220kv grid wapda town lahore
TRANSCRIPT
220kV
Grid
Wapda Town
A Complete overview of Power Grid
Abdul Samad
Presented By
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
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
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.
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.
Equipment's used All Power-Grid Equipment's
MAIN EQUIPMENTS AT WAPDA TOWN SUBSTATION 220KV
Main equipment of Wapda town substation 220kV
* Ring Bus system :
I/C Supply
O/G feeder
Bus
CB
Tie CB
Main 1
Main 2
Feeder 1Feeder 2Feeder 2Tie CB
Feeder 1
* One and Breaker Half :
Page 10© OMICRON
Purpose of Circuit Breakers in Power Systems
> Minimize losses in closed position
> Open and close on command
>Open or close a circuit to connect
the power to/from the transmission
line
(O - break, C - make)
>Open a circuit for planned
maintenance (O - break)
>Open a circuit at system fault to
protect the system behind the
circuit breaker (O break, O-C
reclose, O-CO, auto-reclose)
>Isolate between poles, open
contacts and earth
x
Busbar
Disconnector
Circuit Breaker
PowerTransformer
x Circuit Breaker
Network
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
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
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 strandsH.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
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
Equipment's used
Types of Conductors
Transformer
Transformer Colling Methods
ONAN
ONAF
OFAF
OFAN
Equipment's used
Types of Conductors
Transformer
Transformer Colling Methods
ONAN Cooling Method
Equipment's used
Types of Conductors
Transformer
Transformer Colling Methods
ONAF Cooling Method
Equipment's used
Types of Conductors
Transformer
Transformer Colling Methods
OFAN Cooling Method
Equipment's used
Types of Conductors
Transformer
Transformer Colling Methods
OFAF Cooling Method
Equipment's used
Types of Conductors
Transformer
Transformer Mechanical Protection
Buchholz Relay Working
Equipment's used
Types of Conductors
Transformer
Transformer Mechanical Protection
Buchholz Relay Position on Transformer
Equipment's used
Types of Conductors
Transformer
X-mersTesting
Transformer Testing
Earthing Test of Transformer
Equipment's used
Types of Conductors
Transformer
X-mersTesting
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
Equipment's used
Types of Conductors
Transformer
X-mersTesting
Transformer Testing
Transformer Turn Ratio Test
HV Side LV Side
Equipment's used
Types of Conductors
Transformer
X-mersTesting
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
Equipment's used
Types of Conductors
Transformer
X-mersTesting
Transformer Testing
Megger Insulation Resistance Test
1. HV to LV
Step 1.
Open HV & LV sides of the transformer.
Step 2.
Short the terminals of both sides of Star & Delta Winding
Equipment's used
Types of Conductors
Transformer
X-mersTesting
Transformer Testing
Step 3.
We supplied voltages at the HV side of +5KV DC and -5KV DC at LV side.
Step 4.
By measuring the voltage drop we calculate the resistance of core and
windings.
Step 5.
And then we compare the calculated with the commissioned report.
Equipment's used
Types of Conductors
Transformer
X-mersTesting
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
Equipment's used
Types of Conductors
Transformer
X-mersTesting
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.
Equipment's used
Types of Conductors
Transformer
X-mersTesting
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.
Equipment's used
Types of Conductors
Transformer
X-mersTesting
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.
Equipment's used
Types of Conductors
Transformer
X-mersTesting
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.
Equipment's used
Types of Conductors
Transformer
X-mersTesting
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
Equipment's used
Types of Conductors
Transformer
X-mersTesting
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.
Equipment's used
Types of Conductors
Transformer
X-mersTesting
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.
Equipment's used
Types of Conductors
Transformer
X-mersTesting
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.
Equipment's used
Types of Conductors
Transformer
X-mersTesting
Transformer Testing
Step 6.
Record the capacitance and dissipation factor values once the null meter is
balance for both phasing position. Record values for the five test-variable
selector switch position.
Equipment's used
Types of Conductors
Transformer
X-mersTesting
Transformer Testing
Purpose
Condition of Bushing and overall insulation
of transformer can be investigated.
Aging and decomposition of insulation increase the losses are
determined through this test.
Equipment's used
Types of Conductors
Transformer
X-mers Testing
Monitoring & Control
panel
Monitoring & Control Panels
Monitoring Panel Equipment
• Ampere meters• Voltmeters• Kilowatt meters• KVAR meters• Power factor meters• Energy Meters
In the monitoring and control room, there are two kinds of panels;
Monitoring & Control
Equipment's used
Types of Conductors
Transformer
X-mers Testing
Bus Bar, Safety & Battery Room
Monitoring & Control Panels
Monitoring Panel Equipment
• Alarms• Indications
Breaker open
BuchhlozRelay
SF6 low pressure
Relay active
Monitoring & Control
panel
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
RectifierBattery charger
+Batteries
To control panel(dc)
AC
Backup supply forcontrol panel (dc)
Monitoring & Control
panel
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
Equipment's used
Types of Conductors
Transformer
X-mersTesting
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
Equipment's used
Types of Conductors
Transformer
X-mersTesting
Bus Bar & Safety
Bus Bar Scheme
Double Main Bus-bar scheme
Advantages:I. Any circuit can be taken out of circuit for
maintenanceII. Flexibility in connecting the feeder circuit
to either of the bus barsDisadvantages:I. Most expensiveII. Loose circuits connected to bus bar when
fault occurs on the bus bar
Monitoring & control
Equipment's used
Types of Conductors
Transformer
X-mersTesting
Bus Bar & Safety
Fire Extinguishers Types
Monitoring & control
Equipment's used
Types of Conductors
Transformer
X-mersTesting
BusBar, Safety & Battery Room
Battery Room
What is the purpose of battery room ..??
It is the Heart of Grid Provides backup Protection devices run on this
Monitoring & control
Equipment's used
Types of Conductors
Transformer
X-mers Testing
Bus Bar, Safety & Battery Room
Testing of Batteries
Monitoring & control
Visual Inspection Test
Equipment's used
Types of Conductors
Transformer
X-mers Testing
Bus Bar, Safety & Battery Room
Testing of Batteries
Monitoring & control
Voltage Test