A Remedy for Mitigating Voltage Fluctuations in Small Remote Wind-Diesel Systems Using Network Theory Concepts

This paper presents a practical solution to the voltage fluctuation problem, induced by the aerodynamic aspects of wind turbines (WTs) (viz., wind turbulence, yaw error, wind shears, and tower shadow), of small wind-diesel systems. It utilizes some network theory concepts to develop a decentralized control scheme for improving the system voltage profile without any communication link. In the proposed scheme, the voltage-control-point(s) of diesel-generator(s) (DGs) is properly chosen to maintain the system voltage variations within an acceptable limit. For this purpose, a supplementary control signal is applied to the automatic voltage regulator of DGs. The proposed technique is able to satisfactory regulate the bus voltages over wind speed variations, in as much as the simulation results obtained from several study systems have validated it. Moreover, a frequency regulation scheme is presented to share the active power, not supplied by the wind power, among DGs with the aim of reducing the total fuel consumption of the DGs set. To this end, the governor characteristics of DGs are coordinated by adding two adaptive gains, corresponding to the DG output power, to the speed control system. The type-1 WT is considered for the study since its impact on the system power quality is the worst, and three software packages, including TurbSim, FAST, and Simulink are used to comprehensively model it.