METHOD OF ASYNCHRONOUS ENGINES EQUIVALENCY FOR CALCULATING SHORT CIRCUIT CURRENT IN A SYSTEM OF BALANCE-OF-PLANT NEEDS

Abdullo Sh. Majidov, Yury P. Gusev

DOI: 10.47026/1810-1909-2020-3-102-115

Key words

equivalency, asynchronous motor, balance-of-plant needs, short circuit, differential equations system, simulation, ETAP program.

Annotation

In short-circuiting in power plants of balance-of-power plant needs three-phase asynchronous motors with a short-closed rotor have a significant influence on the nature of the process and the magnitude of the short circuit current. In the system of balance-of-plant needs it is necessary to take into account the components of short circuit current from asynchronous motors when selecting and checking switches, as well as when selecting and checking current-carrying parts (cables, complete current wires, etc.) not only at the initial moment of the short circuit, but at the time of its shutdown as well. The methods for calculating short circuit current taking into account the influence of asynchronous motors continue to be improved; there is a search for new methods that simplify calculations as much as possible while maintaining the credibility of the results. In doing so, some issues require further study and research, such as the possibility of asynchronous motors equivalency. Power plants have to take into account the components of the short circuit current from a large number of asynchronous engines, which is not only time-consuming, but sometimes impossible due to the absence of full information on engines and mechanisms of balance-of-plant needs. To improve the efficiency and accuracy of calculations for power plant design tasks, it is advisable to replace asynchronous engine groups with equivalents. The relevance of improving the method of equivalency of asynchronous engines at power plants increases along with increasing requirements to enhance the reliability of electrical installations of balance-of-power plant needs and to reduce the costs of technical inventory due to calculation errors. The article considers the method for equivalencing the group of low-voltage asynchronous motors on the example of the balance-of-plant needs system at TPP № 1 located in the town of Dushanbe of the Republic of Tajikistan. Modeling the electromechanical processes caused by short circuits of different electrical remoteness was carried out using ETAP software complex (OTI, USA).

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