This paper presents a demand side frequency control scheme in the isolated power system for wind power local utilization. The industrial isolated power system driven by self-owned coal-fired generators and wind farms is both economical and environmentally-friendly. However, the system frequency stability issue is critical due to the lack of power support from the bulk power system. For the isolated power system, the participation of energy-intensive loads in frequency regulation is vital for frequency stability, especially when large scale wind power is integrated in the system. The coordinated control scheme by the saturable reactor and the generator exciter is investigated to realize the energy-intensive load automatic control based on the energy-intensive load model. The coordination of the two control measures significantly enlarges the energy-intensive load regulation range. Energy-intensive load can be regulated to eliminate the power imbalance in the isolated power system together with traditional frequency regulation methods. The hardware-in-the-loop (HIL) testbed is designed to verify the control effect of the proposed coordination method. Time delay of the control method is simulated in this testbed, making the experimental result more practical in the actual power system. Simulations have been carried out in the RTDS-based HIL testbed, verifying that frequency stability of the isolated power system can be maintained by the proposed coordinated control scheme.