Transcript Document

EVENT LOGGER Contd..
 Process of Data Down Load

Data Down Load to Station Monitoring System
EVENT LOGGER Contd..
 Data Down Load for ABB make Relay INDACTIC 425
EVENT LOGGER Contd..
 Data Down Load for Siemens make
Relay 7SA522--series
DISTURBANCE RECORDER
 What is Disturbance Recorder?
 Why is it required for Sub-Station?
 Functions of disturbance Recorder
 Records the sequential data events.
 Provides the status of power systems
 Pre and post fault data of parameters
 Information of the disturbances
 Analysis of values in wave form or vectorial
form .
DISTURBANCE RECORDER Contd…
 Basic Principle of Disturbance recorder:
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




Initiation of Digital or Analog pulse due to disturbance
Sampling of the pulse for data acquisition.
Buffer is used to distinguish the pre and post fault condition of disturbance
Time stamped for correct sequence
DI signal filter is used for correct memory storage
Data becomes ready for communicable
DISTURBANCE RECORDER Contd…
DISTURBANCE RECORDER Contd…
 Application and Settings of Disturbance recorder:
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


Setting through HMI or PC
Selection of Binary Inputs and logical out puts for the relay action.
Application for Trip Analysis and event analysis.
Selection of Electrical Equipments for correct action .
FAULT LOCATOR
 What is Fault Locator?
 Why is it required for Sub-Station?
 Functions of fault Locator
 Records the fault data .
 Pre and post fault data of parameters
 Locates and indicates the distance of fault
occurrence.
SUB STATION OPERATIONAL CONCEPTS
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Equi-Potential Concept:
Synchronization Charging:
Parallel Network Charging
Power flow Calculation
Parallel Operation of
Transformer
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


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

Interlock Scheme
MF for Indicating
meters:
Under frequency Load
Shedding Concept
System Islanding
Pole Discrepancy
concept
LBB Concept
Auto reclose Concept
Concepts on Ground
OPERATIONAL CONCEPTS
Equi-Potential Concept:
Operation for Change to Transfer Bus Equi-potential
Concept
89A
B
A
A
B
C
52L
D
A
B
C
52T
52B
B
PT1
C
52L
D
PT2
Parallel Operation for Bus Change Over
89A
B
A
A
B
C
52L
D
B
PT1
C
52T
C
52L
52B
D
B
PT2
OPERATIONAL CONCEPTS Contd..

Synchronization Charging
PT1
29M
25
52L
29L
29T
PT2
OPERATIONAL CONCEPTS Contd..
 Power flow Calculation
 Thumb rule Current = (600 x MVA)/ KV
 Actual rule Current = (577 x MVA) / KV
OPERATIONAL CONCEPTS Contd..

Parallel Operation of Transformer

CONDITIONS FOR PARALLEL OPERATION
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Same vector group. ,Same voltage ratio
Same frequency, Same polarity
Same phase rotation
LOAD SHARING

For two Transformers
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PA = P (QA.ZB) / (ZA.QB + ZB.QA),
PB = P (QB.ZA) / (ZA.QB + ZB.QA)
For 3 Transformers
PA = P (QA.ZB ZC) /  ,
P (QC.ZA.ZB) / 
PB = P (QB.ZC ZA) / , Pc =
Where  = (QA.ZB ZC + QB.ZC ZA + QC.ZA.ZB)

Parallel Operation of Transformer
Concepts on Contacts and Position of Switch
N I
1
3
5
T
2
4
6
7
8
9
10
Inter lock Concept:
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
Applications for CBs, isolators and earth switches
Can be electrical , mechanical or electromechanical or combined
Circuit Breaker:- Not allowed to operate if adjacent isolators are in
operation
Isolators
 No operation on power current or interconnection of different
voltage system.
 No operation when CB in series in close , adjacent Earth switch
on close condition
 Making or breaking of paralleling circuits is permitted
Earth Switch
 Earth switches may only be operated if the isolators on
both sides are open. Only an open CB is not enough
DIFFERENT BUS ARRANGEMENT..
L1
29M
B1
52B1
B2
52B2
52L
29L
Single Bus System
Ring Bus System
29M
52L
29M1
29M1
52B
29MB2
52B
29M2
29L
29T
29MB1
29T1
29 L1
22 B
52 L
29 L2
Main and Transfer
Bus
Two Bus System
29MA
52A
29LA
29TA
52T
29TB
29LB
52B
29MB
Two Bus and Transfer System
One and Half System
Arrangement for Main and Transfer Bus Scheme
All Bay 29 T Open
29E
T
29M1
29M
52L
29T I/L
52B
52B
29L
N I
29E
29T
29T1
52B
52L
OPERATIONAL CONCEPTS Contd..
MF for Indicating meters
Example1 :- Meter data CTR=-/1, PTR=11KV/110
Line CTR=400/1, PTR=33KV/110, So MF=1200
Example2:- Meter data CTR=-/5, PTR=-/110
Line CTR=400/1, PTR=11KV/110, So MF=200000
OPERATIONAL CONCEPTS Contd..
Under Frequency Load Shedding
Load
Load
Load
Load
Load
Load
Load
Load
Load
Load
OPERATIONAL CONCEPTS Contd..
System Islanding Scheme
Load
Load
Load
Load
Load
Load
Load
Load
Load
Pole Discrepancy Concepts
 Applicable to the Individual pole operated
Breaker.
A
B
C
A
B
C
LBB Concepts
89A
B
52L
A
B
C
52L
D
A
D
B
A
B
C
52T
PT1
C
52L
D
PT2
Auto reclose Concept
.
Auto reclosing principles
SETTING CRITERIA
Dead Time
Auto- reclosing requires a dead time which exceeds the deionising time
 Time required for the de-ionising of the fault path depends
on:- arcing time, fault duration, wind conditions, circuit
voltage, capacitive coupling to adjacent conductors, etc.
Single phase dead time of 1.0 sec is recommended for both
400kV and 220kV system.
Minimum Dead Time (IEEE)
System
Voltage
kV
23
46
69
115
132
230
345
400
500
Minimum deionization time
[ms]
Based on Field
Based on
and
Operating
Laboratory
Experience
Tests
110
180
120
200
130
210
150
230
160
240
210
280
260
340
280
370
330
420
SETTING CRITERIA
Reclaim Time
The time during which a new start of the auto-reclosing equipment is
blocked.
 If reclosing shot has been carried out and the line is energized and a
new fault occurs before the reclaim time has elapsed, the auto-reclosing
equipment is blocked and a signal for definite tripping of the breaker is
obtained.
 After the reclaim time has elapsed, the auto-reclosing equipment
returns to the starting position and a new reclosing sequence can occur.
 The reclaim time must not be set to such a low value that the intended
operating cycle of the breaker is exceeded, when two faults incidents
occur close together.
 If the breaker is closed manually, the auto reclosing equipment is
blocked and cannot start again until the reclaim time has elapsed.
 For the breaker to be used for auto-reclosing, it is essential that it
has the operating mechanism and breaking capacity necessary for
it to be able to perform the auto-reclosing sequences required.
The recommended operating cycle at 400kV and 220kV is as per the
IEC standard. Reclaim time of 25 sec is recommended
Concept on Ground in the system
Gound fault in Unground system
VR
V R1
VR
V RY
V RY1
V BR
N
N
V Y1
VB
V YB
VY
VY
C
C
C
A
120°
N
A
A
N
N
82°
60°
G
G
B
Full Ground Fault on Phase B
B
B
No Ground Fault
50% Ground Fault on Phase B
Meaning of Equipment Codes
89:52:86:67:21:30:51:95:99:81:-
89:- Isolator/ Air Break Switch
52:- Circuit Breaker
86:0 Master Relay
67:- Directional O/C Relay
21:- Distance Protection Relay
30:- Annunciation Relay
51:- Non- Directional O/C Relay
95:- Supervision Relay
99:- Over Flux Relay
81:- Frequency Relay
Meaning of The Drawing Fig-A
Fig-A.
1.89A can be operated
when Breaker is OPEN
2.Isolator 89B can be
operated when
Breaker and Earth
Switch are open.
Explain the Protections
provided to the Transformer
Non- Directional
Back Up Relay,
Temp. Relay
Current Balance
Relay,
Differential Relay,
REF Relay,
Under Voltage,
Over Voltage,
Voltage/Frequenc
y Relay
Positioning of Equipments 220 KV system
LA
Parallel ( Line – Earth)
CVT
Parallel ( Line – Earth)
WAVE TRAP
Series
CT
Series
EARTH SWITCH
Parallel ( Line – Earth)
LINE ISO
Series
CB
Series
BUS ISOLATOR
Series
CT ratio Calculation
I12 R1 = I22 R2
I2/I1 = (R1/R2)
1/2
I2= 200x 2/1.732
I2=231
S1
200/1
S2
Abbreviation of Terms
1. MCOV
2. NDC
3. ONAN
MCOV= Maximum Continuous Operating Voltage
NDC:- Nominal Discharge Current
ONAN= Oil Natural Air Natural
4. HSV
HSV= Highest System Voltage
5. BIL
BIL= Basic Insulation Level
6. ALF
7. IEC
8. ISF
9. IS
10. TOV
ALF= Accuracy Limiting Factor
IEC= International Electro technical Commission
IS= Indian Standard
ISF= Instrument Safety Factor
TOV= Temporary Over Voltage
CT Connection on secondary
Which Connection of CT
Secondary is correct.
S1
S2
R
S1
Fig-1
S2
R
S4
S3
S3
Fig-2
Answer Fig-1
S4
Explain the operations for Main Bus-1 Maintenance Work,
considering the safety aspects in mind
89A
B
A
A
B
C
52L
52B
D
B
A
B
C
52T
PT1
C
52L
D
PT2
Calculate MF of the meter
One MWh Meter has data CTR=-/1, PTR=33KV/110
With Line CTR=400/1, Line PTR=33KV/110,
Meter reading Advance is 20000. Calculate Million
Unit energy Consumed.
MF of MWh meter is 400x20000= 8,000000 Mwh
So Million Unit Consumed= 8,000000x1000 unit=
8,000 Million Unit
Situation for AC source mixed
1St
55th
110th
-Ve
+ Ve
+ve Terminal of 1st Cell, got
connected to the phase of 1 ph AC
source , What will happen to the
Status of Bulb glowing
L
A
THEORY –A
B
Bulb A will glow brighter and
flicker may be fused
Delta Connection Load and One Terminal is
Earthed
Draw the Vector diagram
Vr
R
Vry
Vry
Vbr
Vbr
Y
Vby
B
Vb
Vy
Vby
Questions for discussion
1. What is the difference between earthing and neutral
2. Why Wave Trap is connected in Rph and Bph but not in Yph
3. Why “MW Meter” shows both +ve and –Ve reading ( i.e. Export and Import) while
current (Ammeter) only shows one side reading
4. Why single break Isolator is preferable to double break isolator
5. Why auto transformer ratings are generally rated with ratio less than 2, but two
windings transformer are rated more than 2
6. When two transformers are operating in different tap position is there any
chance of operation of E/F or REF relay in any of the transformer
7. Why O/C relays are connected to R & B Phase but E/F relay is connected to Y
Phase
8. What will happen to a CT of a feeder if its secondary was opened when feeder is
idle charged and drawing no load
9. Why it is not advisable to use AR scheme for Gang operated breaker system
10. Does it need to provide Wave trap on each phase of the transmission line at the
sub-station
Questions for discussion
11. Why the use of combined instrument transformer is not gaining
popularity in India.
12. Why the spring-spring mechanism is gaining popularity in Breaker
Technology
13. Which circuit is important for supervision of breaker trip coil
status?(Pre-close supervision, post-close supervision)
14 Why DC Voltage is preferable for the protection and control circuit in
15.
16.
17.
18.
19.
20.
System Network
What are the reasons for variation of voltage due to increase of
load in the system
Most of the Power transformers are of Y connected, why not ∆
connected
We know that Voltage is directly proportional to frequency, but
sometimes voltage decreases but not the frequencies why?
In case of 3ph, 4wire system, and the neutral is disconnected. Why
the meter showing the value above 350volts in 2 phases?
Why REF protection is not considered as 100% protection to the
equipment winding
Why PT of different rating is used [110V /√3 and 110V]
Questions for discussion
 21. Why PS class core is best suitable for the application to Differential Relay
 22. Can performance of REF relay be reduced if its residual current circuit is
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obtained in series with E/F relay in the scheme
23. Which protection is better, either REF protection or Differential protection for
Transformer
24. Why REF relay is grouped under high impedance relay?
25. What is the significance of INTER position for a NIT switch on a feeder bay
control panel.
26. Why Guard terminal is used during the measurement of IR value of electrical
equipment.
27. Explain the concept for which the IR value at 30 sec becomes more than the
IR value at 15 sec, for good insulator system.
28.Can the Magnetic Balance Test be considered as a signature test for
transformer fault diagnosis?
29.
Draw 3 Over current + E/F Relay circuit and
2 O/C + 1 E/F Relay circuit
Develop REF circuit for a 3 winding Transformer
Auto reclose Concept
Ground fault in Un grounded System.
VR
V R1
VR
V RY
V RY1
V BR
N
N
V Y1
VB
V YB
VY
VY