Dynamic Frequency Response of Wind Power Plants

Electricity generation from wind energy has rapidly increased for the last five years worldwide. In many countries, wind energy targets have been set in the range of 20% to 50% of all electricity generation due to the concerns of CO2 emissions, fossil fuel costs, and energy efficiency. In order to maintain sustainable and reliable operation of the power system for these targets, transmission system operators (TSOs) have revised the grid code requirements. Also, the TSOs are planning the future development of the power system with various wind penetration scenarios to integrate more wind power according to their grid codes. In these scenarios particularly with high wind power penetration cases, conventional power plants (CPPs) such as old thermal power plants are planned to be replaced with wind power plants (WPPs). Consequently, the power system stability will be affected and the control capability of WPPs would be investigated.

The objective of this project is to analyze and identify the power system requirements for the synchronizing power support and inertial response control of WPPs in high wind power penetration scenarios. The dynamic frequency response of WPPs is realized as the synchronizing power support and inertial response control in this thesis. Accordingly, the assessment of dynamic frequency response performance of WPPs is carried out. A generic power system model and a generic WPP model with various wind power penetration scenarios are implemented in a RMS toolbox which is developed for the wind integration studies.

For the inertial response study, a new control method is proposed which improves the existing control concepts in terms of reducing the released energy and peak active power of WPPs. It is also shown that when the capability of WPPs considered proposed control method has less impact of the power system frequency compared to existing control concepts. Another advantage of the proposed inertial response control has the tuning methodology which can be utilized as a generic approach for any power system with high wind power penetration levels.

Additionally, an assessment methodology of the synchronizing power support from WPPs is developed for the synchronizing power support. The simulation results show that integration of WPPs have reduced the synchronizing power flow between CPPs in high wind power penetration scenarios. Moreover, the control methods to support synchronizing power are proposed and evaluated with the developed methodology.