Improving grid frequency dynamics of synchronous generators considering wind energy penetration grid dynamics and operation

This paper presents a technique to improve the frequency response of a grid system having synchronous generators (steam and hydro types) and a fixed speed induction generator wind turbine. An embedded Low Pass Filter (LPF) in the DC chopper unit of an Energy Capacitor System (ECS) control toplogy was used to provide active and reactive power control to the grid network that is supplying heavy and light loads. A control strategy of an external circuit of a Series Dynamic Braking Resistor (SDBR) in the stator of the wind generator was also employed in the wind generator. The grid frequency control was investigated using both the ECS and series dynamic resistor. The results obtained were compared to a case where no frequency control was employed in the grid network. Simulations were carried out in Power System Computer Aided Design and Electromagnetic Transient Including DC (PSCAD/EMTDC) platform. The results show that a high time constant of the LPF in the earlier control strategy effectively damps the oscillations of the grid variables and restores quickly the system during network disturbance compared to the latter.