Power Factor Planning for Wind Power Interconnection

When interconnecting wind power generation in a power system, planners interconnect a “negative” load. Wind power generation normally utilize induction generators which are capable of producing real power (watts) but not reactive power (vars) in contrast with synchronous generators.

In this case, reactive power support is needed for wind power generation to supply power to the system or grid, see figure below. If no sufficient reactive power compensation is present when wind generation operates and provides real power to the network, grid bus voltages can be depressed and produce unreliable power system operation.

Federal Energy Regulatory Commission (FERC) promulgated Order 661 to guide power factor testing/planning when interconnecting wind power resources. New York Independent System Operator (NYISO) implements this guideline via practical steps in NYISO Test Procedure for Evaluating Power Factor Requirements for Wind Generation Interconnection Projects.

The document pertains to the steps to be taken in simulating power factor compliance of the wind power generation at the point of interconnection (POI). In order for the wind power plant to comply, reactive power control or additional reactive power compensation is installed at the POI to support voltages pre and post contingency states. The guide defines power factor compliance with complying with the voltage deviation limits of the power system. Voltage deviation violation(s), at the POI and at the adjacent buses, for any pre-contingency or post-contingency condition will fail the wind power generation power factor test. Reactive power compensation is adjusted for the wind power generation to pass the test, and dynamic reactive power maybe needed to comply.

Power factor planning of wind power ensures that wind power generation maintains a power factor level that will keep buses’ voltage magnitudes, near the wind power plant, are well within voltage deviation limits for any amount of wind real power output level. This type of study aims to keep the reliable operation of the power system with the interconnection of wind power utilizing induction generators.