Model Predictive Control for Load Frequency Control with Wind Turbines

Table 1

Power system variables and parameter.

Parameter/variable	Description	Unit
	Angular velocity of rotor	rad/s
	Angular velocity of high speed shaft and generator	rad/s
	Generator reaction torque	Nm
	Aerodynamic torque	Nm
	Total stiffness on low speed shaft	Nm/rad
	Inertia of the rotor (low speed shaft and gearbox)	Kgm^2
	Inertia of the rotor (high speed shaft and gearbox)	Kgm^2
	Exchange ratio	Null
	Efficiency of the gear box	%
	Actuator time constant	s
	Actuator gain	Hz/p.u.MW
	Wind speed	m/s
	Pitch demand	rad
	Pitch angle	rad
	Power demand	p.u.MW
	The output of wind turbine	p.u.MW
	Frequency deviation	Hz
	Generator output power deviation	p.u.MW
	Governor valve position deviation	p.u.
	Governor valve servomotor position deviation	p.u.
	Tie-line active power deviation	p.u.MW
	Load disturbance	p.u.MW
	Power system gain	Hz/p.u.MW
	Reheat turbine gain	Hz/p.u.MW
	Power system time constant	s
	Reheat turbine time constant	s
	Water starting time	s
,	Hydro governor time constants	s
	Thermal governor time constant	s
	Turbine time constant	s
	Interconnection gain between control areas	p.u.MW
	Frequency bias factor	p.u.MW/Hz
	Speed drop due to governor action	Hz/p.u.MW
	Area control error	p.u.MW