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The inductance matrix transformer (IMT) model reproduces the behavior of a three-phase linear transformer at power frequency. This model works with the Transformer data Tab. Based on excitation and short-circuit tests in positive and zero sequences, the tool computes two matrices [R] and [L] modeling the transformer. The Ri and Li are the resistance and self inductance of each coil. Mij are the mutual inductances between coils. HYPERSIM simulates the transformer as mutually-coupled R-L branches. All computing details of matrices [R] and [L] can be found in the Transformer data Tab documentation.


  • A three-limb core representation
  • A five-limb core representation
  • Internal faults simulation (see 3-Winding Impedance-Matrix-Based Transformer with Internal Fault)

Does not support

  • A three single-phase cores representation 
  • Saturation

titleTable of Contents

Table of Contents

Mask and Parameters

General Parameters

The base parameters are computed in the Transformer data Tab.

Description Use this field to add information and pertinent details about the component
Base primary/secondary/tertiary winding voltage (rmsLL)

Base value for PU conversion (kV); defined in Transformer data Tab (kV).

  • Voltage expressed in kV rms LL
  • This base voltage and nominal voltage will change, if the corresponding winding connection switches between delta and Y.
Base power (total) Base value for PU conversion (MVA)
Base frequency Base value for PU conversion (Hz)

Winding Parameters

The R and L matrices as well as the positive- and zero-sequence parameters are computed in the Transformer data Tab.

Primary/secondary/tertiary connection

Winding type

  • Y ground: Grounded Y connection (can use the internal neutral impedance specified in the other tab)
  • Y floating: Floating Y connection
  • Y neutral: Y connection with impedance connected at the input pin N1 or N2
  • Delta lead: Delta connection with lead of 30°
  • Delta ground: Grounded delta connection (Phase C is grounded)
  • Delta lag: Delta connection with lag of 30°
Rm - positive sequenceDefined in Transformer data Tab (Ω)
Rm - zero sequenceDefined in Transformer data Tab (Ω)
[R]Leakage resistance matrix (Ω)
[L]Leakage inductance matrix (H)

Neutral Impedance Parameters

The neutral impedance parameters are computed in the Transformer data Tab.

R1, R2, R3Neutral resistance of the winding; only applies to Y ground (Ω)
L1, L2, L3Neutral inductance of the winding; only applies to Y ground (H)
C1, C2, C3Neutral capacitance of the winding; only applies to Y ground (F)

Transformer Data

Background Color

To Learn How to Generate Transformer Parameters See:

Ports, Inputs, Outputs and Signals Available for Monitoring


Net_1Primary winding connection (supports only 3-phase connections)
Net_2Secondary winding connection (supports only 3-phase connections)
Net_3Tertiary winding connection (supports only 3-phase connections)
Net_N1Neutral connection for primary winding (supports only 1-phase connections)
Net_N2Neutral connection for secondary winding (supports only 1-phase connections)
Net_N3Neutral connection for tertiary winding (supports only 1-phase connections)


  • None


  • None


IPRIM(a,b,c,n)Primary current for each phase (A)
ISEC2(a,b,c,n)Secondary current for each phase (A)
ISEC3(a,b,c,n)Tertiary current for each phase (A)


[1] Dommel, H., et al., Electromagnetic Transients Program Reference Manual (EMTP Theory Book), 1986
[2] A transformer model for winding fault studies, Patrick Bastard, Pierre Bertrand, Michel Meunier, IEEE, Vol 9, No 2, April 1994