Use of Computerized Web-Based Information System For Determining Losses in 15-6.6 KV Feeders in Traditional Electrical Network Managemment: Case Study Goma Distribution Electrical Network
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(IJCSIS) International Journal of Computer Science and Information Security, Vol. 8, No. 9, 2010 Use of Computerized Web-Based Information System For Determining Losses in 15-6.6 KV Feeders in Traditional Electrical Network Managemment: Case Study Goma Distribution Electrical Network Ezekiel U. Okike Bakunzi G. Joseph Department of Computer Science School of Computer Studies, University of Ibadan Kampala International University Ibadan, Nigeria Kampala, Uganda firstname.lastname@example.org Abstract— Electrical energy plays very vital role in modern global economy. The aim of this study I. INTRODUCTION is to develop a framework for a Web-Based Modern global economy has rapidly increased by Information System (WIS) tool for computing means of the electrical energy. Electrical energy has losses from 15 – 6.6 KV Feeders in Traditional also penetrated each area of human activities in Electrical Network Management (TENM). The such way that it has become a second virtual life. study was conducted in Goma District in the Furthermore, the availability of electrical energy Democratic Republic of Congo. Data were and the quality of services (QoS) to consumers collected from 26 key staff of Goma Distribution shapes and aids national development efforts. Electrical Network who responded to the Goma electrical network is located in North Kivu questionnaires and from metered reading Province East of Democratic Republic of Congo. documents used in the study. The study With the volcanic stones covering the whole Goma implemented a Computerized Web-Based town, laying underground electrical cables is very Information System (CWIS) to compute difficult. Hence the whole electrical network is different losses in Goma electrical distribution made up with overhead aluminum cables. The network. The CWIS computed technical losses in electrical energy supplied to Goma town is from five 15-6.6KV feeders of Goma electrical Ruzizi hydraulic generation power station located in distribution network. The study revealed that the neighboring town of Bukavu in South-Kivu among the five feeders, feeder 1 (Sud feeder) province. consumes 1,469,172.6 KWH representing 66.3% In Democratic Republic of Congo (DRC), the of the total annual energy loss while others company in charge of generation, management, presented lower annual losses. This is an transmission, and distribution of electrical energy is indication that Feeder 1 is overloaded and the “Societe Nationale d’Electricite” (SNEL). The needed to be resized or on the alternative, the head office of SNEL is located in the DR. Congo installation of another overhead cable that will capital town of Kinshasa which is 2000 kilometers take the half of the load in charge. away. Therefore the use of a Computerized Web- based information System (CWIS) can allow Keywords- Electrical energy; energy distribution; managers to use the information resources from feeder loss; computerized information system Goma electrical distribution network through a communication medium. 151 http://sites.google.com/site/ijcsis/ ISSN 1947-5500 (IJCSIS) International Journal of Computer Science and Information Security, Vol. 8, No. 9, 2010 Since SNEL still uses manual reading of energy Goma distribution electrical network metering and manual information system, a CWIS management? becomes inevitable. Goma electrical network has only one Transmission Substation being coded as 2x • What is the level (in percentage) of 10MW-70/15 KV, five primary feeders (1 feeder of maximum losses in 15kV and 6.6kV feeders 6.6kv and 4 feeders of 15kv), and fifty five of Goma distribution electrical network? Distribution Substations with code 15/0.4kv- 6.6/0.4kv. II. RESEARCH METHOD This research is aimed at implementing a Computerized Web-Based Information System that A. The Traditional Approach to Electric Power can compute losses based on data entry from For roughly a century, the developed world has manual reading of the metering system, as well as delivered electric power using the same basic four- compute technical losses (TL) in the 15kv and 6.6kv step approach: 1) generate power in large, feeders. centralized plants; 2) step up the power to high voltages and transmit it to regional utilities; 3) step A. Statement of the Problem down the power to medium voltages to distribute it locally; 4) step down the power a final time to The use of manual information system does not deliver it to customer premises. (Figure 2.1.) show the losses incurred at all the stages of the generation, transmission and distribution of the electrical energy in Goma electrical network system. In addition to this major problem, the manual information system management includes poor data storage, slow and difficult retrieval, inconsistency in data, data redundancy, and the high probability of losing information stored in files on shelves due to damage or theft. Hence the need for a computerized information system which overcomes these problems cannot be over emphasized. B. Objectives of the study The specific objectives of this study are as follows: • To implement a Computerized Web-Based Information System (CWIS) for four 15- Figure 2.1. Traditional Electric Power Approach 6.6KV feeder losses computation • To demonstrate the current state of electrical power supply equipment by showing the Figure 2.1: The “traditional “ electric power value electrical power losses in the four 15-6.6KV chain encompassed centralized generation, high feeder as a result of power assigned to Goma voltage transmission, medium-voltage distribution, electrical network consumers by the use of and end use by industrial, commercial and the manual information management system. residential customers (source: Global Environment Fund, 2008) C. Research Questions The questions to be answered in this study are: B. Goma Electrical Distribution Network Losses • To which level (in percentage) can a Computation procedure and framwork Computerized Web-based Information System (CWIS) be effectively useful for The electrical framework for energy losses in a 15-6.6KV feeder losses computation in distribution system is presented in the figure 2.2 . 152 http://sites.google.com/site/ijcsis/ ISSN 1947-5500 (IJCSIS) International Journal of Computer Science and Information Security, Vol. 8, No. 9, 2010 The steps followed to compute losses at different LLF = 0.8 (LF)2 + 0.2 (LF) (5) levels in the framework (figure 2.2) of the electrical • Peak- power loss (PPL) distribution network are given below. The primary feeders are five feeders that have a total length of 46 Peak- power loss (PPL) in 11kv kilometers. line = 3 I2 R (UF)2 KW (6) • Annual energy loss Annual energy loss Consumer Consumer = PPL 8760 LLF KWH (7) • Average power fed Average power fed = V I (existing pf) (UF) Distribution Substation Service Mains Service Mains (LF) KW with pf as power factor (cosines phi) and KW as kilowatt. (8) The losses in 15kv lines are calculated as shown Distributor (LT lines) below: • Percentage 15/6.6 kv line losses Primary feeder Percentage 15kv line losses Transmission = 100 (9) Substation III. SOFTWARE IMMPLEMENTATION Figure 2.2 Electrical Distribution Network framework A. General architecture of the System • Utilization Factor (UF) at the existing power The general architecture of the system is described by figure 3.1 below: factor is given as UF = (1) Presentation GUI • Load Factor (LF) and Loss Load Factor (LLF) are given as 15.6 kv Transformer losses LT losses Cable losses Peak-Load = Vw ( ) (2) Losses Computation Software Average Load = Vav ( ) (3) System losses Other Network User Login where n is the number of feeders, Vw is Information working voltage, Vav is average voltage, Ipn is the peak current and is average current in Persistence DB files th n feeder. The working voltage Vw and the Figure 3.1 General Architecture of the System peak current Ipn are collected from the metering system. The Graphic User Interfaces (GUI) were Hence , implemented for entering data in the database using PhP 5 with Macromedia dreamweaver 8 LF = (4) programming approaches as proposed by Luke and Laura (2003). 153 http://sites.google.com/site/ijcsis/ ISSN 1947-5500 (IJCSIS) International Journal of Computer Science and Information Security, Vol. 8, No. 9, 2010 The GUI was designed as form fields for input and TABLE 4.1 B display of appropriate data as required by the Feeder Peak Avg Peak Avg Load database for use by the various computational Name current current load load factor processes. The computational processes were Sake 98.000 64.000 1974.087 1211.604 0.613 implemented using appropriate international Sous 191.000 140.500 1693.807 1170.528 0.691 standard empirical formulae (see section 2.2). Nord 100.000 55.000 2014.375 1041.222 0.516 Centre 70.000 45.000 1410.062 851.909 0.604 Forms for reporting errors from the system are Sud 200.000 165.000 4028.750 3123.667 0.775 generated automatically by the application software. The database was implemented using MYSql. In TABLE 4.1C order to access information in the system, Feeder Loss Capacity Peak Annual appropriate user authentication and authorization Name Load Of Utility Power Energy checks were implemented through the system login factor transformer factor loss loss prompt. The web based capability of the system was centres Sake 0.424 5280.000 0.373 18.147 67421.7 implemented using PhP5 with Macromedia 0.520 5725.000 0.295 112.223 511465.2 Sous dreammweaver8. In all, the entire system Nord 0.317 2960.000 0.680 53.874 149664.4 requirement are Mysql, PhP5, macromedia dream Centre 0.412 6510.000 0.216 5.341 19319.0 weaver, Apacher server, and Visio Modeler. Sud 0.635 5350.000 0.753 263.702 1469172.5 IV. SYSTEM RESULT: ELECTRICAL TABLE 4.1 D NETWORK DATA PRESENTATION Feeder Total Total Cosine Avrage AND INTERPRETATION Name Energy Energy phi Power received demded fed A. Feeder Losses Presentation and Interpretation Sake 529.864 345.500 0.837 232.891 The losses and loads in feeders as results of the Sous 529.864 345.500 0.837 200.472 system are presented and interpreted in this Nord 529.864 345.500 0.837 306.804 section. The resistor (Ω), peak load, average load, Centre 529.864 345.500 0.837 93.383 load factor, loss load factor, capacity transformer Sud 529.864 345.500 0.837 1527.712 power, utilization factor, peak power loss, annual energy loss, cosines phi, and average power fed for each feeder have been computed by the CWIS From table 4.1 (a-d) the cumulative sum was done and presented in table 4.1. The peak power losses by the system to provide the results in table 4.2 (a- (ppl) (kw), the average power (kw), and the 15kv- b). From table 4.2a, the total length of the 15/6.6 kv 6.6kv line annual energy loss (kwh) bar charts cable is shown in the first column and last row as below show the repartition of loads and losses in 46.557 kilometers. The next column and last row the five feeders in order to highlight and guide shows the total peak load computed as 11.121kva managers on what decisions for corrective and preventive maintenance may be necessary in (the metered value was 11kva). Other computed order to balance or to reduce losses. values can be seen from the table with the last row of each column accounting for total for total values as follows: average load, utility factor, was equal to TABLES 4.1(A-D). FEEDER LINE 7398.9 kw, utility factor is 2.31991, and total capacity of transformer center is 25.825 kva. TABLE 4.1 A Howerver the total power of the Substation which is Feeder Cable Length(M) Ohm Working Avg 20 kva that shows there is extra power of 5.825 Name code (R) volt volt kva. The system computed the peak power loss in Sake Alu 8761.500 4.505 11.630 10.9 all the feeders as 453.29 kw, and the annual energy Sous Alu 16270.000 11.714 5.120 4.8 loss as 2,217043.14kwh for the year (2008). The Nord Alu 5385.600 3.877 11.630 10.9 average power fed is computed as 2361.26 kw. The Centre Alu 10758.000 7.745 11.630 10.9 loss load factor and utilization factor have been Sud Alu 5382.300 3.875 11.630 10.9 calculated in order to use their average values 154 http://sites.google.com/site/ijcsis/ ISSN 1947-5500 (IJCSIS) International Journal of Computer Science and Information Security, Vol. 8, No. 9, 2010 (2.310337divided by 5 and 2.31991divided by 5) in the electrical network losses calculation. It is noted that the average power factor of 0.84 is less than the standard minimum value of 0.90 as stated by Pabla (2005). From these results the study shows that the CWIS can provide information that can be used in preventive and corrective maintenance of the Goma electrical network distribution. TABLES 4.2(A-B). SUMMING NUMERICAL VALUES FROM FEEDER READABLE TABLE TABLE 4.2 A Feeder Length(M) Peak Avrage Utility Factor Name Load Load Centre 8761.5 1974.08 1211.60 0.37 Fig 4.1 Sake Sous Nord Centre Sud Sake 25031.5 3667.89 2382.13 0.66 The figure 4.1 reveals that the feeder named “Sud” Nord 30417.1 is most overloaded, and has the highest peak power 5682.26 3423.35 1.35 loss (ppl). At the other hand the feeder named Sous 41175.1 “Center” has the lower load. From this observation 7092.33 4275.26 1.56 the managers can well decide which steps can be Sud 46557.4 taken in order to reduce the power loss in feeder 11121.08 7398.93 2.31 Sud, and how to balance loads on other feeders which are lightly loaded. TABLE 4.2 B KW Feeder Loss Capacity Peak Annual Avrage Load Transformer Power Energy power Name Factor Power loss Loss Fed Centre 0.42 5280 18.14 67421.72 232.89 Sake 0.94 11005 130.37 578886.99 433.36 Nord 1.26 15965 184.24 728551.48 740.16 Sous 1.67 20475 189.58 747870.56 833.55 Sud 2.31 25825 453.29 2217043.14 2361.26 B. Descriptive Statistics of the System Results Descriptive statistics of the system results are shown in the bar charts presented in figure 4.1, 4.2, and figure 4.3. The interpretation of results is given Fig 4.2 Sake Sous Nord Centre Sud below each bar chart. 155 http://sites.google.com/site/ijcsis/ ISSN 1947-5500 (IJCSIS) International Journal of Computer Science and Information Security, Vol. 8, No. 9, 2010 According to the formular LLF = 0.8 (LF)2 + 0.2 the Loss Load Factor (LLF) is highly proportional The figure 4.2 shows that the same feeder named to LF powered by 2. That means that at lower load “Sud” was demanding the highest power compared LLF is small. But at high load LLF is near to one to others. It reveals that there is a relationship so that the I2 (the current) is the one highly between peak power loss and average power fed. influencing the annual energy losses. The peak Once again the managers have the precise ampere recorded from the metering system being of knowledge of the average power to be cut off from 200 A, it is visible that the annual energy losses in feeder named “Sud”, or the size of the transformer the feeder named “Sud” must be higher than they that can supply that average power. are in the other feeders where the peak current range Normally the electrical distribution network from 70 A to 100 A. The feeder named “Centre” manager is interested in how to reduce losses in still the one having the lower value of annual losses. order to increase profit. The Computerized Web- The bar charts in figure 5.10 are revealing that there Based Information System has the capability to is a correlation between the average power, the peak compute annual losses to highlight managers about power loss, and annual energy losses. Managers the magnitude of them. The figure 4.3 shows the cannot take decision on how and on which resource annual energy losses magnitude for each feeder. to be engaged to reduce losses if they do not know KWH their magnitude. Once again the Computerized Web-Based Information System has shown it capability to compute technical losses (power losses and annual energy loss) for each feeder and has shown how it is a powerful tool to be used in making decisions for preventive and corrective maintenance. V. DISCUSSION, CONCLUSION AND RECOMMENDATIONS C. Discussion of Findings Technical losses do occur in electrical feeder distribution networks. Pabla (2005) stated that the typical maximum losses (in percentage) in 15KV and 6.6KV Feeders, should be 4.0%. However, Fig 4.3 Sake Sous Nord Centre Sud technical losses in the Goma electrical distribution network appear to be far above this range. Out of the total annual energy loss (see table 4.2 - The bar charts in figure 4.3 reveal that the same 2217043.14 kwh) the feeder called “Sud” takes feeder Sud presents the higher annual losses. Out of 1,469,172.6 kwh (see table 4.1) which represents the total annual energy loss (see table 4.2 - 66.3% of the total annual energy loss. Because the 2217043.14 kwh) the feeder Sud takes itself peak current (of 200 ampere) demanded was very 1,469,172.6 kwh (see table 4.1) which represents high therefore annual energy losses were also 66.3% of the total annual energy loss. Because the increased. peak current (of 200 ampere) demanded was very D. Conclusion high therefore annual energy losses were also The losses in 15-6.6 KV feeders (particularly in increased according to the relation: “Sud feeder”) is very high. The implication of those Annual Energy losses = 3 I2(UF)2 x 8760 x LLF = losses is that they reduce the Company profit, life of K I2(UF)2LLF with K equal to 3 x 8760. 156 http://sites.google.com/site/ijcsis/ ISSN 1947-5500 (IJCSIS) International Journal of Computer Science and Information Security, Vol. 8, No. 9, 2010 cables and transformers, and the number of Economy: New opportunities from the transformation of the Electric Power Sector”, customers to be supplied with electricity. This has Global Smart energy, 2008. been hidden due the operational manual system in place. However, with a Computerized Web-Based W, Luke and T. Laura, PhP and MySQL Web Development, 2nd, Samms Publishing, Information System for computing losses, managers Indianapolis . will have insight as to actual losses and be guided  A.S Pabla, Electric power distribution, 4th ed, towards appropriate corrective and preventive McGraw-Hill , USA 2005. maintenance necessary to minimize Goma distribution network losses.  Y,Wilis and D, David, “A General guide to writing research proposals and report, A hand book for beginning researchers, 2nd ed, E. Recommendation Makerere University, Kampala, 2008. From this study, the following recommendations becomes necessary for Goma electrical network AUTHORS PROFILE distribution: Ezekiel U. Okike received the BSc degree in • Implementation of the Computerized Web- computer science from the University of Ibadan Based Information System in order to Nigeria in 1992, the Master of Information Science monitor losses over time for corrective and (MInfSc) in 1995 and PhD in computer science in preventive maintenance of the electrical 2007 all from the same University. He has been a distribution network lecturer in the Department of Computer Science, • Immediate resizing of the overloaded “Sud University of Ibadan since 1999 to date. Since feeder” or installation of another overhead September, 2008 to date, he has been on leave as a cable that will take the half of the load in senior lecturer and Dean of the School of Computer charge. Whenever the distribution Studies, Kampala International University, Uganda. transformers are overloaded and additional His current research interests are in the areas of loads are anticipated, then the existing software engineering, software metrics, compilers transformers should be replaced by higher and programming languages. He is a member of capacity transformers, or new transformers IEEE Computer and Communication societies. may be provided to cater for the loads. Bakunzi G. Joseph is an Electrical Engineer from Institut Supérieur des Techniques Appliquées de REFERENCES Kinshasa and postgraduate student in the School of Computer Studies, Kampala International University . He holds the B.Eng. in Electrical  B, G. Joseph, “ Use of commputerized wed- based informmation system for determining Engineering and recently graduated with the degree losses in traditional electrical network of Master of Science in Systems Software management: case study of Goma electrical distribution network”. MSc thesis, School of Engineering , MSc(SSE). computer Studies, Kampala International University, xv+ 120 pp, April 2010 Global research Fund. “The Electricity 157 http://sites.google.com/site/ijcsis/ ISSN 1947-5500