Experiment 2.2

The Given power system model can be divided into 6 regions namely R1: Blue, R2: Red, R3: Green, R4: Black, R5: Cyan, R6: Yellow
The components in R1 are:

G1
Primary of T1
Primary of T3

The components in R2 are:

Secondary of T1
Tx1
Primary of T2

The components in R3 are:

Secondary of T2
Secondary of T4
G2

The components in R4 are:

Secondary of T3
Tx2
Primary of T5

The components in R5 are:

Primary of T6
Tx3
Primary of T4

The components in R6 are:

Secondary of T5
Secondary of T6
M1

The procedure to move forward is as follows

First choose a component to be the base for the entire system
Since we have chosen Tx1 as our base component we will consider its MVA as the base MVA for the entire power system.
To determine the base kV though we have to divide the components into regions divided by transformers as shown in the above image.
Once divided, assign the base kV of R2 as the kV of Tx1 this is because the base kV of the region containg the base element is the base kV of the base element.
Now The calculation of the base kV for region 1, 3, 4, 5 and 6 has to be done this is done using the below formule

_bRn

_{Tn,(primary/secondary)}

Once base kV for all the region have been found the perunit impedance can be found using the following formule (here for new base kV of the component use the calculated base kV of the region the component is in)

Zactual through Zpu, Kvb and MVAb of the component

Zpu through the Zpu old along with old and new base MVA, base kV

NOTE: The kV_b,given, Z_pu,given, MVA_b,given are the component's kV, Z_pu, MVA. The "given" may be replace by "old"

Field	Explanation	General Range
G_n	Represents a Synchronous Generator with a unique identification number n (G1, G2,…Gn)	Representation for Symbols which are present in the given Single Line Diagram
M_n	Represents a motor with a unique identification number n (M1, M2,…Mn)
T_n	Represents a transformer with a unique identification number n (T1, T2,…Tn)
Tx_n	Represents a transmission line with a unique identification number n (TX1, TX2,…TXn)
L_n	Represents a load with a unique identification number n (L1, L2,…Ln)
Z(new)_p.u	It is the per unit impedance of the component calculated with respect to the new base values (kV_b,new, MVA_b,new)	0.0001 p.u. to 2 p.u. (but not restricted)
For generator, motor and load
Base MVA	Base Mega Volt Ampere	1 MVA to 1000 MVA (but not restricted)
Base KV	Base kilo Voltage	220 V to 800 kV (but not restricted)
Z(old)_p.u	It is the per unit impedance of the component calculated with respect to its MVA and kV (kV_b,given, MVA_b,given or kV_b,old, MVA_b,old)	0.0001 p.u. to 2 p.u. (but not restricted)
For transformers
Base kV Primary	It is the Base voltage in kV with respect to primary side of the transformer	220 V to 800 kV (but not restricted)
Base kV Secondary	It is the Base voltage in kV with respect to secondary side of the transformer	220 V to 800 kV (but not restricted)
For transmission lines
Z (Impedance)	It is defined as the total opposition of the circuit to the electric current	Based on rating of the equipment (kV, MVA)

Example 1 Example 2

Components	Base MVA	Base kV		Z(old)_p.u	Z(new)_p.u
G1				+j()	+j()
G2				+j()	+j()
M1				+j()	+j()
Components	Base MVA	Base kV		Z(old)_pu	Z(new)_pu
Components	Base MVA	Primary	Secondary	Z(old)_pu	Z(new)_pu
T1				+j()	+j()
T2				+j()	+j()
T3				+j()	+j()
T4				+j()	+j()
T5				+j()	+j()
T6				+j()	+j()
Components	Base MVA			Z (in Ohms)	Z _pu
TX1				+j()	+j()
TX2				+j()	+j()
TX3				+j()	+j()

Per Unit Reactance Diagram