Abstract
PURPOSE. To consider the problems of modeling the processes of run-out, self-starting of a group of asynchronous electric motors (AM) in case of short-term power outages (NEC) and voltage drops in external short circuits (SC), convenient for programming and practical use. To establish the integral reaction of the AM group during self-start to the disturbing effect, taking into account their characteristics and duration to establish the permissible limit values of the NEC. To develop an algorithm for the transient process of self-starting of the AM group when using matrix and vector data representation when solving the basic equation of the rotor motion and its computer implementation. METHODS. When solving the problem, the following methods were used: successive approximations when solving the basic electromechanical equation, taking into account electromagnetic transient processes; Gauss-Seidel method with accelerating the convergence of the iterative process when solving the equations of the parameters of the regime; method of nodal stresses. The algorithm is implemented in VBA and tested in Matlab Simulink. RESULTS. The article describes the relevance of the topic, considers a model of AM according to catalog data, an algorithm for self-starting a group of an AM with NEC and external short circuits, taking into account electromagnetic transient processes, which has high accuracy and is convenient for practical use. CONCLUSION. The use of asynchronous motor catalogs makes it possible not to carry out laborious preliminary calculations of the parameters of asynchronous motors. The application of the Gauss-Seidel method with acceleration of convergence provides a decrease in the number of iterations. Taking into account electromagnetic transients and the effect of displacement of the rotor current allows you to evaluate the mutual influence of motors and increase the accuracy of calculations. The use of the method of nodal voltages makes it possible to determine the residual voltage on the busbar section with AM, if at the first moment the motors are switched on to short circuit. The implementation of the algorithm in the VBA environment is convenient for practical use.
Highlights
Разработанная компьютерная модель для исследования процесса выбега и самозапуска как одиночного так и группы АД удобна для практического применения для обеспечения надежности действия быстродействующих защит и уставок автоматического вода резерва (АВР)
voltage drops in external short circuits
Программа позволяет осуществить проверку обеспеченности самозапуска как одиночного АД, так и группы двигателей; выбрать рациональное время включения; осуществить проверку правильности выбора АД, провести исследования взаимного влияния двигателей как при КНЭ, так и внешних КЗ, удобна для практического применения
Summary
Для решения задачи оценки возможности самозапуска в настоящее время применяют различные модели, основанные на методах с использованием ряда допущений, поскольку точная оценка динамической устойчивости при учете электромагнитных переходных процессов и изменений в системе электроснабжения (СЭС), связанных с сильными возмущениями, весьма сложна [3, 4]. В работе разработан алгоритм и программа переходного процесса самозапуска группы АД с уточненным расчетом параметров схемы замещения АД.
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