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The power transformer is one of the key elements in every substation. Such an important element has to be protected from faults most efficiently. Model-based testing can give provide a deep insight into the behaviour of the power transformer during the fault conditions.
In most applications, three-phase transformers use a three-limb core (core-type transformer). This type of core produces accurate results during an asymmetrical fault for both linear and nonlinear models (including saturation). During asymmetrical voltage conditions, the zero-sequence flux of a core-type transformer returns outside the core, through an air gap, structural steel, and a tank. Thus, the natural zero-sequence inductance L0 (without delta winding) of such a core-type transformer is usually very low (typically 0.5 pu 100 pu). This low L0 value affects voltages, currents, and flux unbalances during linear and saturated operation.[1]
A high-fidelity model of three-phase transformers that use a three-limb core (core-type transformer) plays a key role in testing and validating protection schemes for asymmetrical faults.
Task Requirements
Your task is to create three-phase transformers that use a three-limb core in the Typhoon HIL Control Center. In the attachment of the task, you can find two models.
The first model is the reference Simulink model and the second is the Typhoon HIL model. In the Simulink reference model, the two same transformers are modelled. The only difference is one uses default core mode, while the other transformer uses a three-limb core (core-type) transformer. The results of the different core types during the fault can be seen in the image below:
In the Schematic editor model, you can find the two transformers as well. The one model is enabled which represents the transformer that uses the default core model. The second model is disabled and needs to be implemented. The results of the fault in HIL SCADA can be seen in the image below:
Software requirements
- Typhoon HIL Control Center
- Simulink
Good luck.
References
[1] https://www.mathworks.com/help/sps/powersys/ref/threephasetransformertwowindings.html
Files
Simulink model
Schematic Editor model
SCADA panel
