Multi-source power system FOPID based Load Frequency Control with high-penetration of Distributed Generations

This paper presents a Fractional Order Proportional-Integral-Derivative (FOPID) controller optimized using Social Spider Optimization (SSO) algorithm to Load Frequency Control (LFC) of a two-area multi-source power system in the presence of Distributed Generations (DGs). Here, the effect of DGs consist of wind and diesel power plants for damping frequency deviation of two-area multi-source power system including thermal, hydro and gas units considering nonlinearities such as generation rate constraint and governor dead band has been investigated. The FOPID controller has three main control parameters as known gain, fractional orders of integrator and derivative part that provide the better performance in comparison with the PID controller. On the other hand, to achieve the good performance in the power system, tuning of these parameters is very important. Therefore, the SSO algorithm has been used to optimal tuning of the FOPID based LFC controller. One of the important specifications of the employed algorithm is that it can balance the local and global solutions in the search space that cause to overcome the local optimal and premature convergence. Also, a High Voltage Direct Current link (HVDC) is used to improve the dynamic performance of the LFC task. Finally, the proposed controller has been applied on a two case studies and analyzed based on investigated performance criteria. Results show the good effect of DGs for the solution of LFC task and enhancing system performance characteristics under different operating conditions and considering system nonlinearities.