testing and commissioning report of olakha substation

T e s t i n g &Cm m i s s i o n i n ge p o r t f"66/33 b -t a t i o n "
By:
Olakha Sub-Station, SMD Semtokha.

i
ACKNOWLEDGEMENT
I would like to express profound gratitude to the then Officiating General Manager Mr. Nima
Dorji for placing me at the up gradation works at 66/33 KV Olakha substation without which, I
wouldn’t have been able to come out with this report. This provided me an opportunity to learn
regarding the testing and commissioning of various switch gears, no sooner I graduated from the
college. The placement was very appropriate and at the right time.
I wish to extend sincere gratitude to Mr. Chandan Kamti Chatterjee, Testing Engineer, IPPL for
teaching me all the practical aspect of the 'Testing and Commissioning' works and also the
theoretical part of the same which are beyond the coverage in the books, which he explained
through his 22 years of field experience in 'Testing and Commissioning'. I am indebted for his
effort in revisiting my report and for making necessary correction and addition.
I would also like to offer sincere appreciation which is due to the staff members of SMD
Semtokha and Olakha Substation. Amongst the various persons who have helped me in this
endeavor, I would like to mention the following: Mr. Sonam Tobgay (Manager), Mr. Tandin
Gyeltshen, Mr. Sonam Norbu and Mr. LB Rai.
I gratefully acknowledge the extensive literature referred during the course of writing this report.
Last but not the least I would like to thank all those who have assisted me directly or indirectly in
coming out with this report.

ii
ABSTRACT
This primary goal of this report is to provide in a simple and more of conventional way of
conducting the testing of various switchgears and the system. This report 'Testing and
Commissioning Report of 66/33KV Olakha Sub Station' describes about the various testing that
are required to be done before commissioning of a substation. It contains in a lucid way, a
concise presentation of various technical data and parameters that were obtained while in field
testing. This report intends to serve as a history of Olakha substation in terms of its technical data
and could be used as future reference while testing however the data may vary with different
instruments used and the way it is conducted.
This report is also equipped with the practical and pictorial circuit diagram of the exact field
testing that was done while in the course of testing. Theories have been provided for every
experiment based on the practical hands on experience.
The materials presented in this report are intended to serve as a platform from where young and
enthusiastic technical people could enhance their learning and explore in the area of testing and
commissioning. However it could be used as reference by the one who already have the
experience.
I would like to solicit the readers' kind suggestions and feedback regarding the report so that I
could come up with better one in future.

List of Figures
Figure 1 Experimental set up for checking the winding resistance ................................................ 3
Figure 2 Experimental set up for CT Ratio check ........................................................................ 14
Figure 3 Experimental setup for ratio test of PT and CVT ........................................................... 23
Figure 4 KPV Testing of Current Transformer ............................................................................ 29
Figure 5 Surge Monitor Testing ................................................................................................... 38
Figure 6 SF6 Circuit Breaker Testing SCOT M3K Timer ............................................................ 41
Figure 7 SF6 Circuit Breaker Testing with Circuit Breaker Operational Analyzer .................... 42
Figure 8 Measurement of Transformer's winding resistance ....................................................... 49
Figure 9 Various testing on Transformer ..................................................................................... 57
Figure 10 Conditioning of Transformer Oil ................................................................................. 67
Figure 11 Winding Resistance Check of 33kv CT & PT ............................................................... 79
Figure 12 Ratio Check of 33kv CT ............................................................................................... 80
Figure 13 High POT Test (CABLE HV TEST) ............................................................................. 93
Figure 14 Inverse-Time, Very-Inverse Time and Extremely-Inverse Time characteristics. ....... 100
Figure 15 Testing of IDMT Relays ............................................................................................. 101
Figure 16 System Stability Testing ............................................................................................. 114

CT Ratio Check ......................................................................................................................... 13
Knee Point Voltage Test (KPV Test) of Current Transformer ................................................. 27
Surge Monitor Testing .............................................................................................................. 38
Transformer Winding Resistance .............................................................................................. 48
Winding Resistance and Ratio Check of 33kv CT & PT .......................................................... 78
High Pot Test (Cable HV Test) ................................................................................................. 92
Relay Testing (Over Current Protection) ................................................................................ 100
Stability Testing Report .......................................................................................................... 113
66KV/33KV, Olakha Sub Station, Thimphu. [email protected] Page 1
Checking the Winding Resistance of CT, PT & CVT Bs T #1:T n i e Ln e i d eBs T #2:T n Jm i n a Ln e i d eCT #1:CT n i e Ln e i d eCT #2:CT n Jm i n a Ln e i d eC#1 :C n i e Ln e i d eC#2 :C n r a n s f o r m e r Ii d eC#3 :C n Bs Cu p l e r i d eC#4 :C n Jm i n a Ln e i d eC#5 :C n r a n s f o r m e r IIi d eA:
1. To check the Secondary Winding Resistance.
2. Insulation Resistance (IR) checks of primary-earth and secondary-secondary
winding by using Megger (2.5KV-5KV).
3. Secondary insulation resistance value check of secondary-earth and secondary-
secondary terminals.b j e c t i v e s : 1. To check the resistance of secondary winding (CT, PT and CVT) and compare
with that of name plate rating.
2. To check if there is any short circuit or leakage to ground from primary winding.
To check if there is any short circuit between primary and secondary windings.
3. To check if there is any leakage or short circuit between the secondary winding
and the earth. To check if there is any short circuit between the secondary
windings.Ist r u m e n t s s e d : Sl. no Description Specification Quantity Remarks
1 Megger 2.5KV-5KV, 0-10000Mohms, Waco,
Type 485/08-09, Sl. no. 933090 1
2 Megger 1KV, 0-200Mohms, Waco,
Sl. no. 91611 1
Motwane 1
4 Connecting wires --------------------------------------------- APR
NB: Megger uses Ohm's law V=IR. It gives DC voltage and the current which flows through the

PT Core 1, Core 2 and Core 3 of PT
Secondary Winding Terminals Earth Link
T e s t p p l i e d o;
Cr c u i t i a g r a m 2a
Rph Yph
IR Value check (Meggering)
Secondary Winding Resistance Check
Ep e r i m e n t a l e t p :
Earth
Figure 1 Experimental set up for checking the winding resistance
Multimeter
P r o c e d u r e :1.S e c o n d a r y i n d i n g e s i s t a n c e a. Remove the earth terminal from three phases of PT from the lower side of the
box. Make sure there is no connection from the PT to earth.
b. Use the Multi meter as ohmmeter and measure the winding resistance of the
respective secondary windings and of respective phases.
c. Tabulate the reading and compare with the standard/manufacturer value.2.Is u l a t i o n e s i s t a n c e s h e c k (Mg g e r i n g ). a. Connect the Megger terminal to primary winding and earth terminal. Apply 5KV
by Meggering and note down the readings as shown by Megger.
NB: Since primary winding is on HV (66KV) side we need to apply high voltage i.e. 5 KV.
b. Keeping one of the Megger terminals connected to the primary, connect the other
terminal to the various secondary winding one by one. Apply 5KV by Meggering
and note down the subsequent readings.3.S e c o n d a r y n s u l a t i o n e s i s t a n c e s h e c k (Mg g e r i n g ). a. Use lower rating Megger (1KV) for testing. This is because output voltage from
the secondary windings is 110V, so we cannot apply very high voltage, otherwise
the windings will get burned.
b. Connect the Megger to secondary 1- earth terminal, followed by secondary 2-
earth and secondary 3-earth terminals respectively. Apply 1 KV by Meggering
and note down the subsequent readings.b s e r v a t i o n s : • If there is any short circuit between the windings or earth, then the Megger will show
zero value.
• Else Megger will show some deflections indicating the insulation resistance value.
• Megger gives DC output







P r e c a u t i o n : • Safety of the experimenter, the first preference.
• Never start Meggering if both the terminals is being caught by performer
• Always discharge by connecting the terminal to earth so that the experimenter is free of
shock.Cn c l u s i o n : From this test it is proved that there isn't any leakage or short circuit connection from primary to
earth through the casing. Neither is the secondary windings touching the casing or with each
other nor the primary winding is in contact with the secondary windings. The Potential
transformer is perfectly right.
CT Ratio Check C#1:C n i e i n e i d eC#2:C n r a n s f o r m e r Ii d eC#3:C n Bs Cu p l e r i d eC#4:C n Jm i n a Ln e i d eC#5:C n r a n s f o r m e r IIi d eA:Ratio Test on various Current Transformers.b j e c t i v e : To check the ratio of primary to secondary current under loaded condition and compare
with the name plate rating.T h e o r y : Current transformers (CTs) of all sizes and types find their way into substations to provide the
current replicas for metering, controls, and protective relaying. CT performance is characterized
by ratio correction factor (turns ratio error), saturation voltage, phase angle error, and rated
burden. Bushing CTs are installed in power equipment. They are toroidal, having a single primary turn (the power conductor), which passes through their center. The current
transformation ratio results from the number of turns wound on the core to make up the
secondary. More than one ratio is often provided by tapping the secondary winding at multiple turn's ratios. The core cross-sectional area, diameter, and magnetic properties determine the CT's
performance. Metering CTs are designed with core cross-sections chosen to minimize exciting current effects and are allowed to saturate at fault currents. Larger cores are provided for
protection CTs where high current saturation must be avoided for the CT to faithfully reproduce
high currents for fault sensing. The exciting current of the larger core at low load is not considered important for protection.
Core#1 : Metering.
Earth fault, Differential).
Core#4 : Bus Bar Protection Zone

C u r r e n t T r a n s f o r m e r
Clamp Leaker
Clamp meter
Junction Box
Ist r u m e n t s s e d: Sl. no Description Specification Quantity Remarks
1 Auto Transformer 0-260V, 50Hz 1
2 Loading Transformer 230V,50Hz-7.5KVA, 1V/T 1
3 Multimeter AC/DC, Analog, Multi-range 1
4 Clamp leaker DC-10A, Motwane 1
5 Clamp meter Kyoritsu, DCM, Model 2002 1
6 Connecting wires ----------------------------------------- APR

Figure 2 Experimental set up for CT Ratio check

P r o c e d u r e : 1. Set up the experiment as shown in the circuit diagram.
2. Make the connections in the junction box so as to get the CT ratio 300/1A. Connect the
first terminal and the middle one so that we get the ratio 300/1A i.e. 1S1-1S2, 2S1-2S2,
etc. Never leave any CT secondary open.
3. Load the primary with certain percentage of full load current. Increase the load current in
steps of 25%, 50%, 75% and 100% of the rated primary current. Observe it on the clamp
meter held on the primary side.
4. With the help of clamp leaker measure the current on the secondary side, on each core
and note down the readings.
5. Put off the power supply and then make the connections in junction box so as to get
600/1A CT ratio. Connect first terminal and the last terminal i.e. 1S1-1S3, 2S1-2S3, etc.
6. Load the primary with 12.5%, 25%, 37.5% and 50% of the rated primary current and
check the values on the clamp meter.
7. With the help of clamp leaker, measure the current in each core i.e. secondary side. For
simplicity note down the readings for half core first and then go for full tap readings.
8. Repeat step 1-7 for other two phases also.P r e c a u t i o n : i. Safety the first priority.
ii. Never open the secondary terminal of the Current Transformer while it is on loaded
condition.
iii. Make the connections tight.
iv. To avoid over heating of the primary connections, give 100% primary input for the
lowest tap and 50% primary input for the full tap.R e s u l t s : The results are being tabulated for each current transformer. The actual ratio given on the
name plate is 300-600/1A. The ratio replicates the name plate rating when the applied
load current approaches the name plate rating. The errors are more when 12.5% and 25%
of the total load current is applied. However as we apply more and more towards the
actual load value, the ratio is almost near the actual ratio. The accuracy of CT is
expressed in terms of its ratio from its true ratio. This is called ratio error and is expressed
as;

1.C#1, i e Ln e i d e (Ic o m e r #1)C#1, 11-12, 300/1ADt e :22/10/09, h u r s d a y , 4:40m , u n n y . R-Sl.no. OC 2373/1/5/08, Y-Sl.no. OC 2373/1/12/08, B-Sl.no. OC 2373/1/10/08%f a t e dr i m a r yCr r e n t(A)Ap l i e dr i m a r yCr r e n t(A) S e c o n d a r y Cr r e n t (A)-h a s e Y -h a s e B-h a s e

2.C#2, r a n s f o r m e r #1i d e (Ic o m e r #1)C#2, 11-12, 300/1ADt e :22/10/09, h u r s d a y , 4:55m , u n s e t . R-Sl.no. OC 2373/1/15/08, Y-Sl.no. OC 2373/1/9/08, B-Sl.no. OC 2373/1/1/08%f a t e dr i m a r yCr r e n t(A)Ap l i e dr i m a r yCr r e n t(A) S e c o n d a r y Cr r e n t (A)-h a s e Y -h a s e B-h a s e

3.C#3, Bs Cu p l e r i d eC#3, 11-12, 300/1ADt e :23/10/09, Fi d a y , 9:50m , u n n y . R-Sl.no. OC 2373/1/7/08, Y-Sl.no. OC 2373/1/8/08, B-Sl.no. OC 2373/1/6/08%f a t e dr i m a r yCr r e n t(A)Ap l i e dr i m a r yCr r n t(A) S e c o n d a r y Cr r e n t (A)-h a s e Y -h a s e B-h a s e

4.C#4, Jm i n a Ln e i d e (Ic o m e r #2)C#4, 11-12, 300/1ADt e :22/10/09, h u r s d a y , 6:00m , Dr k . R-Sl.no. OC 2373/1/14/08, Y-Sl.no. OC 2373/1/2/08, B-Sl.no. OC 2373/1/16/08%f a t e dr i m a r yCr r e n t(A)Ap l i e dr i m a r yCr r e n t(A) S e c o n d a r y Cr r e n t (A)-h a s e Y -h a s e B-h a s e
(A) Ratio % error (A) Ratio % error (A) Ratio % error25%750.24 312.50 4.17% 0.23 326.09 8.70% 0.23 326.09 8.70%50%1500.50 300.00 0.00% 0.49 306.12 2.04% 0.49 306.12 2.04%75%2250.76 296.05 -1.32% 0.74 304.05 1.35% 0.74 304.05 1.35%100%3001.01 297.03 -0.99% 1.00 300.00 0.00% 0.99 303.03 1.01%C#4, 11-13, 600/1A12.5%750.11 681.82 13.64% 0.11 681.82 13.64% 0.11 681.82 13.64%25.0%1500.24 625.00 4.17% 0.23 652.17 8.70% 0.23 652.17 8.70%37.5%2250.36 625.00 4.17% 0.35 642.86 7.14% 0.36 625.00 4.17%50.0%3000.49 612.24 2.04% 0.50 600.00 0.00% 0.49 612.24 2.04%C#4, 21-22, 300/1A25%750.24 312.50 4.17% 0.24 312.50 4.17% 0.24 312.50 4.17%50%1500.50 300.00 0.00% 0.50 300.00 0.00% 0.50 300.00 0.00%75%2250.76 296.05 -1.32% 0.76 296.05 -1.32% 0.75 300.00 0.00%100%3001.01 297.03 -0.99% 1.02 294.12 -1.96% 1.00 300.00 0.00%C#4, 21-23, 600/1A12.5%750.11 681.82 13.64% 0.10 750.00 25.00% 0.11 681.82 13.64%25.0%1500.24 625.00 4.17% 0.24 625.00 4.17% 0.24 625.00 4.17%37.5%2250.36 625.00 4.17% 0.36 625.00 4.17% 0.36 625.00 4.17%50.0%3000.50 600.00 0.00% 0.50 600.00 0.00% 0.49 612.24 2.04%C#4, 31-32, 300/1A25%750.24 312.50 4.17% 0.24 312.50 4.17% 0.24 312.50 4.17%50%1500.50 300.00 0.00% 0.50 300.00 0.00% 0.50 300.00 0.00%75%2250.76 296.05 -1.32% 0.75 300.00 0.00% 0.75 300.00 0.00%100%3001.01 297.03 -0.99% 1.01 297.03 -0.99% 1.01 297.03 -0.99%C#4, 31-33, 600/1A12.5%750.11 681.82 13.64% 0.11 681.82 13.64% 0.11 681.82 13.64%25.0%1500.24 625.00 4.17% 0.24 625.00 4.17% 0.23 652.17 8.70%37.5%2250.36 625.00 4.17% 0.36 625.00 4.17% 0.35 642.86 7.14%50.0%3000.49 612.24 2.04% 0.50 600.00 0.00% 0.50 600.00 0.00%C#4, 41-42, 300/1A25%750.24 312.50 4.17% 0.24 312.50 4.17% 0.24 312.50 4.17%50%1500.50 300.00 0.00% 0.50 300.00 0.00%0.50 00 0.00%
50% 150 0202962895(0500008(-1273()28Tc[(300)67(00)-1377297758098400055 TD00024Tc(050)Tj27377-00055TD00026Tc[(300)6 7(00)-114974(000%)5()]T758508200055TD00024Tc[(050)51()]TJ28962-0 0055TD00026Tc[300)67(00)f05(714%)49()]TJET66362155327 350011272ref6636185532 7351272ref6128255 327351272 reff1884553273500112 72ref884189455327 350011272ref88418945532 7350011272ref884 189455327350011272 ref8841894553273500112 72reff997814553273500112 72reff33261455327 80011272ref46674145532 780011272ref40784 145532780011272 ref553561998047998 1278re98196188BT1098070 0103047Tf910021-)7(4)4601Tm41792Tw[(500%)8(22-13772(000%)5()]TJ9191 00210120002000500038(-1273(99Tc[(300-10021-)7(4)4601Tm41112400055TD00024Tc(0 50)Tj27377-00055TD005011278 ref351272ref6128255 32755TD0050112724ref4(0 00%278r1272r5f663616553276 Tc[(3002ref617)]T55327351272reff188653 804812 78ref222541996538 040011278ref18865 380400112 78re72ref653 804812 78ref2272ref6538 0481278ref223(16128255-418(15327(1reff17 8001189403(16128255-411(150011415784189455327 3500112712()]TJ/TT51Tf997760 ()]TJ/TT51Tf997760( )]TJ/TT51Tf997760()]TJ/TT51Tf9 97760()3471998 0479981278re 981333500112
5.C#5, r a n s f o r m e r #2i d e (Ic o m e r #2)C#5, 11-12, 300/1ADt e :23/10/09, Fi d a y , 10:20m , u n n y . R-Sl.no. OC 2373/1/3/08, Y-Sl.no. OC 2373/1/18/08, B-Sl.no. OC 2373/1/4/08%f a t e dr i m a r yCr r e n t(A)Ap l i e dr i m a r yCr r e n t(A) S e c o n d a r y Cr r e n t (A)-h a s e Y -h a s e B-h a s e

Cn c l u s i o n : From this experiment, it is proved that the name plate ratio replicates the field test report.
However the name plate ratio matches the field test ratio at 100% of the actual load current for
lowest tap. For the full tap 50% of the actual load current was provided. The ratio came close to
name plate rating at the 50% of the full load current. From this I conclude had we applied the full
load current we will be getting exact replicate of the name plate rating. We couldn't apply full
load current on 600/1A tap as the primary wire was getting heated up. More or less the obtained
results are correct.
The ratio error of a CT depends on its exciting current. When the primary current increases, the
CT tries to produce corresponding secondary current, and this needs a greater secondary emf,
core flux density and exciting current. A stage comes when any further increase in primary
current is almost wholly absorbed in an increased exciting current and thereby the secondary
current hardly increases at all. At this stage CT becomes saturated. Thus the ratio error depends
on saturation.
An accuracy of 2-3% of the CT is desirable for distance and differential relays, where as for
many other relays, a higher percentage can be tolerated. When the primary current increases, at a
certain value the core commences to saturate and the error increases. The value of current at
which the error reaches a specified error limit is known as its 'Accuracy Limit Primary Current'
or saturation current. The ratio of accuracy limit primary current and the rated primary current is
known as rated accuracy limit factor (ALF) or saturation factor, the standard value of which are
5,10,15,20 & 30.
Ratio Test of CVT and PT CT#1:Cp a c i t i v e o l t a g e r a n s f o r m e r (i e Ln e i d e )CT#2:Cp a c i t i v e o l t a g e r a n s f o r m r (Jm i n a i d e )T #1 :o t e n t i a l r a n s f o r m e r f Bs (r a n s f o r m e r #1i d e )T #2 :o t e n t i a l r a n s f o r m e r f Bs (r a n s f o r m e r #2i d e )A:
To find the ratio of primary voltage to the subsequent secondary voltage and then
compare with the given ratio in the name plate rating.b j e c t i v e : To measure the voltage of three cores of each phase on the secondary winding and check
if the ratio is alright upon doubling the applied voltage on primary side.Ist r u m e n t s e d Sl. no Description Specification Quantity Remarks
2 Transformer 230V-3000V, 50Hz 1
4 Multimeter DM3540A (Motwane) 1
6 1- Supply 230V, 50Hz 1h e o r y :Potential transformers are used to reduce the system voltage level low enough to
suit the ratings of protective relays. The voltage rating of protective relay is usually 110V. The %
error is given by;
100
Where K= Nominal voltage ratio, Vs= Secondary voltage and Vp=Primary voltage.
The accuracy of PTs used for meters and instruments is only important at normal system voltage
where as PTs used for protection requires errors to be limited over a wide range of voltages

Secondary Voltage Measurement
T e s t p p l i e d o /x p e r i m e n t a l e t p;
Capacitive Voltage Transformer
Figure 3 Experimental setup for ratio test of PT and CVT
Circuit diagram
1
P r o c e d u r e: 1. Set up the connection as shown below.
2. Connect one wire from HV side of transformer to the top of CVT.
3. Connect the other to the earth.
4. Adjust the voltage from the auto transformer so that 1KV is available on the secondary
side of transformer which is shown on the voltmeter. (In fact we are applying 1KV to the
primary winding of CVT).
5. Connect a multimeter (Voltmeter) to the core 1, core 2 and core 3 of each phase of CVT
upon the application of 1KV to the primary and note down the reading.
6. Repeat the same for other two phases.
7. Repeat step 4 so that we get 2KV on the secondary side of the transformer and follow

Bs T #1(r a n s f o r m e r #1i d e )Dt e :19/10/09, Mn d a y , 11:35m , u n n y . R-Sl.no. OP 2373/1/7/08, Y-Sl.no. OP 2373/1/3/08, B-Sl.no. OP 2373/1/4/08r i m a r y () S e c o n d a r y ()-h a s e Y -h a s e B-h a s eCr e 1Cr e 2Cr e 3Cr e 1Cr e 2Cr e 3Cr e 1Cr e 2Cr e 10001.709 1.706 1.706 1.670 1.670 1.724 1.701 1.682 1.681R a t i o 585 586 586 599 599 580 588 595 595%Er o r-2.5% -2.33% -2.33% -0.17% -0.17% -3.33% -2.0% -0.83% -0.83%20003.29 3.29 3.29 3.25 3.26 3.26 3.30 3.30 3.30R a t i o 608 608 609 615 614 614 606 606 606%Er o r1.3% 1.3% 1.5% 2.5% 2.33% 2.33% 1.0% 1.0% 1.0%Bs T #2(r a n s f o r m e r #2i d e )Dt e :19/10/09, Mn d a y , 11:35m , u n n y . R-Sl.no. OP 2373/1/5/08, Y-Sl.no. OP 2373/1/6/08, B-Sl.no. OP 2373/1/8/08r i m a r y () S e c o n d a r y ()-h a s e Y -h a s e B-h a s eCr e 1Cr e 2Cr e 3Ce 1Cr e 2Cr e 3Cr e 1Cr e 2Cr10001.75 1.75 1.75 1.78 1.78 1.78 1.70 1.74 1.74R a t i o 571 571 571 562 562 562 588 575 575%Er o r-4.83% -4.83% -4.83% 6.3% 6.3% 6.3% 2.0% 4.17% 4.17%20003.30 3.31 3.31 3.37 3.37 3.37 3.38 3.38 3.38R a t i o 606 604 604 594 594 594 592 592 592%Er o r1.0% 0.67% 0.67% -1.0% -1.0% -1.0% -1.3% -1.3% -1.3%b s e r v a t i o n:
1. From the result obtained the ratio of primary to secondary voltage is within the range
607-626 where as the actual ratio are 600. The experimented ratio is slightly greater than
the actual value.
110/√ 3 600
There is slight error which may be because of the inaccuracy of voltage applied from the
transformer. However the results are fairly correct.

P r e c a u t i o n: • Safety of the experimenter, the first preference.
• Always take the reading after it reaches a stable value.
• Always avoid parallax error while noting the reading.
• Always give proper connection to CVT and to earth.Cn c l u s i o n : From this test it is seen that the ratio of primary to secondary voltage is fairly correct with
maximum of 6.5% error. For Lab test an error of ±5% is the accepted while for the field test an
error of ±15% is accepted. The error can be eliminated by using more accurate meter, and
applying the accurate voltage. Since the analog meter was used for noting the reading on the
primary side, may be exact voltage wasn’t applied, parallax error might have introduced in the
process. However the result doesn’t deviate much from the exact value thus the name plate rating
is ok.
Knee Point Voltage Test (KPV Test) of Current Transformer C #1 :Ic o m i n g n e C (i e Ln e )C#2 :C n r a n s f o r m e r Ii d eC#3 :Bs Cu p l e r CC#4 :Ic o m i n g i n e #2C (Jm i n a Ln e )C#5 :C n r a n s f o r m e r IIi d eA:Knee Point Voltage Testing of Current Transformers.b j e c t i v e : This test should confirm that at any case the saturation point shouldn’t lie before 100% of
KPV. It may occur at 110% or higher, doesn’t matter but saturation point shouldn't occur
before 100% of the KPV. If saturation point occurs before 100% of KPV then the relays
will operate before reaching its set value (100%) which is not desirable.
To find the saturation point of CT i.e. at what point of voltage it get saturated.
Compare the obtained saturation point with that of the name plate rating.T h e o r y : Knee point voltage is the point on the graph obtained between voltage and current beyond which
the current rise is very sharp when voltage in increased slightly. When the applied voltage is
increased in steps the current also rises in certain step. When the knee point voltage is reached
then the current shoots up beyond its normal increasing step. Therefore in this test we see
whether the KPV given on the name plate is correct or not. If the saturation point is reached
before the actual KPV then the relays are going to trip before fault occurs. In fact the relays
should trip upon reaching KPV or later. Therefore for proper coordination and tripping or relays
KPV should be checked accurately. Since minimum KVP at lowest tap is provided for core 3 &4
of CT, so we test KPV for only these cores.
V
I
KPV
0
Ist r u m e n t s e d: Sl. no Description Specification Quantity Remarks
2 Transformer 230V-3000V, 50Hz 1
4 Clamp leaker DC-10A, Motwane 1
Name plate rating
P r o c e d u r e: 1. Set up the connection as shown below.
2. Apply certain percentage of Knee point Voltage to Core #3 and Core #4 and then note
down the readings as shown by clamp leaker.
3. Repeat the same step for other two phases.
4. Compare the readings.
AV Meter
T e s t p p l i e d o/x p e r i m e n t a l e t p :
Figure 4 KPV Testing of Current Transformer
1
l y
Junction box
Clamp leaker
Cr r e n t r a n s f o r m e r #1 Sl.No. 2373/1/5/08
Sl.No. 2373/1/12/08
Sl.No. 2373/1/10/08Cr r e n t r a n s f o r m e r #3 Sl.No. 2373/1/7/08
Sl.No. 2373/1/8/08
Sl.No. 2373/1/6/08
Primary

(650V)
T e c h n i c a l e r m s: Name plate rating :Mn i m u m Ke e o i n t o l t a g e t o w e s t a p =325 There are two tapping in each core of CT. Therefore in this case lowest tap refers to the tapping
between one end and the middle point. So at full tapping the Knee Point Voltage will be the
double of the KPV of lowest tap.
KPV for Core#3 and Core#4
Knee Point Voltage is available for only core #3 and core #4. This is because these cores are
specifically designed for protection class core. For protection class core, saturation of current is
very important and need to protect the equipment from over current. Whenever the current
reaches its saturation point, relay should trip off. Therefore these cores have Knee point Voltage,
before which saturation shouldn’t occur.
Accuracy rating for Core#1 and Core#2
However this is not the case with core#1 and core#2. These cores are specifically designed for
metering purposes, where accuracy is of much importance. If saturation point exists for these
cores then when the current increases beyond certain value, the meter will stop reading, in fact
the meter should record whatever the amount of current drawn. Therefore these cores are rated at
0.2 class of accuracy.
For half the winding of each core, the rated KPV is 325V therefore for full winding the rated
KPV is 650V. More the number of turns, greater will be the voltage and lesser will be the
current, thereby the ratings 325V, 60mA and 650V, 30mA.

R e s u l t s :1.Ic o m i n g i e i n e C, C#1C#1, 31-32, 325, 60At/2Dt e :19/10/09, Mn d a y , 3:30m , u n n y . R-Sl.no. OC 2373/1/5/08, Y-Sl.no. OC 2373/1/12/08, B-Sl.no. OC 2373/1/10/08%f KV Ap l i e d o l t a g e ()-h a s e (A)-h a s e (A)B-h a s e (A)25%81.257.31 8.22 7.7950%162.5010.99 12.43 12.0875%243.7516.31 20.34 19.45100%325.0029.98 40.00 36.70110%357.5045.90 71.00 67.80C#1, 31-33, 650, 30At/225%162.503.65 3.97 3.7650%325.005.55 6.31 5.9175%487.507.46 9.69 8.88100%650.0011.93 18.55 15.39110%715.0015.79 25.77 23.10C#1, 41-42, 325, 60At/225%81.257.54 8.25 8.3450%162.5011.95 12.74 13.1675%243.7517.14 19.55 20.42100%325.0031.26 42.50 39.50110%357.5053.90 70.30 72.60
For demonstration of saturation current, 400V was being applied to B-phase and the current





81.25
162.5
243.75
325
357.5
400
0
50
100
150
200
250
300
350
400
450
0 50 100 150 200 250
( ) Cr r e n t (A)
KV Cr v e Ca r a c t e r i s t i c KPV Curve
162.5
325
487.5
650
715
0
100
200
300
400
500
600
700
800
0 5 10 15 20 25
( ) Cr r e n t (A)
KV Cr v e Cr a c t e r s t i c s KPV Curve
Ga p h i c a l Aa l y s i s o r C#1, 41-42, 325, 60A, B-h a s e
C#4, 41-43, 650, 30At/2, -h a s e

P r e c a u t i o n : • Safety of experimenter and the teams the first priority.
• Always take the readings after it has settled to a particular value.
• Make sure that no heavy equipment like welding machines, are operating from the same
source from which testing is being done.
• Always note the name plate reading and then perform the experiment.Cn c l u s i o n : From this experiment it is proved that the saturation point of current doesn’t occur below 100%
of KPV. In fact it occurs beyond 110% of the rate KPV. Therefore this equipment is safe to use.
If the saturation point occurs before 100% of KPV then the relays connected to it will operate
under normal conditions also. When the saturation point occurs, the current rises to a very high
value, crossing the set point of relays which makes it to trip off, thus protecting the equipments.

D : 13/10/09Dy : TuesdayT i m e : 5:45pmW e a t h e r : Sunset
Surge Monitor Testing A :To check the deflection in the surge monitor.b j e c t i v e :To find out whether the surge monitor is working or not.Ist r u m e n t s e d : Sl. no. Description Specification Quantity Remarks
1 Megger 1KV, 0-200Mohms, Waco, Sl. no. 91611
1
2 Connecting Wires ----------------------------------ARe s t p p l i e d o/e s t e t p;
Lightening Arrester Surge Monitor
Model : SMT2B3R
P r o c e d u r e: 1. Connect positive terminal of the Megger to the top portion of the surge monitor as shown
above.
2. Connect the other terminal to the earth terminal.
3. Start Meggeringb s e r v a t i o n: • When voltage (1KV) was applied to the surge monitor by Meggering, the pointer inside
the surge monitor started deflecting.
• In some case the pointer didn’t deflect indicating that the monitor is not working.P r e c a u t i o n : • Safety of the experimenter, the first priority.
• Never start Meggering if both the terminals is being caught by performer
• Always discharge by connecting the terminal to earth so that the experimenter is free of
shock.Cn c l u s i o n : From this test we can know whether the surge monitor is working or not. If there is no deflection
then it is proved that the surge monitor is not working and need to be replaced. If the indicator
inside the surge monitor starts to deflect upon the application of voltage then it is proved that the
surge monitor is working.
SF6 Circuit Breaker Testing CB#1 :Cr c u i t Be a k e r n Ic o m e r #1(i e Ln e )CB#2 :Cr c u i t Be a k e r n r a n s f o r m e r #1i d eCB#3 :Cr c u i t Be a k e r n Bs Cu p l e r i d eCB#4 :Cr c u i t Be a k e r n Ic o m e r #2(Jm i n a Ln e )CB#5 :Cr c u i t Be a k e r n r a n s f o r m e r #2i d eA:Testing of SF6 Circuit Breaker.b j e c t i v e : To find out the Alarm 'Loss of SF6' at 20ºC.
To find out the General Lock out SF6 at 20ºC.
To find the closing and opening time of SF6 Circuit Breaker.T h e o r y : The Nominal pressure of SF6 gas at 20ºC is 6.0 bars. When the loss of SF6 gas occurs below
certain set value it gives an alarm indicating less SF6 gas. So we need to attend to it by refilling.
If we fail to attend to the alarm, then when the pressure of SF6 gas falls further, then Lock out of
SF6 occurs. At this point the circuit breaker neither opens nor closes i.e. it remains in deadlock
position.
Ist r u m e n t s s e d : Sl. no Description Specification Quantity Remarks
1 SCOT M3K Time Interval Meter
Model no. 2100.02W.166, T&M Pvt. Ltd., Pune India.
1 Set
Motwane 1
Model CPS LS790B, Sl.No. 581964,

Master Earthing
(Double Earthing)
12 for trip 2
S F6Be a k e r e s t i n g i t h h e e s t i n g Eu i p m e n t f BC( Circuit Breaker Operational
Analyzer Model 2406 HISAC, Sl. no. 3290-009).
Figure 7 SF6 Circuit Breaker Testing with Circuit Breaker Operational AnalyzerNB:The terminals from the kit are to be connected as given in the earlier diagram and the
wires refer the same definition.
B Po w e r u p p l yTo Circuit
Breaker
P r o c e d u r e :AT -I 1. Connect the SF6 gas pipe to the breaker and start filling up the gas.
2. Fill up till the pressure reaches 1.0bar.
3. Check all the pipes and SF6 breaker for any leakage with the help of Refrigerant Leak
Detector. If leakage is there, then it makes continuous beeping sound. To find the exact
leak area, apply shampoo foam over the area. Wherever the pore is, the bubble becomes
big and burst out.
4. Leave the Breaker at 1.0bar for few hours. If leakage is there, the pressure falls down.
5. If there is no leakage then fill up the breaker with SF6 gas at 6.0bars.
6. At certain pressure (5.0 bars approx.) general lock out SF6 will occur. The multimeter
connected across alarm (X1-4, K11-A1) and trip contact (X1-4, K10-A1) will make
continuity sound.
7. Increase the pressure until it reaches certain point (5.3bars approx.) when the multimeter
connected across alarm and trip contact stops making continuity sound. This is the Alarm
Loss of gas pressure.
8. Still fill up the breaker with SF6 gas until the pressure reaches 6.0bars and disconnect it.P AT -II 1. Set up the experiment with SCOT M3K Time Interval Meter.
2. Connect the RYB terminals at the top and middle (make and break) points and plug it to
the SCOT M3K Time Interval Meter.
3. Connect two ground wires so as to have effective earthling. If one fails other will work.
4. Connect the control cable with the Circuit Breaker
a. Red one is DC +ive and it is the CB coil source. DC signals flows from Breaker
to the SCOT M3K Time Interval Meter. Connect it to X1-3, 4, and 5.
b. The command (Close command and Trip command) that we give flows to the CB
through the other two wires.
c. The yellow wire is C +ive and it is the close coil terminal. The close command
that we punch goes through this cable to operate the CB. Connect it to X1-17.
d. Green wire is T +ive and is the Trip coil terminal. The trip command that we
punch passes through this wire to trip the CB. Connect it to X-7.
5. Supply AC power to the motor so that it energizes the spring. When spring compresses to
its set position, the limit switch disconnects the AC supply and the motor stops, thus the
spring is charged.
6. Give the close, open-1 and close/open command consecutively with simultaneous
recording of the time (ms).
7. Change the green terminal to X1-12 and give open-2 command and note down the
readings.
R e s u l t s : 25/10/2009, u n d a y , u n n y .66K Cr c u i t Be a k e r F6a s i l l i n g r e s s u r e Dn s i t y Mn i t o r t a t u sl . N.e m p e r a t u r e(C)r i p Cn t a c tLc k o u t a sr e s s u r e(a r )g /m2t a t u s o u n d Aa r mCn t a c tLs s f F6as r e s s u r e(a r )t a t u s o u n d 2009/IND/03/6059 20
X1-4 K10-A1
K11-A1
5.3 OKl . N. Mt o r l . N. Co s e Cl ()T r i p Ci l 1()T r i p Ci l 2() 2009/IND/03/6059 - 50.0 50.0 50.0
2009/IND/03/6060 289-087 50.4 50.3 50.6
2009/IND/03/6061 289-349 48.5 50.1 50.6
2009/IND/03/6058 289-436 50.9 50.2 50.0
2009/IND/03/6062 289-543 49.7 49.7 50.1

T e s t e s u l t f F6Cr c u i t Be a k e r Location : Transformer#2 Side.
Serial Number : 2009/IND/03/6062. Date of Testing : 26/10/2009, 10:25am, Sunny.
Feeder Name : CB5
Type : 3AP1FG
Make : SEIMENS STC : 40KAP h a s e Co s i n g /p e n i n g i m eCo s e (s )p e n -1(s )p e n -2(s )C/(s )
R 57 32 30 33
Y 57 32 30 33
B 57 32 30 33Cil e s i s t a n c eCi l R e s i s t a n c e () Close coil 49.7
Trip Coil-1 49.7
Trip Coil-2 50.1
T e s t e s u l t f F6Cr c u i t Be a k e r Location : Bus Coupler Side. Serial Number : 2009/IND/03/6061.
Date of Testing : 26/10/2009, 9:45am, Sunny.
Feeder Name : CB3 Rated Voltage : 145KV
Rated Current : 3150A
Type : 3AP1FG Make : SEIMENS
STC : 40KAP h a s e Co s i n g /p e n i n g i m eCo s e (s )p e n -1(s )p e n -2(s )C/(s ) R 59 33 30 29
Y 58 34 31 31
Trip Coil-1 50.1
Trip Coil-2 50.4
T e s t e s u l t f F6Cr c u i t Be a k e r Location : Transformer#1 Side.
Serial Number : 2009/IND/03/6058.
Rated Voltage : 145KV
Type : 3AP1FG
Make : SEIMENS
Y 59 34 34 30
Trip Coil-1 50.2
Trip Coil-2 50.0T e s t e s u l t f F6Cr c u i t Be a k e r Location : Incomer#1 Tie Line Side.
Serial Number : 2009/IND/03/6060.
Type : 3AP1FG
Make : SEIMENS
Y 58 32 33 31
Trip Coil-1 50.3
Trip Coil-2 50.6
T e s t e s u l t f F6Cr c u i t Be a k e r Location : Incomer#2 Jemina Line Side. Serial Number : 2009/IND/03/6059.
Date of Testing : 28/12/2009, 4:15pm, Sunny. Feeder Name : CB4
Type : 3AP1FG Make : SEIMENS
STC : 40KAP h a s e Co s i n g /p e n i n g i m eCo s e (s )p e n -1(s )p e n -2(s )C/(s ) R 59.0 28.8 60.4 29.8
Y 57.4 30.0 58.0 31.0
B 58.2 29.6 58.4 30.4Cil e s i s t a n c eCi l R e s i s t a n c e () Close coil 48.9
Trip Coil-1 49.0
Trip Coil-2 49.0e s u l t : • The rated time for closing is 50±8 ms; therefore the value that we obtained is within the
range.
• The rated opening time is 30±4 ms; therefore the value we obtained is within the
permissible limit.
• The rated close-open time is 30±10 ms; therefore the value we obtained is within the
normal range.P r e c a u t i o n : • Safety the first priority.
• Always take the steady value.
• Connect the wires properly and tightly.
• Note down the readings properly.Cn c l u s i o n : From this field test I came to learn that the results are correct and the SF6 circuit breaker is safe
to use. Of course one SF6 circuit breaker on Jemina side had leakage therefore it was replaced
and tested. Rests of the circuit breaker are working fine. Sometimes the tripping coil gets burned
often as in case of Jemina line circuit breaker, the reason being the flow of continuous current,
low resistance of the coil and appearance of high voltage across its terminal. For resistance
check, apply voltage across the terminals for 15s and then check the current obtained and cross
check with the actual value.

Transformer Winding Resistance A:To find out the Winding Resistance of Transformer and of its respective CTs.b j e c t i v e : • To check the winding resistance of Transformer in R, Y and B phase on HV side.
• To check the winding resistance on LV side at Tap # 9.
• To check the winding resistance of WTICT, NCT and LV phase CT.T h e o r y :There are three current transformers in 20MVA Transformer viz. winding
temperature indicator current transformer (WTICT), Neutral current transformer (NCT) and LV
phase current transformers. WTICT is connected to the bellow heater in the WTI. When
transformer is loaded the current flows through the CT and flows through the heater coil, thereby
the temperature indicated by WTI becomes the winding oil temperature and the winding
temperature. In no load condition the WTI temperature and the OTI temperature are same as
indicated in the dehydration curve. NCT is located below the neutral point in secondary winding
and for each LV phases there is CT. Tap # 9 is normal position with turn's ratio two, so whenever
we do normal test we take tap # 9. For this test we simply use Ohm's law.T r a n s f o r m e r 1l . o . 21067/1 WTICT : 350/5A, CL-5, 20VA.
NCT : Core (i), 400/1A, 5P10, 10VA
Core (ii), 400/1A, 5P10, 10VA
Core (iii), 400/1A, CL-PS, Vk ≥ 800V.
Imag ≤ 100mA at Vk, RCT ≤ 1.5
LV Phase CT Core (i), 400/1A, 5P10, 10VA.
Core (ii), 400/1A, 5P10, 10VA
Core (iii), 400/1A, CL-PS, Vk ≥ 800V.
Imag ≤ 100mA at Vk, RCT ≤ 1.5
Connections: WTICT (15, 16). NCT (18, 19, 20). LV R-Ph CT (21, 22, 23), LV Y-Ph CT (24,
25, 26), LV B-Ph CT (27, 28, 29).
15-2WS7,
16-2WS8
17-2WS9
Ist r u m e n t s s e d : Sl. no Description Specification Quantity Remarks
1 AV Meter Motwane 1
2 Multimeter Digital Multimeter DM3540A,
Motwane 1
3 Connecting wires --------------------------------------------- APRCr c u i t i a g r a m :
N.B: Part I and II refers to connections of different experiment.
Figure 8 Measurement of Transformer winding resistance

P r o c e d u r e : 1. Disconnect the earth terminal from the neutral point.
2. Position the tap at 01.
3. Connect a wire to the R-phase (incoming) whose end will be connected to +ive supply
and connect a wire from the other end and connect it to voltmeter.
4. Connect a wire to the Y-phase (incoming) whose end will be connected to -ive supply
and connect a wire from the other end and connect it to voltmeter.
5. Connect an ammeter to the negative wire.
6. Switch on the power supply and note down the readings on voltmeter and ammeter.
7. Calculate the resistance from the values observed.
8. Increase the tap to next level and repeat step 1 to7.
9. Repeat the above step for Y-B and B-R phases.
10. For LV side repeat the above step for R-N, Y-N, B-N and B-Y, however here we need
not change the tapings. Just position at the normal tap.
11. To find the winding resistance of CT connect ohmmeter across respective terminals i.e.
15,16,17,18,19,20,21,22,23,24,24,25,26,27,28 and 29 in our case.
12. Record the reading.e s u l t : T r a n s f o r m e r 1, l . N. 21067/1Dt e :3/11/09, 11:00m , u n n y .- h a s e Y -Bh a s epo s i t i o nCr r e n t(A)ol t a g e()e s i s t a n c e()po s i t i o nCr r e n t(A)ol t a g e()e s i s t a n c e() 01 4.40 4.00 909.09 17 4.90 3.57 728.57
02 4.48 3.98 888.39 16 4.81 3.59 746.36
03 4.42 3.96 895.93 15 4.79 3.61 753.65
04 4.42 3.91 884.62 14 4.71 3.63 770.70
05 4.50 3.88 862.22 13 4.68 3.65 779.91
06 4.50 3.88 862.22 12 4.61 3.68 798.26
07 4.52 3.85 851.77 11 4.60 3.71 806.52
08 4.59 3.82 832.24 10 4.52 3.73 825.22
09b 4.60 3.79 823.91 09b 4.50 3.74 831.11
10 4.69 3.78 805.97 08 4.49 3.77 839.64
11 4.70 3.77 802.13 07 4.41 3.79 859.41
12 4.79 3.75 782.88 06 4.40 3.82 868.18
13 4.80 3.72 775.00 05 4.38 3.84 876.71
14 4.85 3.70 762.89 04 4.31 3.86 895.59
15 4.90 3.68 751.02 03 4.29 3.88 904.43
16 4.95 3.65 737.37 02 4.22 3.90 924.17
17 5.00 3.62 724.00 01 4.20 3.92 933.33

T r a n s f o r m e r 1, l . N. 21067/1Dt e :3/11/09, 11:00m , u n n y .B- h a s e L i d e a p #9po s i t i o nCr r e n t(A)ol t a g e()e s i s t a n c e()h a s e Cr r e n t(A)ol t a g e()e s i s t a n c e() 01 4.42 3.80 859.73
R-N 3.59 0.2794 77.83 02 4.49 3.79 844.10
03 4.53 3.78 834.44 Y-N 7.30 0.5730 78.49
04 4.49 3.77 839.64
06 4.69 3.73 795.31
08 4.78 3.69 771.97
09b 4.80 3.66 762.50
In LV side, the Line resistance is double to that of Phase Resistance.
10 4.84 3.65 754.13
11 4.89 3.64 744.38
12 4.93 3.62 734.28
13 4.99 3.60 721.44
14 5.01 3.57 712.57
15 5.06 3.55 701.58
16 5.12 3.52 687.50
17 5.19 3.49 672.45T r a n s f o r m e r 1, l . N. 21067/1.Nu t r a l C (NC)W T ICBN. i r e Cd e e s i s t a n c e ()BN. i r e Cd e e s i s t a n c e () 18 2S1-2S2 15 2WS7
19 2S3-2S4 16 2WS8
20 2S5-2S6 16 2WS8L h a s e Cs 17 2WS9T BN.Wire Code Resistance () 15 2WS7
21 2US1-2US2 17 2WS9
wires alternatively.
23 2US5-2US6
24 2VS1-2VS2
25 2VS3-2VS4
26 2VS5-2VS6
27 2WS1-2WS2
28 2WS3-2WS4
29 2WS5-2WS6
T r a n s f o r m e r 2, l . N. 21067/2Dt e :4/11/09, 12:40m , u n n y .- h a s e Y -Bh a s epo s i t i o nCr r e n t(A)ol t a g e()e s i s t a n c e()po s i t i o nCr r e n t(A)ol t a g e()e s i s t a n c e() 01 3.62 3.150 870.17 01 3.63 3.175 874.66
02 3.68 3.130 850.54 02 3.69 3.150 853.66
03 3.70 3.110 840.54 03 3.70 3.130 845.95
04 3.62 3.090 853.59 04 3.71 3.110 838.27
05 3.76 3.060 813.83 05 3.74 3.090 826.20
06 3.79 3.037 801.32 06 3.79 3.070 810.03
07 3.80 3.018 794.21 07 3.80 3.050 802.63
08 3.85 2.998 778.70 08 3.81 3.030 795.28
09b 3.90 2.977 763.33 09b 3.84 3.000 781.25
10 3.95 2.974 752.91 10 3.89 2.990 768.64
11 3.99 2.952 739.85 11 3.90 2.960 758.97
12 4.00 2.930 732.50 12 3.92 2.940 750.00
13 4.01 2.905 724.44 13 3.97 2.915 734.26
14 4.05 2.880 711.11 14 3.99 2.892 724.81
15 4.10 2.850 695.12 15 4.00 2.869 717.25
16 4.12 2.030 492.72 16 4.02 2.844 707.46
17 4.19 2.000 477.33 17 4.09 2.813 687.78T r a n s f o r m e r 2, l . N. 21067/2Dt e :4/11/09, 12:00m , u n n y .B- h a s e L i d e a p #9po s i t i o nCr r e n t(A)ol t a g e()e s i s t a n c e()h a s e Cr r e n t(A)ol t a g e()e s i s t a n c e() 01 3.58 3.190 891.06
R-N 4.32 0.352 81.48 02 3.60 3.170 880.56
03 3.62 3.140 867.40 Y-N 4.35 0.353 81.15
04 3.68 3.110 845.11
06 3.78 3.060 809.52
08 3.81 3.008 789.50
09b 3.80 3.004 790.53
In LV side, the Line resistance is double to that of
Phase Resistance.
T r a n s f o r m e r 2, l . N. 21067/2.Nu t r a l C (NC)W T ICBN. i r e Cd e e s i s t a n c e ()BN. i r e Cd e e s i s t a n c e () 18 2S1-2S2 2.6 15 2WS7
2.6 19 2S3-2S4 2.4 16 2WS8
20 2S5-2S6 2.6 16 2WS8 1.7L h a s e Cs 17 2WS9T BN.Wire Code Resistance () 15 2WS7 1.9
21 2US1-2US2 3.5 17 2WS9
22 2US3-2US4 2.3
wires alternatively.
23 2US5-2US6 2.6
24 2VS1-2VS2 2.4
25 2VS3-2VS4 2.5
26 2VS5-2VS6 2.8
27 2WS1-2WS2 1.2
28 2WS3-2WS4 2.4
29 2WS5-2WS6 2.4P r e c a u t i o n s : • Safety of experimenter the first priority.
• Always adjust the DC voltage level as per the ranges of the meters used.
• Avoid parallax error.Cn c l u s i o n : From this field test, the winding resistances of CTs are below 1.5. As indicated on the name

Transformer Testing (I Ce c k , a t i o Ce c k , Mg n e t i z i n g Bl a n c e Ce c k , Mg n e t i z i n g Cr r e n tCe c k , e c t o r Go u p Ce c k )A: 1. To check the 'Insulation Resistance' of the Transformer.
2. To check the 'Ratio of HV-LV winding'.
3. To check the 'Magnetizing Balance' or 'Core Balance'.
4. To check the 'Magnetizing Current'.
5. To check the 'Vector Group'. b j e c t i v e s : To find out the insulation resistance between HV-Earth, LV-Earth and HV-LV terminals
and to ensure there is no leakage to earth i.e. continuity check.
To ensure that the turns ratio for each tapping is in accordance to the name plate rating.
To ensure that the magnetic balance is not disturbed.
To observe the no load magnetizing current.
To ensure the vector group DYN 11.T h e o r y :I.Is u l a t i o n e s i s t a n c e e s t Insulation resistance of a two-winding transformer insulation system, HV to ground, LV to ground, and HV to LV is determined with a Megger type of instrument. Historically,
insulation resistance measurements are also made to assess the amount of moisture in
transformer insulation. However, the measurement of insulation dissipation factor has shown to be a better indicator of the overall condition of insulation in a power
transformer.II.R a t i o e s t The purpose of this test is to ensure that all windings have the correct number of turns
according to the design. Since the transformer is equipped with a load tap changer (LTC),
ratio tests is also carried out at the various positions of the tap changer(s). The objective of ratio tests at different tap positions is to ensure that all winding taps are made at the
correct turns and that the tap connections are properly made to the tap changing devices.
ANSI/IEEE general standard [1] requires that the measured voltage ratio between any two windings be within ± 0.5% of the value indicated on the nameplate. To verify this
requirement, ratio tests are performed in which the actual voltage ratio is determined
through measurements. Ratio tests can be made by energizing the transformer with a low AC test voltage and measuring the voltage induced in other windings at various tap

indicated on the transformer's nameplate. More commonly, Transformer Turns Ratio
(TTR) test sets are used for making the tests.III.Mg n e t i z i n g Bl a n c e e s t This test is performed to ensure that the HV and LV windings are not displaced from its
original 120º displacement from respective phases.
In this, two phase supply is applied to one of the winding and the induced voltages on the
other two windings are measured. The voltage applied on the windings should be the sum
of the voltage induced on other two windings. If the phase displacements are correct then
the flux distribution on each winding will also be proportionate i.e. upon repeating the
applied voltage to other phases too, the sum of induced voltages should be equal to the
applied voltage. In the readings one will see the maximum value being in the diagonal.
In case of LV side which is star connected, magnetic balance test ensures that the
windings are not displaced with respect to the neutral point. If windings are displaced
from each other then we say neutral is displaced, which means some currents are flowing
in the neutral point (Earth Fault). By KCL, current flowing in the neutral point should be
zero at balanced condition however practically it is not true. Therefore in order to satisfy
this condition neutral point is grounded so that any current flowing through neutral point
goes to earth. Here too the diagonal characteristic is observed.I.Mg n e t i z i n g Cr r e n t Ce c k This test ensures that the magnetizing current under no load condition doesn’t exceed 4%
of the rated current. When voltage is applied to the exciting or primary winding of the transformer, a magnetizing current flows in the primary winding which produces the flux
in the core. The flow of flux in magnetic circuits is analogous to the flow of current in

30° Lag or +30°
Magnetizing Current
V .V e c t o r Go u p Ce c k This test is from the design point of consideration and is required to check the vector
group indicated on the name plate of the transformer. There are various vector groups and
in our case the transformer is Dy11. Some of the typical examples are as follows.
The vector diagram for Dy11 is shown below.
Here, RYB forma an equilateral triangle.
R-b=R-y, Y-b=Y-y, R-Y=R-N+Y-N, B-y is the shoot point.
This confirms the Dy11 vector group test.
Dy11
Ist r u m e n t e q u i r e d :l. o Dsc r i p t i o n S p e c i f i c a t i o n Q u a n t i t y e m a r k s 1 Motorized Megger
5KV, 0-10000M, Sl. no. 850302, WACO
1
Motwane 1
4 Testing Board MCB C16 attached, handmade 1 See picture
5 Connecting wires 2.5 sq.mm APR
6 Transformer Sl. no 21067/1, 20MVA 1
7 3- Supply 415V, 50Hz 1
8 AV Meter AC/DC Range 1

P r o c e d u r e :I.Is u l a t i o n e s i s t a n c e Ce c k a. Connect wires from HV, LV and Earth terminals.
b. Use 5KV Motorized Megger with external power supply.
c. Connect HV and Earth terminals to the Megger. Switch on the power supply and
note down the readings indicated on the Megger at 15 th
and 60 th
seconds.
d. Switch off the Megger and discharge the current in the lines used by shorting the
terminals to avoid risk of shock.
e. Connect LV and Earth terminals to the Megger. Switch on the power supply and
and 60 th
f. Repeat step d.
g. Connect HV and LV terminals to the Megger. Switch on the power supply and
and 60 th
h. Repeat step d.
i. Calculate R 15/R 60 and then tabulate the readings.II.R a t i o e s t a. Connect the circuit diagram as in the figure above.
b. Disconnect the neutral from Earth terminal.
c. Apply 3- power from nearby BMK to the connection board.
d. Since the transformer has 17 taps, begin one by one.
e. Positioning the tap at 01, check the voltage at HV side, LV side (line as well as
phase voltage) and note down the readings.
f. Increase the tap to next level and then repeat step 'e'.
g. Repeat step 'f' till the highest tap.
h. Tabulate the readings for further analysis.III.Mg n e t i z i n g Bl a n c e Ce c k (Cr e Bl a n c e ), a p #9. a. The experiment continues from above tests.
b. Make sure that the table for recording data is made sequentially.
c. Switch on the power supply and always work offline.
d. Remove the HV B-phase out and then measure the voltage on HV lines and LV
side (Line as well as phase voltages).
e. Remove the HV R-phase out and then measure the voltage on HV lines and LV
side (Line as well as phase voltages).
f. Remove the HV Y-phase out and then measure the voltage on HV lines and LV
side (Line as well as phase voltages). Switch off the power supply.
g. Record the data sequentially and correctly.

I.Mg n e t i z i n g Cr r e n t Ce c k (N o a d u r r e n t ), p #9. a. Reconnect every connection as shown in the circuit diagram.
b. Switch on the power supply but while changing the connections switch it off.
c. Disconnect the R-phase on HV side and then measure the current on R-phase
itself. Record the voltage on R-Y phase too. Use Clamp leaker.
d. Reconnect R-phase and disconnect the Y-phase on HV side. Measure the current
on Y-phase itself. Record the voltage on Y-B phase too. Use Clamp leaker.
e. Reconnect Y-phase and disconnect the B-phase on HV side. Measure the current
on B-phase itself. Record the voltage on Y-B phase too. Use Clamp leaker.
f. Disconnect HV side and give the supply to LV terminals.
g. Use clamp leaker to measure the current in the lines.
h. Disconnect the r-phase on LV side and then measure the current on r-phase itself.
Record the voltage on r-y phase too.
i. Reconnect r-phase and disconnect the y-phase on LV side. Measure the current on
y-phase itself. Record the voltage on y-b phase too.
j. Reconnect y-phase and disconnect the b-phase on LV side. Measure the current
on b-phase itself. Record the voltage on b-r phase too.
k. Observe the readings very carefully such that the magnetizing current is not less
than 4% of the actual rated current in both the cases.V .V e c t o r Go u p Ce c k , a p #9. a. Reconnect every connection as shown in the circuit diagram.
b. Here we need to check the name plate rating. The vector Group is Dy11 so we
need to prove this. Refer the vector diagram given in theory.
c. Short the R-phase of HV and LV terminals.
d. Apply voltage on HV side.
e. Check the voltage R-Y, Y-B, B-R, R-n, Y-n, R-b, R-y, Y-b, Y-y, B-b and B-y
terminals.
f. Check if the results are matching with that given in theory.P r e c a u t i o n s : 1. Safety of experimenter the first priority.
2. While Meggering, always discharge the current to avoid shock.
3. Always switch off the power supply when connecting the circuit to avoid spark.
Insulation Resistance Values of Power Transformers (M)
Class Winding Temperatures °C
33-132KV 20°C 30°C 40°C 50°C 60°C 70°C
R15 450 300 200 140 60 40
R60 900 600 400 280 120 50
R60-Value of IR at 60sec & R15 at 15 sec. after the application of test voltage of Megger
Courtesy: Installation, commissioning and maintenance of electrical equipment, Tarlok Singh

R e s u l t :R ANFR ME #1, l . o 21067/1r a n s f o r m e r e s t i n g , l . N. 21067/1Dt e :30/10/2009, 12:00m , u n n y .Is u l a t i o n e s i s t a n c e (I)Ce c k y 5K Mt o r i z e d Mg g e r (M) Terminals IR-R 60 IR-R 15 R 15/R 60
HV-Earth 10000+∞ 10000 1
HV-LV 10000+∞ 5000 0.5
LV-Earth 10000+∞ 8000 0.8T r a n s f o r m e r e s t i n g , l . N. 21067/1Mg n e t i z i n g Bl a n c e Ce c k (a p #9)r Cr e Bl a n c e
-out R-Y(V) Y-B(V) B-R(V) r-y(V) y-b(V) b-r(V) r-n(V) y-n(V) b-n(V)
B 416.0 318.0 98.3 213.5 65.4 148.1 120.0 93.1 28.5
R 216.7 417.0 201.6 184.5 180.1 10.19 62.5 121.3 59.9
Y 81.4 335.4 416.0 78.4 219.6 145.2 23.96 97.3 121.4T r a n s f o r m e r e s t i n g , l . N. 21067/1Mg n e t i z i n g Cr r e n t Ce c k (a p #9)r N Ld Cr r e n tH i d e L i d e -out
Applied Voltage(V)
Current (mA) -out Applied
Voltage (V) Current (mA)
R R-Y 417.0 R-ph 3.50 r r-y 417.0 r- ph 9.63
Y Y-B 415.0 Y-ph 2.46 y y-b 415.0 y- ph 6.30
B B-R 416.0 B-ph 2.49 b b-r 416.0 b- ph 9.82T r a n s f o r m e r e s t i n g , l . N. 21067/1V e c t o r Go u p Ce c k (a p #9), D11 Terminals Voltage(V)
R-b=R-y, Y-b=Y-y,
B-y is the shoot point. These conditions are found correct.
R-Y 416.0
Y-B 417.0
B-R 417.0
R-N 121.8
Y-N 300.0
B-b 261.0
B-y 475.0
R-b 208.2
R-y 208.5
Y-b 259.4
Y-y 259.4
a t i o e s t f r a n s f o r m e r #1, l . o 21067/1p H ()i d e(o l t s )L (t a r )i d e(o l t s )At u a la t i o a t i o %Er o rBB H/Lp h Y p h Bh R p h p h Bh 01 415 415 415 189.6 191.9 189.3 109.4 110.1 110.3 2.202.19 2.16 2.19 -0.45% -1.82% -0.45%
02 413 416 416 190.8 193.3 191.2 110.6 111.2 111.4 2.182.16 2.15 2.18 -0.92% -1.38% 0.00%
03 415 415 416 193.3 194.6 193.6 111.9 112.6 112.8 2.152.15 2.13 2.15 0.00% -0.93% 0.00%
04 413 417 415 195.3 197.3 196.9 113.4 114.0 114.2 2.132.11 2.11 2.11 -0.94% -0.94% -0.94%
05 415 416 415 198.1 199.5 198.2 114.8 115.4 115.6 2.102.09 2.09 2.09 -0.48% -0.48% -0.48%
06 417 415 416 200.3 201.3 200.4 116.1 116.9 116.9 2.082.08 2.06 2.08 -0.00% -0.96% 0.00%
07 415 416 417 202.9 204.5 203.4 117.7 118.3 118.3 2.052.05 2.03 2.05 -0.00% -0.98% 0.00%
08 415 416 417 205.7 206.6 206.2 119.5 119.6 119.9 2.032.02 2.01 2.02 -0.49% -0.99% -0.49%
9b 414 415 416 208.0 209.2 208.5 120.6 121.2 121.3 2.001.99 1.98 2.00 -0.50% -1.00% 0.00%
10 417 417 418 210.0 212.3 211.5 122.0 122.5 122.3 1.981.99 1.96 1.98 +0.51% -1.01% 0.00%
11 418 416 417 213.2 215.0 214.3 123.6 124.4 124.5 1.951.96 1.93 1.95 +0.51% -1.03% 0.00%
12 414 416 418 215.7 217.3 216.8 125.3 125.5 126.2 1.931.92 1.91 1.93 -0.52% -1.04% 0.00%
13 414 415 416 218.9 220.3 219.7 126.9 127.4 127.7 1.901.89 1.88 1.89 -0.53% -1.05% -0.53%
14 417 417 416 221.9 223.3 222.7 129.0 129.2 129.5 1.881.88 1.87 1.87 0.00% -0.53% -0.53%

T R ANFR ME #2, L. N. 21067/2r a n s f o r m e r e s t i n g , l . N. 21067/2Dt e :4/11/2009, 10:00m , u n n y .Is u l a t i o n e s i s t a n c e (I)Ce c k y 5K Mt o r i z e d Mg g e r (M) Terminals IR-R 60 IR-R 15 R 15/R 60
HV-Earth 6000 10000 1.67
HV-LV 5000 10000 2.00
LV-Earth 9000 10000 1.11T r a n s f o r m e r e s t i n g , l . N. 21067/2Mg n e t i z i n g Bl a n c e Ce c k (a p #9)r Cr e Bl a n c e
-out R-Y(V) Y-B(V) B-R(V) r-y(V) y-b(V) b-r(V) r-n(V) y-n(V) b-n(V)
B 421.0 349.0 72.60 223.3 81.6 142.0 121.7 101.7 21.03
R 209.0 422.0 213.1 182.5 183.4 477 60.0 121.8 61.40
Y 60.20 356.0 421 85.8 223.9 138.5 17.78 103.2 120.8T r a n s f o r m e r e s t i n g , l . N. 21067/2Mg n e t i z i n g Cr r e n t Ce c k (a p #9)r N Ld Cr r e n tH i d e L i d e -out
Applied Voltage(V)
Voltage(V) Current (mA)
R R-Y 422.0 R-ph 3.90 r r-y 422.0 r- ph 11.0
Y Y-B 423.0 Y-ph 2.00 y y-b 421.0 y- ph 6.50
B B-R 423.0 B-ph 2.20 b b-r 423.0 b- ph 11.0T r a n s f o r m e r e s t i n g , l . N. 21067/1V e c t o r Go u p Ce c k (a p #9), D11 Terminals Voltage(V)
R-b=R-y,
R-Y 420.0
Y-B 421.0
B-R 423.0
R-N 122.10
Y-N 299.0
B-y 475.0
R-b 210.5
R-y 211.4
Y-b 261.6
Y-y 261.3
a t i o e s t f r a n s f o r m e r #2, l . o 21067/2p H ()i d e(o l t s )L (t a r )i d e(o l t s )At u a la t i o a t i o %Er o rBB H/Lp h Y p h Bh R p h p h Bh 01 422 421 422 191.6 190.9 191.0 110.9 111.3 110.7 2.202.20 2.21 2.21 +0.11% +0.24% +0.43%

R e s u l t: The field testing of the ratio of HV/LV at various tapings is found correct with slight
errors.
The phase voltage of secondary is also found to be 1/√3 times that of line voltage.
The actual ratio at normal tap is 2 i.e. 66/33KV.
It is observed in the magnetizing balance check that the maximum voltage exists across
the diagonal element for HV and LV phase voltage.
NB: If the diagonal characteristics holds true for the phase voltages at LV side then it
is true for HV side. Further Vector Group check will also hold true.
The vector group check for Dy11 also proved the equations or the vector characteristic
given. Cnc l u s i o n: From the above field test it is proved that the results obtained are tallying with the name plate
ratings. Ratios at various taps are correct with some errors. The windings at the core are also
balanced at 120° from each other. The magnetizing current as observed during the field test is far
below 4% of the actual rated current. No load current should not exceed above 4% of the actual
rated current. It is observed that in the Y phase the current is comparatively less. The reason
being, the Y phase winding lies at the middle so the flux gets distributed equally to other
windings too thereby resulting in low currents. Whereas in other case very less flux gets to the
third winding (see the fig. below). The vector group is found to be Dy11. There are a total of

Transformer Oil Testing A :Dehydration & filtration of Transformer oil in the Transformer.b j e c t i v e : 1. To remove the moisture present in the core, windings, tank, radiator and the conservator
tank.
2. To check the insulation resistance (IR Value) of the Transformer using Megger and
observe the reading.
3. Check the Breakdown Voltage value (BDV) of the dehydrated oil.T h e o r y :After the erection of Transformer at site, dehydration and filtration of oil is very
important. Here 'Transformer Oil Conditioning Machine' is used. There are two outlets in this
machine; one is used as incoming oil source and the other acts as outgoing source. After
connecting one pipe to the transformer tank and the other to the oil barrel start the machine and
fill the transformer with oil. Don’t fill it fully; as transformer oil gets heated its volume expands.
Now connect both pipes to transformer where one draws oil from the transformer and the other
pumps in the dehydrated oil coming from the Transformer oil conditioning machine. There are
moistures present in core and windings. When the oil is heated, by virtue of core and windings
being immersed in the oil, it gets heated. As a result of this the moisture present, in the core and
windings vaporize out and gets mixed with the oil. This oil is then passed into the oil
conditioning machine. The oil passes through 'degassing chamber' in two stages where the oil is
set to flow in the form of fountain. When this process happens the moisture is sent out from the
oil which is then sucked by the vacuum pump. The oil further passes through heater and filter
vessel where the oil gets heated and gets filtered of carbon deposits, dirt, sludge, etc. particles.
The oil is again pumped in the transformer. It heats the core and the process continues. During
the process of Transformer Oil Conditioning, check the IR value of the transformer every after
one hour. Theoretically the Megger value should come down and then rise up until it attains a
stable value. When it attains stable value for multiple Meggering then it shows that the oil is
dehydrated. Then collect sample oil for BDV test. The BDV value shouldn’t come below 60KV.
While Meggering we go with checking the insulation resistance value of primary-earth,
secondary-earth and primary-secondary winding (see fig. 1). The theory behind is as follows;
Primary-Earth :Basically we are observing the change in the characteristics of the
insulation resistance between primary winding and the earth. The IR value of primary to earth
will be high before conditioning. When the conditioning of the oil is started the moisture gets
removed and the value comes down. Upon further conditioning the IR value will go up
indicating that there is no conduction path from primary to earth.S e c o n d a r y -Er t h : Here we are checking the insulation resistance between secondary

Time
I a l u e r y -e cI a l e e c -Er t hI a l u e r y -Er t h r i m a r y-e c o n d a r y : The insulation resistance of primary-secondary is observed. Upon
heating, dehydrating and filtering, the IR value should come down and the rise up until it attains
a stable value. Thus moisture is indicated, vaporized and removed out.
Fig. 1S a m p l e Ga p h
I R V a l u e
0
Ist r u m e n t s s e d:l. o Dsc r i p t i o n S p e c i f i c a t i o n Q u a n t i t y e m a r k s 1
Transformer oil conditioning machine
1 Set
Motwane 1
WACO 1
4 Connecting wires 2.5 sq.mm APRCr c u i t i a g r a m Transformer Oil Conditioning Machine
Motorized Megger Internal diagram
Er t hLH
P r o c e d u r e :AI 1. Connect the pipes at respective inlet and outlet of the Transformer oil conditioning
machine.
2. Connect the other end to the oil drum and the inlet to the 'Top Oil Filter Valve' of the
transformer tank.
3. Start the machine and fill up the transformer to certain level but not fully so that when at
peak temperature of the oil the volume expanded will not overflow the oil from the
transformer.
4. When heating the oil, please observe the source load and the load that the one heater
absorbs. (In our case the source load was 130A whereas each heater consumes 80A.
There are three heaters, so we were bound to switch on only one heater.)
5. Now for dehydration and filtration, connect the pipe connecting the oil drum to the
'Bottom Oil Filter Valve' of the transformer tank.
6. Start the machine with one heater being switched on.
7. Disconnect the earth terminal from the neutral point. Start Meggering with HV-Earth,
LV-Earth and HV-LV and record the reading every one hour until the readings comes
down and rise up to attain a stable value. N.B The process may go on for two to three
days. Then put off the heater and cool the oil with machine under running condition.
8. Take the oil sample (two bottles) for Breakdown Voltage test. The average of six
readings obtained should be above 60KV. This ends the dehydration and filtration test.P AT II(BD e s t ) 1. Arrange the BDV testing kit (Automatic Oil Test Set OTS100AF/Megger)
2. Wash the oil container thoroughly with oil form one bottle.
3. Pour the oil sample from other bottle and place it in the testing kit.
4. Adjust the space between the electrodes to 2.5mm.
5. Keep it idle for 15minutes so that the oil sample settles down.
6. Set the standard to IEC 156 1995 and then press the button to apply voltage.P r e c a u t i o n : Safety of the experimenter the first priority.
Make sure not to fill the transformer tank fully so that the oil will not overflow when
heated at peak temperature.
Drying of a transformer must be done under continuous and competent supervision.
Careful observation of temperature is essential during drying as high temperature can
result in damage to the insulation.

R e s u l t s :Dh y d r a t i o n n d Fl t r a t i o n f r a n s f o r m e r i lr a n s f o r m r #1, 20MA, 66/33K, l . o . 21067/1.Dt e /i m eI y 5K Mt o r i z e d Mt o r(M) T e m p e r a t u r e (C)
Date Time HV-Earth LV-Earth HV-LV Machine oil OTI WTI Remarks
2 6 / 1 0 / 2 0 0 911:56am 10000 10000 8000 35 34 31 6 0 C .
4 : 2 0 , , .
1:25pm 10000 10000 10000 38 38 38
2:30pm 10000 10000 10000 42 39 40
3:30pm 10000 10000 10000 51 46 45
5:18pm 10000 10000 10000 52 48 47
6:20pm 10000 10000 10000 56 51 50
7:25pm 10000 10000 10000 60 54 52
10:30pm 8000 8000 8000 60 56 54
2 7 / 1 0 / 2 0 0 9 12:30am 8000 8000 8000 60 57 55
2:35am 7000 7000 7000 60 57 55
4:30am 7000 7000 7000 60 57 55
6:30am 7000 7000 7000 60 57 55
8:30am 7000 7000 7000 60 57 55
9:30am 7000 8000 9000 60 58 58
10:30am 8000 10000 10000 60 59 59
11:30am 9000 10000 10000 60 59 59
12:30am 7000 9000 10000 60 59 59
1:30pm 7000 9000 10000 60 60 60
2:30pm 7000 9000 10000 60 60 60
3:30pm 8000 10000 10000 60 60 60
4:30pm 8000 10000 10000 60 60 60
5:30pm 8000 10000 10000 60 59 60
6:30pm 8000 10000 10000 60 59 60
7:30pm 8000 10000 10000 60 59 60
8:30pm 8000 10000 10000 60 59 60
9:30pm 8000 10000 10000 60 59 60
10:30pm 8000 10000 10000 60 59 60
11:30pm 8000 10000 10000 60 59 60

Dhy d r a t i o n n d Fl t r a t i o n f a n s f o r m e r i lr a n s f o r m e r #1, 20MA, 66/33K, l . o . 21067/1.Dt e /i m eI y 5K Mt o r i z e d Mt o r(M) T e m p e r a t u r e (C)
2 8 / 1 0 / 2 0 0 9 12:30am 8000 10000 10000 60 59 60
1 : 3 0 , , . 2 : 1 0 , M .1:30am 8000 10000 10000 60 59 60
2:30am 8000 10000 10000 60 59 60
3:30am 8000 10000 10000 60 59 60
4:30am 8000 10000 10000 60 59 60
5:30am 8000 10000 10000 60 59 60
6:30am 8000 10000 10000 60 59 60
7:30am 8000 10000 10000 60 59 60
8:30am 8000 10000 10000 60 59 60
9:30am 8000 10000 10000 60 59 60
10:30am 8000 10000 10000 60 59 59
11:30am 8000 10000 10000 60 59 59
12:30pm 8000 10000 10000 60 59 59
2:30pm 10000 10000 10000 60 56 56
3:30pm 10000 10000 10000 60 55 56
4:30pm 10000 10000 10000 60 54 56
5:30pm 10000 10000 10000 60 54 55
6:30pm 10000 10000 10000 60 52 54R a d i a t o r sa d i a t o r p e n (i m e)Co s e (i m e) R e m a r k s 1 10:15am 10:50am Al a d i a t o r s p e n e d n 28/10/2009t6:30m . Ha t e r w i t c h e d f f n d o o l i n gf h e i l t a r t e d i t h a c h i n e n d e ru n n i n g o n d i t i o n . Mch i n e t o p p e d t29/10/2009t 9:45m . i l a m p l e a k e no r BD e s t t MD, e m t o k h a .
OLTC Filtration started at 4:00pm till
6:00pm on 29/10/2009.
2 11:00am 11:40am
3 12:30pm 1:30pm
4 1:30pm 2:40pm
5 2:40pm 3:10pm
6 3:10pm 3:40pm
7 3:40pm 4:10pm
8 4:10pm 4:40pm
9 5:10pm 5:40pm
10 6:10pm 6:30pm
0
2000
4000
6000
8000
10000
12000
I T i m e
T r a n s f o r m e r i l Ca r a c t e r i s t i c Cr v eH-Er t h Transformer Oil Characteristic
Curve
Bea k d o w n o l t a g e e s t f h e a m p l e i l a k e n r o m r a n s f o r m e r#1.Dt e :29/10/2009, 10:55m t e m t o k h a .Ep e r i m e n t e r :e m a Jm p e l . Eu i p m e n t :At o m a t i c i l e s t e t (T S 100AF/Mg ge a d i n g s T i m e (Mu t e s ) BD(K) 1
st Reading 5 84.8
6 th

0
2000
4000
6000
8000
10000
12000
Transformer Oil Characteristic Curve LVEarth
Transformer Oil Characteristic
Curve LVEarth
I T i m e

Dhy d r a t i o n n d Fl t r a t i o n f r a n s f o r m e r i lr a n s f o r m e r #2, 20MA, 66/33K, l . o . 21067/2.Dt e /i m eI y 5K Mt o r i z e d Mt o r(M) T e m p e r a t u r e (C)
3 0 / 1 0 / 2 0 0 9 1:00pm 10000 10000 10000 - 38 38
1 : 0 0 , F .
A 3 : 0 0 3 1 / 1 0 / 0 9 .
2:00pm 10000 10000 10000 42 40 42
3:00pm 10000 10000 10000 43 40 42
4:00pm 10000 10000 10000 44 43 44
5:00pm 10000 10000 10000 50 48 49
6:00pm 10000 10000 10000 55 53 54
7:00pm 8000 8000 8000 57 54 55
8:00pm 8000 7000 8000 60 55 56
9:00pm 8000 7000 8000 60 56 57
10:00pm 8000 7000 8000 60 56 57
11:00pm 8000 7000 8000 60 56 57
3 1 / 1 0 / 2 0 0 9 12:00am 7000 7000 7000 60 56 57
1:00am 7000 7000 7000 60 57 58
2:00am 7000 7000 7000 60 57 58
3:00am 7000 7000 7000 60 57 58
4:00am 7000 7000 7000 60 58 58
5:00am 7000 7000 7000 60 59 59
6:00am 7000 7000 7000 60 60 60
7:00am 6000 7000 7000 60 61 61
8:00am 6000 7000 7000 60 62 62
9:00am 6000 7000 7000 60 62 62
10:00am 6000 7000 7000 60 62 62
11:00am 6000 7000 7000 60 62 62 1 / 1 1 / 2 0 0 912:00pm 7000 8000 8000 60 63 63
1:00pm 7000 8000 8000 60 63 63
2:00pm 7000 8000 8000 60 63 63
3:00pm 7000 8000 8000 60 63 63

testing and commissioning report of olakha substation

Documents