Capacitor Bank Sizing for a Large Wind Farm Project


Pterra’s Amin Najafabadi, Senior Consultant, is presenting on the title subject. This is at the Electric Power Conference and Exhibition to be held in Rosemont, IL, April 23-25, 2015. Following is the abstract of the presentation.

Utilities generally require large wind power plants to meet power factor capability, similar to those of traditional generating facilities such as gas, steam, or coal power plants.  Reactive power compensation equipment such as capacitors, reactors, static VAR compensators, static synchronous compensators, and the like, are usually needed so that a large wind farm project can meet the ±0.95 power factor requirement at the point of interconnection. Switched capacitor banks serve as one of the more effective and economic solutions.

When sizing capacitor banks for a 200 MW wind farm consisting of Type III wind turbine generators, several challenges are encountered due to limitation of power flow programs used in industrial power system application. User’s customized functions and iterations may not be possible to be added to the programs. As alternative tools, Matlab and OpenDSS power flow engines are used in order to meet the requirement and to properly utilize reactive capability from each wind farm unit as well as to update main transformer impedance according to manufacturer specification. The results of the study showed capacitor banks needed for the project are about 30 percent less than the results from traditional power flow program. Simple switching schemes are tested and the voltage change due to capacitor switching is insignificant.

The full text of the presentation will be available at the conference or upon request via