Renewable Integration – Advances in Primary Frequency Control
(Room Nile 1)
20 Sep 17
11:00 AM
-
12:30 PM
Tracks:
Track E - Integration, Storage and Distributed Generation
The need for cleaner, sustainable power generation is driving higher penetrations of renewable energy resources that are electronically coupled to the grid. This presents some new and different technical challenges, particularly in the reduction of system inertia from the displacement of conventional generation resources. Large frequency excursions could trigger undesirable reactions from frequency-sensitive smart grid loads and electronically coupled renewable resources. Without appropriate controls, variation in frequency levels can lead to under-frequency load shedding or even blackouts. It is important that the industry understands the growing complexities of frequency control and is ready with comprehensive strategies to stay ahead of potential problems. Primary Frequency Control (PFC) and Regulation Margin Control (RMC) have become a requirement for thermal power generation by many transmission grid authorities. PFC provides grid stability by allowing the gas turbine to automatically increase (or decrease) load when a grid frequency deviation occurs outside of a frequency band, and maintains this increased (or decreased) load while the deviations persist. RMC is used to ensure that a percentage of the generating capability is reserved for use when grid frequency excursions occur. There are different grid control regulations for different countries and regions. For example, the European Grid Code requires enough Primary Reserve set aside to support a +/-200 mHz grid frequency deviation and sets response times. In North America, guidelines include deadbands of ±16.67 mHz, droop settings of 3%–5% depending on turbine type, and a continuous, proportional (non-step) implementation of the response. This paper reviews the role of primary frequency response in bulk electric system reliability, and the approach developed for prime movers that provides flexibility to adopt to global requirements to stabilize the grid in response to frequency deviations.