Research of operating modes of a fragment of the power grid of PJSC "Lvivoblenrgo" under the condition of its perspective development with installation of SES
Students Name: Holovatyi Vitalii Andriiovych
Qualification Level: magister
Speciality: Electric Systems and Networks
Institute: Institute of Power Engineering and Control Systems
Mode of Study: full
Academic Year: 2020-2021 н.р.
Language of Defence: ukrainian
Abstract: Distribution electric networks are electric networks that are designed to transfer electricity from the source of production to the source of consumption, which includes distribution between specific consumers [1-4]. Therefore, such an important element of the grid has a number of specific requirements. One of the main is a reliable and uninterrupted power supply to consumers, especially for consumers of category I [1]. The main feature of the efficiency of the electrical network is the property of trouble-free operation for a given period of time, which will provide the necessary indicators of electricity quality [2-4]. The main problem of electrical distribution networks is the obsolescence of their electrical equipment with ever-increasing electricity consumption [3]. To this is also added the rapid introduction in recent years of sources of distributed generation (mainly solar and wind power plants). The section of the studied electric network is not an exception and the construction of such generation sources is also envisaged here. The main element in the research of this master’s qualification work is a fragment of the electrical network of PJSC "Lvivoblenergo", which provides for the construction of a solar power plant "Vytkivska" with an installed capacity of 8 MW. For the considered fragment of the scheme of PJSC "Lvivoblenergo" for the area of connection of the solar power plant "Vytkivska" we will consider power sources: 110 and 35 kV busbars of DTES; 110 kV busbars of M-110 substation; 110 kV busbar of Ch2 substation; 110 kV busbars of Krasne substation [5]. Study object – fragment of 110-35 kV electric network of PJSC "Lvivoblenergo" for connection of solar power plant "Vytkivtsi". Scope of research – steady state of the investigated section of the electrical network and and their optimization. Goal of research – establishment of conditions for the operation of the 110-35 kV electric network section of PJSC Lvivoblenergo for the connection of the Vytkivtsi solar power plant. Analysis of the impact of an additional generation source on the grid in normal, repair and emergency repair modes. According to the research results, we see that in normal modes of the network without SES "Vytkivtsi" the load of 110 kV OHL "DTES-110-Radekhiv-151 and SSh 110" did not exceed 23%, with SES "Vytkivtsi" - 17.4%. In general, the SES unloads the 110 kV OHL “DTES w 110-Radekhiv-151 I ssh 110” by (4-8)%. In this mode of the network, the load of the HV winding of the transformers of Radekhiv-151 substation did not exceed: T1 - 36.4%; T2 - 53.6%. The load on the HV winding of the T2 transformer of Radekhiv-151 substation during the operation of SES Vytkivtsi did not exceed 52.7%. Installation in the network of SES "Vytkivtsi" does not change the load of 35 kV overhead lines. The load of the main sections of the network departing from the 35 kV busbars of Radekhiv 151 substation is insignificant and did not exceed 14.7%. In repair and emergency modes of the network with SES, the load of 35 kV overhead lines in the direction from the substation "Radekhiv 151" to the substation "Vuzlova" does not exceed 20.8%. In the normal mode of operation of the network with SES on the 35 kV and 10 kV buses of Radekhiv 151 substation and on the buses of 35 kV substations of the network, the voltage level corresponds to the desired one from the condition of counter voltage regulation in the network. In repair and emergency modes of summer daily load reduction, voltage on MV and LV buses of Radekhiv 151 substation and on 35 kV substations of the network, which are supplied by Radekhiv 151 substation, do not meet the requirements due to counter voltage regulation in the network. The desired voltage level can be provided by increasing the voltage on the 35 kV busbars of DTES. The normal and emergency modes of the network during the construction of SES "Vytkivtsi" for the maximum winter load in the perspective of 5 years are investigated. The load of the 110 kV overhead line "DTES w 110-Radekhiv-151 I ssh 110" will not exceed 11%, 35 kV overhead lines powered by 35 kV tires of Radekhiv 115 substation will not exceed 46.6%. Voltages on the busbars of Radekhiv 151 substation and on the busbars of 35 kV substations meet the conditions of counter-regulation. The voltage deviation on the busbars of SES is in the range from 10.3 kV to 10.5 kV and does not exceed the normalized allowable value for SES "Vytkivtsi" ± 10% Unom. Key words: steady state, electrical network, voltage regulation, solar power plant, modes research. References 1. Rules of arrangement of electrical installations. The publication is official. Ministry of Energy and Coal Industry of Ukraine. - Kharkiv: Fort Publishing House, 2017. - 760 p. (in Ukrainian) 2. A. V. Zhurakhivskyi, Z. M. 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