Overview on fast primary frequency adjustment technology for wind power future low inertia systems

Abstract

This paper deals with the established research trend that seeks to enhance wind turbine generator involvement levels in fast regulation of the grid frequency (inertia emulation) along with traditional power system Alternators. At the beginning, the scattered control objectives in previous studies for wind energy conversion system are gathered in a unified scheme where it portrays an augmented control horizon that assorts different control objectives into levels and layers along with its interconnection. In accordance with that, the recently imposed constraints by the system operator in some countries for shaping the necessary behavior of such wind turbine systems to ensure efficient and reliable power supply is briefly discussed in two operational conditions: normal and abnormal (fault) conditions. The paper then identified four control approaches to supply an inertial response emulation in order to alleviate frequency excursion especially for the first 10 s time frame. These control techniques are namely “Natural Inertia Control,” “Stepwise Inertial Control”, “Virtual Synchronous Machine Control,” and “De-loading Control”. Several forms for each control approach are introduced and discussed in terms of the main principle, general advantages, and disadvantages. Finally, for each control technique and its variants, comprehensive comparisons between the surveyed controllers are presented.

Keywords

• Frequency
• Grid support
• Inertial response
• Wind energy