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FAQs: How can I model an Induction Generator in PTW?
Prior to V7.0, PTW did not have a specific induction generator model (it only had a synchronous generator model). However, if you are running PTW V6.5 or earlier, induction generators can be easily modelled. A synchronous generator has its own excitation system, whereas an induction generator takes its excitation by absorbing reactive power from the rest of the network.
For new projects created in PTW V7.0 onwards, there is now a dedicated model for induction generators or wind turbines. See below.
For new projects created in PTW V7.0 onwards, there is now a dedicated model for induction generators or wind turbines. See below.
Induction generators in PTW V6.5 and earlier:
Running a load-flow study
An induction generator should be modelled as a PQ generator when running a load-flow. The values should be set to absorb reactive power and produce active power. Therefore, a network must always be modelled with either a utility or swing-bus (SB) generator in order for the study to run correctly.
An induction generator should be modelled as a PQ generator when running a load-flow. The values should be set to absorb reactive power and produce active power. Therefore, a network must always be modelled with either a utility or swing-bus (SB) generator in order for the study to run correctly.
Running a TMS study
A network must always be modelled with either a utility or swing-bus generator in order for the study to converge correctly. Click here for more information.
Running a fault study
As far as the Comprehensive Fault Study is concerned, there is no difference between an induction generator and a synchronous generator, so the standard model can be used. The IECFault study does, on the other hand, consider the excitation of machines. Therefore for the purposes of the IEC60909 and IEC61363 studies, the induction generator will be treated as a PQ-type synchronous generator.
Running an I*SIM study
The I*SIM module includes an induction generator as one of the standard generator models. Although its exact behaviour will depend on the network and the scenarios modelled, an induction generator will generally continue to operate until there is insufficient stored energy to continue.
As far as the Comprehensive Fault Study is concerned, there is no difference between an induction generator and a synchronous generator, so the standard model can be used. The IECFault study does, on the other hand, consider the excitation of machines. Therefore for the purposes of the IEC60909 and IEC61363 studies, the induction generator will be treated as a PQ-type synchronous generator.
Running an I*SIM study
The I*SIM module includes an induction generator as one of the standard generator models. Although its exact behaviour will depend on the network and the scenarios modelled, an induction generator will generally continue to operate until there is insufficient stored energy to continue.
Induction generators in PTW V7.0 and later:
Since a PTW project cannot be downgraded to earlier versions, the dedicated Induction Motor model can be used in any project opened in PTW V7.0 or later. However, note that some projects created prior to V7.0 may have been set up with induction generators modelled as PQ-type synchronous generators (as above) - even if the project was later converted to V7.0 or higher.
Running a load-flow study
An induction generator modelled using the "Induction / Wind Generator" component will behave in essentially the same manner as a PQ-type synchronous generator would. The values should be set to absorb reactive power and produce active power (kW is positive and kVar is negative).
Running a load-flow study
An induction generator modelled using the "Induction / Wind Generator" component will behave in essentially the same manner as a PQ-type synchronous generator would. The values should be set to absorb reactive power and produce active power (kW is positive and kVar is negative).
(Right): From PTW V7.0 onwards, there is a new symbol in the toolbar for adding induction generators to your model. The default prefix for these items is "IGEN..."
(Left): Extract from the Component Editor screen of an induction generator in PTW V8.0. To model an induction generator correctly, the kW figure should be positive and the kVar figure negative.
(Left): Extract from the Component Editor screen of an induction generator in PTW V9.0. Data fields are the same as V8.0 (above) but terminology and formatting is slightly different.
(Left): Extract from the Component Editor screen of an induction generator in PTW V9.0. Data fields are the same as V8.0 (above) but terminology and formatting is slightly different.
PTW V8.0
PTW V9.0
There are some considerations if the PTW model represents one or more islanded induction generators:
Be aware that studies using the TMS module still require either a utility or swing-bus generator in the model, or the result will not converge. This applies regardless of which version of PTW is in use.
Running a fault study
As with synchronous PQ generators, the Comprehensive Fault Study will work with induction generators. Similarly, IECFault studies will treat an induction generator model as if it were a PQ-type synchronous generator.
Running an I*SIM study
The I*SIM module includes an induction generator as one of the standard generator models. Although its exact behaviour will depend on the network and the scenarios modelled, an induction generator will generally continue to operate until there is insufficient stored energy to continue.
- (Version V7.0 and earlier) A network must always have a utility or a swing-bus generator to run a study; this is not a problem because an induction generator will always be connected to an external source of reactive power.
- (Version V8.0 onwards) There is no longer a requirement for a utility or swing-bus generator (this would represent an islanded system). There are however changes which need to be made to account for the variability in system frequency when the system is islanded. Click here for more information.
Be aware that studies using the TMS module still require either a utility or swing-bus generator in the model, or the result will not converge. This applies regardless of which version of PTW is in use.
Running a fault study
As with synchronous PQ generators, the Comprehensive Fault Study will work with induction generators. Similarly, IECFault studies will treat an induction generator model as if it were a PQ-type synchronous generator.
Running an I*SIM study
The I*SIM module includes an induction generator as one of the standard generator models. Although its exact behaviour will depend on the network and the scenarios modelled, an induction generator will generally continue to operate until there is insufficient stored energy to continue.