High-voltage alternating-current-motor multistage-reactance adjustable voltage-reduction soft start device

Abstract

The invention relates to a high-voltage alternating-current-motor multistage-reactance adjustable voltage-reduction soft start device. The device comprises a power grid transformer substation voltage transformer PT, a power grid transformer substation distribution loop current transformer CT, a power grid transformer substation distribution loop vacuum circuit breaker QF1, a soft starter starting vacuum circuit breaker QF2, a bypass vacuum circuit breaker QF3, a vacuum contactors KM1, KM2 and KM3, a multitapped high voltage reactor L, a soft starter internal voltage transformer VT and an intelligent controller PLC. In the invention, through collecting and detecting a three-phase power grid voltage, a motor current and other parameters, a multistage reactor is driven to carry out impedance adjustment control and high-voltage electric voltage-reduction soft start is realized. The device possesses advantages that start performance is good; reliability is high; there is no harmonic pollution; stability is high; a service life is long; and maintenance and repairing are convenient and so on.

Description

technical field [0001] The invention relates to a multi-stage reactance-adjustable step-down soft starter for a high-voltage AC motor, which belongs to the technical field of high-voltage motors. Background technique [0002] As a device that converts electrical energy into mechanical energy, electric motors are widely used in various industries. 6KV and 10KV voltage grade motors are preferred for large-scale motors. However, at present, the power grid capacity is limited, and the pace of transformation and expansion of the power grid in the factory area is relatively slow. When the high-voltage motor starts at full voltage, the starting current is relatively large (4-8 times the rated current ). The large starting current will cause a voltage drop to the power grid and affect the normal operation of other equipment on the power grid. At the same time, the electrodynamic heat and impact risk generated by the starting current is relatively large, which will affect the servic...

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Problems solved by technology

The above-mentioned soft starters have various problems or disadvantages, such as large power consumption of liquid soft starters, poor working stability, and heavy maintenance workload; solid-state thyristor soft starters, which have similar working principles A large number of high-order harmonics are generated in the system, which causes great pollution to the power grid, high manufacturing cost, complex structure, and difficult maintenance for users; the motor power range of the autotransformer soft starter is limited, and it is only used below 2000KW

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