Electromagnetic and Electromechanical Processes in the Variable Electric Drive of a Circulating Pump with Double-Speed Asynchronous Engines

摘要

Electric drives with gradually varied rotational speed used for regulation of the main circulating pumps (MCPs) of nuclear power stations maintain reliable operation of the reactor plant at different operational modes, including partial load levels of power generating units. The use of powerful asynchronous engines with short-circuited rotor and primary voltage of 6000 V in such electrical drives has made it necessary to use average voltage with a variable output frequency in order to produce the rotational speed of control converters. One effective technical solution that maintains reliable operation and safety of the reactor plant is use of the main first contour circulating pumps of an asynchronous engine with two independent windings on the stator: the main one of 6000 V connected to the converterand an additional low-voltage winding connected to the emergency supply circuit under "de-energization" conditions of auxiliary power needs, formed by the diesel-generator unit. Implementation of the circulating pump with double-speed asynchronous engine in the variable electric drive determined it necessary to carry out investigations of electromagnetic and electromechanical processes at control modes of the main and additional stator windings. Those modes were modeled on the basis of mathematical models and on a full-scale hydraulic test stand intended for testing circulating pumps. The main results concerning investigation of electromagnetic and electromechanical processes in an electrical drive with a double-speed asynchronous engine of 5000 kWand 6 kV used for operating control of the main circulating pumps of the reactor unit of an 800-MW power unit are given in the article.