Ipsa 2 Transient Stability


  • Critical clearing times and fault ride through response
  • Motor starting and re-acceleration
  • Built in governor and AVR models
  • Block diagram based user defined models
  • DLL based plugin models for complex controllers


  • Not necessary to run a load flow analysis first as it will run automatically
  • Critical clearing times and fault ride through response
  • Integrated protection operation and intertripping

 The integrated transient stability module enables the user to analyse the dynamic response of an electrical power system to faults and switching operations. This enables the determination of critical clearing times, fault ride through compliance, motor starting and re-acceleration as well as governor and AVR response and tuning. Both AC and DC networks can be analysed.

Dynamic controllers, such as governors and AVRs, can be added to virtually all network components. In addition network controllers can be added which can represent distributed control systems.


Simulation Options

  • Simulation time and step size
  • Maximum step size if variable
  • Result plotting interval
  • Power imbalance factor for large multi-generator systems
  • DC switch factor for DC networks to simulate breaker opening
  • Individual switching times within equipment properties menu


Results Output Options

  • Directly plot on up to eight in built graphs for interactive analysis
  • Each plot configurable to display specific system parameters of the busbars or connected equipment
  • Store output results in files
  • View and save results as a report
  • Results timeline

Transient Models

Synchronous Machine

  • Five synchronous machine models included
  • Full D-Q axis model with sub-transient, transient, and synchronous representation
  • Standard AVRs and governors provided
  • Custom AVR and governor models using UDM or Plug-in controllers
  • Multi-mass shafts with standard, UDM or Plug-in controllers

Induction Machine

  • Single and double cage models
  • Inner-outer or running – standstill impedances
  • Polynomial representation of mechanical torque
  • UDM or Plug-in modelling for multi-mass shafts or complex torque/speed characteristics
  • Under voltage drop-out relay
  • Lock-out time
  • Default DFIG rotor converter power control
  • Default rotor converter over-current protection

Universal Machine

  • For modelling complex and specialised controllers such as wind turbines
  • Transient response specified as UDM or Plug-in controllers
  • Current injection on system or DQ axis reference frame
  • Power injection

Wind Turbine and PV Modelling

  • Wind turbines modelled using induction, DFIG, synchronous or full converter generators
  • Dynamic controls provided by built in, UDM or Plug-in controllers
  • Manufacturer plug-in controllers available for Gamesa, Siemens, Nordex, Enercon and others.
  • Implementation of PV Controllers

Mechanically Switched Capacitors

  • Controllers using UDM or Plug-ins

Static Var Compensators

  • Controllers using UDM or Plug-ins

AC/DC Converters

  • Line commutated and PWM converter built in models
  • Separate AC and DC side controllers using UDM or Plug-ins
  • DC machines
  • Batteries

Branch Switching

  • Time dependent switching operations
  • Protection relay operations
  • Circuit breaker intertrip operations

Network Controllers

Network controllers represent devices such as SCADA and smart grid controllers that manage multiple network components. These are implemented using plug-in controllers. Inputs and outputs can be configured to link to any network component.

Built in Models

  • IEEE type 1 and type 2 AVR models included as standard
  • Standard governor models include steam turbines, diesel generators and gas turbines

User Defined Models (UDM)

  • Block diagram representation for non-standard controllers
  • Models can be developed for all controllers including governors and AVRs
  • Models can be created and edited by the user

Plug-in Models

  • Used to represent specialised controllers, for example wind turbine or SCADA controllers.
  • Written in C++ and Fortran
  • Provided as a ‘black box’ to the end user
  • Parameter entry is through an automatically generated dialog during network setup