Analysis of emergency modes of 110/35/10 kV transformer substation "Dibrova" "Lvivoblenergo" and protection against them
Students Name: Shvets Oleksandr Viktorovych
Qualification Level: magister
Speciality: Electric Power Generation and Distribution Management Systems
Institute: Institute of Power Engineering and Control Systems
Mode of Study: full
Academic Year: 2020-2021 н.р.
Language of Defence: ukrainian
Abstract: In the process of operation of electric machines, devices, overhead power lines, etc. there may be violations of normal modes of operation and damage, leading to short circuits [1]. In the event of damage, the relay protection must respond and disconnect the damaged element or section of the network from the power system, acting on special power switches designed to open the fault currents. Recent trends in the development of relay protection of power systems indicate that electromechanical relay protection devices are being replaced by a new generation of devices, the principle of which is based on digital technologies [2]. Now the introduction of digital relay means and automation means has started very actively, which allows to significantly increase the reliability of power supply and minimize faulty protection. The largest companies producing such protections and recording devices are: - General Electric (USA); - ABB (Sweden-Switzerland); - Siemens (Germany); - Mikronika (Poland); - IMCKOE (Ukraine). These companies make a very significant contribution to the creation of reliable and high-quality equipment for relay protection. And also very actively implemented in the power system of Ukraine. To study the emergency modes of operation of the power transformer TDTN-16000/110 in the digital complex REC [3] was formed a calculation scheme, which is represented by digital models of individual elements of the electrical network: power supplies, power transformers. These elements of the electrical network were taken into account in the parameters, taking into account their type and design. After analyzing the damage that occurs in transformers, emergency modes, in which they are sometimes forced to work, there is a need to upgrade, replace outdated protections with more modern, microprocessor [4]. One of the advanced such protections is a digital terminal from the Swedish company ABB. Terminal RET 670, built using the best algorithms of its predecessor - the terminal RET 521. It is actively used to protect transformers during the construction of new substations and in the reconstruction and modernization of existing ones [5]. Study object - a three-winding transformer type TDTN-16000/110. Scope of research - emergency modes of transformer operation and protection against them. Goal of research: types of emergency modes, their calculation and methods of implementation of protection against them, a brief description of digital microprocessor protection of the transformer, differential protection, gas protection, maximum current protection and transformer overload protection. Calculation of parameters of operation of all types of protections. The paper describes the emergency modes of operation, types of transformer damage and, accordingly, means of protection against them. Emergency modes was researched in the digital complex REC. The description of the digital protection device of the three-winding transformer of the TDTN-16000/110 type is carried out. The RET 670 digital terminal from ABB was chosen for the implementation of differential protection. The verification of providing digital equalization of currents of protection arms, parameterization of input data on analog inputs of the terminal, transformer and on-load tap-changer is carried out. The parameters of the electrical network, short-circuit currents in the modes of maximum and minimum load and the selected parameters of operation of all types of transformer protection are calculated. Key words - emergency modes, digital model, digital terminal, short circuit, differential protection, microprocessor protection. References. 1. Bukovich N.V., Mirkevich GN "Calculation of short-circuit currents" - K .: NMK VO, 1991 2. Kidiba V.P. (2015). Relay protection of electric power systems. Lviv: Lviv Polytechnic National University Publishing House. 3. O.Ravlyk, N.Ravlyk. Digital Complex for Modeling Processes in Electric Circuits with Protection and Automatic Devices // Energy Engineering and Control Systems. 2017.– Vol.3, № 1.– P.23–28. 4. Digital devices for protection of elements of electric power systems of ABB company, materials of ABB presentation, 2015 5. Methodical instructions on the choice of parameters of operation of relay protection devices of the equipment of substations of production of LLC ABB Power and Automated Systems, the Standard of the organization of JSC FGC UES HUNDRED 56947007-29.120.70.98-2011.