Review of existing reactive power requirements for variable generation

In order to reliably operate the bulk electric grid generators are expected to meet certain reactive power requirements depending on the system they operate in. In the past reactive power requirements were tailored to the capabilities of synchronous generators. Variable generators such as wind and solar plants were in the past small enough relative to the entire system that they were not required to supply voltage support to the grid. As the penetration of renewable resources have grown beyond insignificance, it is now the trend that variable generators connected to transmission and subtransmission grids should be required to provide reactive power support. The goal of this paper is to educate the reader on the current state of reactive power requirements for variable generation. This paper discusses reactive power requirements from various regions across the world with a focus on those in North America.