Kratkoročno napovedovanje moči na VN/SN transformatorju ob visokem deležu obnovljivih virov

ILKOVSKI, MARJAN (author), Blažič, Boštjan (mentor)

Električno energijo s trenutno, širše dostopno tehnologijo, ne moremo skladiščiti v velikih količinah , zato je za optimalno obratovanje elektroenergetskega sistema potrebna usklajenost med porabo in proizvodnjo v sistemu. Do pred nekaj let je elektroenergetski sistem obratoval po uveljavljenem načinu proizvodnje električne energije v centraliziranih proizvodnih enotah ter distribucije energije do končnih odjemalcev. Danes vključevanje razpršenih virov proizvodnje , vse večja razširjenost elektromobilnosti, zahteve po učinkovitejši rabi energije in aktivnejši vlogi odjemalcev, ki so pripravljeni svojo porabo premikati izven okvirjev svojih standardnih vzorcev, pa postavljajo pred načrtovalce elektroenergetskega sistema kopico novih izzivov. Količina in dinamika oddane električne energije razpršenih virov v omrežje sta v veliki meri odvisna od vremenskih dejavnikov. Vse večji delež razpršenih virov, predvsem obnovljivih virov električne energije, ne prinaša velikih izzivov le na področju upravljanja elektroenergetskega sistema, temveč ima zelo izrazit vpliv tudi na dogajanje na elektroenergetskem trgu. Zato je zelo pomembno poznavanje napovedi porabe in proizvodnje, še posebej razpršenih virov, saj je ključno za stabilno obratovanje elektroenergetskega sistema, za prilagoditev proizvodnje konvencionalnih virov porabi in za trgovanje z električno energijo. V magistrskem delu je predmet našega zanimanja analiza in kratkoročna napoved pretoka (delovne) moči skozi RTP Breg. Za omrežje RTP Breg je značilno, da ima instalirano veliko število razpršenih virov. Njihov vpliv, predvsem sončnih elektrarn, katerim pripada skoraj 87 % skupne moči razpršenih virov, je najbolj opazen na dnevnem diagramu pretoka moči skozi RTP Breg. Elektrodistribucijsko podjetje Elektro Maribor nam je za potrebe analize in izračuna napovedi posredovalo zgodovinske podatke o pretoku moči skozi RTP Breg in o proizvodnji sončnih elektrarn v tem omrežju. Napovedi se lotevamo z uporabo ARIMA (avtoregresijski integrirani modeli drsečih povprečij) modela, oziroma njegove kombinacije. V magistrskem delu opišemo časovne vrste in njihove komponente, nato sledi še opis ključnih pojmov, ki so potrebni v analizi časovnih vrst. Nadalje je opisana metodologija ARIMA modela, ki spada v skupino statističnih metod. Razložen je postopek izdelave in izbire najprimernejšega ARIMA modela za kratkoročno napovedovanje pretoka moči za en dan vnaprej. Na koncu je podana primerjava treh metod napovedi pretoka moči skozi RTP Breg. Prva metoda temelji na združitvi napovedi proizvodnje in porabe električne energije, druga temelji na podlagi zgodovinskih podatkov pretoka moči, tretja pa poleg zgodovinskih podatkov pretoka moči vključuje še zunanjo pojasnjevalno spremenljivko sončnega obsevanja.

• Language: Slovenian
• Keywords: : kratkoročna napoved, pretok moči, RTP Breg, obnovljivi viri, sončne elektrarne, ARIMA model, sončno sevanje
• Work type: Master's thesis/paper
• Organization: FE - Faculty of Electrical Engineering
• Year: 2019
• PID: 20.500.12556/RUL-107478
• Publication date in RUL: 18.04.2019

Secondary language

• Language: English
• Title: Short-term forecast of the power on a HV/MV transformer with a high share of renewable sources

Abstract

With currently widely available technology, we cannot store electricity in large quantities, therefore it requires consistency between consumption and generation of electricity for optimal operation of the electric power system. Until couple of years ago, the power system operated according to the established models of electricity generation in centralized power plants and distributing electricity to consumers. Nowadays, integration of distributed energy resources (DER), increasing prevalence of electromobility, expectation of more efficient use of energy and a more active role for consumers, who are prepared to change their habits of consumption, all bring new challenges for power system planners The amount and dynamics of the electricity generated by DER in the network depend to a large extent on the weather factors. An increasing proportion of DER, especially renewable energy sources, does not only bring major challenges in the field of power system management, but it also affects the electricity market. Therefore it is very important to make forecasts of consumption and generation of electric energy, especially for DER, since it’s crucial for the stable operation of power system and for adaptation of generation of conventional sources to consumption and also for trading with electrical energy. In the master’s thesis, the subject of interest is the analysis and short-term forecast of (active) power flow through substation Breg. It is characteristic for the network of substation’s Breg, that it has installed a large number of DER. Their influence, especially solar power plants, which have almost 87 % of total power of DER, is the most noticeable on the daily diagram of power flow. Elektro Maribor d.d. gave us historical data of the power flow through substation Breg and the generation of solar power plants in that network. We tackle the forecasts with the use of ARIMA (autoregressive Integrated Moving Average) model and its combinations respectively. In the master’s thesis we describe time series and their components, followed by a description of key concepts, which are needed in the analysis of time series. Further it describes the methodology of the ARIMA model, which belongs to the group of statistical methods. The building and selection process of the most appropriate ARIMA model for short-term forecasting for one day ahead is explained. At the end, a comparison of all three methods of forecasting power flow is given. The first method is based on a combination of forecasts of production and generation of electrical energy, the second method is based only on historical data of power flow, the third method uses exogenous time series of global irradiance in addition to historical data of the power flow.

• Keywords: short-term forecast, power flow, substation Breg, renewable resources, solar power plants, ARIMA model, solar irradiance