SMJE 1103 �Electrical Power System
3- Ph Power Apparatus
References & Circuit Simulator
Can be downloaded from;
Circuit simulator: Matlab
Observation
Power Apparatus
Transformer
Transformer
Transformer�-Connection Types and Symbol
Transformer�-Connection Types and Symbol
Transformer�-Application-
Application
Equivalent Circuit
Equivalent Circuit (simplified)
Equivalent Circuit (simplified)
Problems/Examples
Look at the given problems/examples;
-[1]p408, example 24.1
-[1]p409, example 24.4
-[1]p411, example 24.7
-[1]p412, example 24.9
-[9]p23, example 2-1
Problems/Examples
Look at the given problems/examples;
-[1]p408, example 24.2
-[1]p410, example 24.5
-[1]p412, example 24.8
-[9]p28, example 2-4
Problem 10
(b) Suppose a 1:10 step-up transformer is placed at the generator end of the transmission line and a 10:1 step-down transformer is placed at the load end of the line (Figure (b)). What will the load voltage be now? What will the transmission line losses be now?
Problem 11
Some Important Points on�Equivalent Circuit
Please, observe these parameters by comparing difference type of transformer (step up and step down) and give your comment on it.
Quiz 15
Testing
To know the value of the inductance and resistance
Short circuit test
Power factor, PF = cos θ = PSC / VSC ISC (lagging)
The series impedance ZSE = Req + jXeq
= (RP + a2 RS) + j(XP + a2 XS)
Open circuit test
Conductance of core loss
Susceptance of magnetizing
Total admittance
Admittance referred to primary
Angle of admittance
Impulse voltage test
Problems/Examples
Look at the given problems/examples;
-[9]p35, example 2-7
-[4]p666, example 32.8
-[1]p424, example 24.28
Problems/Examples
Look at the given problems/examples;
-[9]p26, example 2-3
-[6]p105, example 3.2
-[4]p662, example 32.6
Problem
Open circuit test (primary) | Short circuit test |
VOC = 8000 V | VSC = 489 V |
IOC = 0.214 A | ISC = 2.5 A |
POC = 400 W | PSC = 240 W |
The equivalent circuit impedances of a 20kVA, 8000/240V, 50Hz transformer are to be determined. The open circuit test and the short circuit test were performed on the primary side of the transformer, and the following data were taken:
Find the impedance of the approximate equivalent circuit referred to the primary side, and sketch the circuit.
Some Important Points on�Testing
Please, observe these parameters by comparing difference type of transformer (step up and step down) and give your comment on it.
Quiz 16
3-Phase Transformer
Transformers for 3-phase circuits can be constructed in two ways:
connect 3 single phase transformers
Three sets of windings wrapped around a common core
The primaries and secondaries of any three-phase transformer can be independently connected in either a wye (Y) or a delta (∆)
The important point to note when analyzing any 3-phase transformer is to look at a single transformer.
The impedance, voltage regulation, efficiency, and similar calculations for three phase transformers are done on a per-phase basis.
Circuit Configuration
Three-phase two winding Y-Y transformer bank
Circuit Configuration
Three-phase two winding Y- ∆ transformer bank
Problems/Examples
Look at the given problems/examples;
-[1]p426, example 24.33
-[4]p668, example 32.9
Some Important Points on�Three-Phase
Please, observe these parameters by comparing difference type of transformer connection (Delta and Star) and give your comment on it.
Quiz 17
Transformer�(Per-Unit System)
Problems/Examples
Look at the given problems/examples;
-[6]p110, example 3.3
-[6]p115, example 3.5
-[6]p123, example 3.7
-[6]p128, example 3.9
-[5]p94, example 3.8
Some Important Points on�Per-Unit System
Please, observe these parameters by comparing difference value of load power factor and give your comment on it.
Quiz 18
Please refer to [9]p30, example 2-2. Solve the given problem but now the transformer ratio will be changed to 480/8000 V.
The End�-Thanks-