Transmission and Distr

Transcription

1 Trasmissio ad Distr tributio Losses (Power) er) Itroductio I Idia, average T & D (Trasmissio & Distributio) losses, have bee officially idicated as 23 percet of the electricity geerated. However, as per sample studies carried out by idepedet agecies icludig TERI, these losses have bee estimated to be as high as 50 percet i some states. I a recet study carried out by SBI Capital Markets for DVB, the T&D losses have bee estimated as 58%. This is cotrary to claims by DVB that their trasmissio ad distributio losses are betwee 40 ad 50 percet. With the settig up of State Regulatory Commissios i the coutry, accurate estimatio of T&D Losses has gaied importace as the level of losses directly affects the sales ad power purchase requiremets ad hece has a bearig o the determiatio of electricity tariff of a utility by the commissio. Compoets of T&D losses Eergy losses occur i the process of supplyig electricity to cosumers due to techical ad commercial losses. The techical losses are due to eergy dissipated i the coductors ad equipmet used for trasmissio, trasformatio, sub- trasmissio ad distributio of power. These techical losses are iheret i a system ad ca be reduced to a optimum level. The losses ca be further sub grouped depedig upo the stage of power trasformatio & trasmissio system as Trasmissio Losses (400kV/220kV/132kV/66kV), as Sub trasmissio losses (33kV /11kV) ad Distributio losses (11kV/0.4kv). The commercial losses are caused by pilferage, defective meters, ad errors i meter readig ad i estimatig umetered supply of eergy. Level el of T& D Losses The officially declared trasmissio ad distributio losses i Idia have gradually rise from about 15 percet up to the year to about 23 percet i The cotiued risig tred i the losses is a matter of serious cocer ad all out efforts are required to cotai the them. Accordig to a study carried out by Electric Power Research Istitute (EPRI) of the USA some time

2 Trasmissio ad Distributio Losses (Power) 2 back, the losses i various elemets of the T&D system usually are of the order as idicated below: - System elemet Power Losses (%) Miimum Maximum Step-up trasformers & EHV trasmissio system Trasformatio to itermediate voltage level, trasmissio system & step dow to sub-trasmissio voltage level Sub-trasmissio system & step-dow to distributio voltage level Distributio lies ad service coectios Total Losses The losses i ay system would, however, deped o the patter of eergy use, itesity of load demad, load desity, ad capability ad cofiguratio of the trasmissio ad distributio system that vary for various system elemets. Accordig to CEA vide its publicatio (July 1991) Guidelies for Reductio of Trasmissio ad Distributio Losses it should be reasoable to aim for total eergy losses i the rage of 10-15% i the differet states i Idia. The eclosed Aexure-B idicates the risig tred of T&D losses i the various states i the past. This ca be compared with T&D losses i the other coutries idicated i the eclosed Aexures-A. A glimpse of this Aexure idicates that i most developed coutries the T&D losses are less tha 10 percet. Reasos for high T&D Losses Experiece i may parts of the world demostrates that it is possible to reduce the losses i a reasoably short period of time ad that such ivestmets have a high iteral rate of retur. A clear uderstadig o the magitude of techical ad commercial losses is the first step i the directio of reducig T&D losses. This ca be achieved by puttig i place a system for accurate eergy accoutig. This system is essetially a tool for eergy maagemet ad helps i breakig dow the total eergy cosumptio ito all its compoets. It aims at accoutig for eergy geerated ad its cosumptio by various categories of cosumers, as well as, for eergy required for meetig techical requiremet of system elemets. It also helps the utility i brigig accoutability ad efficiecy i its workig. Reasos for high tec echical losses The followig are the major reasos for high techical losses i our coutry: - Iadequate ivestmet o trasmissio ad distributio, particularly i sub-trasmissio ad distributio. While the desired ivestmet ratio

3 Trasmissio ad Distributio Losses (Power) 3 betwee geeratio ad T&D should be 1:1, durig the period it decreased to 1:0.45. Low ivestmet has resulted i overloadig of the distributio system without commesurate stregtheig ad augmetatio. Haphazard growths of sub-trasmissio ad distributio system with the short-term objective of extesio of power supply to ew areas. Large scale rural electrificatio through log 11kV ad LT lies. Too may stage of trasformatios. Improper load maagemet. Iadequate reactive compesatio Poor quality of equipmet used i agricultural pumpig i rural areas, cooler air-coditioers ad idustrial loads i urba areas. Reasos for commercial cial losses Theft ad pilferage accout for a substatial part of the high trasmissio ad distributio losses i Idia. Theft / pilferage of eergy is maily committed by two categories of cosumers i.e. o-cosumers ad boafide cosumers. Atisocial elemets avail uauthorized/urecorded supply by hookig or tappig the bare coductors of L.T. feeder or tampered service wires. Some of the boafide cosumers willfully commit the pilferage by way of damagig ad / or creatig disturbaces to measurig equipmet istalled at their premises. Some of the modes for illegal abstractio or cosumptio of electricity are give below: Makig uauthorized extesios of loads, especially those havig H.P. tariff. Tamperig the meter readigs by mechaical jerks, placemet of powerful magets or disturbig the disc rotatio with foreig matters. Stoppig the meters by remote cotrol. Willful burig of meters. Chagig the sequece of termial wirig. Bypassig the meter. Chagig C.T.ratio ad reducig the recordig. Errors i meter readig ad recordig. Improper testig ad calibratio of meters. T&D losses i res estr tructur uctured SEBs Some states have embarked o programs of power sector reforms ad have take steps to restructure their SEBs (State Electricity Boards). The reformig states that were reportig T&D losses of aroud twety percet before restruc-

4 Trasmissio ad Distributio Losses (Power) 4 turig process suddely reported higher losses after carryig out detailed studies of their system. For example, before restructurig its power sector, Orissa reported 23 percet loss, after restructurig, T&D loss were show to be 51 percet. I AP where these losses were of the order of about 25 percet before restructurig, it is ow estimated to be aroud 45 percet after restructurig. Haryaa has ow estimated its losses at 40 percet ad Rajastha at 43 percet agaist earlier level of 32 percet ad 26 percet respectively Regulat egulator ory cocers s I the absece of a realistic estimate of T&D losses, it is ot possible for the regulatory commissios to correctly estimate the reveue requiremets ad also avoid the situatio where the cosumers pay for the iefficiecies of the utilities. I order to determie a appropriate tariff, the first step is to determie the justified cost icurred by the etity. This would provide a idicatio of the reveue requiremet, which i tur is the basis of ay tariff desig. The regulator has therefore to be very careful about how losses are worked out. The aim of the regulator must be to ecourage the utility to make every effort to reduce losses while at the same time esurig that those coditios applied which threate the viability of the utility are ot applied. Barrier iers s i priv ivat ate sector participatio The lack of realistic estimates of T& D losses acts as a disicetive for private sector participatio i power distributio as the party ca ot have a idea of the realistic reveue potetial of the area beig privatized. Ume meter ered ed supply Umetered supply to agricultural pumps ad sigle poit coectios to small domestic cosumers of weaker sectios of the society is oe of the major reasos for commercial losses. I most states, the agricultural tariff is based o the uit horsepower (H.P.) of the motors. Such power loads get sactioed at the low load declaratios. Oce the coectios are released, the cosumers get ito the habit of icreasig their coected loads, without obtaiig ecessary sactio, for icreased loadig, from the utility. Further estimatio of the eergy cosumed i umetered supply has a great bearig o the estimatio of T&D losses o accout of iheret errors i estimatio. Most of the utilities deliberately overestimate the umetered agricultural cosumptio to get higher subsidy from the State Govt.ad also project

5 Trasmissio ad Distributio Losses (Power) 5 reductio i losses. I other words higher the estimates of the umetered cosumptio, lesser the T&D loss figure ad viceversa. Moreover the correct estimatio of umetered cosumptio by the agricultural sector greatly depeds upo the croppig patter, groud water level, seasoal variatio, hours of operatio etc. To icrease the food output, almost all the State Govermets show beevolece to farmers ad arrage supply of electric power for irrigatio to the farmers at a omial rate, ad i some States, without charges at all. I view of this, most Electricity Boards supply power to agriculture sector ad claim subsidy from the State Govt. based o eergy cosumptio. Sice the eergy supplied to the agriculture sector is a geerous gesture by the State Govt., all the electricity boards have elimiated eergy meters for agriculture sector services. The absece of eergy meters provides ample opportuities to SEBs to estimate average cosumptio i agriculture sector at a much higher value tha the actual. I the absece of eergy meters, most of the SEBs resort to fudgig cosumptio figures to iclude ot oly the uder estimated T&D Losses but also eergy theft from their system. The extet of fudgig is more i the States where agricultural activity is high. The beefit derived by these boards is ot oly the extet of subsidy from the respective States but also self praise, by showig much less T&D losses. Further the boards are igorig the iefficiecy i operatig the distributio system by blamig the agricultural supply for all ills ad raisig the tariff of other cosumers. Most of the methods beig employed by SEBs for estimatig the umetered eergy cosumptio are as follows: - Load factor based estimatio. Estimatio based o feederwise theoretical calculatio of losses. Estimatio based o readigs of meters istalled at all the Distributio Trasformers located o a feeder. However, oe of the these methods provide correct estimatio of umetered cosumptio. Measures es for reducig tec echical losses Short term measures Idetificatio of the weakest areas i the distributio system ad stregtheig /improvig them so as to draw the maximum beefits of the limited resources.

6 Trasmissio ad Distributio Losses (Power) 6 Reducig the legth of LT lies by relocatio of distributio sub statios/ istallatios of additioal distributio trasformers (DTs). Istallatio of lower capacity distributio trasformers at each cosumer premises istead of cluster formatio ad substitutio of DTs with those havig lower o load losses such as amorphous core trasformers. Istallatio of shut capacitors for improvemet of power factor. Log term measures Mappig of complete primary ad secodary distributio system clearly depictig the various parameters such as coductor size lie legths etc. Compilatio of data regardig existig loads, operatig coditios, forecast of expected loads etc. Carryig out detailed distributio system studies cosiderig the expected load developmet durig the ext 8-10 years. Preparatio of log-term plas for phased stregtheig ad improvemet of the distributio systems alog with associated trasmissio system. Estimatio of the fiacial requiremets for implemetatio of the differet phases of system improvemet works. Formulatio of comprehesive system improvemet schemes with detailed ivestmet program so as to meet system requiremet for first 5 years period. Measures es for reducig o-tec echical losses Accordig to the Iteratioal Utilities Reveue Protectio Associatio. (IURPA), research carried out o utilities worldwide idicates that service quality, customer relatioships, ad overall service satisfactio ca miimize reveue losses. This has bee demostrated i Pakista where rampat power theft has cotributed fiacial crisis for WAPDA (Water & Power Developmet Authority). The World Bak ad Asia Developmet Bak which had supplied the bulk of WAPDA s developmet loas wated the authority to recover its upaid dues, cut power theft ad reduce its T&D Losses. Accordigly WAPDA was forced to raise power rates. But istead of improvig the fiacial situatio, this actio resulted i icreased fiacial crisis of WAPDA due to icreased icidece of theft ad upaid bills. I view of this, the authority applied extreme measures to curb power theft. The Chairma of the authority (a servig army officer) deployed 35,000 troops to tackle the crisis. The troops were istructed to idetify ad arrest people resposible for power theft. As a result of this more tha 36

7 Trasmissio ad Distributio Losses (Power) 7 military courts bega tryig cases of power theft. There are a rage of methods beig employed by utilities the world over to mitigate power theft. Some of these measures are give below. Set up vigilace squads to check ad prevet pilferage of eergy. Severe pealties may be imposed o those tamperig with the meter seals etc. Eergy audits should be itroduced ad persoal resposibility should be fixed o the district officers (executive egieers) for eergy received ad eergy sales i each area. Istallatio of tamper-proof meter boxes ad use of tamper-proof umbered seals. Providig adequate meter testig facilities. A time boud program should be chalked out for checkig the meters, ad replacemet of defective meters with tested meters. Iitiatives req equir uired Keepig the above i view it is very essetial that immediate steps are iitiated to have a assessmet of the realistic T &D losses i each of the states ad that immediate steps are take to reduce the same i a systematic maer by all the players i the field. The cetral or the state govermets should draw plas to provide fiacial support to the utilities for istallatios of meters o at least all the distributio trasformers i a phased maer. It should be made obligatory for all the big idustries as well as the utilities to carry out eergy audit of their system to idetify high loss areas ad take remedial measures to reduce the same. Schemes for icetive awards to utilities who are able to reduce T&D losses beyod a certai pre-fixed limit. The fiacial istitutios should be ecouraged to provide easy loas to utilities for takig remedial measures to reduce the T&D losses. Publicity campaigs should be carried out to make the cosumer aware of the high pealties o the uauthorized use of electricity. Utilities should prepare realistic power Master Plas for their systems to develop a strategy to meet the growig electricity demads of the differet sectors of the state s ecoomy over the ext 15 years.

8 Trasmissio ad Distributio Losses (Power) 8 Issues for discussio 1. Status of meterig ad steps required for early istallatio of the same I view of the fiacial assistace beig provided by the Cetral govermet for istallatio of meters, the feasibility of achievig the proposed targets ca be a importat issue for discussio. 2. Mitigatig power theft Idia Electricity Act 1910 has bee ameded through Sectios 39 ad 39A to make theft of eergy ad its abetmet as a cogizable offece with deterret puishmet of upto 3 years imprisomet. Theft of electric power is a problem experieced i varyig degrees by all electric utilities. The impact of theft is ot limited to loss of reveue, it also effects power quality resultig i low voltage ad voltage dips. Adequacy of the existig measures to curb power theft could be a issue for discussio. 3. Implemetatio of eergy audits schemes It should be obligatory for all big idustries ad utilities to carry out Eergy Audits of their system. Further time boud actio for iitiatig studies for realistic assessmet of the total T&D Losses ito techical ad o-techical losses has also to be draw by utilities for idetifyig high loss areas to iitiate remedial measures to reduce the same. The realistic assessmet of T&D Loss of a utility greatly depeds o the chose sample size which i tur has a bearig o the level of cofidece desired ad the tolerace limit of variatio i results. I view of this it is very essetial to fix a limit of the sample size for realistic quick estimates of losses. 4. Settig of bech marks for yearly reductio of T&D losses (techical ad o-techical) Ref efer ereces eces 1. Power Miisters Coferece February Ageda Notes 2. Electric Power Iteratioal Fall, Guidelies for Eergy Audit i Power Systems, CEA, New Delhi May P. N Khare MSEB, Power Theft A Root Cause of T& D Losses 5. Mr.M.H.P. Rao Power Sector bogged dow by T&D Losses i Fiacial Express, dated July 9,1999

9 Trasmissio ad Distributio Losses (Power) 9 Aexure A: Trasmissio ad distributio loss Coutry T&D losses Coutry T&D losses percet percet Japa 4.0 Switzerlad 6.0 Demark 4.0 Swede 6.4 Germay 4.0 Uited States 7.0 Ghaa 4.0 Uited Kigdom 7.0 Sigapore 4.0 Taiwa 7.0 Guam 4.50 a Italy 7.4 Macau 4.81 a Lodo 8.3 Korea 5.4 Malaysia 10.0 Frace 5.9 Thailad 10.3 Australia 6.0 Fiji a Caada 6.0 Idoesia 12.0 Chia 6.0 Mexico 14.0 South Africa 6.0 Hog Kog 15.0 a Source is Electric Power i Asia ad Pacific, Uited Natios, 1997 Source. World Developmet Report 1997, ad Lodo Electricity of UK

10 Trasmissio ad Distributio Losses (Power) 10 Aexure B: Trasmissio ad distributio losses as a percetage of availability i state electricity departmets: 1991/92 to 1999/2000 State 1991/ / / / / / /98 a 1998/99 b 1999/00 c Adhra Pradesh Aruachal Pradesh Assam Bihar Dama ad Diu Goa Gujarat Haryaa Himachal Pradesh Jammu ad Kashmir Karataka Kerala Lakshadweep Madhya Pradesh Maharashtra Maipur Meghalaya Mizoram Nagalad Orissa Pujab Rajastha Sikkim a Tamil Nadu Tripura Uttar Pradesh West Begal All-Idia (utilities) a provisioal; b revised ; c estimate Source. Plaig Commissio Aual Report o the Workig of State Electricity Boards ad Electricity Departmets. p. 66.

11 Trasmissio ad Distributio Losses (Power) 11