Multi-stage compression system, control device, control method, and program

A multi-stage compression system wherein gas which has already been compressed by a pair of first-stage compressors is compressed using subsequent-stage compressors which are connected in series to the first-stage compressors, said multi-stage compression system being equipped with a valve control unit which outputs an open/close signal for opening/closing valves, which are disposed on the entrance side of the first-stage compressors to adjust the flow rates of the gas flowing into the first-stage compressors. After an abnormality of one of the valves not reaching an opening degree corresponding to an open/close signal is detected and until the abnormality is eliminated, the valve control unit outputs, as the open/close signal, an open/close signal whereby the opening degree difference from that of the valve prior to the detection of the abnormality becomes equal to or smaller than a prescribed value.