Analysis of the Impact of the Distributed Generation Facilities on Protection Systems and Voltage Mode: Review

In recent decades, in the process of restructuring energy systems, centralized energy sources are being replaced by decentralized ones. This led to the emergence of a new concept (power generation) in power supply systems, especially in distribution systems, known as «distributed generation». Distributed generation was introduced into the power systems, especially at the low voltage level, to make them more reliable, safer and efficient. At the same time, various problems appeared in the power supply systems that require solving issues of ensuring the selectivity and sensitivity of the protection action, maintaining the required voltage level. Since the current and future trends in the development of electric power systems are aimed at increasing the integration of distributed generation, especially through installations, made based on renewable energy sources, it is required to conduct studies on the impact of these generation technologies on the distribution networks. When using distributed generation, setting up the protection system is associated with the problems associated with changes in the magnitude and direction of emergency currents. Distributed generation installations affect the fault current in a certain way, while influencing the overcurrent protection systems in terms of their coordination. In this regard, the alternative protection systems and algorithms can be used, such as directional overcurrent relays. In addition, highly penetrating distributed generation devices such as photovoltaic installations can cause overvoltage in the distribution systems, which must be effectively prevented. Thus, the paper considers the problems caused by the distributed generation and related to protection systems and voltage regulation in the distribution networks. Solutions for mitigating the negative impact of distributed generation on the power supply systems are proposed and considered in detail.