The document discusses data download processes for various event loggers and disturbance recorders used in substations, highlighting their functions, applications, and operational concepts. It also covers critical operational guidelines for fault locators, synchronization, transformer parallel operations, and interlocking mechanisms for circuit breakers and isolators. Additionally, it provides insight into various electrical concepts, protection schemes, and practical calculations relevant to electrical systems.

1. EVENT LOGGER Contd..
 Process of Data Down Load
 Data Down Load to Station Monitoring System

2. EVENT LOGGER Contd..
 Data Down Load for ABB make Relay INDACTIC 425

3. EVENT LOGGER Contd..
 Data Down Load for Siemens make
Relay 7SA522--series

4. 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 .

5. DISTURBANCE RECORDER Contd…
 Basic Principle of Disturbance recorder:
 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

6. DISTURBANCE RECORDER Contd…

7. DISTURBANCE RECORDER Contd…
 Application and Settings of Disturbance recorder:
 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 .

8. 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.

9. SUB STATION OPERATIONAL CONCEPTS
 Equi-Potential Concept:
 Synchronization Charging:
 Parallel Network Charging
 Power flow Calculation
 Parallel Operation of
Transformer
 Interlock Scheme
 MF for Indicating
meters:
 Under frequency Load
Shedding Concept
 System Islanding
 Pole Discrepancy
concept
 LBB Concept
 Auto reclose Concept
 Concepts on Ground

10. OPERATIONAL CONCEPTS
Equi-Potential Concept:

11. Operation for Change to Transfer Bus Equi-potential
Concept
B
A
A
C
B
52B
89A
52L
C
D
B B
A
52T
52L
C
D
PT1 PT2

12. Parallel Operation for Bus Change Over
B
A
A
C
B
52B
89A
52L
C
D
B
B
52T
52L
C
D
PT1 PT2

13.  Synchronization Charging
OPERATIONAL CONCEPTS Contd..
29M
52L
29L
29T
25
PT1
PT2

14.  Power flow Calculation
 Thumb rule Current = (600 x MVA)/ KV
 Actual rule Current = (577 x MVA) / KV
OPERATIONAL CONCEPTS Contd..

15.  Parallel Operation of Transformer
 CONDITIONS FOR PARALLEL OPERATION
 Same vector group. ,Same voltage ratio
 Same frequency, Same polarity
 Same phase rotation
 LOAD SHARING
 For two Transformers
 PA = P (QA.ZB) / (ZA.QB + ZB.QA),
 PB = P (QB.ZA) / (ZA.QB + ZB.QA)
 For 3 Transformers
PA = P (QA.ZB ZC) /  , PB = P (QB.ZC ZA) / ,
Pc = P (QC.ZA.ZB) / 
Where  = (QA.ZB ZC + QB.ZC ZA + QC.ZA.ZB)
OPERATIONAL CONCEPTS Contd..

16.  Parallel Operation of Transformer

17. Concepts on Contacts and Position of Switch
N I T
1
5
3
10
8
4
6
2
7
9

18. Circuit Breaker:- Not allowed to operate if adjacent isolators are in
operation
 Applications for CBs, isolators and earth switches
 Can be electrical , mechanical or electromechanical or combined
Inter lock Concept:
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

19. L1
B1 52B1 B2 52B2
Ring Bus System
DIFFERENT BUS ARRANGEMENT..
29M
52L
29L
Single Bus System

20. Main and Transfer
Bus
29M
52L
29L
29T
29M1
29T1
52B
29M1
29M2
52B
29 L1
52 L
29 L2
22 B
29MB1
29MB2
Two Bus System

21. Two Bus and Transfer System
29MA
52A
29LA
29TA
52T
29TB
52B
29LB
29MB
One and Half System

22. Arrangement for Main and Transfer Bus Scheme
29M
52L
29L
29T
29M1
29T1
52B
29E
52B
29E
29T I/L
All Bay 29 T Open N I T
52B 52L

23. 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

24. OPERATIONAL CONCEPTS Contd..
Under Frequency Load Shedding
Load
Load
Load
Load
Load
Load
Load
Load
Load
Load

25. OPERATIONAL CONCEPTS Contd..
System Islanding Scheme
Load
Load
Load
Load
Load
Load
Load
Load
Load

27. Pole Discrepancy Concepts
 Applicable to the Individual pole operated
Breaker.
A A
C
C
B
B

28. B
A
A
C
B
52L
89A
52L
C
D
B B
A
52T
52L
C
D
PT1 PT2
LBB Concepts
D

29. Auto reclose Concept

30. .
Auto reclosing principles
SETTING CRITERIA
Dead Time
Auto- reclosing requires a dead time which exceeds the de-
ionising 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.

31. Minimum Dead Time (IEEE)
System
Voltage
Minimum deionization time
[ms]
kV Based on Field
and
Laboratory
Tests
Based on
Operating
Experience
23 110 180
46 120 200
69 130 210
115 150 230
132 160 240
230 210 280
345 260 340
400 280 370
500 330 420

32. 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

33. Concept on Ground in the system
N
60°
B
C A
N
120°
B
C A
G
N o G ro u n d Fau lt
F u ll G ro u n d F au lt o n P h ase B
N
B
C A
50% G ro u n d F au lt o n P hase B
G
82°
Gound fault in Unground system
V R
N
V Y
V B
V RY
V YB
V BR
N
V Y1
V RY1
V R1
V R
V Y

34. Meaning of Equipment Codes
89:-
52:-
86:-
67:-
21:-
30:-
51:-
95:-
99:-
81:-
89:- Isolator/ Air Break Switch
52:- Circuit Breaker
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
86:0 Master Relay

35. Meaning of The Drawing Fig-A
1.89A can be operated
when Breaker is OPEN
2.Isolator 89B can be
operated when
Breaker and Earth
Switch are open.
Fig-A.

36. 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

37. 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

38. CT ratio Calculation
S2
S1
I1
2
R1 = I2
2
R2
I2/I1 = (R1/R2) 1/2
I2= 200x 2/1.732
I2=231
200/1

39. Abbreviation of Terms
1. MCOV
2. NDC
3. ONAN
4. HSV
5. BIL
6. ALF
7. IEC
8. ISF
9. IS
10. TOV
MCOV= Maximum Continuous Operating Voltage
NDC:- Nominal Discharge Current
ONAN= Oil Natural Air Natural
HSV= Highest System Voltage
BIL= Basic Insulation Level
ALF= Accuracy Limiting Factor
IEC= International Electro technical Commission
IS= Indian Standard
TOV= Temporary Over Voltage
ISF= Instrument Safety Factor

40. CT Connection on secondary
Which Connection of CT
Secondary is correct.
S2
S1 S3 S4
R
S2
S1 S3 S4
R
Fig-1
Fig-2
Answer Fig-1

41. Explain the operations for Main Bus-1 Maintenance Work,
considering the safety aspects in mind
B
A
A
C
B
52B
89A
52L
C
D
B B
A
52T
52L
C
D
PT1 PT2

42. 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

43. L
A B
-Ve
+ Ve
1St
55th
110th
THEORY –A
+ve Terminal of 1st
Cell, got
connected to the phase of 1 ph AC
source , What will happen to the
Status of Bulb glowing
Bulb A will glow brighter and
flicker may be fused

44. Delta Connection Load and One Terminal is
Earthed
Draw the Vector diagram
B
Y
R
Vbr
Vry
Vby
Vr
Vb Vy
Vby
Vbr Vry

45. 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

46. 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
System Network
15. What are the reasons for variation of voltage due to increase of
load in the system
16. Most of the Power transformers are of Y connected, why not ∆
connected
17. We know that Voltage is directly proportional to frequency, but
sometimes voltage decreases but not the frequencies why?
18. In case of 3ph, 4wire system, and the neutral is disconnected. Why
the meter showing the value above 350volts in 2 phases?
19. Why REF protection is not considered as 100% protection to the
equipment winding
20. Why PT of different rating is used [110V /√3 and 110V]

47.  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
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.
Questions for discussion

48. Draw 3 Over current + E/F Relay circuit and
2 O/C + 1 E/F Relay circuit

49. Develop REF circuit for a 3 winding Transformer

50. Auto reclose Concept

51. Ground fault in Un grounded System.
V R
N
V Y
V B
V RY
V YB
V BR
N
V Y1
V RY1
V R1
V R
V Y