Analysis of alternants for the development of the 110 kV PJSC "Lvivoblenergo" electrical grid and the equipment choice for the substation "Bovarska"
Students Name: Brovarskyi Valentyn Vitaliiovych
Qualification Level: magister
Speciality: Electric Systems and Networks
Institute: Institute of Power Engineering and Control Systems
Mode of Study: full
Academic Year: 2021-2022 н.р.
Language of Defence: ukrainian
Abstract: In PJSC "Lvivoblenergo" there is a problem of power shortage, which requires the development of 110 kV electrical networks [1]. Development of the project of development of an electric network demands the decision of problems: reconstruction of operating substations, their switchgears; reconstruction of existing power lines; design of new substations and power transmission lines of electric networks; research of modes of the scheme of development of an electric network. The object of the study is a fragment of the existing 110 kV electrical network of PJSC "Lvivoblenergo" with substations "Drohobych-20", "Stebnyk", "Stryi-30", "Boryslav", "Stryi" and overhead lines "Boryslav - Drohobych-20", "Drohobych-20 - Stebnyk", "Stebnyk - Stryi". The subject of the research is the analysis of variants of development of a fragment of the 110 kV electric network scheme of PJSC "Lvivoblenergo" with the new substation "Bovarska". The purpose of the work is to choose the best variant of the scheme of development of a fragment of 110 kV electric network of PJSC "Lvivoblenergo" with substation "Bovarska", to choose its main power electrical equipment, to choose overhead lines and to analyze the modes of the new electric network. The scheme of development of a fragment of the electric network with the new substation "Bovarska" was developed taking into account the geographical location of the substation "Bovarska" [2], maps-schemes of 110 kV OHL PJSC "Lvivoblenergo", requirements of current regulations [3] . Three variants of EN circuit development are considered. Option 1: power supply of Bovarska substation by single-circuit submarines from Boryslav and Stryi nodal substations. Option 2: supply of the Bovarska substation with a single-circuit OHL from the Stryi nodal substation and a branch from the Stebnyk-Stryi substation. Option 3: power supply of Bovarska substation with single-circuit substation from Stryi nodal substation and soldering from Stryi-Stryi-30 substation. A technical and economic comparison of options by the method of consolidated costs [4]. Option 2 turned out to be the cheapest. In compliance with the current rules and methods [5] selected: wires of the new overhead lines; the scheme of electrical connections of substation “Bovarska” and its main power electrical equipment for voltage classes 110, 35, 10 kV, namely: switches and disconnectors; current and voltage transformers; current-carrying parts (flexible and rigid busbars); insulators, transformers of own needs. On the digital model of the scheme of development of the fragment of the electric network from the substation "Bovarska", which is formed in the dialog automated complex of the analysis of the DAKAR ELEKS [6] modes, were investigated normal and post-accident steady-state modes at maximum load of substations "Drohobych-20", " Stebnyk", "Stryi-30" “Bovarska”. In the electrical network with two-way power supply of “Bovarska” substation according to option 2 in the mode of maximum loads, the currents in the branches do not exceed the values allowed under the heating conditions; voltages on the tires of all substations - also within acceptable values. The results of calculation of post-emergency modes № 1 with disconnection of the line “Stryi-Bovarska” and № 2 with disconnection of the branch line from the substation “Stebnyk - Stryi” - “Bovarska” show that voltages and currents also correspond to the permissible ones. Wires of the operating overhead lines"Boryslav - Drohobych-20", "Drohobych-20 - Stebnyk", "Stebnyk - Stryi" and the new overhead lines “Stryi - Bovarska” and branch on the OHL “Stebnyk - Stryi” in post-accident steady-state modes of the network with the substation “Bovarska "were not overloaded. Therefore, it is not necessary to replace the wires of the existing overhead lines with wires of larger cross-section, and the wires of the new overhead lines were chosen correctly. The developed scheme of development of the EN of PJSC "Lvivoblenergo" with the new substation "Bovarska" can be implemented, as the 110 kV overhead lines"Boryslav - Drohobych-20", "Drohobych-20 - Stebnyk", "Stebnyk - Stryi", "Stryi - Stryi-30" “Stryi -Bovarska" and the new overhead lines a branch of the OHL “Stebnyk - Stryi”, according to the results of the study of normal, post-accident steady-state modes and perspective load mode of operation of the electrical network, have a sufficient margin for bandwidth, and the voltage level on 6, 10 and 35 kV busbars of substations "Drohobych-20", "Stebnyk", "Stryi-30" and “Bovarska" lies within acceptable limits. In addition, substation transformers are equipped with voltage regulation devices - on-load tap-changers and PBZ, which allows to provide the required voltage level on the busbars of substation consumers. Keywords: voltage, electric network, overhead lines, substations, steady state, active power losses References. Plan rozvytku systemy rozpodilu PrAT "Lvivoblenerho" z 2021 do 2025rr - Access mode: https://www.nerc.gov.ua/data/filearch/elektro/energo_pidpryemstva/plany_rozvytku/2020-2024/Plan_rozvytku_Lvivoblenergo_2020-2024.pdf . 2. Rules of arrangement of electrical installations. - Official publication. Ministry of Energy and Coal of Ukraine. - X.: Fort Publishing House, 2017. - 760 p. 3. SOU-N EE 40.1-00100227-101: 2014 Standards of technological design of power systems and electrical networks of 35 kV and above. 4. Ukrupneni pokaznyky vartosti budivnytstva pidstantsii napruhoiu vid 6 kV do 150 kV ta linii elektroperedavannia napruhoiu vid 0,38 kV do 150 kV. 5. Design of substations of electric networks: textbook / ZM Bakhor, AV Zhurakhivsky. - Lviv: Lviv Polytechnic Publishing House, 2017. - 308 p. 6. Kompiuterna prohrama «DAKAR ELEKS» - Access mode: https://dakar.eleks.com