BEV
bus
CHP
CIP
CNG
NOX
ORC
RES
    Print  

SREĆKOVIĆ, N., BELIČ, E., ŠTUMBERGER, G.
COMPARISON OF METHODS FOR LOAD FLOW CALCULATION IN LOW VOLTAGE DISTRIBUTION NETWORK WITH CONNECTED DISPERSED PRODUCTION
KOMUNALNA ENERGETIKA / POWER ENGINERING, 8
Load flow analysis represents one of the core methods used in modern distribution system operation. Therefore, it is necessary to provide efficient, numerically robust load flow algorithms with fast convergence and minimum usage of memory, suitable for variety of operating scenarios. The paper presents, compares and evaluates two efficient methods for load flow calculation in distribution network – backward/forward sweep method and direct method. The procedure of modeling the distribution network elements – line sections, loads, distributed generation units, as well as the implementation of algorithms, has been presented. The analysis has been performed on low voltage distribution network system.

KOUBA, D., NOHÁČOVÁ, L.
TWO SIMULTANEOUS FAULTS IN MIDDLE VOLTAGE DISTRIBUTION NETWORK
KOMUNALNA ENERGETIKA / POWER ENGINERING, 14
This paper deals with the method of solution of two simultaneous faults in the middle voltage distribution network, specifically two-port network theory. The main focus of this thesis is on the earth faults, in the resonant earthed neutral system of the middle voltage network and hence simultaneous single-phase earth faults are described in detail. Theoretical formulations are used to solve examples and results are commented.

BELIČ, E., SUKIČ, P., DEŽELAK, K., ŠTUMBERGER, G.
DYNAMICAL MODEL OF DISTRIBUTION NETWORK WITH DISTRIBUTED GENERATION
KOMUNALNA ENERGETIKA / POWER ENGINERING, 18
In this paper a dynamical model of distribution network with distributed generation is presented. Model of distribution network was developed using software package Matlab/Simulink with its blockset SymPowerSystems. Elements of utility network like supply network, power lines, load, and distribution transformer were modeled with elements which are already included in this blockset, but the distributed generator model was developed based on the current injection to the grid, considering references of active and reactive power. The aim of network modeling was to analyze the voltage profiles and transmission loses before and after connection of the distributed generation to the grid. Presented are the results of performed analysis.

SOTLAR, T., PIHLER, J., ROŠER, M.
IMPACT OF THE GENERATOR TO SHORT-CIRCUIT CONDITIONS IN THE DISTRIBUTION NETWORK
KOMUNALNA ENERGETIKA / POWER ENGINERING, 27
The article deals with the analysis of the impact of the generator to short-circuit conditions in the distribution network. The aim is to determine the effect of synchronous generator on short-circuit currents, which are at the point of connection baseline data for the design and sizing of individual network elements. Short-circuit currents will be in point of short circuit determined using a DMS software tool that is developed for the analysis of the actual situation in the network and also enables the calculation of the parameters of all types of short circuits. Analysis of the impact of the generator to the short-circuit currents in the distribution network is carried out in point near the generator and point away from the generator by comparing the results with the generator on and off.

NOHÁČOVÁ, L., ŽÁK, F., KROPÁČEK, V.
CAPACITIVE EARTH-FAULT CURRENT IN DISTRIBUTION NETWORKS OPERATED WITH THE ISOLATED NEUTRAL POINT
KOMUNALNA ENERGETIKA / POWER ENGINERING, 29
This paper deals with the method of solution of capacitive earth-fault current in distribution. The value of phase earth capacity in the network can be determined using the voltage ratio in the network and the capacity value of the connected capacitor. The new indirect method of measurement and calculation of phase-earth capacity in networks with isolated neutral point is based on creation of short-term phase capacity asymmetry in the network. When expanded, the method can be also used for leakage current estimation. Furthermore, this method can be applied to periodic controls of the earth capacitive current value. For the evaluation of the phase earth capacity, a single-purpose automatic can be used and thus the whole process of measurement and evaluation is conducted with a defined period (at a given hour, day, month…) or on operator’s command.

SOVIČ, B., GOVEDIČ, B.
IMPACT OF THE ELECTROMOBILITY DEVELOPMENT ON THE DISTRIBUTION NETWORK OF ELEKTRO MARIBOR
KOMUNALNA ENERGETIKA / POWER ENGINERING, 30
The use of clean, alternative fuels for transport and development of electromobility can have significant influence on the reduction of carbon dioxide emissions and other environmental impacts, including the reduction of PM10 and PM2,5 emissions. Development trends of electromobility envisage a gradual increase in the number of electric vehicles (EV). Prerequisite is sufficient number of EV charging stations. The expansion of electromobility largely depends on development of the EV, balanced incentive measures, regulatory framework, development of business models and local communities initiatives. Electricity distribution network must be prepared for large scale of EV penetration and increased number of charging stations. In particular, an increase in peak power has great influence on the development of the distribution network and introduction of the Smart Grids concept.

SREĆKOVIĆ, N., TRBUŠIČ, M., BELIČ, E., ŠTUMBERGER, G.
PROVIDING THE PROPER VOLTAGE PROFILES WITHIN THE MEDIUM VOLTAGE DISTRIBUTION NETWORK WITH PV SYSTEMS
KOMUNALNA ENERGETIKA / POWER ENGINERING, 32
Proliferation of the distributed electric power generation (DG) units requires the evaluation of different effects that DG units may have on the electricity network operation. Photovoltaic (PV) systems that are properly placed and sized, as well as equipped with the suitable control systems, may have positive impact on the voltage profiles and the reduction of losses of electric energy within the network. This paper discusses the possibility of providing the proper voltage profiles within the medium voltage distribution network, using the optimal reactive power generation and/or optimal reduction of active power generation from PV systems. Time – discrete calculation of the network operating conditions throughout the year were performed on two existing medium voltage distribution networks. Optimal values of reactive power generation and the reduction of active power generation were determined using the differential evolution in time points, where voltage rise, higher than the allowed, occurred. The results obtained suggest that reactive power generation from the existing PV systems should be used in voltage control, followed by the reduction of active power generation when necessary.

BELIČ, E., VOH, J., SUKIČ, P., ŠTUMBERGER, G.
IMPACT OF PHOTOVOLTAIC SYSTEMS’ REACTIVE POWER GENERATION ON ACTIVE POWER GENERATION AND TRANSMISSION LOSSES IN THE LOW VOLTAGE DISTRIBUTION NETWORK
KOMUNALNA ENERGETIKA / POWER ENGINERING, 33
This paper evaluates the impact of photovoltaic systems’ reactive power generation on active power generation and transmission losses in the low voltage distribution network. The introduced experimental system consists of two major parts. The photovoltaic system represents the first part, in which every photovoltaic module is connected to the low voltage network by the individual microinverter. Two way communication is established to each microinverter by the communication gateway. The second part consists of a control system with data acquisition system. The flexible experimental system offers a possibility to add and establish different network connections of the single-phase or three-phase smart grids. Within the scope of this work, additional cable was installed to establish one phase low voltage network with the photovoltaic system on one side and network on the other. The results of the analysis and measurements performed for operation of experimental low voltage network show that the reactive power generation in photovoltaic systems increases the amount of active power that can be generated in photovoltaic systems without to violate voltage profile. However, with both of these actions transmission losses in the low voltage network increase.

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.

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.

  HOME MEETING SCHEDULE CONTENT PRESENTATION ARCHIVE E-REGISTRATION