Education at Lviv Polytechnic

Analysis of the modes of a fragment of the 110 kV electric network of PJSC "Lvivoblenergo" with a new substation "Verkhnya Bilka". Switching processes of the designed substation into a grid

Students Name: Pylat Iryna Vasylivna

Qualification Level: magister

Speciality: Electric Systems and Networks

Institute: Institute of Power Engineering and Control Systems

Mode of Study: part

Academic Year: 2020-2021 н.р.

Language of Defence: ukrainian

Abstract: In PJSC "Lvivoblenergo" power shortage in some areas of the city and region is a significant problem, to solve which requires the development of 110 kV electrical networks [1]. Development of the project of development of an electric network demands the decision of a number of necessary tasks: reconstruction of operating substations, their distribution arrangements; reconstruction of existing power transmission lines; design of new substations and lines of electric networks; research of modes of the scheme of development of an electric network. The object of the research is a fragment of the existing electric network with substations "Vynnyky", "Kurovychi NPS", "Pidbirtsi-T" and overhead power lines "Lviv-2–Vynnyky", "Vynnyky–Kurovychi NPS" and "Lviv-2–Pidbirtsi-T". The subject of the research is the scheme of fragment development of electric network taking into account the reconstruction of Vynnyky substation and the analysis of its established modes. The purpose of the work is to develop a scheme for the development of a fragment of the 110-330 kV electric network of PJSC "Lvivoblenergo" with a new substation "Verkhnya Bilka", to replace the T2 transformer at the substation "Vynnyky", to select overhead power lines and analyze of modes of a new electric network, select its main power electrical equipment. The scheme of development of a fragment of the electric network with the new Verkhnya Bilka substation was developed taking into account the geographical location of Verkhnya Bilka substation [2], maps-schemes of 110 kV overhead power lines (OHLs) of PJSC "Lvivoblenergo" [3], requirements of current normative documents [4, 5]. The Verkhnya Bilka substation will be powered by 110 kV busbars of the Pidbirtsi-T substation by the single-circuit Pidbirtsi-T–Verkhnya Bilka substation and the Kurovychi NPS substation by the single-circuit Kurovychi NPS–Verkhnya Bilka substation. In compliance with the current rules and methods [5, 6] the following were selected: wires of the new OHL “Pidbirtsi-T–Verkhnya Bilka” and “Kurovychi NPS–Verkhnya Bilka”; main electrical circuit scheme of Verkhnya Bilka substation and its main power electrical equipment and power transformer for reconstruction of Vynnyky substation. On the digital model of the scheme of development of a fragment of the electric network from the substation "Verkhnya Bilka", which is formed in the graphical and computational complex DAKAR ELEKS [7], normal and post-emergency steady-state regimes at maximum load of substations "Vynnyky", "Kurovychi NPS", "Pidbirtsi-T" and "Verkhnya Bilka" to the reconstruction of the substation "Vynnyky" and the mode of long-term load taking into account the reconstruction of the substation "Vynnyky". Losses of active power in the electric network from the substation "Verkhnya Bilka" with the power supply of the electric network from the substation "Pidbirtsi" and the substation "Kurovichi NPS" amount to 1749 kW with a network load of 71 + j37.2 MVA before the reconstruction of the substation "Vynnyky". After the reconstruction of Vynnyky substation, the network load will increase to 88.5 + j46.2 MVA. With such a load on the network, the loading of newly built lines is as follows: "Lviv-2–Vynnyky" - 80.6%, "Vynnyky–Kurovychi NPS" - 7.3%, "Lviv-2–Pidbirtsi-T" - 80.6%, "Pidbirtsi-T–Verkhnya Bilka" - 33.01%, "Kurovychi NPS–Verkhnya Bilka" - 12.4%. The scheme of development of the electric network from the substation "Verkhnya Bilka" with power supply of the substation from the substation "Lviv-2" and the substation "Kurovychi NPS" is optimal. The losses of active power in it is minimal and amounts to 1749 kW. The wires of the existing OHLs “Lviv-2–Vynnyky”, “Pidbirtsi-T– Vynnyky” and “Vynnyky–Kurovychi NPS” and new lines “Pidbirtsi– Verkhnya Bilka” and “Kurovychi NPS–Verkhnya Bilka” in post-emergency network modes with the substation “Verkhnya Bilka" were not overloaded. Therefore, it is not necessary to replace the wires of the existing OHL with wires of larger cross-section, and the wires of the new OHL "Verkhnya Bilka" were chosen correctly. With the help of the graphic-calculation complex DAKAR ELEKS the calculation of electromechanical transients in the designed electric network is carried out [7]. The processes of connecting the Verkhnya Bilka substation to the network were also studied. The developed scheme of development of the electric network of PJSC "Lvivoblenergo" with the new substation "Verkhnya Bilka" can be implemented, as the OHLs-110 kV "Lviv-2–Vynnyky", "Lviv-2–Pidbirtsi-T", "Vynnyky–Kurovychi NPS", "Pidbirtsi–Verkhnya Bilka" and "Kurovychi NPS–Verkhnya Bilka" according to the results of the research of normal, post- emergency steady-state EN modes and the mode of perspective load, have a sufficient margin for bandwidth. However, in the post-emergency mode, when the overhead power line "Pidbirtsi-T–Verkhnya Bilka" is switched off, the substation "Vynnyky" should be unloaded, and in the future the AC-120/19 wire should be replaced with the AC-240/32. The voltage level on the 10 and 35 kV busbars of Vynnyky, Kurovychi NPS, Pidbirtsi-T and Verkhnya Bilka substations will be provided with the RPN and PBZ control devices of transformers. Keywords: an electric network, overhead power lines, substations, a steady state mode, active power losses, a voltage. 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