Thermal Governor Transfer Functions

Approximate Mechanical-Hydraulic Controls (GOV1)

Mechanical-Hydraulic Controls (GE) (GOV2)

As indicated previously, each of the five thermal governor models have a unique transfer function. The schematic diagram of each is given below.

Approximate Mechanical-Hydraulic Controls (GOV1)

Where,

	Initial Value of Control Valve Flow Area [pu]
	Inverse of Regulation [1/pu]
	Gate Servo Time Constant [s]
	Speed Relay Lag Time Constant [s]

Mechanical-Hydraulic Controls (GE) (GOV2)

Where,

	Control Valve Flow Area [pu]
	Intercept Valve Flow Area [pu]
	Permanent Droop [pu]
	IV Servo Time Constant [s]
	Gate Servo Time Constant [s]
	Speed Relay Lag Time Constant [s]

NOTE: The speed relay feedback loop is implemented using a single real pole in order to eliminate the one time step delay of such a loop in the discrete time solution. Also, the non-linearities of the cam and the valve are ignored in the model.

Electro-Hydraulic Controls (GE) (GOV3)

Where,

	Control Valve Flow Area [pu]
	Intercept Valve Flow Area [pu]
	Permanent Droop [pu]
	IV Servo Time Constant [s]
	Gate Servo Time Constant [s]
	Steam Pressure (constant)

NOTE: Since a constant steam pressure is assumed, this model is not valid in the presence of boiler dynamics. However, due to the long time constants of the boiler, up to a few minutes of simulations should not be affected by this assumption.

DEH Controls (GOV4)

Where,

	Control Valve Flow Area [pu]
	Initial Value of Control Valve Flow Area [pu]
	Permanent Droop [pu]
	Speed Relay Lag Time Constant [s]
	Speed Relay Lead Time Constant [s]
	Gate Servo Time Constant [s]

NOTE: This governor model does not have any over speed controls. Only the normal speed controls are modeled.

NEI Parsons Controls (GOV5)

Where,

	Control Valve Flow Area [pu]
	Intercept Valve Flow Area [pu]
	Permanent Droop [pu]
	Cv Phase Compensation Lead Time Constant [s]
	Cv Phase Compensation Lag Time Constant [s]
	Iv Phase Compensation Lead Time Constant [s]
	Iv Phase Compensation Lag Time Constant [s]
	Transducer Time Constant [s]
	Gate Servo Time Constant [s]
	Iv Servo Time Constant [s]

NOTE: This governor model does not have any over speed controls. Only the normal speed controls are modeled.