In this paper, a 600 KW electrical balance of plant (EBOP) for a molten carbonate fuel cell (MCFC) power plant is introduced. The requirements for EBOP are categorized into as follows : demands on grid interconnection and operational interface with a fuel cell. EBOP has three modes of operation, i.e. grid-connected (GC) mode, grid-independent (GI) mode, and grid-synchronization (GS) mode, to control its output currents, power, and voltages. LCL filter is adopted to meet power qualities demanded by IEEE std. 1547 which defines terms and criterions on interconnection of inverter with grid. EBOP of MCFC is also required to get the ability of fast and smooth transition from GC mode to GI mode to protect a fuel cell under abnormal grid conditions. A 600 KW EBOP was tested and installed in a MCFC power plant. Simulations and tests are carried out under various load conditions. Results of simulations and tests are presented and show the effectiveness of control algorithm.