Machine & Device

Transient stability simulation is designed to simulate electromechanical transients due to a large disturbance (Dynamic Event) or a sequence of such events in electric power systems. This reference manual presents InterPSS transient stability simulation machine and other component model implementation technical details. Machine excitation system models, governor system models and stabilizer models are covered in separate manuals. Please refer to the InterPSS Transient Stability User Guide for information regarding how to define these models for a transient stability simulation run.

Machine Model

InterPSS machine model implementation is based on IEEE Std 1110™-2002: IEEE Guide for Synchronous Generator Modeling Practices and Applications in Power System Stability Analysis. Currently the following models are implemented.

Please Note :

• Machine parameters, such as Xd, supplied by the manufacture could be saturated values directly from field measurement or adjusted to unsaturated values. In the transient stability project panel, under the Machine Data, you can select either Unsaturated or Saturated.
• Per Unit system - All machine parameters, you entered into InterPSS are, assumed based on the machine rating and machine rated voltage. Internally, these machines are transfered to the system Kva base and the bus base voltage, to which the machine is connected to, when necessary.
• Machine output - All machine output, such as Pm, Pe are based on machine rating.
• InterPSS also allows you to create you own custom machine model by writing scripts, see more details at How to Script Dynamic Bus Device .

EConstant Machine Model

• Name - Machine name, optional
• Rating - Machine rating
• RatedVolt - Machine rated voltage
• Poles - Number of poles
• H - Unit Inertia Constant
• D - Shaft Mechanical Damping Factor
• Xd1 - Transient-Direct Axis Reactance
• X0 - Zero Sequence Reactance
• X2 - Negative Sequence Reactance
• Ra - Armature Resistance
• Grounding - Machine grounding description
  • SolidGrounded：Solid grounded bus
  • Z-Grounded：Grounded through an impedance Z (GroundR + jGroundX)
  • UnGrounded：Not grounded

InfinitBus Machine Model

• Name - Machine name, optional
• RatedVolt - Machine rated voltage
• Poles - Number of poles
• Grounding - Machine grounding description
  • SolidGrounded：Solid grounded bus
  • Z-Grounded：Grounded through an impedance Z (GroundR + jGroundX)
  • UnGrounded：Not grounded

For an infinite bus, all quantities are based on the system KVA base and bus base voltage.

Internal Z Calculation

Eq1 Model Machine Model

• Name - Machine name, optional
• Rating - Machine rating
• RatedVolt - Machine rated voltage
• Poles - Number of poles
• H - Unit Inertia Constant
• D - Shaft Mechanical Damping Factor
• XL - Armature Leakage Reactance
• X0 - Zero Sequence Reactance
• X2 - Negative Sequence Reactance
• Ra - Armature Resistance
• Xd - Synchronous-Direct Axis Reactance
• Xq - Synchronous-Quadrature Axis Reactance
• Xd1 - Transient-Direct Axis Reactance
• Td01 - Open Circuit Transient-Direct Axis Time Constant
• Sliner - Voltage at the End Point of Liner Area on Generator OCC Cuver
• S100 - Saturation Factor at 100% Terminal Voltage
• S120 - Saturation Factor at 120% Terminal Voltage
• Grounding - Machine grounding description
  • SolidGrounded：Solid grounded bus
  • Z-Grounded：Grounded through an impedance Z (GroundR + jGroundX)
  • UnGrounded：Not grounded

Eq1 Ed1 Machine Model

• Name - Machine name, optional
• Rating - Machine rating
• RatedVolt - Machine rated voltage
• Poles - Number of poles
• H - Unit Inertia Constant
• D - Shaft Mechanical Damping Factor
• XL - Armature Leakage Reactance
• X0 - Zero Sequence Reactance
• X2 - Negative Sequence Reactance
• Ra - Armature Resistance
• Xd - Synchronous-Direct Axis Reactance
• Xq - Synchronous-Quadrature Axis Reactance
• Xd1 - Transient-Direct Axis Reactance
• Xq1 - Transient-Quadrature Axis Reactance
• Td01 - Open Circuit Transient-Direct Axis Time Constant
• Tq01 - Open Circuit Transient-Quadrature Axis Time Constant
• Sliner - Voltage at the End Point of Liner Area on Generator OCC Cuver
• S100 - Saturation Factor at 100% Terminal Voltage
• S120 - Saturation Factor at 120% Terminal Voltage
• Grounding - Machine grounding description
  • SolidGrounded：Solid grounded bus
  • Z-Grounded：Grounded through an impedance Z (GroundR + jGroundX)
  • UnGrounded：Not grounded

E11 Round Rotor Machine Model

• Name - Machine name, optional
• Rating - Machine rating
• RatedVolt - Machine rated voltage
• Poles - Number of poles
• H - Unit Inertia Constant
• D - Shaft Mechanical Damping Factor
• XL - Armature Leakage Reactance
• X0 - Zero Sequence Reactance
• X2 - Negative Sequence Reactance
• Ra - Armature Resistance
• Xd - Synchronous-Direct Axis Reactance
• Xq - Synchronous-Quadrature Axis Reactance
• Xd1 - Transient-Direct Axis Reactance
• Xq1 - Transient-Quadrature Axis Reactance
• Xd11 - Subtransient-Direct Axis Reactance
• Xq11 - Subtransient-Quadrature Axis Reactance
• Td01 - Open Circuit Transient-Direct Axis Time Constant
• Tq01 - Open Circuit Transient-Quadrature Axis Time Constant
• Td011 - Open Circuit Subtransient-Direct Axis Time Constant
• Tq011 - Open Circuit Subtransient-Quadrature Axis Time Constant
• Sliner - Voltage at the End Point of Liner Area on Generator OCC Cuver
• S100 - Saturation Factor at 100% Terminal Voltage
• S120 - Saturation Factor at 120% Terminal Voltage
• Grounding - Machine grounding description
  • SolidGrounded：Solid grounded bus
  • Z-Grounded：Grounded through an impedance Z (GroundR + jGroundX)
  • UnGrounded：Not grounded

E11 Salient Pole Machine Model

• Name - Machine name, optional
• Rating - Machine rating
• RatedVolt - Machine rated voltage
• Poles - Number of poles
• H - Unit Inertia Constant
• D - Shaft Mechanical Damping Factor
• XL - Armature Leakage Reactance
• X0 - Zero Sequence Reactance
• X2 - Negative Sequence Reactance
• Ra - Armature Resistance
• Xd - Synchronous-Direct Axis Reactance
• Xq - Synchronous-Quadrature Axis Reactance
• Xd1 - Transient-Direct Axis Reactance
• Xd11 - Subtransient-Direct Axis Reactance
• Xq11 - Subtransient-Quadrature Axis Reactance
• Td01 - Open Circuit Transient-Direct Axis Time Constant
• Td011 - Open Circuit Subtransient-Direct Axis Time Constant
• Tq011 - Open Circuit Subtransient-Quadrature Axis Time Constant
• Sliner - Voltage at the End Point of Liner Area on Generator OCC Cuver
• S100 - Saturation Factor at 100% Terminal Voltage
• S120 - Saturation Factor at 120% Terminal Voltage
• Grounding - Machine grounding description
  • SolidGrounded：Solid grounded bus
  • Z-Grounded：Grounded through an impedance Z (GroundR + jGroundX)
  • UnGrounded：Not grounded

Machine Field Current Ifd Calculation

Machine Saturation Calculation

Machine parameters, such as Xd, supplied by the manufacture could be saturated value directly from field measurement or adjusted to unsaturated value. InterPSS allows you to enter the parameter in either way. The following equations are used to calculated machine parameters based on machine air-gap voltage and machine Sliner, Se(100%), Se(120%) enter by the user.

Unsaturated Machine Parameter

Saturated Machine Parameter

Bus Model

Bus Frequency Measurement

Bus frequency is measure by the change rate of bus voltage angle. The transfer function for the measurement is shown in the following diagram:

The following values are set:

Tf = 0.01 sec

Tw = 0.01 sec

You can modify the properties/coreLibContext.xml to change their values:

<bean id="busFreqMeasurementImpl"

class="org.interpss.dstab.measure.BusFreqMeasurementImpl"

scope="prototype">

<constructor-arg index="0"><value>0.01</value></constructor-arg>

<constructor-arg index="1"><value>0.01</value></constructor-arg>

</bean>

InterPSS bus frequency implementation Java source code can be found Here.