JSPL-ETL training report 2018

OP JINDAL UNIVERSITY
OP Jindal Knowledge Park, Punjipathra, Raigarh – 496109. (C.G.)
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INDUSTRIAL TRAINING REPORT
SESSION 2017-18
A
Degree of Bachelor of Technology
In
Electrical & Electronics Engineering
Electro-Technical Laboratory
(EPS & MRSS)
Submitted By
Name: Abhishek Prajapati
University Roll No.:01UG15030004 Semester/Branch: 7th/EEE
SUBMITTED TO:
Jindal Steel & Power Limited
Raigarh (Chhattisgarh)
&
School of Electrical & Electronics & Engineering
O P JINDAL UNIVERSITY
Raigarh (Chhattisgarh)

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DECLARATION
I hereby declare that the Industrial Training Report on ETL (Electro-Technical Laboratory)
of EPS & MRSS in Jindal Steel & Power Limited, Industry is an authentic record of my
own work as requirements of Major Industrial Training during the period from 28th May 2018
to 22nd June 2018 for the award of degree of B.Tech. (Electrical & Electronics &Engineering),
O P Jindal University, Punjipathra, Raigarh (C.G.), under the guidance of Mrs. Smita Shukla
(AGM).
Abhishek Prajapati
Roll No.: 01UG15030004
Date: ____________________
Certified that the above statement made by the student is correct to the best of our knowledge
and belief
Examined by:
Mr. Srikant Prasad
Mr. Srikant Prasad
Head of Department

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ACKNOWLEDGMENT
JINDAL STEEL & POWER LTD
J.S.P.L is one of the leading companies in steel & power sector. JSPL is part of the US$ 6 billion
Jindal organization. Located at Raigarh in state Chhattisgarh on main railway track Mumbai -
Howrah. It is not pioneer in steel & power sector but also producing sponge iron, Ferro chrome
& heavy machinery & under the leadership of Mr. NAVEEN JINDAL, EC & MD.
This training report provides the Acknowledgment about the ETL (Electro-Technical
Laboratory) of EPS & MRSS section. Which I learn during the period of 4 weeks, under
valuable guidance very senior members of the organization at various departments, hence I
could get clear details of ETL (Electro-Technical Laboratory) of EPS & MRSS.
I am very much thankful to all above senior faculties who spared their valuable time & guide
me to understand the system. This training was not possible without the kind permission of
“Mrs. Smita Shukla” who given an opportunity to complete my training at JSPL.
Next I would like to tender my sincere thanks to “Prof. Srikant Prasad” (Head of Electrical &
Electronics & Engineering Department, OPJU) for his co-operation and encouragement.
Under guidance: Submitted by:
Mrs. Smita Shukla Abhishek Prajapati
AGM, Electro-Technical Laboratory Student, B. Tech. (EEE), OPJU
EPS & MRSS, JSPL, Raigarh, (C.G.) Roll No. – 01UG15030004

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 Always hold onto the railing
 Take care not to slip or trip
 Choose a safe location to have a phone call
 Park your car in the designated spot
 Ask for permission to take photos
 Find out the nearest exit and the place of assembly
 Remember that use of alcohol and drugs is prohibited in the plant area
 Smoke only in the designated areas
Personal protective equipment
 Safety glasses, shoes
 Safety Jackets
 Helmet
 Reflective vest
 Hearing protector in noisy areas
 Additional protective equipment on worksites as instructed by the visit’s host

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 PROFILE OF JINDAL STEEL & POWER LIMITED
Jindal Steel and Power Limited (JSPL) is an Indian steel and energy company based on
New Delhi, India. With turnover of approx. US$ 6 billion, JSPL is a part of about US$18
billion diversified Jindal Group conglomerate. JSPL is a leading player in steel, power,
mining, oil and gas and infrastructure in India. The company produces steel and power
through backward integration from its own captive coal and iron-ore mines.
In terms of tonnage, it is the third largest steel producer in India. The company
manufactures and sells sponge iron, mild steel slabs, Ferro chrome, iron ore, mild steel,
structural, hot rolled plates and coils and coal-based sponge iron plant.
History: In 1969, O. P. Jindal (1930–2005) started Pipe Unit Jindal India Limited at Hisar,
India. After Jindal's death in 2005, much of his assets were transferred to his wife, Savitri Jindal.
Jindal Group's management was then split among his four sons with Naveen Jindal as the
Chairman of Jindal Steel and Power Limited. His elder brother, Sajjan Jindal is the head of
JSW Group, part of O.P. Jindal Group.

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Contents: -
Sr. No. Topic
1. EPS (Electrical Power System)
2. MRSS (Main Receiving Substation)
3. ETL (Electro-Technical Laboratory)
4. Transformer Testing
1. Type Test of Transformer
2. Routine Test of Transformer
3. Special Test of Transformer
4. Pre-Commissioning Test of Transformer
5. Transformer Winding Resistance Measurement
6. Magnetic Balance Test of Transformer
7. Induced Voltage Test of Transformer
8. Temperature Rise Test of Transformer
9. Magnetizing Current Test of Transformer
10. Vector Group Test of Transformer
11. Insulation Resistance Test or Megger Test of
Transformer
12. Dielectric Tests of Transformer
13. Transformer Oil Testing
1. BDV Test for Dielectric Strength of Transformer Oil
2. DGA or Dissolved Gas Analysis Test of Transformer Oil
14. Circuit Breaker Testing
1. Contact resistance test
2. Insulation resistance test
3. Dielectric withstand voltage test
15. Protective Relay Testing
16. Types of Relay Testing
1. Acceptance Test
2. Installation Test
3. Maintenance Test
4. Repair Test

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EPS (Electrical Power System)
An electric power system is a network of electrical components deployed to supply, transfer,
and use electric power. An example of an electric power system is the grid that provides power
to an extended area. An electrical grid power system can be broadly divided into the generators
that supply the power, the transmission system that carries the power from the generating
centers to the load centers, and the distribution system that feeds the power to nearby homes and
industries. Smaller power systems are also found in industry, hospitals, commercial buildings
and homes. The majority of these systems rely upon three-phase AC power—the standard for
large-scale power transmission and distribution across the modern world. Specialised power
systems that do not always rely upon three-phase AC power are found in aircraft, electric rail
systems, ocean liners and automobiles.
We call the entire arrangement from generating plants to consumer ends for delivering
electricity efficiently and reliably as the electric power system. The generation plants produce
electrical energy at a low voltage level. We keep the generation voltage at a low level because
it has some specific advantages. Low voltage generation creates less stresses on the armature of
the alternator. Hence at low voltage generation, we can construct smaller alternator with thinner
and lighter insulation. From engineering and design point of view, smaller alternators are more
practical. We cannot transmit this low voltage power to the load centres. Low voltage
transmission causes more copper loss, poor voltage regulations and more installation cost of the
transmission system. To avoid these three difficulties, we have to step up the voltage to a
specific high voltage level. We cannot raise the system voltage beyond a certain level because
beyond a limit of voltage the insulation cost tremendously increases and also to keep adequate
ground clearance the expenses of the line supporting structures also abruptly increase. The
transmission voltage depends on the quantity of power to be transmitted. The surge impedance
loading is another parameter which determines the voltage level of the system for transmitting
an amount of energy. For stepping up system voltage, we use step-up transformers and their
associated protections and operations arrangements at generating station. We call this as
generation substation. At the end of the transmission line, we have to step down the transmission
voltage to a lower level for secondary transmission and or distribution purposes. Here we use
step down transformers and their associated protection and operational arrangements. This is
transmission substation. After primary transmission, the electrical energy passes through
secondary transmission or primary distribution. After secondary transmission or primary
distribution again we step down the voltage to a desired low voltage level to distribute at the
consumer premises.
This was the basic structure of an electrical power system. Although, we have not mentioned
the details of each equipment used in an electrical power system. In addition to three main
components alternator, transformer and transmission line there are numbers of associated
equipment. Some of these pieces of equipment are circuit breaker, lightning arrestor, isolator,
current transformer, voltage transformer, capacitor voltage transformer, wave trap, capacitor
bank, relaying system, controlling arrangement, the earthing arrangement of the line and
substation equipment etc.

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MRSS (Main Receiving Substation)
This is mainly a system arranged at generating or distributing areas to control and protect the
electric power being transmitted through transmission lines. In other words, this helps to
maintain the balanced power flow and outgoing to any feeder.
These substations are arranged also to protect the equipments installed at the line or to provide
isolation to a specific line in faulty conditions, such as short circuit or ground faults.
Components of a substation:
 Lightening Arrester
 Incoming line
 Main bus
 Isolator
 Potential transformer
 Current transformer
 Circuit breaker
 Bushings
 Insulators
 Power Transformer
 Outgoing feeders
 Conductor & cables
LAYOUT & CONNECTION DIAGRAM OF ELECTRICAL
POWER SYSTEM FOR ALL INTERCONNECTED JINDAL
PLANTS:

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ETL (Electro-Technical Laboratory)
Electro Technical Laboratory is well equipped with high precision reference source-measure
standards for calibration of metrological parameters viz. voltage, current, resistance,
capacitance, inductance, time, frequency, power. ETL has well established quality system
complying with ISO/IEC 17025. The laboratory is accredited by the National Accreditation
Board for Testing & Calibration Laboratories (NABL), Department of Science and technology,
Govt. of India. The reference standards maintained in the laboratory are traceable to national
standards. The state of the art electro technical calibration facilities includes Electronic Standard
Cells, Standard Resistors, Multifunction Transfer Standard, Multifunction Calibrators, CRO
calibrator, Transconductance standards, AC/DC Current Shunts, LF Power Standard, RLC
Standard, Cesium and Rubidium Frequency Standard, LF & RF Standard Sources etc.
1.State-of-the-art calibration standards are used by highly experienced electrotechnical
calibration technicians.
2. We provide extensive, accurate and timely electrotechnical calibration services at extremely
competitive prices.
3.Our electrotechnical calibration services can be performed at your site or in our state-of-the-
art laboratories
This laboratory is capable of calibrating industrial and laboratory grade sourcing and measuring
instruments.
All the equipments must be treated so healthily as to maintain proper working and lossless
operation. In order to maintain these operations regular and standardised testing is required. In
ETL lab, testing of various components of transformers, breakers and other equipments is done
under expertise surveillance. On field as well as sample testing is done in this laboratory. Some
of the tests are named as given below:

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Transformer Testing:
For confirming the specifications and performances of an electrical power transformer it has
to go through numbers of testing procedures. Some tests are done at manufacturer premises
before delivering the transformer. Mainly two types of transformer testing are done at
manufacturer premises- type test of transformer and routine test of transformer. In
addition to that some transformer tests are also carried out at the consumer site before
commissioning and also periodically in regular and emergency basis throughout its service
life.
Type of Transformer Testing:
 Tests done at factory
1. Type tests
2. Routine tests
3. Special tests
 Tests done at site
4. Pre-commissioning tests
5. Periodic/condition monitoring tests
6. Emergency tests
1. Type Test of Transformer:
To prove that the transformer meets customer’s specifications and design expectations,
the transformer has to go through different testing procedures in manufacturer premises.
Some transformer tests are carried out for confirming the basic design expectation of that
transformer. These tests are done mainly in a prototype unit not in all manufactured units
in a lot. Type test of transformer confirms main and basic design criteria of a production
lot.
Type tests of transformer includes:
1. Transformer winding resistance measurement
2. Transformer ratio test.
3. Transformer vector group test.
4. Measurement of impedance voltage/short circuit impedance (principal tap) and
load loss (Short circuit test).
5. Measurement of no load loss and current (Open circuit test).
6. Measurement of insulation resistance.
7. Dielectric tests of transformer.
8. Temperature rise test of transformer.
9. Tests on on-load tap-changer.
10. Vacuum tests on tank and radiators.

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2. Routine Tests of Transformer:
Routine tests of transformer are mainly for confirming the operational performance of
the individual unit in a production lot. Routine tests are carried out on every unit
manufactured.
Routine tests of transformer include:
1. Transformer winding resistance measurement.
2. Transformer ratio test.
3. Transformer vector group test.
4. Measurement of impedance voltage/short circuit impedance (principal tap) and
load loss (Short circuit test).
5. Measurement of no load loss and current (Open circuit test)
6. Measurement of insulation resistance.
7. Dielectric tests of transformer.
8. Tests on on-load tap-changer.
9. Oil pressure test on transformer to check against leakages past joints and gaskets.
That means Routine tests of transformer include all the type tests except temperature rise
and vacuum tests. The oil pressure test on transformer to check against leakages past
joints and gaskets is included.
2. Special Tests of Transformer:
Special tests of transformer are done as per customer requirement to obtain information
useful to the user during operation or maintenance of the transformer.
Special Tests of transformer include:
1. Dielectric tests.
2. Measurement of zero-sequence impedance of three-phase transformers
3. Short-circuit test.
4. Measurement of acoustic noise level.
5. Measurement of the harmonics of the no-load current.
6. Measurement of the power taken by the fans and oil pumps.
7. Tests on bought out components / accessories such as buchhloz relay, temperature
indicators, pressure relief devices, oil preservation system etc.
3. Pre Commissioning Test of Transformer:
The Test performed before commissioning the transformer at site is called pre
commissioning test of transformer. These tests are done to assess the condition of
transformer after installation and compare the test results of all the low voltage tests with
the factory test reports. All transformers are subjected to the following Pre
commissioning tests:
1. IR value of transformer and cables
2. Winding Resistance
3. Transformer Turns Ratio
4. Polarity Test
5. Magnetizing Current
6. Vector Group
7. Magnetic Balance
8. Bushing & Winding Tan Delta (HV)
9. Protective relay testing
10. Transformer oil testing
11. Hipot test.

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Transformer Winding Resistance Measurement:
Transformer winding resistance measurement is carried out to calculate the I2R losses
and to calculate winding temperature at the end of a temperature rise test. It is carried out
as a type test as well as routine test. It is also done at site to ensure healthiness of a
transformer that is to check loose connections, broken strands of conductor, high contact
resistance in tap changers, high voltage leads and bushings etc.
There are different methods for measuring of the transformer winding, likewise:
1. Current-voltage method of measurement of winding resistance.
2. Bridge method of measurement of winding resistance.
3. Kelvin bridge method of Measuring Winding Resistance.
4. Measuring winding resistance by Automatic Winding Resistance Measurement Kit.
NB: - Transformer winding resistance measurement shall be carried out at each tap.
Transformer Turns Ratio Test:
The performance of a transformer largely depends upon perfection of specific turns or
voltage ratio of transformer. So transformer ratio test is an essential type test of
transformer. This test also performed as a routine test of transformer. So for ensuring
proper performance of electrical power transformer, voltage and turn ratio test of
transformer one of the important tests. The procedure of the transformer ratio test is
simple. We just apply three phase 415 V supply to HV winding, with keeping LV winding
open. We measure the induced voltages at HV and LV terminals of the transformer to
find out actual voltage ratio of the transformer. We repeat the test for all tap position
separately.

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Transformer Turns Ratio Test Meter

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Magnetic Balance Test of Transformer:
Magnetic balance test of transformer is conducted only on three-phase transformers to
check the imbalance in the magnetic circuit.
Procedure of Magnetic Balance Test of Transformer
1. First keep the tap changer of transformer in normal position.
2. Now disconnect the transformer neutral from ground.
3. Then apply single phase 230 V AC supply across one of the HV winding terminals
and neutral terminal.
4. Measure the voltage in two other HV terminals in respect of neutral terminal.
5. Repeat the test for each of the three phases.
In case of auto transformer, magnetic balance test of transformer should be repeated for
LV winding also. There are three limbs placed side by side in a core of the transformer.
One phase winding is wound in one limb. The voltage induced in different phases
depends upon the respective position of the limb in the core. The voltage induced in
different phases of a transformer in respect to neutral terminals given in the table below.
Induced Voltage Test of Transformer:
The induced voltage test of the transformer is intended to check the inter-turn and line
end insulation as well as main insulation to earth and between windings.
1. Keep the primary winding of transformer open circuited.
2. Apply three-phase voltage to the secondary winding. The applied voltage should be
twice of the rated voltage of secondary winding in magnitude and frequency.
3. The duration of the test shall be 60 seconds.
4. The test shall start with a voltage lower than 1/3 the full test voltage, and it shall be
quickly increased up to a desired value.
The test is successful if no breakdown occurs at full test voltage during the test.
Temperature Rise Test of Transformer:
Temperature rise test of transformer is included in type test of transformer. In this test,
we check whether the temperature-rising limit of the transformer winding and oil as per
specification or not. In this type test of the transformer, we have to check oil temperature
rise as well as winding temperature rise limits of an electrical transformer.

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Magnetizing Current Test of Transformer:
Magnetizing current test of transformer is performed to locate defects in the magnetic
core structure, shifting of windings, failure in between turn insulation or problem in tap
changers. These conditions change the effective reluctance of the magnetic circuit, thus
affecting the current required to establish flux in the core.
1. First of all, keep the tap changer in the lowest position and open all IV and LV
terminals.
2. Then apply three phase 415 V supply on the line terminals for three-phase
transformers and single phase 230 V supply on single phase transformers.
3. Measure the supply voltage and current in each phase.
4. Now repeat the magnetizing current test of transformer test with keeping tap changer
in normal position.
5. And repeat the test with keeping the tap at highest position.
Normally, there are two similar higher readings on two outer limb phases on transformer
core and one lower reading on the centre limb phase, in the case of three phase
transformers. An agreement to within 30% of the measured exciting current with the
previous test is usually considered satisfactory. If the measured exciting current value is
50 times higher than the value measured during factory test, there is a likelihood of a fault
in the winding which needs further analysis.
Caution: This magnetizing current test of transformer is to be carried out before
DC resistance measurement.
Vector Group Test of Transformer:
In three phase transformer, it is essential to carry out a vector group test of transformer.
Proper vector grouping in a transformer is an essential criteria for parallel operation of
transformers. There are several internal connection of three phase transformer are
available in market. These several connections give various magnitudes and phase of the
secondary voltage; the magnitude can be adjusted for parallel operation by suitable choice
of turn ratio, but the phase divergence cannot be compensated. So we have to choose
those transformer for parallel operation whose phase sequence and phase divergence are
same. All the transformers with the same vector ground have same phase sequence and
phase divergence between primary and secondary. So before procuring one electrical
power transformer, one should ensure the vector group of the transformer, whether it will
be matched with his or her existing system or not. The vector group test of transformer
confirms his or her requirements.
Insulation Resistance Test or Megger Test of Transformer:
Insulation resistance test of transformer is essential type test. This test is carried out
to ensure the healthiness of the overall insulation system of an electrical power
transformer.
Procedure of Insulation Resistance Test of Transformer:
1. First disconnect all the line and neutral terminals of the transformer.
2. Megger leads to be connected to LV and HV bushing studs to measure insulation
resistance IR value in between the LV and HV windings.

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3. Megger leads to be connected to HV bushing studs and transformer tank earth
point to measure insulation resistance IR value in between the HV windings and
earth.
4. Megger leads to be connected to LV bushing studs and transformer tank earth
point to measure insulation resistance IR value in between the LV windings and
earth.
NB: It is unnecessary to perform insulation resistance test of transformer per
phase wise in three-phase transformer. IR values are taken between the
windings collectively as because all the windings on HV side are internally
connected together to form either star or delta and also all the windings on LV
side are internally connected together to form either star or delta.
Measurements are to be taken as follows:
1. For autotransformer: HV-IV to LV, HV-IV to E, LV to E.
2. For two winding transformer: HV to LV, HV to E, LV to E.
3. Three winding transformers: HV to IV, HV to LV, IV to LV, HV to E, IV to E,
LV to E.
4. Oil temperature should be noted at the time of insulation resistance test of
transformer. Since the IR value of transformer insulating oil may vary with
temperature.
5. IR values to be recorded at intervals of 15 seconds, 1 minute and 10 minutes.
6. With the duration of application of voltage, IR value increases. The increase in
IR is an indication of dryness of insulation.
7. Absorption coefficient = 1-minute value/15 secs. value.
8. Polarization index = 10 minutes’ value/1-minute value.
Dielectric Tests of Transformer:
Dielectric test of a transformer is one kind of insulation test. This test is performed to
ensure the expected overall insulation strength of the transformer. There are several
tests performed to ensure the required quality of transformer insulation; the dielectric
test is one of them. Dielectric test of the transformer is performed in two different
steps. First one is called Separate Source Voltage Withstand Test of transformer,
where a single phase power frequency voltage of prescribed level, is applied on
transformer winding under test for 60 seconds while the other windings and tank are
connected to the earth, and it is observed that whether any failure of insulation occurs
or not during the test. The second one is the induced voltage test of Transformer
where, three-phase voltage, twice of rated secondary voltage is applied to the
secondary winding for 60 seconds by keeping the primary of the transformer open
circuited. The frequency of the applied voltage should be double of power frequency
too. Here also if no failure of insulation, the test is successful. In addition to dielectric
tests of transformers, there are other types of test for checking insulation of
transformer, such as lightning impulse test, switching impulse test and partial
discharge test.

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Transformer Oil Testing:
Introduction of Transformer Insulating Oil
Insulating oil in an electrical power transformer is commonly known as transformer oil.
It is normally obtained by fractional distillation and subsequent treatment of crude
petroleum. That is why this oil is also known as mineral insulating oil. Transformer
oil serves mainly two purposes one it is liquid insulation in electrical power transformer
and two it dissipates heat of the transformer i.e. acts as a coolant. In addition to these,
this oil serves other two purposes, it helps to preserve the core and winding as these are
fully immersed inside oil, and another important purpose of this oil is, it prevents direct
contact of atmospheric oxygen with cellulose made paper insulation of windings, which
is susceptible to oxidation.
Types of Transformer Oil
Generally there are two types of transformer Oil used in transformer,
1. Paraffin based transformer oil
2. Naphtha based transformer oil
Naphtha oil gets more easily oxidized than Paraffin oil. But oxidation product, i.e.,
sludge in the naphtha oil is more soluble than Paraffin oil. Thus sludge of naphtha-based
oil is not precipitated in the bottom of the transformer. Hence it does not obstruct
convection circulation of the oil, means it does not disturb the transformer cooling
system. But in the case of Paraffin oil although oxidation rate is lower than that of
Naphtha oil the oxidation product or sludge is insoluble and precipitated at the bottom
of the tank and obstruct the transformer cooling system. Although Paraffin-based oil has
the disadvantage as mentioned earlier but still in our country, we use it because of its
easy availability. Another problem with paraffin-based oil is its high pour point due to
the wax content, but this does not affect its use due to warm climate condition of India.

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Testing of Transformer oil:
1. BDV Test for Dielectric Strength of Transformer Oil:
Dielectric strength of transformer oil is also known as breakdown voltage of
transformer oil or BDV of transformer oil. Break down voltage is measured by
observing at what voltage, sparking strands between two electrodes immerged in the oil,
separated by specific gap. low value of BDV indicates presence of moisture content and
conducting substances in the oil. For measuring BDV of transformer oil, portable BDV
measuring kit is generally available at site. In this kit, oil is kept in a pot in which one
pair of electrodes are fixed with a gap of 2.5 mm (in some kit it 4mm) between them.
Now slowly rising voltage is applied between the electrodes. The rate of rising voltage
is controlled at 2 KV/s and observe the voltage at which sparking starts between the
electrodes. That means at which voltage dielectric strength of transformer oil between
the electrodes has been broken down.

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BDV Testing kit
Input & Output Panels of BDV Testing Kit
This measurement is taken 3 to 6 times in the same sample of oil, and we take the average
value of these readings. BDV is an important and popular test of transformer oil, as it is
the primary indicator of the health of oil and it can be easily carried out at the site.
Dry and clean oil gives BDV results, better than the oil with moisture content and other
conducting impurities. Minimum breakdown voltage of transformer oil or dielectric
strength of transformer oil at which this oil can safely be used in transformer, is
considered as 30 KV.

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2. DGA or Dissolved Gas Analysis Test of Transformer Oil:
Whenever electrical power transformer goes under abnormal thermal and electrical
stresses, certain gases are produced due to decomposition of transformer insulating oil,
when the fault is major, the production of decomposed gases are more and they get
collected in Buchholz relay. But when abnormal thermal and electrical stresses are not
significantly high the gasses due to decomposition of transformer insulating oil will get
enough time to dissolve in the oil. Hence by only monitoring the Buchholz relay it is not
possible to predict the condition of the total internal healthiness of electrical power
transformer. That is why it becomes necessary to analyse the quantity of different gasses
dissolved in transformer oil in service. From dissolved gas analysis of transformer Oil
or DGA of transformer oil, one can predict the actual condition of internal health of a
transformer.
It is preferable to conduct the DGA test of transformer oil in routine manner to get
prior information about the trend of deterioration of transformer health and life. Actually
in dissolved gas analysis of transformer oil or DGA of transformer oil test, the gases
in oil are extracted from oil and analyse the quantity of gasses in a specific amount of
oil. By observing percentages of different gasses present in the oil, one can predict the
internal condition of transformer. Generally, the gasses found in the oil in service are
hydrogen (H2), methane (CH4), Ethane (C2H6), ethylene (C2H4), acetylene (C2H3),
carbon monoxide (CO), carbon dioxide (CO2), nitrogen (N2) and oxygen(O2).
Most commonly used method of determining the content of these gases in oil, is using a
Vacuum Gas Extraction Apparatus and Gas Chronographs. By this apparatus first gasses
are extracted from oil by stirring it under vacuum. These extracted gasses are then
introduced in gas Chronographs for measurement of each component.

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Although by dissolved gas analysis one can predict the condition of the paper insulation
primarily, but it is not very sensitive method. There is a guide line in IEC-599, where it
is told that if the ratio of CO2 and CO in DGA results is more than 11, it is predicted
that the condition of paper insulation inside the transformer is not good. A healthy
cellulose insulation gives that ratio in a range of 4 to 11. But still it is not a very sensitive
way of monitoring the condition of paper insulation. Because CO2 and CO gases also
produced during oil breakdown and sometimes the ratio may mislead the prediction.
When oil is soaked into paper, it is damaged by heat and some unique oil soluble
compounds are realized and dissolved in the oil along with CO2 and CO. These
compounds belong to the Furfur aldehyde group. These are sometimes called Furfural
in short. Among all Furfurals compounds 2- Furfural is the most predominant. These
Furfural family compound can only be released from destructive heating of cellulose or
paper. Furfur aldehyde analysis is very sensitive as because damage of few grams of
paper is noticeable in the oil even of a very large size transformer. It is a very significant
diagnostic test. It is best test for assessing life of transformer. The rate of rise of
percentage of Furfurals products in oil, with respect to time, is used for assessing the
condition and remaining life of paper insulation in power transformer.

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Circuit Breaker Testing:
Circuit breakers perform three main tasks: When closed, they must conduct the current
as effectively as possible. When open, they must insulate the contacts from one another
as effectively as possible. In the event of a malfunction, they must disconnect the fault
current as quickly and reliably as possible, thereby protecting all subsequent equipment.
In the US market and regions of frequent earthquakes, the most popular high-
voltage circuit breakers are "dead tank" units, whereas in central Europe "live tank"
breakers are standard. In other parts of the world, both circuit breaker types can be found.
In the worst case, a circuit breaker might stand still for several years, but then, in the
event of a malfunction, it has to disconnect fault currents of many kilo amps reliably
within just a few milliseconds. Typical faults that occur on circuit breakers are short
circuits in the coils, incorrect behavior, for example due to worn contacts, as well as
damage/wear to the mechanical connections or the insulation material. Therefore, circuit
breakers need to be regularly and carefully tested.
Circuit breaker testing typically focuses on performing motion and time measurements
on the units. However, our testing solutions have revolutionized circuit breaker testing.
The testing solutions we offer include systems that can supply power during the testing
process and are capable of measuring the micro-ohm resistance across the closed
contacts. Performing the tests without use of the station battery greatly increases safety
throughout the testing process.

t: +91 7762 304 000 www.opju.ac.in
When a fault occurs on the electrical power system, fast and reliable protection means
everything. If a circuit breaker fails to clear the fault at that critical moment, the resulting
damage can be disastrous in terms of both personnel injury and equipment damage.
Even though circuit breakers can be very reliable, they tend to gather dirt, moisture, and
contaminants while in service. Breakers used in hostile environments can be exposed to
various corrosive contaminants, which damage not only the insulation system but also
metal components, including the main contacts in air circuit breakers.
For these reasons and more, it’s essential that circuit breakers be tested and maintained
to ensure proper operation during electrical faults. There are three basic electrical tests
that should be performed on medium-voltage circuit breakers as part of a preventive
maintenance program:
1. Contact resistance test:
The main contacts and primary stabs need to be checked periodically to detect
abnormal wear, inadequate lubrication, and loose pivot points inside the circuit
breaker. Poorly maintained or damaged contacts can cause arcing, single phasing,
and electrical fires.
Electrical resistance of the circuit breaker's primary circuit is calculated by measuring the
voltage drop across the line and load terminals for each phase. This test should be
performed using a low voltage, direct current (DC) power supply (low-resistance
ohmmeter) to pass current from line to load, with the circuit breaker in the closed
position.

t: +91 7762 304 000 www.opju.ac.in
Test current should be equal to the rating of the circuit breaker or 100 amperes. Using
a test current less than 100A is acceptable, but know that equipment manufacturers
usually don't recognize warranty claims based on a 10 ampere DLRO test.
Measured resistance values should be within 50% of each adjacent phase, and
comparable to similar breakers as stated in NETA Maintenance Testing Specifications.
The resistance should not exceed the factory test levels by more than 200% as stated
in IEEE C37.09.
After maintenance testing, the contact resistance should be as low, and as even as
possible, across the three phases of the circuit breaker. The actual contact resistance will
vary, depending on the circuit breaker's continuous current rating.
2. Insulation resistance test:
The circuit breaker's insulation system is a critical area that requires testing and
evaluation. Insulation systems can weaken due to the heat created by arc interruption,
especially if they are not routinely maintained.
Weak insulation can result in a catastrophic failure, especially during arc interruption.
The insulation resistance test is useful for detecting major defects in the insulation
system, but it can also be used as a final safety check before returning the breaker to
service.
This test should be performed using a megohmetter phase-to-phase and phase-to-
ground with the breaker in the closed position, as well as across the open contacts for
each phase. Use the manufacturers recommended test voltage and acceptance values
for this test. When no factory recommendations are available, NETA Maintenance
Specifications may be used.

t: +91 7762 304 000 www.opju.ac.in
ETL (Electro-Technical Laboratory
All circuit breaker control wiring should be insulation tested as it can easily be cut on
sharp edges when moving the breaker in and out of its cell. It only takes a single
wire shorted inside of the circuit breaker to prevent it from effectively clearing a fault.
This could result in failure of the trip coil, charging circuit, or even the protective relay.
Perform this test by connecting all points of the secondary disconnect pins together and
measure insulation resistance from the wire to the circuit breaker frame or chassis.
Use caution when conducting this test, don't apply high voltage to the spring charging
motor or solid-state devices; isolate these items prior to insulation resistance testing.
3. Dielectric withstand voltage test:
This is basically a Hipot test. Dielectric withstand picks up where insulation resistance
left off; it's used to detect tracking, deterioration, and moisture in the insulation
system.
The use of an AC high potential test set is recommended when testing medium-voltage
circuit breakers. Always use test voltages specified by the manufacturer. When
recommendations are not available, or not provided, NETA Maintenance
Specifications can be used.
Dielectric withstand testing is performed from the line side of each phase, with the
breaker open, all other phases tied together and connected to ground. For vacuum
circuit breakers, this test will also provide an indication of the vacuum bottle integrity.
Use manufacturer provided test voltages to avoid potential damage to the bottle.
Note: Power-factor or dissipation-factor testing should be considered as an additional
test of the insulation system.

t: +91 7762 304 000 www.opju.ac.in
Protective Relay Testing:
ITI specialties ranges from testing the relays within power system faults to configuring
relays to perform more complex function like restoring voltage to a “dead” bus by
implementing:
 Automatic transfer schemes
 AC/DC wiring schematics
 Generation of wiring diagrams
 I/O specifications and assignments
 SEL Boolean or Flex LOGIC or control logic development
 Calculation of settings:
 Pickup
 Reach
 Time Delays
 Generation of setting files
 Supervision logic
 Dynamic testing with Test Sets
 Generation of documents and test reports

t: +91 7762 304 000 www.opju.ac.in
Types of Relay Testing
The type of testing required for each specific relay needs to be designed with the goal of
accomplishing the objective. The objective depends on the specific needs and wants of
the customer and ITI is geared towards satisfying our customer base. We perform
testing in four specific classes which are:
1.) Acceptance Tests
 New Programmable Relay First Time Applied
 Test on each Product Received
2.) Installation Tests
 Field tests to determine installation will correctly
 Generally, not repeated unless installation was incorrect during operations
 Performed by simulated tests with secondary circuits energized from portable
test source
3.) Maintenance Tests
 Inspection and burnishing of contacts (old electromechanical style of relays)
 Automatic self-test of relay
 Adjustments checked.
 Breakers tripped by manual contact closing.
 Screws checked for tightness.
 Covers cleaned.
 As Found and as Left tests made
4.) Repair Tests
 Signs of damage are noticed
 Failure of relay to perform assigned tasks

t: +91 7762 304 000 www.opju.ac.in

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