Analiza jalove moči v razdelilni transformatorski postaji

LIKAR, DIMITRIJ (author), Papič, Igor (mentor)

Osrednji del diplomske naloge je povezan s kompenzacijo jalove moči. Poudarek je predvsem na zbiranju podatkov o jalovi moči in vplivu le-teh na spremembo cos v RTP Koper v primeru, da bi spreminjali stopnjo kompenziranosti jalove moči. V ta namen smo obdelali tudi konkreten primer kompenzacije jalove moči na odjemalcu z izredno slabim cos, dejansko ekonomsko upravičenost naložbe in čas povrnitve le-te. Predvsem zadnje bo v našem konkretnem primeru zanimivo. Vprašanje kompenzacije jalove moči se z odpiranjem trga z električno energijo še posebej poudari, saj je v računu za dobavo električne energije zajeta le delovna energija in konica, tako da se problem jalove energije dobavitelja električne energije ne tiče. S tem se ukvarja operater omrežja, ki je med drugim zadolžen tudi za priključitev novih odjemalcev na omrežje. Zato sem v nalogi obdelal konkreten primer v RTP Koper, kjer sem analiziral obstoječe stanje, tako da sem na podlagi meritev in izračuna prišel do zaključka, da trenutno v RTP Koper ni potrebe po kompenzaciji jalove moči, saj je trenutni cos boljši od 0,95. Izračunal sem tudi, kako bo leta 2020, ko naj bi, glede na predvideno letno rast porabe električne energije, to je 2,3 % letno, poraba v RTP Koper toliko narasla, da bo treba sedanja dva transformatorja po 31,5 MW zamenjati z dvema transformatorjema po 40 MW. Kaj se bo zgodilo z jalovo močjo oziroma s cos? Pri enakem razmerju delovne in jalove moči seveda cos ostane isti, le količina jalove moči se poveča. V tistem obdobju bi bilo smiselno ponovno preučiti zadeve in takrat mogoče vgraditi kompenzacijsko napravo moči 3,0 MVAr na fazo. Na enake rezultate sem naletel tudi v študiji EIMV REDOS 2020 za slovensko Istro in obalo z zaledjem. Za zaključek naj povem, da so porabniki, ki se napajajo iz RTP Koper, zelo dobro kompenzirani. To se vidi iz podatkov, saj imajo, povečini, zelo dober cos. Imamo pa tudi nekaj izjem, ki imajo izredno slab cos. Na srečo imajo ti porabniki zelo majhno porabo delovne energije (so relativno majhni) tako, da je njihov vpliv na skupni cos v RTP Koper zanemarljiv. Naredil sem tudi izračun, kaj pomeni za skupni cos v RTP Koper, če bi vsi upravičeni odjemalci, ki imajo cos slabši od 0,95, kompenzirali na to vrednost. Dobil sem rezultat, da bi se cos izboljšal za 0.005, kar pomeni, da bi se iz sedanjih 0,975 povečal na 0,98. Izračunal sem tudi, kaj bi se zgodilo, če bi se vsi upravičeni odjemalci, ki imajo cos boljši od 0.95, kompenzirali le do te vrednosti. V tem primeru bi se skupni cos v RTP Koper poslabšal iz dosedanjih 0,975 na 0,961, kar pa je še vedno solidno in v okviru predpisov. Za konec naj omenim še primer upravičenega odjemalca s cos = 0,69, za katerega sem izračunal, kaj bi pri njegovi porabi pomenilo, če bi vgradil kompenzacijsko napravo. Rezultat izračuna je, da bi se še prej kot v enem letu kompenzacijska naprava izplačala in bi vsako naslednje leto prihranili približno 23.500 EUR pri računu za omrežnino. Iz zgoraj navedenega je razvidno, da se lahko na področju jalove moči še marsikaj naredi. Vendar je treba pred vsakim posegom zelo dobro preučiti, kaj in kako se bomo stvari lotili, kakšno kompenzacijo bomo vgradili ter kakšne moči naj bo ta naprava. Ne glede na ekonomsko upravičenost je treba na zadevo gledati tudi s tehničnega vidika. To pomeni, da je, poleg kompenzacije jalove energije, treba dati velik poudarek tudi na harmonske komponente, ki tudi vplivajo na kakovost električne energije. Z vse večjim številom močnostnih elektronskih komponent in drugih onesnaževalcev omrežja je to že postal velik problem, ki se bo v prihodnje stopnjeval.

• Language: Slovenian
• Keywords: jalova moč, kompenzacija, faktor moči, distribucija, elektroenergetski sistem
• Work type: Undergraduate thesis
• Organization: FE - Faculty of Electrical Engineering
• Year: 2016
• PID: 20.500.12556/RUL-83505
• Publication date in RUL: 16.06.2016

Secondary language

• Language: English
• Title: Analysis of reactive power in transformer substation

Abstract

The central part of the graduation thesis is related to the reactive power compensation. The emphasis is mainly on collecting the data on the reactive power and their influence on the change of cos in the substation RTP Koper in the case we would monitor the level of the reactive power compensation. Therefore, we have also discussed an actual case of the reactive power compensation on the consumer with extremely poor cos, actual economic justification ,of the investment, and the time of investment´s recovery. In our case, the latter will be especially interesting. The question of the reactive power compensation is especially highlighted by opening up the electricity market, since the bill for the electricity encompasses only working energy and the tip. Therefore, the electricity supplier is not concerned with the reactive power. Network operator, who is also responsible for connecting new consumers to the network, deals with the reactive power. In the thesis, I have therefore discussed an actual example in the substation ,RTP Koper, where I have analysed the existing situation. Based on the measurements and calculation, I came to a conclusion that currently in the substation RTP Koper there is no need for the reactive power compensation, since the current cos is better than 0.95. I have also ,calculated the situation for 2020 when, given the foreseen annual growth of the electricity ,consumption, which is 2.3 % per year, the consumption in the substation RTP Koper will rise so much that the two current transformers of 31.5MW will have to be replaced by the two transformers of 40MW. What will happen to the reactive power or cos? With the same ratio of the working and reactive power the cos will remain the same, only the amount of the reactive power will increase. In that period, it would be reasonably to re-examine the case, and then maybe install the compensation device with a power of 3.0MVAr per phase. I have encountered the same results in the study EIMV REDOS 2020 for Slovenian Istria and the coast with hinterland. In conclusion, I shall say that the consumers powered from the substation RTP Koper have a good compensation. That can be seen from the data, since they have a very good cos. However, there are some exceptions with a very poor cos. Fortunately, these consumers have a very small consumption of the working energy (they are relatively small). Therefore, their impact on the total cos in the substation RTP Koper is negligible. I have also made a calculation of what would happen to the total cos in the substation RTP Koper if all the consumers with the cos worse than 0.95 compensated it to this value. According to the result the cos would improve for 0.005, meaning that it would increase from the current 0.975 to 0.98. I have also calculated what would happen if all the eligible consumers with the cos better than 0.95 compensated it only up to this value. In this case, the total cos in the substation RTP Koper would deteriorate from the current 0.975 to 0.961, which is still solidly and within the regulations. In conclusion, I shall mention the case of the eligible consumer with the cos = 0.69 for whom I have calculated what would happen if they installed the compensation device. The result of the calculation revealed that the compensation device would pay back in less than a year, and in each of the following years they would save approximately EUR23,500 with the network costs. From the above, it is evident that in the field of the reactive power much more can be done. However, prior any intervention it must be very well considered what and how we will deal with things, what kind of compensation will be installed, and of what kind of power should the device be. Regardless of the economic justification, the matter must also be viewed from the technical perspective. That means that, in addition to the reactive power compensation, a great emphasis must be given to the harmonic components that influence the quality of electricity. With an increasing number of power electronic components and other network polluters, that has already become a great problem that will be increased in the future.

• Keywords: reactive power, compensation, power factor, distribution, electric power system