The manuscript addresses a robust three-dimensional fuzzy-PID controller (Fuzzy-3D PID) to control frequency of a diverse energy source integrated hybrid power system under various loadings. In order to obtain stability over system frequency under any disturbances, a secondary control loop called load frequency control (LFC) loop is required in the system. LFC tries to monitor power generation irrespective of load demand. Further, a novel hybridized harmony search and random search (hyHS-RS) algorithm is proposed to optimally design the suggested Fuzzy-3D PID controller. The proposed hybrid network is incorporated with integration of different diverse energy sources such as wind-plant (WP), solar-plant (SP), diesel-generator (DEG), and micro-turbine (MT) along with conventional power-generating sources like thermal system, hydro system, and nuclear power plant. The wind-plant and solar-plant exhibit large dynamics and low inertia which degrades the system frequency seriously. The proposed Fuzzy-3D PID controller makes necessary control actions over disturbed frequency and trying to amend steady nominal frequency in the system. It has been observed the percentage improvement in ITAE with proposed hyHS-RS over basic harmony search (HS) and random search (RS) are 54.5% and 201.6% respectively. Finally, proposed hyHS-RS designed Fuzzy-3D PID controller justifies its superiority through different comparative studies.