Multi-Mass Torsional Shaft Interface (Obsolete)

For Use With...	Choice		Select Synchronous Machine, Induction Machine, DC Machine or PM Machine.

Number of Turbines	INTEGER	Literal	Enter the number of turbines (1 to 25). If 25 turbines are desired, the exciter mass cannot be modeled.

Model Exciter Mass	Choice		Select Yes or No. If 5 turbines are desired, the exciter mass cannot be modeled

Machine Total MVA	REAL	Constant	The 3-phase MVA of the machine, to which the multi-mass is attached [MVA]

Electrical Base Frequency	REAL	Constant	Enter electrical base frequency [Hz]

Machine Mechanical Synchronous Speed	REAL	Constant	Actual speed of the machine [rpm]

Machine Initial Electrical Speed	REAL	Constant	Initial speed of the machine [pu]

Unit System Number (see help)	Choice		Select 1 to 10. See the table below for definitions

Initialization switch: 0-Init;1-Release	INTEGER	Variable	0-Initialization, 1-Release. Until the switch turns 1 the generator will be spinning at the 'Machine rated speed' or at rated slip. The variable name can come from the one assigned in the synchronous machine under the Output Variables for Controller Initialization section of the input parameters.

System of Units Table

Unit System	Inertia Constant Ji or Hi	Mutual Damping MDij	Spring Constant Kij	Torque Share TFi	Self Damping SDi
1	lb•ft•ft	-	lbf•ft/rad	pu	-
2	in•lbf•s2	-	lbf•in/rad	pu	-
3	lb•in•in	-	lbf•in/rad	pu	-
4	H [s]	-	pu	pu	-
5	kg•m•m	-	N•m/rad	pu	-
6	lb•ft•ft	lbf•ft•s/rad	lbf•ft/rad	pu	lbf•ft•s/rad
7	in•lbf•s2	lbf•in•s/rad	lbf•in/rad	pu	lbf•in•s/rad
8	lb•in•in	lbf•in•s/rad	lbf•in/rad	pu	lbf•in•s/rad
9	H [s]	pu	pu	pu	pu
10	kg•m•m	N•m•s/rad	N•m/rad	pu	N•m•s/rad

Output Initialized Mechanical Torque	Choice	Select Yes or No. This input could be used to initialize the governor/turbine and is available only if the For Use With... input parameter is set to Synchronous Machine

Input Initialized Steady Electrical Torque	Choice	Select Yes or No. If the steady state Electrical Torque is available, this could be used to initialize the multi-mass and is available only if the For Use With... input parameter is set to Synchronous Machine.

NOTE: The inertia constants must be entered in the units specified in the Unit System Number input parameter

Turbine # Inertia Constant

REAL

Constant

Enter the inertia constant for the corresponding turbine

NOTE: The spring constants must be entered in the units specified in the Unit System Number input parameter

Spring Constant From Turbine # to #

REAL

Constant

The shaft spring constants are used to describe the dynamics of the shaft. The torque exerted on the adjacent masses by the shaft is proportional to the relative mechanical angles between those masses.

Torque Share for Turbine #

REAL

Constant

The total mechanical torque applied to the multi-mass system may be distributed over the turbine masses. Each turbine receives a fraction of the total mechanical torque: Its torque share. The sum of the torque shares for all turbines modeled must total 1 (one) [pu]

Modal Damping for all Modes

REAL

Constant

A uniform modal damping factor for all modes. This input is used only for Unit System Numbers 1 to 5. The time constant for the decay of all modal oscillations is inverse of this [1/s]

NOTE: The damping constants must be entered in the units specified in the Unit System Number input parameter

Turbine # Self Damping

REAL

Constant

The self-damping coefficient creates a torque on the appropriate mass which is proportional to the speed of the mass. This may be used to represent friction and windage for the mass.

NOTE: The damping constants must be entered in the units specified in the Unit System Number input parameter

Damping Between Turbine # & #

REAL

Constant

The mutual damping coefficient creates a torque, which is proportional to the difference in speed from one mass to the next. Thus, this torque will not be applied in steady state, but will damp out oscillations between masses.

Generator Inertia Constant	REAL	Constant	Enter the inertia constant for the generator

Exciter Inertia Constant	REAL	Constant	Enter the inertia constant for the generator exciter

Spring Constant from the Last Turbine to Generator	REAL	Constant	Spring constant for the shaft between the generator and the turbine connected to it.

Spring Constant from Generator to Exciter	REAL	Constant	Spring constant for the shaft connecting the generator to the excitor.

Generator Self Damping	REAL	Constant	The self-damping coefficient creates a torque on the appropriate mass which is proportional to the speed of the mass. This may be used to represent friction and windage for the mass.

Exciter Self Damping	REAL	Constant	The self-damping coefficient creates a torque on the appropriate mass which is proportional to the speed of the mass. This may be used to represent friction and windage for the mass.

Damping Between Last Turbine and Generator	REAL	Constant	The mutual damping coefficient creates a torque, which is proportional to the difference in speed from one mass to the next. Thus, this torque will not be applied in steady state, but will damp out oscillations between masses.

Damping Between Generator and Exciter	REAL	Constant	The mutual damping coefficient creates a torque, which is proportional to the difference in speed from one mass to the next. Thus, this torque will not be applied in steady state, but will damp out oscillations between masses.

Torque on Shaft from Mass # - #

REAL

Output

Torque experienced by the shaft # [pu].

Mechanical Position of Mass # Relative to Generator

REAL

Output

Mechanical position of mass # with respect to the generator [rad].

Rated Mechanical Speed of the system	REAL	Output	Rated mechanical speed [rad/s].

Delta Mechanical Speed of Mass #	REAL	Output	Difference between the rated speed and the speed of mass # [rad/s].

Multi-Mass Torsional Shaft Interface (Obsolete)

Description

Input Parameters