Non-Linear Inductance Model Used with BCTRAN

Submitted by Anonymous (not verified) on Wed, 05/18/2011 - 15:20
Forums
General Discussion

I have a question regarding how to use a non-linear inductance to represent the transformer mag Z when using the BCTRAN model.  The BCTRAN documentation is not very clear on how to treat this situation.  The documentation says that the rated excitation value should be subtracted from the non-linear inductance curve.  I'm not quite sure what the author intended there.  Some clarification would be greatly appreciated.

Anonymous (not verified)

BCTRAN model does not take into account saturation. If you want to model saturation and use BCTRAN model, a nonlinear inductance must be connected to the RL circuit generated by BCTRAN.

As explained in the documentation of BCTRAN, it is best to put the nonlinear inductance across the terminals of the winding closest to the core, which is usually the tertiary winding in three-winding transformers. The nonlinear inductance will be in parallel with the unsatured value of the magnetizing inductance. In such a case the magnetizing current must be substracted from the characteristic of the nonlinear inductance.

An example of modeling transformer with BCTRAN and saturation effect is described in the following paper:

"Modeling Ferroresonnance in a 230kV Transformer-Terminated Double-Circuit Transmission Line", D.A.N Jacobson, IPST'99, June 20-24, 1999 Hungary.

The test case presented in this paper is available in the Example section in EMTP-RV : Examples>'Main Examples' and select 'Ferroresonance'.   You can also find this case in : ~\EMTPWorks\Examples\ferro_demo\man_ferro_case.ecf

Wed, 05/18/2011 - 15:20 Permalink
Neriton

Dear, I want to adapt the example present in ~EMTPWorks\Examples\ApplicationCases\Transformer_data\TestExample\TransformerModel in the case of a magnetizing branch connected in the delta connection of the transformer (tertiary side). The "L nonlinear" block is used to convert the I-V curve to I-phi curve. 1) However, I do not know if I have to use the phase-to-ground voltage for the base (as in the example) or the phase-to-phase voltage. 2) Also in the example the power base in divided by 3 (10 MVA used in the L nonlinear block but the no-load test is made for 30MVA). This division is also necessary for the delta connection? 3) The current of the no-load test given in % are given by I = P/V (single phase system) or I = P/sqrt(3)*U (three-phase system) Thanks a lot in advance,
Thu, 05/25/2023 - 18:58 Permalink
X