Power frequency and variable frequency switching system and method of circulating pump frequency converter

Abstract

The invention belongs to the technical field of electrics, and particularly relates to a circulating pump frequency converter power frequency and frequency conversion switching system and method. The system comprises a circulating pump frequency converter, a switching device, a circulating pump motor, a voltage transformer, a circuit breaker and a power supply bus. Wherein one end of the circulating pump frequency converter is connected to a power supply bus through the circulating pump frequency converter inlet wire circuit breaker and the circulating pump upstream circuit breaker in sequence, and the other end of the circulating pump frequency converter is connected with the circulating pump motor through the circulating pump frequency converter outlet wire circuit breaker; the circulating pump frequency converter inlet wire circuit breaker is connected with the circulating pump frequency converter outlet wire circuit breaker through another bypass line, and a switching device is arranged on the circulating pump frequency converter inlet wire circuit breaker; one end of the circulating pump frequency converter bypass circuit breaker is connected to a path between the circulating pump frequency converter inlet wire circuit breaker and the circulating pump upstream circuit breaker, and the other end of the circulating pump frequency converter bypass circuit breaker is connected to a path between the circulating pump frequency converter outlet wire circuit breaker and the circulating pump motor. On-line undisturbed switching of the power supply of the high-power circulating pump motor can be realized according to the requirements of a process system.

Description

Technical field [0001] The present invention is an electrical technology field, which involves a switching system and method for working frequency and frequency conversion of pump transformer. Background technique [0002] The circulating water pump (hereinafter referred to as: the pump) in various power plants is mainly used to provide the cyclic cooling water required for the lack of vapor after working in the cooler turbine to ensure the normal thermal cycle of the unit. At present, the existing nuclear power plants in China have adopted advanced variable frequency speed adjustment technology for the first time of high -power pump pumps to achieve smooth adjustment of circulating water flow online. "Road", you can reduce the speed of the pump in winter to reduce the amount of circulating water. The pump can switch to the industrial frequency bypass when the inverter fails or the frequency conversion operation is not economical. However, in the actual application of the inverte...

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Problems solved by technology

[0003] 1. For the circulating pump configured with "inverter + power frequency bypass", the two operating modes of frequency conversion and power frequency cannot be automatically switched online. When switching manually, the circulating pump must be stopped, and the power of the unit needs to be greatly reduced;

[0004] 2. In order to ensure the stable power of the unit, the operation mode of the frequency converter with the circulation pump is used throughout the year. In summer, when the frequency converter operates at 50Hz, it consumes more operating power of the forced ventilation cooling system accompanying the operation of the frequency converter than the power frequency (bypass). It reduces the economy, and at the same time increases the loss of the frequency converter itself, reducing the service life of the frequency converter;

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