP). Keywords— reliability, etap, failure rate, distribution, indices, rbts 1, INTRODUCTION Radial Distribution systems are much simple and less costly. However they are more vulnerable to outages instead of meshed system. During outage normal operating conditions of distribution systems are disturbed and fail to supply loads. Despite the fact that distribution system outages have localized effects, statistics show that distribution system failures affect the system as much as 85% towards the unavailability of supply to a load as compared with failure of other parts of electric power system [1]. Forced or scheduled outages will cause momentary or sustained interruptions and reliability of distribution system worsens. Connections of various protection devices reduce the passive failure of components. Integration of distributed generations (DG) will add extra generation for the normal and captive power supply [2]. The placement of DG and protection devices will affect the reliability of system with respect to DG penetration [3]. Reliability assessment of power distribution networks and customers has been done in conjunction with micro-grid. While using some logical and matrix operations and some different methods it is evaluated in a different way [4-7]. The Paper is structured in five sections. Section 1 Describes about the requirement of this work and historical background of research. Section 2 briefs about the basic concepts of the indices, impact of DG. Section 3 leads to modeling of network in various scenarios. Section ISRJournals and Publications Page 24 International Journal of Advanced Research in Electrical and Electronics Engineering Volume: 2 Issue: 1 08-Mar-2014,ISSN_NO: 2321-4775 4 comprises the results and their comparison with base case values. Section 5 discusses the conclusion and possible future work. 2, BASIC CONCEPTS FOR RELIABILITY EVALUATION The basic concepts for reliability evaluation of the distribution side, integrated with distributed generation are classified as follows— 2.1 Reliability Indices Reliability Indices are the functions of various factors such as failure rate, repair time, switching time, etc. of various components. As factors are random in nature, reliability indices are also random in nature. Three primary indices average failure rate, average outage duration and average annual unavailability or annual outage time are fundamentally important, they do not always give a complete representation of system behavior and response. So customer oriented indices and load-oriented indices such as System Average Interruption Frequency Index (SAIFI), System Average Interruption Duration Index (SAIDI), Customer Average Interruption Frequency Index (CAIFI), Customer Average Interruption Duration Index (CAIDI), Average Service Availability (or Unavailability) Index (ASAI (or ASUI)), Average Energy Not Supplied (AENS) are used to evaluate the complete scenario of reliability of distribution system [1, 8-9]. 2.2 Impact of Distributed Generation on Reliability DGs are defined on different bases depending upon capacity, point of interconnection, etc. But summarizing all points it can be stated as-“DG are the electric power sources, connected to grid at distribution level voltages, serving a customer on-site or providing support to a distribution network” [10,11]. DG affects the power system positively in terms of voltage and reactive power support, losses-reduction, and enhancement of reliability by using complete available assets. While negative impact of DG on power system includes the voltage rise and fluctuation, frequency and voltage instability, etc. [12-14]. While deploying a DG on distribution side need a complete effect analysis for stand-alone and integrated operation. The proper utilization of DG in distribution side can minimize its negative impact by enhancing the positive ones [15]. Utilizing DG resources in proper manner the sustained interruption time can be reduced by using it as an alternate supply. All system and load point indices will be improved. This procedure performs the summary operation. The restoration capability of feeders can be improved using DG [16]. Various different conventional and other type of modeling of DG with distribution system is available [17-18]. 3, NETWORK MODELLING AND RELIABILITY EVALUATION RBTS, developed at University of Saskatchewan, Canada, is a Six-Bus Test System with 5 load buses, 2 generator buses [19-20]. The network modeled here in ETAP is Bus 2 of RBTS. The software tool used in these analyses is ETAP, which is a fully integrated AC and DC electrical power system analysis tool. The reliability analysis using ETAP provide distribution system reliability level for radial and looped systems with a very efficient algorithm [21]. ISRJournals and Publications Page 25 International Journal of Advanced Research in Electrical and Electronics Engineering Volume: 2 Issue: 1 08-Mar-2014,ISSN_NO: 2321-4775 For the purpose of reliability evaluation, impact of lateral distributor protection and passive failure rate and impact of DG on reliability of a complete Bus 2 of RBTS has been done. 3.1 Impact of Passive Failure Rate and Lateral Distributor Protection Passive failure is defined as a component failure mode that does not cause operation of protection breakers and does not have an impact on the remaining energized system [21]. While lateral distributor protection is required to isolate healthy part if there is any fault on lateral side otherwise it will lead to operation of main circuit breaker of that feeder. In this analysis Bus 2 of RBTS is selected with its own data [14]. Bus 2 is modeled in ETAP with and without lateral circuit breaker on every load point. Figure-1 shows the Bus 2 of RBTS and its ETAP modeling. Figure.1 ETAP Modeling of Bus 2 of RBTS 3.2 Impact of DG on Reliability With consideration of fully reliable generation and transmission units bus 2 of RBTS is modeled in ETAP (shown in figure-1). A wind Turbine Generator (WTG) is used as DG at different locations so that the variation in system reliability indices can be recognized with variation of distances from feeder. All the active and passive failure rates of components are considered here as per RBTS data [14, 15]. The Data for WTG is provided in table-1: Type of Unit Failure Rate Repair Time Switching Time 1 MW WTG 2 f/yr 80 hr 1 hr Table.1 Reliability Parameters of WTG used ISRJournals and Publications Page 26 International Journal of Advanced Research in Electrical and Electronics Engineering Volume: 2 Issue: 1 08-Mar-2014,ISSN_NO: 2321-4775 The WTG is integrated with the system described above at various points, shown in figure1 and various reliability indices are obtained for all points. 4, RESULTS The results obtained as shown in table-2, clearly indicates that the indices of system (i.e. Bus 2 of RBTS) with lateral protection and passive failure rate are a bit higher than some values but still it is more useful because this case is more near to real-world problem. With Passive Failure Rate Without Passive Failure Rate Without Without With Lateral With Lateral Lateral Lateral Protection Protection Protection Protection 0.4264 1.1435 0.2733 1.0096 SAIFI 3.0128 6.5696 2.4003 4.0916 SAIDI 7.066 5.745 8.784 4.053 CAIDI 0.9997 0.9993 0.9997 0.9995 ASAI 0.00034 0.00075 0.00027 0.00047 ASUI Table.2 Comparison of Reliability Indices for Bus 2 of RBTS RELIABILITY INDICES With integration of DG at different locations the reliability of system improves. But it is dependent on the location at which the WTG is coupled. Point A is farthest more from 11 bus feeder i.e. 2.9 km, while point E is at minimum distance from 11 KV feeder, i.e. 0.75 km. While the distances of points B, C, D, F from 11kv feeder bus are 2.3, 2.15, 2.25, 1.35 km. respectively. It is clear from the table-3 that indices values are increasing as we come near to the feeder i.e. from point A to point F, as distance from feeder decrease and load supplied is also decreasing. Thus from these six locations, best location is found as point A at which system is most reliable. Base With DG connected case RELIABILITY (without At At At At At At INDICES any point A point B Point D Point C Point F Point E DG) 3.0128 2.3511 2.3546 2.4080 2.4640 2.6280 2.5372 SAIDI 0.4264 0.3100 0.3108 0.3227 0.3367 0.3762 0.3534 SAIFI 7.066 7.585 7.577 7.461 7.319 6.985 7.180 CAIDI 0.9997 0.9997 0.9997 0.9997 0.9997 0.9997 0.9997 ASAI 0.00034 0.00027 0.00027 0.00027 0.00028 0.00030 0.00029 ASUI 0.0193 0.0151 0.0153 0.0154 0.0157 0.0164 0.0166 AENS Table.3 Comparison of Indices with WTG integration with Bus 2 of RBTS V. CONCLUSION AND FUTURE WORK In this paper, RBTS has been modeled in ETAP. From reliability analysis in ETAP, we find that reliability improves after integration of DGs. The indices value depends upon the lateral protection and passive failure rate as shown in table-2. Considering all possibilities in that case the indices with lateral protection and with passive failure rate are found to be more ISRJournals and Publications Page 27 International Journal of Advanced Research in Electrical and Electronics Engineering Volume: 2 Issue: 1 08-Mar-2014,ISSN_NO: 2321-4775 useful in further analysis. Results show that, the DG impact on reliability is most when it is placed farthest from feeder bus (i.e. point A in figure-1). The indices value is minimum at these conditions. While the variation of indices also depends upon the load they are feeding. This can be concluded from values of indices when DG is connected to point D and point F. Further reliability-worth assessment and optimized utilization of assets can be done. The effect of collaborated use of renewable sources with their power output pattern and the loadpattern of distribution side can be analyzed. REFERENCES [1]. [2]. [3]. [4]. [5]. [6]. [7]. [8]. [9]. [10]. [11]. [12]. [13]. [14]. [15]. R. Billinton and R.N. Allan, Reliability evaluation of power systems, 2nd edition, Plenum Press, New York, 1996. G.T.Heydt, The next generation of power distribution systems, IEEE Trans. Smart Grid, vol. 1, no. 3, pp. 225–235, Dec. 2010 M. Al-Muhaini, G.T.Heydt, Evaluating Future Power Distribution System Reliability Including Distributed Generation, IEEE Transactions on Power Delivery, 2013. I. S. Bae and J. O. Kim, Reliability evaluation of customers in a microgrid, IEEE Trans. Power Syst., vol. 23, pp. 1416–1422, 2008. S. Kennedy, Reliability evaluation of islanded microgrids with stochastic distributed generation, in Proc. IEEE Power Energy Soc. Gen. Meeting, Canada, pp. 1–8. , Jul. 2009. D. Midence, S. Rivera, and A. Vargas, Reliability assessment in power distribution networks by logical and matrix operations, in Proc. IEEE/PES Transmission and Distribution Conf. Expo. Latin America, pp. 1–6, 2008. M. Al-Muhaini, G. T. Heydt, A Novel Method for Evaluating Future Power Distribution System Reliability, IEEE Transactions On Power Systems, Vol. 28, No. 3, August 2013. R. Billinton and R.N. Allan, Reliability Evaluation of Engineering Systems, 2nd edition, Plenum Press, New York, 1992. R.E. Brown, Electrical power distribution reliability, 2002. T. Ackermann, G. Andersson, L. S.oder, Distributed generation: a definition, Electric Power Systems Research 57, pp. 195–204, 2001. Chambers, A., Distributed Generation:A Nontechnical Guide, PennWell, Tulsa, Oklahoma, p. 283, 2001. Philip P. Barker, Robert W. de Mello, Determining the impact of distributed generation on power systems: part 1 – radial distributed systems, IEEE Power Engineering Society Summer Meeting, 2000, vol. 3:1645-1656, 2000. T.E. McDermott, R.C. Dugan, Distributed generation impact on reliability and power quality indices, Rural Electric Power Conference, 2002 IEEE, vol., no., pp.D3-D3_7, 2002. I. Hernando-Gil, I-sorin Ilie , J.L.Acosta and Sasa Z. Djokic , Impact of DG and Energy Storage on Distribution Network Reliability : A comparative Analysis,2nd IEEE energycon conference & exhibition , 2012 R. E. Brown and L. A. Freeman, Analyzing the reliability impact of distributed generation, in Proc. IEEE Summer Meeting, Jul. 2001, pp. 1013–1018. ISRJournals and Publications Page 28 International Journal of Advanced Research in Electrical and Electronics Engineering Volume: 2 Issue: 1 08-Mar-2014,ISSN_NO: 2321-4775 [16]. [17]. [18]. [19]. [20]. [21]. M. Hlatshwayo , S. Chowdhury, S.P. Chowdhury, K.O. Awodele, Impacts of DG Penetration in the Reliability of Distribution Systems, International conference on power system technology,IEEE, 2010. A.A.Chowdhury, S.Kumar Agarwal, D.O. Koval, Reliability modeling of distributed generation in conventional distribution systems planning and analysis, IEEE Trans. Industry Applications, vol. 39, pp. 1493-1498, Oct. 2003. M. Al-Muhaini, G. T. Heydt, and A. Huynh, The reliability of power distribution systems as calculated using system theoretic concepts, IEEE Power Energy Soc. Gen. Meeting, Minneapolis, MN, Jul. 2010. R.N. Allan, R. Billinton,I.Sjarief, L. Goel, K.S. So, A Reliability Test System for Educational Purposes-Basic Distribution System Data and Results,IEEE transactions on power systems, Vol.6, No.2, 1991. R. Billinton, S. Jonavithula, Atest sytem for teaching overall power system reliability assessment, IEEE transaction on power systems, 1996. ETAP, http://www.etap.com/. BIOGRAPHY Rakesh Chandra Jha received his B.E. degree from BIT-Sindri, Jharkhand, India, M.E. and Ph.D. degree from BIT-Mesra, Ranchi, India. Currently, he is Professor in Electrical & Electronics Engineering Department at Birla Institute of Technology, Mesra, Ranchi, India. His research interests are power system stability. Prem Prakash received his B.E. degree from NIT-Kurukshetra, Haryana,India, M.E. degree in High Voltage Engineering from IISC, Bengaluru, India. , pursuing Ph.D. from EEE department, BIT-Mesra, Ranchi, India. Currently, he is assistant Professor in Electrical & Electronics Engineering Department at Birla Institute of Technology, Mesra, Ranchi, India. His research interests are electric power distribution system, renewable sources, smart grid and high voltage engineering. Vivek Anand Verma received his B. Tech degree from VBSPU, Jaunpur, India in 2012. Currently he is pursuing M.E in Power System in Electrical & Electronics Department at Birla Institute of Technology-Mesra, Ranchi, India. His research interests are reliability engineering and electrical power distribution systems. ISRJournals and Publications Powered by TCPDF (www.tcpdf.org) Page 29