DECISION MAKING ON LOAD CONNECCTION FROM DIFFERENT SUBSTATIONS OF SPECIFIC CAPACITY ON THE BASIS OF MINIMUM TRANSMISSION LOSS

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1 Proceedigs of the Iteratioal Coferece o Mechaical Egieerig 27 (ICME27) 29- Deceber 27, Dhaka, Bagladesh ICME7-AM- DECISION MAKING ON LOAD CONNECCTION FROM DIFFENT SUBSTATIONS OF SPECIFIC ON THE BASIS OF MINIMUM TRANSMISSION LOSS Sikder Maiul Hasa ad Md. Siful Isla 2 Dept. of IEM, Khula Uiversity of Egieerig & Techology, Khula 92, 2 Khula Power Statio(BPDB), Goal Para, Khula 9. ABSTRACT To coect large electric loads of certai MW dead, the B costructs high tesio lie ( KV/ KV) fro substatio to load ed. The trasissio loss of electricity fro substatio to load-ed depeds o lie legth, quatity of load, resistace of wire etc. If i a area there exists soe ewly costructed large electric loads of various deads ad there exists facilities ad if load coectio is possible fro differet substatios of specific capacity, it would be ore viable to give coectio accordig to lowest trasissio loss. Paper idicates three substatios are available to coect four large loads (Cold storage, ceet factory, fertilizer factory & textile ill) existig i differet locatio of Jessore district. A coutable aout of trasissio loss ay be reduced if the coectios are give o the basis of lowest trasissio loss deteried by trasportatio odel. A educatio versio software TORA was used for trasportatio odel aalysis ad subsequet decisio akig o load coectio. Keywords: Trasportatio Model, Trasissio Loss, Load Coectio. INTRODUCTION The trasportatio odel is a special class of liear prograig that deals with shippig a coodity fro sources to destiatios. The objective is to deterie the shippig schedule that iiizes the total shippig cost while satisfyig supply ad dead liits []. The odel assues that the shippig cost is proportioal to the uber of uits shipped o a give route. Sources Destiatios c : x a b a 2 b 2 uits of 2 2 uits of supply dead a c : x b likig the sources ad the destiatios. Arc (i,j) joiig source i to destiatio j carries two pieces of iforatio : the trasportatio cost per uit, c ij, ad the aout shipped,. The aout of supply at source i is a i, ad the aout of dead at destiatio j is b j. The objective of the odel is to deterie the ukows that will iiize the total trasportatio cost while satisfyig all the supply ad dead restrictios.. The Trasportatio Algorith The trasportatio algorith is based o the assuptio that the odel is balaced, eaig that the total dead equals the total supply [2] & []. The trasportatio algorith is explaied by the followig exaple: Let represets the aout trasported fro source i to destiatio j; the the LP odel represetig the trasportatio proble is give orally as subject to iiize j= a i z = i= j= c ij i =, 2,.., Figure.: Represetatio of the trasportatio odel with ode ad arcs. b i j =, 2,., The geeral proble is represeted by the etwork i i= Figure.. There are sources ad destiatios, each x ij for all i ad j represeted by a ode. The arcs represet the routes ICME27 AM-

2 the first set of costraits stipulates that the su of the shipets fro a source caot exceed its supply; siilarly the secod set requires that the su of the shipets to a destiatio ust satisfy its dead. The odel just described iplies that the total supply = i ai ust at least equal the total dead. j = Whe the total supply dead equals the total dead ( i = a i = j = b j ), the resultig forulatio is called a balaced trasportatio odel. It differs fro the odel above oly i the fact that all costrait are equatio; that is j= i= a i b i i =, 2,.., j =, 2,., i real life it is ot ecessarily true that supply equal dead or, for that atter, exceed it. However a trasportatio odel ca always be balaced. If the odel is ubalaced, we ca always auget it with a duy source or a duy destiatio to restore balace. Whe dead exceeds the supply, a duy source is added to balace the trasportatio odel. I this case, the uit trasportatio cost fro the duy plat to the destiatios is zero because the plat does ot exist. b j Table 2.: Distaces fro the differet substatios to differet loads P 25k 7k 5k 22k K 5k 5k 2k 2k K 2k k 8k 2k K Dead 5 2. DESCRIPTION OF THE PROBLEM [ MW There are three substatios aed as Moirapur, oapara, ad Basudia of Jessore district of capacity, ad MW respectively. The loads at the locatio of Noapara, Basudia, Rajarhat, ad Jessore of dead MW, 5MW, MW ad MW are to be coected fro the above etioed substatios. The distaces fro the differet substatios to differet loads are give i Table 2.. FORMATION OF TRANSPORTATION ALGORITHM To costruct the trasportatio algorith, it is ecessary to calculate the per uit trasissio loss. If MW load is coected to a lie of k legth, the lie loss is.87 KW (see calculatio). The lie legths fro differet substatios to differet loads are differet, so the losses of per MW trasissio through differet routes are also differet. The per MW trasissio loss of differet routes are show i the Table. Table.: Per MW trasissio loss of differet routes P UR De. I MW 5 To fid the startig solutio of the algorith, there are three ethods. ) North west corer ethod 2) Least cost ethod ad ) Vogel s approxiatio ethod. Here least cost ethod is used to solve the algorith.. Least-Cost Method The Least-cost ethod fids a better startig solutio by cocetratig o the cheapest routes []. The ethod starts by assigig as uch as possible to the cell with the sallest uit cost. Next, the satisfied row or colu is crossed out ad the aouts of supply ad dead are adjusted accordigly. If both a row ad a colu are satisfied siultaeously, oly oe is crossed out. Next, look for the ucrossed out cell with the sallest uit cost ad repeat the process util exactly oe row or colu is left ucrossed out. The least-cost ethod is applied i Table. to fid out the startig solutio. The startig solutio is show i the table below: Table.2: Startig solutio least-cost ethod P [ MW Dead 5 Actually lie loss does ot icreases proportioally to the load. For exaple, if MW load is coected to k lie, the lie loss is.87 KW, which is 62 KW ot 5.8 (*.87=5.8) KW for MW load. Therefore, lie loss is calculated for differet loads. Though load of differet ratigs are coected to lie, the per MW trasissio loss is ot take as.87 KW 8 8 ICME27 2 AM-

3 istead average. KW (see calculatio). Takig. KW loss for per Mw load trasissio the table.2 becoes Table.: Table.: startig solutio P [ MW Dead 5 If the loads etioed i the proble are coected fro the substatios accordig with the startig solutio of table., the total lie loss will be: Total loss = = 277.8KW= =9726 Kwh. The fial solutio by TORA software is show i Table : TORA. If the loads are rearraged i aother way (rado order) described i table., say i the followig way i Table., Table:.: Fial solutio by TORA software P Dead 5 [ MW The othly lie loss for the arrageet of Table. =( = KW) 2 = 9552 Kwh.. CALCULATION The coductor used to costruct the lie is kot ACSR. The resistace of the wire is.8ω/k. Power (P)= V L I L CosΘ If the substatio s trasforer secodary is Y coected ad MW load is coected with KV lie of legth k the, I L.9= [P.F, Cosθ=.9] I L =58. Apere. Lie loss (legth of lie = k) due to MW load, P = I 2 R = (58.) 2.8=.87 KW [ultiplied by for phases] To get lie loss for Mwh trasissio through differet routes of legth k, 5k, 8k, 2k, 5k, 2k, 22k, 2k, 25k & 7k etioed i the proble,.87kw is ultiplied by the respective legth of the lie ad the loss is.6kw, 9.5KW,.96W, 6.KW, 58.5KW, 77.KW, 85.KW, 92.88KW, 96.75KW,.9KW. Kilowatt-hour loss for Megawatt hour trasissio through differet routes is foud by ultiplyig these Kilowatt losses with hour (used i table.2). Actually oly MW load is ot coected with the differet lies, so lie loss ust be calculated for differet Megawatt loads. For MW load with k lie legth the loss is.87kw (calculated before). Siilarly for 2 MW, MW, MW, & 5 MW, the lie loss is 5.5 KW,.89 KW,62 KW,96.9KW respectively. It is see that lie loss is ot proportioal with loads, so average loss per MW trasissio loss should be calculated o the basis of coected loads give i table.2. Fro table.2 the load coected fro differet substatios are MW, MW, MW, MW & MW. Therefore, average per MW loss = ( )KW/(++++)MW=.KW. Takig this.kw loss per MW per k ito cosideratio, the per MW loss of various routes will be calculated ad the losses are2.2 KW,7.2 KW,2.2 KW,68.8 KW,2.6 KW,28.8 KW,8.88 KW,6.96 KW,5 KW &59.8 KW. 5. SOLUTION OF THE PROBLEM BY TORA SOFTWA The developed odel of trasportatio proble of load coectio was solved by TORA software. The results has bee show below. ICME27 AM-

4 Table: TORA TRANSPORTATION MODEL Title: Trasissio Loss Calculatio Size:( x 5) Origial data D D2 D D D5 SUPPLY S S S DEMAND 5 ~**************~ Table: TORA 2 OPTIMUM TRANSPORTATION SOLUTION Title: Trasissio Loss Calculatio Size:( x 5) Fial iteratio o: 2 Total Loss = Fro To Aout Uit Loss Route Loss S D 5.. D D D D5.. S2 D D D D D5.. S D D D 2.2. D D5.. Suary of Trasportatio Loss Node Supply/Dead Total Loss Av. Loss/uit S S S D D D D D5.. Ed of solutio suary 6. CONCLUSION If the load coectio is give radoly, for istace like Table: TORA TRANSPORTATION MODEL Table. the lie loss would be 9552 Kwh. If there is o load sheddig over the oth, the total uit cosued by the cosuers will be, 6 2 =52 Kwh. I this case the lie loss will be (9552/52) =6.%., which is sigificatly high ad therefore objectioable. Agai if we cosider the startig solutio (usig least cost ethod Table.) the percetage loss would be (277.8/6)*= 7.%. By successive iteratio we get fial solutio (by TORA) ad the table is give i Table: TORA. Cosiderig this fial solutio the percetage loss would be (228.9/6)*= 5.8%..Whatever be the arrageets to give coectios of the loads etioed i the proble fro specified substatios, the loss will ever be less tha 5.8% ad this is abruptly high because the stadard KV losses i the power distributio syste is tried to aitai withi oly.6% [5]. So it will ot be viable to costruct all kv lies to coect the loads fro existig substatios. If the calculated loss by trasportatio odel is withi the stadard liit (.6%), the coectio will be give by costructig kv lie accordig to arrageet i Table: TORA. Table 5: Depicts idividual Load s Trasissio Loss Nae of Loads Nae of Percetage Lie Substatios Loss Noapar (D) Noapara (S2) 28/= 7% Basudia (D2) Noapara (S2)+ 2/=2% Basudia (S) & 68/=.2% Rajarhat (D) Moirapur 82/= Jessore (D) Duy (D5) Title: Trasissio Loss Calculatio Size:( x 5) Fial Iteratio No: 2 Total Loss = Ui D D2 D D D5 SUPPLY S S S Vj V5=. DEMAND 5 (S) Moirapur (S) 2.5% 926.6/=.88% Alterately we ca revise the percetage lie loss ICME27 AM-

5 cosiderig idividual load coectio accordig to Table: TORA 2. The percetage table is show is Table 5 Fro the statistics of Percetage Lie Loss i Table 5, it is evidet that the Lie Rajarhat~Moirapur ad Jessore ~ Moirapur would ot be feasible sice lie loss is very high. Therefore, a ew / kv substatio ust be costructed ear the above etioed loads (Rajarhat & Jessore ). The lie (Noapara~Noapara) ca be cosidered favorably sice the loss is very close to stadard liit, provided that other coditios is also favorable. The load of Basudia is shared by Noapara & Basudia substatio which is ot techically perissible(if oe substatio fails, the other will be overloaded).the lie loss of Basudia ~ Basudia is oly.2% which is below the stadard liit, so Basudia substatio ca be upgraded ad the coectio is give. 7. FENCES. HAMDY A. TAHA Operatios Research: A Itroductio, 5 th ed., H. Taha Coputer Algoriths for OPERATIONS ASEARCH, 6 th ed., 997. Gupta P. K. ad Moha M Probles i Operatios Research 8 th ed., 998. Wisto L. W. Operatios Research- applicatios ad algoriths th ed., 2 5. Mr. Abul Bashar, Stakig Egieeri, ECBL, JPBS 2, Jessore. 8. NOMENCLATU Sybol Meaig Uit KV KiloVoltage - KW Killo Watt(Power) Watt LP Liear Prograig - Ω Resistace Oh MW ACSR Mega watt(power) Aluiu Coductor Steel Reiforced Watt - ICME27 5 AM-