Davor Bajs

Impact of Wind Power Plants on Power System Operation in Croatia

The system operators need for secure and stable system operation is on the contrary to wind power plant investors need for evacuation of higher level of wind power production. In overtaking this gap the most significant role is given to definition of clear and non-discriminatory technical criteria for connecting and operation of wind power plants. This is for the sake of the system operator (safe and stable system operation) and the sake of wind power plant investors (larger share of wind power plants in the system). This paper gives an overview of technical criteria for wind power plant operation from the system operator point of view and respecting experience and suggestions for Croatian power system.

Preparation of large scale wind integration in South East Europe

This paper presents the main technical issues raised by large wind power plants integration in South East Europe. Regional wind power plant (WPP) integration perspective of necessary grid reinforcements, system balancing and network losses are described. The analyses were based on the power system and WPP input data collected and verified by the 12 TSOs through different questionnaires and intensive cooperation in the last few years [1].

Modified dynamic programming method for reactive power compensating device allocation

The main topic of this paper refers to reactive power compensating device allocation. By means of modified dynamic programming method, as proposed in this paper, optimal rated power and location of a compensating device are obtained in order to simultaneously satisfy voltage limit constraints, minimize active power loss and avoid voltage collapse in transmission network. In other words, it is necessary to unify all three criteria and find single optimal solution. Software package OPTLOK is developed on the basis of proposed method. At the end, an example given for the realistic transmission network of Croatia is exercised. Croatia, as well as some other South East Europe countries is expected to face serious reactive power compensation problem after the UCTE reconnection that happened recently.

Identification of critical network elements and recommendations to sustain electricity market in Southeast Europe

Net Transfer Capacity (NTC) values are an indication of cross-border transmission capacities that may be used by market participants to conduct electricity transactions across the borders of two or more areas (countries) in Europe. Cross-border transmission capacities, defined by neighboring TSOs, are generally restricted due to capacity limitations of tie-lines and concerns related to the secure operation of an internal transmission network. In this paper the NTC values are analyzed in a specific area of Southeast Europe in order to identify critical network elements which limit cross-border trade as a result of low NTC. Recommendations are also given that could be implemented to increase cross-border trade without large investments in transmission infrastructure. Analyses were based on the comprehensive study [1, 2] prepared by the Southeast Europe Cooperation Initiative regional transmission system planning working group (SECI TSP WG), supported by USAID and USEA with active participation of 11 regional TSOs.

Existing SEE transmission system and development

This paper presents basic data about Southeast Europe power systems with emphasizing the transmission system and its development. The region of SEE is going through the process of economic transition from state controlled to market oriented economies. One aspect of the transition is an establishment of common electricity market. All power supply companies in the region are going through the processes of restructuring, market opening and privatization at the same time. Regional transmission system, controlled by several Transmission System Operators, should support market activities in the future.