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KARG, L.
»SMART ENERGY MADE IN GERMANY: FIRST RESULTS OF THE E-ENERGY PROGRAMME«
KOMUNALNA ENERGETIKA / POWER ENGINERING, 1
Affordable and reliable energy supply is essential for our industrial growth. In the course of the basic energy reform in Germany, the structure of the supply system will undergo far-reaching changes in the coming decades. For example, the number of small and decentralised producers with highly volatile, weather-dependent power generation will increase. These developments pose a great challenge for grid operators.
PAPIČ, I.
»SMART GRIDS DEVELOPMENT PROGRAM IN SLOVENIA«
KOMUNALNA ENERGETIKA / POWER ENGINERING, 2
The concept of Smart Grids builds upon the modern concept of operation and power system planning. By joining classical (large centralized generation units, a transmission and distribution network) and new elements (distributed generation, advanced metering infrastructure, demand side management, virtual power plants, electric vehicles and energy storage systems), SmartGrids creates an effective system.
BENEŠ, I.
»DISTRIBUTED ENERGY AND SMART GRID CAN CONTRIBUTE TO SURVIVE DISASTER«
KOMUNALNA ENERGETIKA / POWER ENGINERING, 4
The paper presents Czech research project in the field of smart critical infrastructure. Aim of this project is to create bridge between liberalized power business and new challenges rising from global risks. During the disaster it is necessary to ensure basic human needs and protection. The continuity of critical infrastructure must be secured against the consequences of cascading phenomena and the domino effect. Project solves the resilience of power distribution against national transmission grid blackout. Project’s goal is to demonstrate possibility of crisis demand side management that enables to provide necessary electricity for residents and critical infrastructure through adaptive distribution grid islanding. This function should be a basic functionality of smart grids. Project No2A-1TP1/065 „Increasing the resilience of the distribution system against long-term transmission grid blackout in order to enhance public safety” was supported by the Czech Ministry of Industry and Trade in the framework of “Sustainable prosperity” program. Project is called RESPO - REsilient POwer. This paper presents successful story of how society is willing to invest in resilience after a disaster experience.
ROPOŠA, S., ŠTUMBERGER, G.
»SMARTGRIDS IMPLEMENTATION IN THE CASE OF ELEKTRO MARIBOR«
KOMUNALNA ENERGETIKA / POWER ENGINERING, 5
Limited sources of fossil fuels and emissions of greenhouse gases related with the combustion of these fuels force use to increase the use of renewable energy sources. Unfortunately, the renewable energy sources are often distributed in the space and are not always available. Technical solutions for utilization of renewable energy sources are relatively expensive while the cost of energy, produced in this way, are too high to be economically bearable without national support schemes.
In spite of aforementioned drawbacks, European Union and Slovenia have made political decisions to support energy production from renewable energy sources. The electrical power generation based on renewable energy sources in Slovenia is focused on utilization of sun energy, water energy and biomass. A substantial increase in the number of installed electric power generation units, based on renewable energy sources, has been reported the last years. The share of photovoltaic power plants is dominant. It must be pointed out that the power system, as well as the transmission and distribution networks, were designed and build considering the energy flow from the power plants towards consumers. However, the increasing share of distributed electrical power generation units, connected to the electricity network, can change the direction and increase the dynamics of changes in the power flow. Such operation could cause problems in the electricity networks not designed for that kind of operation. The solution called SmartGrids should help to solve problems, related with the increased share of distributed power generation connected to the electricity networks.
KOLENC, M., PAPIČ, I., BLAŽIČ, B.
LOCAL VOLTAGE CONTROL IN SMART GRIDS WITH TIME DEPENDENT POWER FACTOR
KOMUNALNA ENERGETIKA / POWER ENGINERING, 14
This paper deals with the influence of a lagre share of dispersed generation (DG) on a voltage profile in distribution networks. Until recently, the newly installed DG operated only with constant power factor, which was usually cos = 1. Countries around the world are now accepting the new rules and guidelines, which require that all DG participate in the voltage regulation, as they are the main reason for the voltage rise in distribution networks. Slovenia has already issued a document that prescribes different static characteristics Q(U), which determine the power factor of DG with respect to the voltage at the connection point.
As the new technologies nowadays allow bidirectional data flow in almost real time, more active participation of generators in voltage regulation is possible. Concept of voltage regulation which exploits these ideas is presented. At a certain intervals desired cos can be send to all generators in the network. Advantages of such a regulation are pinpointed out. Different solutions were evaluated by means of simulation on a real medium-voltage network, which demonstrate good flexibility when using such a methods.
AIGNER, M., RAUNIG, C., SCHMAUTZER, E., FICKERT, L.
SMART GRIDS – CONSIDERATIONS REGARDING PROTECTION OF ELECTRICAL INSTALLATIONS AND SAFETY IN CASE OF DECENTRALIZED POWER SUPPLY
KOMUNALNA ENERGETIKA / POWER ENGINERING, 19
Parallel to the progress of information- and communication technology in recent years, energy production and energy distribution get more economic and efficient; so called Smart Grids get more attention. The focus of the Smart Grid infrastructure lies in the increased involvement of decentralized power generation, exemplarily photovoltaic plants, small hydro power generators or stirling engines in the low-voltage or medium-voltage network. Due to the increased integration of distributed (renewable) energy generation systems, a significant contribution concerning the reduction of CO2 emissions claimed in the 20-20-20 targets and transmission losses is provided.
An important advantage of Smart Grids is the possibility of a multivalent up to a fully independent power supply for islanded grids and microgrids. In case of a failing (separation from the distribution network) a certain degree of power can be principally maintained by decentralized feed-in. Short circuit currents from distribution transformers and additional short circuit currents from decentralized sources (bidirectional current flow) can lead to a incompatibility with existing protection systems.
Therefore the increased integration of decentralized generation requires new considerations regarding protection systems in terms of personal safety and safety of electrical equipment.
The neutral point treatment of decentralized sources, transformers and uninterrupted supply units in combination with distribution transformer is important for security of networks and personal safety.
This paper shows exemplary the effects of a missing neutral point to earth connection (earthing) of decentralized generators in case of parallel supply.
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