Analysis of wind power plant impact on micro grid operating conditions
Students Name: Harhalia Pavlo Stepanovych
Qualification Level: magister
Speciality: Power Stations
Institute: Institute of Power Engineering and Control Systems
Mode of Study: part
Academic Year: 2020-2021 н.р.
Language of Defence: ukrainian
Abstract: Gargala P.S., Varetsky Y.O. (supervisor). Analysis of the influence of the wind power plant on the modes of operation of the microgrid. Master’s thesis - National University "Lviv Polytechnic", Lviv, 2020. Significant investments and the growing level of technology show that wind power plants are becoming increasingly profitable sources of energy, which are the result of changes in energy policy around the world [1]. The European Union’s climate and energy security policy requires Member States to increase the share of energy from renewable sources, while reducing greenhouse gas emissions - including carbon dioxide [2]. Their development is also influenced by the system of financial support in the form of green certificates. In Ukraine, conditions are less favorable than in some other countries for the use of wind energy due to the remoteness of its territory from the centers of cyclones, but the analysis shows that some regions are suitable for economic conditions to build wind farms with current equipment. As studies have shown, the parameters of the used wind power equipment allow to expect the efficiency of wind power plants under the condition of the average annual wind speed at a height of 10 m at the level of 5-6 m/s [3]. Increasing the number of renewable energy sources directly affects the operation of the entire power system. The impact on the power system has several advantages, but also causes some problems [4]. The electricity generated by these sources is mainly distributed in a distributed system, which increases the reliability of the network. However, due to the fact that they depend on often random factors, i.e. wind and solar energy, it is impossible to accurately predict and determine the amount of electricity produced. Due to the variable wind force driven by wind turbines, they rarely work with optimal efficiency, and the generated power is unstable [5]. During the operation of wind farms, many unwanted disturbances are introduced into the grid. This has a direct impact on the power quality for end users, the parameters of which are specified in the standards. The impact of wind power plants on the power system depends on the design of wind turbines, but above all on the way they are connected to the system. The location of wind farms is due to good wind conditions, so these are mostly sparsely populated areas where the energy system is not developed. The operation of the wind turbine is influenced by the parameters of the network, its structure and place of connection. It also affects the degree of impact of the power plant on the grid. There are several common ways to connect a wind farm to the grid. The most commonly used connection to an existing medium voltage distribution network, which also provides consumers. Due to the usually short distance of the wind turbine from the connection point, this is usually the cheapest way. The second method is to connect wind power plants to the medium voltage buses of the HV/MV substation. This method of connection is used when the medium voltage network is weak due to negative impact on the power quality or the distance to the substation is small. Object of study - electrical distribution grids. Scope of research - algorithms for calculating impact of wind farms on the microgrid operating conditions. Goal of research - calculations and analysis of the wind farm impact on voltage fluctuations and energy losses in the distribution network. The work is devoted to the analysis of the influence of the wind power plant on the state of the microgrid operating conditions. The theoretical part describes the renewable energy state-of-the art in the world and in Ukraine. The focus is on wind energy and a description of wind energy technologies in today’s economy. The principle of operation and commonly used designs of wind turbines and wind generators are considered. Disturbances brought by wind power plant to the power supply grid are characterized and the problems of their operation in electric power systems are considered. In the computational part of the work, algorithms and a program in the Mathcad software platform for studying the wind power plant impact on voltage fluctuations and energy loss in the electrical network are developed. Using this program on the example of the selected microgrid, which is connected to the bulk power system, calculations of its operating conditions are performed. As a result of the work it is shown that use of a wind power plant in the investigated electric grid allows to reduce considerably losses of active power and energy under supplying the microgrid consumers. The study of the reactive power impact of a wind power plant on the losses of power and energy in the electric network is carried out. An analysis of the influence of a wind power plant on voltage fluctuations in the electrical grid is carried out. The levels of voltage fluctuations in the microgrid buses at different values ??of the reactive power factor of the wind power plant are analyzed. It is shown that voltage fluctuations in the electric network decrease with the reduction of the reactive power factor of the wind power plant. Keywords - microgrid, wind speed, wind power plant, voltage fluctuations, active power losses, energy losses. References 1. Renewables 2018. Global Status Report . 2. Wiser R., Yang Z. (2011) Chap 7. Wind Energy // Renewable Energy Sources and Climate Change Mitigation. Cambridge University Press. 3. Velichko S.A. Energy of the environment of Ukraine (with electronic maps). Educational and methodical manual for undergraduates. Kharkiv – 2003. (ukr) 4. Ackermann, T. (ed.) (2005). Wind Power in Power Systems. John Wiley and Sons. 5. Fundamentals of wind energy: textbook / G. Pivnyak, F. Shkrabets, N. Neuberger, D. Tsyplenkov; Ministry of Education and Science of Ukraine, - D.: NSU, 2015. (ukr)