Two-winding transformer#

Note

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The Two-winding transformer block is designed for conversionof AC voltage into another voltage system by means of electromagneticinduction in accordance with the set transformation ratio without frequency change.

Note

The conversion is non-ideal due to natural lossesin transformer steel and windings.

Equivalent circuit of the double-winding transformershown below (see Fig. 1) is suitable for simulation ofsteady-state modes and electromechanical transients:

Fig. 1 Double-winding transformer equivalent circuit#

All values of the equivalent circuit parameters shall be calculated fromthe catalog data of the transformer and brought to its ratedvoltage (in case of step-up transformer, when the low voltage winding is primary, the valueof the rated voltage of the low side shall be specified in the block):

the active resistance of the transformer is determined on the basis of \(∆P_{sc}\) loss power obtained during the short-circuit experiment (1):

(1)#\[R=\frac{∆\mathrm{P}_{\mathrm{к}\mathrm{з}}\cdot U_{\mathrm{н}\mathrm{о}\mathrm{м}}^{2}}{S_{\mathrm{н}\mathrm{о}\mathrm{м}}^{2}};\]

the impedance is determined on the basis of \(U_{sc}\) short-circuit voltage value determined during the short-circuit experiment and given as a percentage of the rated voltage (2):

(2)#\[Z=\frac{U_{кз}}{100}\cdot \frac{U_{\mathrm{н}\mathrm{о}\mathrm{м}}^{2}}{S_{\mathrm{н}\mathrm{о}\mathrm{м}}};\]

reactance is determined on the basis of the total and activeresistances (3):

(3)#\[X=\sqrt[]{Z^{2}-R^{2}};\]

the active and reactive shunt resistances are calculated from catalog (4):

(4)#\[\mathrm{G}=\frac{P_{\mathrm{х}\mathrm{х}}}{U_{\mathrm{н}\mathrm{о}\mathrm{м}}^{2}};\mathrm{Y}=\frac{I_{\mathrm{х}\mathrm{х}}}{100}\frac{S_{\mathrm{н}\mathrm{о}\mathrm{м}}}{U_{\mathrm{н}\mathrm{о}\mathrm{м}}^{2}};\mathrm{B}=\sqrt[]{Y_{}^{2}-G_{}^{2}};\]

transformation factor (5):

(5)#\[k_{\mathrm{т}\mathrm{р}}=\frac{U_{2}}{U_{1}}.\]

1. Properties#

Property	Default value	Description	Units of measurement
Transformer rated power	1	Rated power of transformer primary winding	MVA
Transformer ratio	0.04	Rated transformation factor	-
Primary voltage	10	Primary winding rated voltage	kV
Short-circuit voltage	35	-	%
Short-circuit power losses	7.5	-	kW
Incorporate no load power losses	Off	-	-
No load power losses	43	idle run losses (losses in steel)	kW
No load current	0.6	idle current as a percentage of the rated current of the primary winding	%
Fixed tap changer: No tap changer; Primary winding; Secondary winding; External tap changer	No tap changer	-	-
Positive tap number	2	Available, when `Fixed tap changer` - `Primary winding` or `Secondary winding`	-
Negative tap number	-2	Available, when `Fixed tap changer` - `Primary winding` or `Secondary winding`	-
Tap setting	2.5	Available, when `Fixed tap changer` - `Primary winding` or `Secondary winding`	%
Current step	0	Available, when `Fixed tap changer` - `Primary winding` or `Secondary winding`	-

2. Inputs and outputs#

Parameters	Input/Output	Description	Units of measurement	Port type
Input	Input	-	V	Electrocity
Transformer ratio	Input	Available, when `Fixed tap changer` - `External tap changer`	-	Автоматика
Secondary voltage	Output	-	V	Electrocity

In order to see the connection capabilities of the block, you need to go to page Description of block ports