It is Multimedia presentation made by Abdul Samad, An Electrical Engineer From UET Lahore Pakistan. For queries contact Abdulsamad.pisces@hotmail.com
Hope u find it useful
3. Substation
An Electrical Substation is a subsidiary station of an
electricity Generation , Transmission And Distribution
System where voltage is transformed high to low or
reverse using transformer.
Examples of Substation:-
220kV/132kV substation
132kV/66kV substation
66kV/11kV substation
4. 220kV Substation
It is divided into to(3) parts:-
I. Panel Section
Control Panel Section
Relay and Protection Panel Section
II. Switch Yard
220kV Section
132kV section
33kV section
III. Battery Room
5. Panel Section
It has two sections
I. Control Panel Section
It contain panels related to controlling of instruments.
E.g.:- feeder panel, X-mer panel, etc.
II. Relay And Protection Panel Section
It contains panels related to relay systems and
protection systems.
E.g.:- Relay panel, line protection panel, etc.
6. Switch Yard
It is the field where components used in controlling
supply and measuring supply(incoming and outgoing)
are placed
Some of these many components are:-
C.Bs
Isolators
C.Ts
P.Ts
L.As
X-mers, etc.
7. Equipment's
used All Power-Grid Equipment's
MAIN EQUIPMENTS AT WAPDA TOWN SUBSTATION 220KV
Main equipment of Wapda town substation 220kV
8. * Ring Bus system :
I/C Supply
O/G feeder
Bus
CB
9. Tie CB
Main 1
Main 2
Feeder 1Feeder 2Feeder 2
Tie CB
Feeder 1
* One and Breaker Half :
11. Equipment's
used
Types of
Conductors
What we have learnt …??
Conductors
Why We use Aluminum in place of Copper …??
Types of conductors used in 220kV substations are
AAC -> All Aluminum Conductors
AAAC -> All Aluminum Alloy Conductors
ACSR -> Aluminum Conductor Steel Reinforced
ACAR -> Aluminum Conductor Alloy Reinforced
12. Equipment's
used
Types of
Conductors
What we have learnt …??
All Aluminum Conductors (AAC) &
All Aluminum-Alloy Conductor (AAAC)
For 36 kV transmission and above both aluminum conductor steel
reinforced (ACSR) and all aluminum alloy conductor (AAAC) may
be considered. Aluminum conductor alloy reinforced (ACAR) and
all aluminum alloy conductors steel reinforced (AACSR) are less
common than AAAC and all such conductors may be more
expensive than ACSR
13. Equipment's
used
Types of
Conductors
What we have learnt …??
Aluminum Conductor Steel Reinforced (ACSR)
Names of ASCRs
No. Of strands / No. Of steel Strands/diameter of strands
H.T Overhead Line
Sr. No. Names Size(mm)*
1. Rabbit 6/1/3.55
2. Panther 30/7/3.00
3. Zebra 54/7/3.00
4. Moose 54/7/3.53
14. Equipment's
used
Types of
Conductors
What we have learnt …??
Aluminum Conductor Aluminum Alloy Reinforced
(ACAR)
I. improved strength to weight ratio
II. better mechanical properties
III. improved electrical characteristics
IV. excellent resistance to corrosion
23. Equipment's
used
Types of
Conductors
Transformer
X-mers
Testing
Transformer Testing
Earthing Test of Transformer Observations
(2-1) at 100A voltage drop was 0.5V at test set
(2-3) at 100A voltage drop was 0.39V because of test lead
(2-10) at 100A voltage drop was 0.701V at test set
(2-9) at 100A voltage drop was 0.6V at test set
(2-8) at 100A voltage drop was 0.68V at test set
(2-7) at 100A voltage drop was 0.59V at test set
(2-6) at 100A voltage drop was 0.78V at test set
(2-5) at 100A voltage drop was 0.43V at test set
25. Equipment's
used
Types of
Conductors
Transformer
X-mers
Testing
Transformer Testing
Step 1.
First, the tap changer of transformer is kept in lowest position and LV
terminals are kept open. In this test we check that the voltages at the LV
side according to the turn ratio of rated LV side and HV side are according
to the rated value. We use Megger for the supply of 400V during the testing
of TTR.
Step 2.
For testing purpose we open both the LV and HV sides. We supply 400V
using Megger Device. And at the side we received 34.28V.
Star-Delta Turns Ratio Delta-Star Turns Ratio
28. Equipment's
used
Types of
Conductors
Transformer
X-mers
Testing
Transformer Testing
Step 1.
Open HV & LV sides of the transformer.
Step 2.
Short the terminals of both sides of Star
& Delta Winding.
Step 3.
We supplied voltages at the HV side of +12KV DC and GND at LV side.
Step 4.
By measuring the voltage drop we calculate the resistance between
windings turns of HV side
Step 5.
And then we compare the calculated with the commissioned report.
2. HV to GND
29. Equipment's
used
Types of
Conductors
Transformer
X-mers
Testing
Transformer Testing
3. LV to GND
Step 1.
Open HV & LV sides of the transformer.
Step 2.
Short the terminals of both sides of
Star & Delta Winding.
Step 3.
We supplied voltages at the LV side of
+12KV DC and GND at HV side.
Step 4.
By measuring the voltage drop we calculate the resistance between
windings turns of LV side.
Step 5.
And then we compare the calculated with the commissioned report.
30. Equipment's
used
Types of
Conductors
Transformer
X-mers
Testing
Transformer Testing
Winding Resistance Test
Step 1.
We open the HV & LV windings of the
transformer.
Step 2.
Current is injected into winding using
current injection set.
Step 3.
Supply should be DC 100A because of measuring resistance and if we use
AC then it consists of capacitive reactance, inductive reactance and the
total combination of impedance of the above. So that’s why we don’t use
AC and hence we use DC to avoid the above problems to find the winding
resistance.
Step 4.
For LV side testing we test between red & Neutral, Yellow & Neutral, and
Blue & Neutral for LV side or star connected side.
31. Equipment's
used
Types of
Conductors
Transformer
X-mers
Testing
Transformer Testing
Step 5.
For HV side or Delta connected side we measure resistance between
phases (red,blue), (red,yellow) and (yellow,blue).
Purpose
Calculate the I2 R losses in conductor.
Calculation of winding temperature at the end of temperature test
cycle.
It provides a base line which tells us about the possible damage in the
field.
32. Equipment's
used
Types of
Conductors
Transformer
X-mers
Testing
Transformer Testing
Temperature Rise Test
Step 1.
First the LV winding of the
transformer is short circuited.
Step 2.
Then one thermometer is placed
in a pocket in transformer top
cover. Other two thermometers
are placed at the inlet and outlet
of the cooler bank respectively.
Step 3.
The voltage of such value is applied to the HV winding that power
input is equal to no load losses plus load losses corrected to a
reference temperature of 75°C.
33. Equipment's
used
Types of
Conductors
Transformer
X-mers
Testing
Transformer Testing
Step 5.
During the test, hourly readings of top oil temperature are taken from
the thermometer already placed in the pocket of top cover.
Hourly readings of the thermometers placed at inlet and outlet of the
cooler bank are also noted to calculate the mean temperature of the
oil. And finally we read the temperature at steady state and stop the
testing method.
Step 6
34. Equipment's
used
Types of
Conductors
Transformer
X-mers
Testing
Transformer Testing
Current Transformer Test
The voltage shall be applied between:
1. Primary to secondary plus ground
(covered during switchgear test).
2. Secondary to primary plus ground.
3. Secondary core to core.
The above diagram shows that how a CT measure the current practically
or numerically.
35. Equipment's
used
Types of
Conductors
Transformer
X-mers
Testing
Transformer Testing
Capacitance and dissipation factor test
It is a low AC voltage maintenance test similar to power factor test to
measure capacitance and dissipation of transformer insulation system.
Acceptance testing stage to establish base line reading for future.
Step 1.
Isolate the equipment, apply working grounds to all incoming and outgoing
cables and disconnect all incoming and outgoing cables from the
transformer bushing terminals. Disconnected cables should have sufficient
clearance from the switchgear terminals greater that the phase spacing
distance.
36. Equipment's
used
Types of
Conductors
Transformer
X-mers
Testing
Transformer Testing
Step 2.
Isolate the neutral bushing connection if applicable from the transformer
grounding bar.
Step 3.
Short-circuit all high voltage bushing terminals together.
Step 4.
Short-circuit all low voltage bushing terminals and the neutral bushing
terminal together.
Step 5.
Connect the capacitance and dissipation factor test set. Refer to Figure , on
next slide.
41. Equipment's
used
Types of
Conductors
Transformer
X-mers
Testing
Bus Bar,
Safety &
Battery
Room
Monitoring & Control Panels
• Push buttons and switches
• Power supply
• Relays
Control Panel Equipment
Rectifier
Battery charger
+
Batteries
To control panel
(dc)
AC
Backup supply for
control panel (dc)
Monitoring
& Control
panel
42. Equipment's
used
Types of
Conductors
Transformer
X-mers
Testing
Bus Bar,
Safety &
Battery
Room
Transformer
DY - 132/11kV, 20/26MVA
Rated current HV = 114 A
Rated current LV = 1366 A
If 10% of rated voltage (suppose), rated current flows in
secondary when short circuited.
13.2kV ==== 1366 A
13.2kV * 10 === 1366 A * 10
V1 V2Transformer
43. Equipment's
used
Types of
Conductors
Transformer
X-mers
Testing
Bus Bar &
Safety
Bus Bar Scheme
Different bus bar arrangements:
Some of the switching schemes are bus bar
arrangements employed in the substations are
listed below:
Single Bus-bar arrangement
Double Main Bus-bar scheme
Main and Transfer bus-bar scheme
One and half breaker scheme
Ring Main arrangement scheme
Monitoring
& control
44. Equipment's
used
Types of
Conductors
Transformer
X-mers
Testing
Bus Bar &
Safety
Bus Bar Scheme
Double Main Bus-bar scheme
Advantages:
I. Any circuit can be taken out of circuit for
maintenance
II. Flexibility in connecting the feeder circuit
to either of the bus bars
Disadvantages:
I. Most expensive
II. Loose circuits connected to bus bar when
fault occurs on the bus bar
Monitoring
& control
