KOMUNALNA ENERGETIKA / POWER ENGINERING 2017
DIMNIK, J.
U-1-ENERGY MANAGEMENT: REGULATIONS, CURRENT PRACTICE AND FUTURE DIRECTIONS
KOMUNALNA ENERGETIKA / POWER ENGINERING, 000
KOKALJ, F.
U-3-HEAT MANAGEMENT
KOMUNALNA ENERGETIKA / POWER ENGINERING, 000
GRAPULIN, A.
U-4-GAS MANAGEMENT
KOMUNALNA ENERGETIKA / POWER ENGINERING, 000
ŠTUMBERGER, G.
U-5-ENERGY MANAGEMENT PLANNING IN CASE OF ELECTRIC ENERGY
KOMUNALNA ENERGETIKA / POWER ENGINERING, 000
PAPLER, D.
U-6-ISO 50001 STANDARD FOR EFFICIENT ENERGY MANAGEMENT
KOMUNALNA ENERGETIKA / POWER ENGINERING, 000
Godina, D.
U-2-ROLE OF ENERGY AGENCY IN SUPPLY WITH ELECTRIC ENERGY, NATURAL GAS AND HEAT
KOMUNALNA ENERGETIKA / POWER ENGINERING, 000
Komunalna energetika 2017, _.
KOMUNALNA ENERGETIKA / POWER ENGINERING, 000
Komunalna energetika 2017, _.
KOMUNALNA ENERGETIKA / POWER ENGINERING, 00
Komunalna energetika 2017, _.
KOMUNALNA ENERGETIKA / POWER ENGINERING, 0
PIHLER, J.
KOMUNALNA ENERGETIKA / POWER ENGINERING, 0
KOKOT KRAJNC, M., DOMJAN, A.
Performing Energy Efficiency Policy in Slovenia
KOMUNALNA ENERGETIKA / POWER ENGINERING, 1
Energy efficiency is one of the key pillars of the EU's climate and energy policy, as it pursues the awareness that only the energy that we don’t use is the cheapest, cleanest and the most reliable. This awareness was the basis for amendments of existing Directive on energy efficiency, which extends the energy savings targets by 2030. In this article, we present novelties that Slovenia will have to take into account regarding energy efficiency. We also introduce the results of energy savings that were reported for 2015, as well as new measures, which will contribute to achieving the objectives set out in the amended Directive.
ČIŽMAN, J., STANIČIĆ, D., ČESEN, M., ROŽMAN, M., GERMIČ, L., KOKALJ, F.
Concept of Conducting a Spatial Analysis of Heat Consumptionand Supply in the City Of Maribor
KOMUNALNA ENERGETIKA / POWER ENGINERING, 9
Sustainable heating and cooling solutions are based on modern technologies and increasing integration of various sectors of energy consumption and energy production – buildings, industry, electricity generation, and transport. District heating and cooling systems enable integration of various sectors, thus allowing for efficient management of all available energy sources and sinks. When planning energy management in a local community, such solutions require a systemic approach based on thorough spatial analysis of the current state and future development. The paper introduces the concept of conducting a spatial analysis of heat consumption and supply by using geographic information system tools of the City of Maribor.
KOŽELJ, K., KOS, A., BOBEK, D.
Involving Consumers in the Programmes of Consumption Adjustment by Using Dynamic Tariffing Within the European Project Flex4Grid
KOMUNALNA ENERGETIKA / POWER ENGINERING, 19
The distribution company Elektro Celje d.d. as a member of the International Consortium has successfully applied for the European Programme Tender on Research and Innovations Horizon 2020 with Flex4Grid project focusing on solutions that would allow flexibility management of users – the so-called prosumers of the distribution network in the field of consumption as well as power generation.
Flex4Grid, a European Development Project, focuses primarily on the development of an open technological system for data management and service provision which would allow managing user or prosumer flexibility of the distribution network in respect of their power consumption as well as power generation. Prosumer flexibility is a capability of prosumers to adjust their consumption or power generation to the needs of other stakeholders within the system, and could be rewarded for such adjustment. The service will be offered in a computer cloud where anonymised data will be collected. Some new business models will be developed and some new incentives for prosumer participation in such projects will be introduced.
GETINO, E., GARCÍA, E., DEŽELAK, K.
Analysis of the Spanish Electricity Market and Proposals for Future Development
KOMUNALNA ENERGETIKA / POWER ENGINERING, 33
Nowadays the electricity is found in any daily activity, while a state can not develop its economic and social potential without a consolidated electricity system. In sense of the liberalized electrical systems, the figure of an electric market becomes fundamental. This paper shows an overview of the Spanish electricity market, involving its problems and future objectives. Spain as a member of the European Union faces the demands proposed by the European Commission. The European challenge is not an individual challenge for individual member but requires the cooperation of all member states, moving towards an energetically integrated European Union.
GSODAM, P., STIGLER, H.
What is it Worth? Determining the Capital Stock of European Hydropower Plants
KOMUNALNA ENERGETIKA / POWER ENGINERING, 41
High lifetimes and high capital intensities characterize fixed assets of electric utilities. The historical cost concept implicate that long-lasting fixed assets are shown too low in balance sheets of electric utilities: the real value of long-lasting assets is not shown because of nominal price increases. An alternative to show the real value of long-term assets represents the capital stock concept based on replacement values less depreciations (net capital stock). To calculate the capital stock, information regarding the level of investment in each power plant at the time of construction (historical acquisition values) and with regard to a common base year (replacement values) is necessary. This paper shows how the not-standardized investments in hydropower plants can be estimated and how the capital stock of run-of-river and threshold hydropower plants can be calculated. Long-term assets in the form of run-of-river and threshold hydropower plants are compared based on historic costs and replacement values. The paper concludes that given nominal price increases for replacement investments, as is the case with long-lasting hydropower plants, only depreciations based on replacement values can ensure preservation of the company’s assets.
POLAJŽER, B., SRPAK, D.
Evaluation of Probability-Distribution Models for Wind-Power Forecast Error
KOMUNALNA ENERGETIKA / POWER ENGINERING, 53
This paper discusses different probability-distribution models for wind-power forecast error. Models known from the literature (beta, Weibull, gamma) are discussed along with the models with extended-skew generalized-normal distribution. Furthermore, a versatile model is discussed, which enables analytical calculation of the percentile function; however, it is sensitive to wavelets in the probability distribution. Obtained results show that beta, Weibull and gamma probability distributions do not capture the actual (empirical) one; far more adequate are models with skew generalized-normal probability distribution.
BHAT, K. S., BACHHIESL, U.
Practicality of Base Load Renewable Generation in India
KOMUNALNA ENERGETIKA / POWER ENGINERING, 61
India, among several other countries globally, now faces a unique situation where managing the energy transition process without hurting the economic development becomes the highlight of its policies. The Indian power sector is highly carbon intensive, with coal based power providing 70% of the total electricity generated. Renewable energy occupies around 15% of the capacity mix. Energy access along with several other challenges, pose an obstacle to the needed transition to clean energy. As the seasonal load variations in India are not prominent, cheap coal based power supplies most of the load profile, while gas power plants are used for peak loads. The myth that renewable energy sources cannot meet baseload demand has become widely accepted and wide-spread, given their fluctuating nature. Several studies demonstrate an optimistic transition to 100% renewable sources might just be possible in the coming decades. In a carbon-rich power sector like India, the ‘base load’ mind set is a pretty big and powerful hurdle, as ensuring base load generation becomes a major issue with implications directly affecting the country’s economy. In this study, an effort has been made to discuss whether base load renewable generation in India is feasible, and the challenges involved.
BACHHIESL, U., KORDASCH, N.
Development Scenarios for E-Mobility in Europe
KOMUNALNA ENERGETIKA / POWER ENGINERING, 73
This paper presents development scenarios for e-mobility in Europe. The analysis of the initial situation shows, that key factors such as climate change or dependence on oil in the mobility sector call for a promotion of e-mobility globally and in Europe. This development is influenced by given targets in the European Union regarding alternative mobility. Furthermore, the fundamental aspects of e-mobility like the advantages and disadvantages or the different types of vehicles are introduced. With the help of recent sales numbers the European EV market has been divided into battery electric vehicles (BEV) and plug-in hybrid electric vehicles (PHEV) and has been analysed in detail for each country for the years 2011 to 2015. Based on this data, an in-depth research on the countries’ promotion and support measures regarding e-mobility has been conducted. The global e-mobility targets (IEA2DS, IEA4DS, Paris Declaration) are converted into European targets and in relation to these targets three different scenarios (LOW, MEDIUM and HIGH) have been developed. These scenarios describe the growth of the EV market from 2016 to 2030 and are based on the actual numbers of EV. In addition, by using predefined average values for the EV the power consumption of the EV has been calculated and put in relation to the overall power consumption of the countries for every year until 2030. Concluding a summary of the present supporting measures of the investigated European countries for EV will be given in this paper.
ČERNEC, D.
Challenges in Sustainable Use of Phosphorus
KOMUNALNA ENERGETIKA / POWER ENGINERING, 87
With the increasing world population growth a global demand for food is increasing rapidly. Until recently phosphate rock deposits were not thought of being a finite reserve and extracting phosphorus from this rock seemed to be the ultimate source of phosphorus for the future generations. But on the basis of new findings it has become evident that these reserves cannot last forever. This article summarizes some of these findings and presents some alternative ways of phosphorus recovering from waste streams.
KEŽMAH, B.
Personal Data Protection in Electric Energy Distribution
KOMUNALNA ENERGETIKA / POWER ENGINERING, 97
Personal data protection remains a central regulatory mechanism for ensuring the overall security of information systems. The regulations guide information systems owners towards best governance, management and information security practices. An important part of security controls are audit trails and systematic identification of personal data. In this paper, we analyse the definition of the audit trail, its importance and practical examples to present identification of personal data in the area of electricity distribution.
JELENC, B.
Slovenian-Japanese Research and Development Demonstration Project
KOMUNALNA ENERGETIKA / POWER ENGINERING, 105
In control theory, observability is a measure for how well internal states of a system can be inferred by knowledge of its external outputs. The observability and controllability of a system are mathematical duals. Both of them are also final goal of every System operator.The development of the Smart Grid concept is the pathway for assuring flexible, reliable and efficient distribution networks while integrating high shares od Distributed Energy Resources. Within smart grid paradigm the highly flexible and controllable Low Voltage Network is able to decentralize the distribution management and control system while providing additional controllability, observability and improves the security and reliability of the system.
THALER, S., URAN, C., PECNIK, M.
“AKKU 4 LIFE” - An Experimental Health Condition Diagnosis of Second-Life Lithium-Ion Batteries
KOMUNALNA ENERGETIKA / POWER ENGINERING, 115
In order to enable the reuse of a second hand battery a reliable assessment of their health status is necessary. For preselection in the recycling route very quick and meaningful status analyzes are required. This preselection whether total loss, alteration, rebuilding or reloading and ”Refreshing” is necessary, and is to take place via electronic analysis systems. The basis for this measurement system integration is to take place under the Device title ”Dynamic Battery Analyzer DBA” in this project.
LOVREC, D., TIČ, V.
The Importance of Hydraulic Oil Real-Condition Identification as a Basis for Strategical Desicion-Making
KOMUNALNA ENERGETIKA / POWER ENGINERING, 127
Conventional mineral-based hydraulic oils and turbine oils used within energy plants and machines have different long service-lives. This depends on variety of different factors: by proper maintenance, monitoring activities and strategies, and by careful selection of oil-type. Aging mechanism of hydraulic oils and the fact why they need to be replaced are well-known to the user, but lesser-known is the fact that there are great differences in the durability of hydraulic oils when exposed to machine-operating conditions.
Any extensions in the service-lifetimes of hydraulic or turbine oils can deliver both, cost savings and environmental benefits, but requires the knowledge of real oil-condition. In order to evaluate the service-life of oil, this paper proposes a novel method appropriate for on-line condition monitoring and testing the durability and oxidation stabilities of different hydraulic oils. The test results can be used for selecting the more adequate oil with a long service-lifetime.
TIČ, V., LOVREC, D.
Challenges of on-Line Condition Monitoring of Hydraulic Oils
KOMUNALNA ENERGETIKA / POWER ENGINERING, 137
Ensuring adequate quality of hydraulic oil and planning its change is crucial for a stable and smooth operation of many industrial machines. The best reliability can certainly be provided by using continuous monitoring of hydraulic oils, which is usually carried out remotely by means of modern online sensors.
Nevertheless, the development and implementation of such a system represents a unique challenge, since the measurement of the oil condition is much more complicated than measuring usual operating parameters, such as pressure or temperature.
BONE, G., RUDEŽ, U., MIHALIČ, R.
On-Line Identifiability of a Synchronous Generator by Linearized Equivalent
KOMUNALNA ENERGETIKA / POWER ENGINERING, 157
In this paper the identifiability of synchronous generator’s parameters from time domain measurements at the terminals using a linearized equivalent is examined and a decoupled brute force algorithm for identification is presented. The generator model has two windings on both, the quadrature and the direct axis of the rotor. Measurements are carried out at the terminals; therefore the instantaneous values for rotor’s angle and rotational speed are unknown. A synchronous generator operating in a single machine infinite bus (SMIB) system was simulated. Field voltage was simulated to undergo a rectangular pulse change and the electrical quantities at the generator’s terminals were measured. To search the values of generator’s parameters brute force algorithm was used, since it provides an insight into all possible parameter sets which satisfy the identification criteria. After it has been established that some measured variables are insensitive to changes of certain parameters, a multistage approach was justified; without it, brute force search would not be feasible. Since the dynamics obtained with various parameter sets nearly coincides with that of the original simulation it is concluded that the synchronous generator’s parameter identification using the eighth order model in a linearized set up is not generally possible.
BOGOVIČ, J., MIHALIČ, R.
Flexible Alternating Current Transmission System Devices Compensator for Distribution System
KOMUNALNA ENERGETIKA / POWER ENGINERING, 171
One of the possible solutions for improving voltage conditions in an electric power system (EPS) is applying power electronics based or so called flexible alternating current transmission system (FACTS) devices. However, the appropriate inclusion of a FACTS device into the EPS is not a straightforward procedure. On the contrary, it requires several steps. One of the first steps is the power flow analysis, which requires an appropriate FACTS device modelling.
In the past the models of FACTS devices for Newton-Raphson (NR) power-flow and current-injection calculation methods have been developed. The NR analysis, however, is not always suitable for distribution networks due to convergence problems. This is why new three-phase models of FACTS devices for the forward/backward sweep method are presented in this paper. Their application is demonstrated on an IEEE 34 and 123 bus test systems, in order to clearly present the approach virtues for FACTS modelling in distribution networks with included distributed generation units (DGs).
RUDEŽ, U., MIHALIČ, R.
Impact of Considered SVC Implementation in the Slovenian Power System on Inter-Area ENTSO-E Oscillation Damping
KOMUNALNA ENERGETIKA / POWER ENGINERING, 191
During the planning process of possible future investments into the Slovenian power system, a need arose for the comprehensive analysis related to low-frequency inter-area oscillation damping of a static var compensator (SVC) device. The SVC device was initially considered for solving local steady-state voltage issues on highest 220 kV and 400 kV voltage levels in the region. As the SVC device features fast dynamic response, it seemed reasonable to verify whether its implementation benefits the operation of the entire ENTSO-E interconnection as well. The presented analysis was performed using a complex model for dynamic studies, comprising publicly available ENTSO-E model and internally constructed Slovenian power-system model, which was successfully tested and verified in the past. Modelling of the SVC device was achieved by means of available research publications dealing with the subject, both foreign as well as domestic. By implementing a simple damping strategy, the results showed a positive effect on a small-signal stability and indicated which inter-area oscillations can be successfully damped when considered devices are connected to the Slovenian high-voltage transmission network.
HRASTNIK, D.
Analysis of the Impact of Distributed Power Generation on Distribution Network in Upper Savinjska Dolina
KOMUNALNA ENERGETIKA / POWER ENGINERING, 201
The load flow calculation is one of the main functionalities incorporated in modern distribution network management systems. In this article, an already known load flow calculation method, combined with an optimization procedure, is applied and tested in the case of real distribution network in Zgornja Savinska dolina (upper part of valley Savinjska dolina), more precisely on distribution lines Rastke and Logarska dolina. The impact of electrical energy produced in distributed generation units on discussed distribution network is evaluated. The optimization procedure is applied to determine the reference values for active and reactive power generation in distributed generation units connected to the low voltage side of distribution transformers, where the impact of generated active and reactive power on voltage profile and distribution network losses in medium voltage network is analyzed.
PINTARIČ, M., ROŠER, M., ŠTUMBERGER, G.
Optimization of Distribution Network Operation Based on Reconnection, Clossed-Loop Operation and Reactive Power Generation – A Case Study
KOMUNALNA ENERGETIKA / POWER ENGINERING, 221
The paper deals with problems of increasing the load in the distribution network that already operates near the limit load. Optimization procedure with reconnections, operation in loop and reactive power generation is being used to determinate maximal acceptable load. All analyses are made with program for load flow calculations. This paper shows results of the load flow calculations on the existing distribution network. Maximal power of two industrial consumers, which want to increase their power, was calculated based on the maximal load of the network without considering distribution generation. Operation of network in loop is also analyzed at normal network load and at maximal load. Solution to problem of too high voltage in the network, because of big distribution generation, is presented.
SKORNŠEK, M., ŠTUMBERGER, G.
Algoritem for Predicting Solar Power Plant Output Power with an Artificial Neural Network
KOMUNALNA ENERGETIKA / POWER ENGINERING, 229
This work deals with the comparison of operating propertis of photovoltaic power plants. All derogations in the operation of photovoltaic power plant can be monitored with additional measurements of solar irradiation and temperature of photovoltaic cells. Based on data acquired during six months operation of discussed photovoltaic power plant an Artificial Neural Network (ANN) has been built in order to predict output power of the power plant. The ANN complements the already existing monitoring system. When the difference between the ANN predicted and measured output power of the photovoltaic power plant is too high, a detail check of the power plant components is required.
SARAJLIĆ, M., KITAK, P., SARAJLIĆ, N., PIHLER, J.
Electric Field Strength of the Medium Voltage Post Insulator with Different Number of Ribs
KOMUNALNA ENERGETIKA / POWER ENGINERING, 239
The paper describes the designing of a medium voltage post insulator. The insulator model was designed in Matlab software and calculations of the electric field were in Elefant software. The emphasis is on the external shape of the insulator. The paper presents examples of the insulator with different number of ribs and their influence on the insulator’s electric field strength.