Study of the influence of overvoltage on the quality of electricity in energy systems.
Authors:   State Institution of Higher Education «Donetsk National Technical University, S. SKRYPNYK 
Published: February 2021

Our world with its high technologies has long been deeply dependent on the quality of electricity supply. In most countries of the world there are national power grids that combine the entire set of generating capacity and loads. This network provides the operation of household appliances, lighting, heating, refrigeration, air conditioning and transport, as well as the functioning of the state apparatus, industry, finance, trade, health services and utilities across the country. Without this utility, namely electricity, the modern world simply could not live at its current pace. Sophisticated technological improvements are firmly rooted in our lives and workplaces, and with the advent of e-commerce began the process of continuous transformation of the way individuals interact with the rest of the world. But with the achievement of intelligent technologies, an uninterrupted power supply is required, the parameters of which exactly meet the established standards. These standards maintain our energy security and create a reliable power system, that is maintaining the system in a trouble-free state. Overvoltage is the deviation of the rated voltage from the value of the corresponding quality standard (frequency, sinusoidal voltage and compliance of harmonics). Overvoltage in terms of fire hazard is one of the most dangerous emergency modes of electrical equipment, which causes conditions that in most cases are sufficient for the occurrence of fire hazards (exceeding the allowable voltage leads to disruption of normal operation or possible ignition). Against the background of deteriorating engineering systems, increased power consumption and poor maintenance, power supply of electrical installations, the main causes of overvoltage in electrical networks are thunderstorms (atmospheric overvoltage), switching switches, uneven phase load in electrical networks, etc. The physical picture of internal overvoltage is due to oscillatory transients from the initial to the established voltage distributions in the conductive sections due to the different situation in the electrical circuit. In the conditions of operation of electric networks planned, mode or emergency situations are possible. Therefore, the ranges of overvoltage are determined by the range from several hundred volts to tens and hundreds of kilovolts, and depend on the types of overvoltage. Atmospheric overvoltage is considered to be one of the most dangerous types of emergency modes of operation of the electrical network. This overvoltage occurs as a result of lightning discharge during precipitation by concentrating electricity on the surface of the object, the introduction of potential through engineering networks and systems. Internal overvoltage is switching, which occur due to mode or emergency switching of high-voltage equipment; resonant - when the electrical circuit contains an excessive number of elements of reactive power (the principle of capacitive-inductive oscillating circuit works). The existing groups of overvoltage can also include the third group, which combines overvoltage due to accidents, poor maintenance and installation: break of the neutral wire, single-phase short circuits, violations of the rules of operation of electrical installations. Overvoltage of the third group most often occur at the stage of operation of electrical networks, so mentions of them in most literature sources are superficial. Studies of surges in energy systems show us that the quality of electricity is influenced by a large number of factors related to the reliability and proper use of electricity as the main energy resource of the XXI century. Also, it is possible to note that each type has detrimental consequences for electricity consumers and receivers, that is suffers as technical equipment in electrical systems, and have economic consequences that affect the further development of the economy of each enterprise and each country as a whole. Thus, the importance of studying the nature of surges in power systems is important today, namely ways to prevent the above surges in electrical systems and measures to prevent factors that contribute to the development of emergency power supply.