Author(s)

Le Mingxiao, Zhang Dewu

Corresponding Author

Le Mingxiao

Abstract

When connecting the shore power, the different voltage, frequencies, and phases of ship power and shore power form a voltage difference envelop, and the control closing at the lowest point of the envelop is detected to realize the seamless connection of the ship power and shore power. The grid-connected circulating current of the ship power generator and shore power transformer has self synchronization effect on the generator, however, the excessive circulating current will cause protection action. The shorter the duration of envelope detection waveform over 0, the larger the circulating current. The simulation model of frequency and phase change envelope is established to analyze the envelop lowest point f/P control performance. The frequency difference and power change ratio control of closing at the lowest point of envelope is established to realize the ideal synchronous control of closing and transferring load. The above conclusions are confirmed by simulation and model tests. This paper solves the key problems of seamless shore power connection and load transfer.

Keywords

Voltage difference envelope; circulating current; f/P control; shore power connection; seamless connection