In this paper, the autonomous hybrid power system consisting of wind-turbine generator (WTG), dieselengine generator (DEG), fuel-cell (FC) and aqua-electrolyzer (AE) is studied. DEG acts as slack generator, whose output power is controlled to have real power balance in the system to keep the frequency deviation within the limit. This paper proposes a new control scheme incorporating PID and PD controllers, to control the output power of DEG to keep real power-frequency balance in the system. PID controller is introduced to make the frequency deviation zero under steady-state, after any disturbance. PD controller is incorporated to damp out the oscillations in system frequency, after disturbance. Detail analysis of the effect of PID and PD controllers on system mode is presented using participation factor. The sensitivity of system modes to the variation of controller parameters is investigated. Simulated responses under isolated operation are presented to show that the proposed control strategy is capable of maintaining power-frequency balance in the system, following any disturbance. The mathematical model of the interconnected system is developed. One feedback loop is added to the existing PID controller in each area to reduce the tie-line power loss. Grid-connected and distribution system connected operation of the hybrid power system are also investigated. (C) 2016 Elsevier Ltd. All rights reserved.