Study of the reactive power control methods of a solar power plant in a 35 kV distribution grid
Students Name: Pohrebniak Maksym Olehovych
Qualification Level: magister
Speciality: Electric Power Generation and Distribution Management Systems
Institute: Institute of Power Engineering and Control Systems
Mode of Study: full
Academic Year: 2022-2023 н.р.
Language of Defence: ukrainian
Abstract: The introduction of solar power plants into the electricity systems of Ukraine has increased significantly in recent years. Thus, in 2017-20, more than 6.2 GW of renewable energy solar power plants were put into operation in Ukraine, and already in the first half of 2021, the total capacity of solar power plants reached 6.4 GW [1,2]. As indicated in the latest analyzes of the operation modes of the energy system of Ukraine, this causes significant problems related to the regulation of frequency, power flows and voltage [3]. Analyzing the influence of solar power plants on the operation of electric power systems, it should be noted that their use significantly increases the efficiency of providing consumers with electric energy [4, 5]. But at the same time, it creates a number of problems in the operation of electric power systems, which requires the use of appropriate means of mitigating these negative effects and purposeful management of normal and transient modes of operation of solar plants. In many studies related to the use of solar power plants in electric power systems, considerable attention has been paid to the technologies for controlling its reactive power in order to mitigate the above-mentioned problems [3,6]. In distribution networks with solar stations, the voltage on the buses of remote substations increases. Reactive power flows also affect the network voltage. The capacitive reactance of solar stations leads to an additional increase in voltage, which can reach a critical level. Reactive power and voltage control functions allow operators to effectively mitigate the problems of the negative impact of solar power plants on electric network modes, related to voltage regulation, optimization of active power losses, and maintenance of stability and reliability of power supply. The object of study - electrical distribution grids. The scope of research - the operating conditions of the power grid with solar plants. The goal of the research - operating conditions calculations and analysing the influence of reactive power control methods of a solar power plant on voltage variations and energy loss in the power grid. The work is devoted to the study of the influence of the solar power plant on the operating conditions of the power grid. In the theoretical part, an analysis of the state of solar energy in the world and in Ukraine was carried out. Attention is focused on the peculiarities of using solar energy and the problems of its implementation in an electrical power grid. In the practical part of the work, a model was developed in the environment of the DAKAR software complex for researching the operating conditions of the electrical grid with a solar power plant. With the help of this model, an analysis of the influence of the solar power plant on energy losses and voltage variations in the investigated electrical grid was carried out. The results of the study showed that the use of a solar power plant inverter to compensate for reactive power in the analyzed distribution network is associated with the following contradiction: a decrease in energy losses due to an increase in the reactive power of a solar power plant leads to an increase in the amplitude of voltage variations in the network. Understanding this interaction is important when putting solar power plants into operation and choosing a way to control reactive power in real distribution networks.