Application Of Frequency Converters In Large Gas-steam Combined Cycle Power Unit

3×390MW gas-steam combined cycle power unit of Guangdong Huizhou LNGPower Plant, static frequency converter (SFC) supplied by Mitsubishi Electric as theauxiliary boot device, and implementation of condensate pumps and closed coolingwater pumps frequency conversion transformation. In this paper, we study the staticfrequency converter and motor frequency converter. The main work is as follows:1. Base on the analysis of SFC main components and working principle, westudied SFC control of the unit startup process, combined with the interaction of SFCand generator, explored SFC and generator protection settings, in the last we analyzedSFC anomalies appeared in the actual operation and putted forward a transformationproposal of SFC control logic, to provide assistance for the design and application ofthe same type SFC.2. Through the research of condensate pump high voltage inverter and closedcooling water pump low pressure inverter, we introduced of frequency converterenergy-saving principle, analyzed the energy loss in constant frequency，and estimatedthe energy-saving effect through operation data calculation before and after thefrequency conversion transformation.3. Based on actual operating data of the feed water pump, we analyzed theoperating characteristics and carried out the suitable operating conditions of the thewater supply system, so had the preliminary economy result after the feed water pumpfrequency conversion transformation. According to the experience of condensate pumpand closed cooling water pump frequency conversion, we putted forward the electricalconnection scheme, control logic and matters needing attention of the feed water pumpfrequency conversion transformation...