Transformer BAT.12 PLTGU Priok is a power transformer which has an important role in distributing electrical power from PLTGU Priok to the load network. BAT 12 transformer which has been operating for a long time will certainly experience a decrease in standard and quality due to electrical, thermal, mechanical, chemical, and aging factors. One of the decreases in the standard and quality of the transformer is the decrease in the quality of the winding insulation. During the last two years of operation, there were several disturbances in the BAT. 12 PLTGU Priok transformer. Based on the Maximo 201819647 work order, there is a disturbance that can damage the isolation on the transformer. To determine the condition of the isolation quality and anticipate unexpected transformer breakdowns, it is necessary to test the transformer standard parameters. This test includes testing the insulation quality of the transformer windings. The Tangent Delta, Insulation Resistance and Dielectric Frekeuncy Respone test methods were carried out to determine the standard parameters of the dissipation factor, insulation resistance, polarity index, moisture content and oil conductivity. The test results are Tangent Delta of <0.5%, Oil conductivity of <6.7 pS / m, moisture content of <1.5%, HV / LV Insulation Resistance of 538 MΏ and polarity index of 2.76. The results of this test show that the transformer is still in good condition.

1. LIFETIME STUDY OF TRAFO 150KV BAT.12 ON GAS TURBINE 1.2 PT PLN
INDONESIA POWER PRIOK GAS AND STEAM POWER PLANT
1st
Jujun Tugistan Dana Atamaja
Power Generation Unit Priok
PT PLN Indonesia Power
Jakarta, Indonesia
jujun.tugistan@plnindonesiapower.co.id
2
2nd
Syamsir Abduh
Industrial Technology Faculty
Trisakti University
Jakarta, Indonesia
syamsir@trisakti.ac.id
l
3rd
Dheny Cipta Firnanda
Power Generation Unit Priok
PT PLN Indonesia Power
Jakarta, Indonesia
dheny.cipta@plnindonesiapower.co.i
Abstract : Transformer BAT.12 PLTGU Priok is a power
transformer which has an important role in distributing electrical
power from PLTGU Priok to the load network. BAT 12
transformer which has been operating for a long time will
certainly experience a decrease in standard and quality due to
electrical, thermal, mechanical, chemical, and aging factors. One
of the decreases in the standard and quality of the transformer is
the decrease in the quality of the winding insulation. During the
last two years of operation, there were several disturbances in the
BAT. 12 PLTGU Priok transformer. Based on the Maximo
201819647 work order, there is a disturbance that can damage the
isolation on the transformer. To determine the condition of the
isolation quality and anticipate unexpected transformer
breakdowns, it is necessary to test the transformer standard
parameters. This test includes testing the insulation quality of the
transformer windings. The Tangent Delta, Insulation Resistance
and Dielectric Frekeuncy Respone test methods were carried out
to determine the standard parameters of the dissipation factor,
insulation resistance, polarity index, moisture content and oil
conductivity. The test results are Tangent Delta of <0.5%, Oil
conductivity of <6.7 pS / m, moisture content of <1.5%, HV / LV
Insulation Resistance of 538 MΏ and polarity index of 2.76. The
results of this test show that the transformer is still in good
condition.
Keywords: Tangent Delta, Insulation Resistance, Dielectric
Frekeuncy Respone.
I. INTRODUCTION
With the rapid development of technology and the
increasing demand for electrical energy in Indonesia, the
reliability of the electric power system continues to be
improved. Various methods have been taken to maintain a
continuous and reliable power distribution power system. In
Indonesia, the electrical energy distribution system is still not
evenly distributed, so that in certain places the quality and
continuity of electricity distribution is very dependent on one
distribution system. Along with the increasing electricity load,
the load growth and the use of electricity in high voltage
systems are increasing and require the use of special and
reliable electrical equipment specifications such as
transformers. Indirectly, the large capacity and high voltage
levels require a large power transformer and a large size. The
large size of the transformer requires an increasingly complex
distribution of installation and maintenance. If sudden damage
occurs, the process of replacing and transporting a new
transformer will be more difficult and require a long time. To
overcome these limitations due to the need for load power and
the quality of electricity distribution, it is necessary to carry
out periodic and regular maintenance to keep the equipment
in good condition.
The transformer is electrical equipment that is
operated continuously in the electric power system because
of its very vital role in power distribution. As time goes by,
transformer operation can fail due to electrical,
thermal, mechanical, chemical, and aging factors. One of
these factors can cause insulation failure in the
transformer. The quality value of the
insulation on the transformer can determine the length of use
of the transformer. The isolation of this transformer is very
important as a separator between several winding or
conductors that are wrapped around the core of a live
transformer so that electric jumps or sparks do not occur
between these conductors.
PLTGU Priok Block 1 & 2 network transformer GT.12
unit, one of the PLTGU Priok block 1 & 2 power transformers
built in 1994 by PLN in cooperation with the company ABB.
This network transformer or BAT transformer operates
continuously in operating or non-operating generating unit
conditions due to the generator's own use factor. With this
operating pattern, the BAT GT.12 transformer needs to be
conditionally monitored and tested for power dissipation due
to the influence of continuous high voltage operation to
determine the value of insulation quality. From the results of
the testing and analysis, a standard of isolation feasibility and
maintenance recommendations for the next period can be
determined.
II. LITERATURE VIEW
A. Transformator
A transformer is an electric machine that can transform
power at the same level, and also change and transfer the level
of electrical energy (voltage and or current) from one electric
circuit to another with a magnetic coupling using
electromagnetic principles.
A transformer is a static device in which a magnetic and
winding circuit consisting of 2 or more winding, by
electromagnetic induction, transforms the power (current and
voltage) of an AC system to another current and voltage
system at the same frequency (IEC60076 -1 of 2011). The
transformer uses electromagnetic principles, namely
Ampere's law and Faraday induction, where changes in
current or electric fields can generate magnetic fields and
changes in magnetic fields / magnetic field flux can generate
induced voltages [19].
B. Transformer Working Principle
The working principle of a transformer uses the principle
of electromagnetic induction and works on an alternating
current voltage. The working principle of a transformer is
mutual induction between two circuits connected by magnetic
flux. In its simplest form, a transformer consists of two coils
which are electrically separate but magnetically connected by
an induction path. The two coils have a high mutual induction.
If one of the coils is connected toan alternating voltage source,
an alternating flux arises in the iron core connected tothe other
coil causing an induced emf (according to electromagnetic
induction) from Faraday's law. Figure 2.1 explains The basic
principles of transformer circuits are:
2023 4th International Conference on High Voltage Engineering and Power Systems (ICHVEPS)
OS1-B6

2. Figure 2.1 Transformator Circuit 1 phase with two winding
[3]
According to Faraday's law, the magnitude of the
electromotive force (emf) is proportional to changes in flux.
Lenz's law states that the direction of the emf is opposite to
the direction of the flux as a resistance reaction to the change
in flux, so we get the equation :
( dψ
𝑑𝑡
) ( 2.1 )
e = (instantaneous emf) Volt
Ψ = (linked flux)
And for an ideal transformer excited by a sinusoidal
source the equation applies:
E = 4,44 Φm N f (2.2 )
Note :
E = Voltage (rms) (volt)
N = Number of Turn (time)
Φm = peak flux (Weber)
f = frecuency (Hz)
and Equality :
𝐸1
𝐸2
=
𝑁1
𝑁2
(2.3)
Because in an ideal transformer all the mutual flux
produced by one coil will be fully received by the other coil
without any leakage flux or other losses, for example turning
into heat. Based on this, the equation is also obtained:
P1 = P2
V1.I1 = V2.I2
N1.I1 = N2.I2 (2.4)
III. METHODE
Before you begin to format your paper, first write and save
the content as a separate text file. Complete all content and
organizational editing before formatting. Please note sections
A-D below for more information on proofreading, spelling
and grammar.
Keep your text and graphic files separate until after the text
has been formatted and styled. Do not use hard tabs, and limit
use of hard returns to only one return at the end of a paragraph.
Do not add any kind of pagination anywhere in the paper. Do
not number text heads-the template will do that for you.
A. Block Transformer From The Network
Transformer BAT.12 PT. Indonesia Power PLTGU
PRIOK is connected to the PLN Pulo Gebang Gas Insulation
Station (GIS) before being channeled to the 150 KV
transmission network. Preparation for removing the
transformer from this network was carried out by PLN GIS
Pulo Gebang. The procedure for disconnecting this network
transformer is through removing the power breaker (PMT) in
the GIS. The release of this PMT is through the release of
PMT 52A7 , PMT 52B7 and PMT 52AB7.
B. Block Transformer Protection
Protection blocking on the transformer includes Bucholz
protection, Over temperature relay, Sudden pressure relay,
Pressure relief device,
C. Block Voltage Transformer
To maintain the safety of the Voltage Transformer when
the BAT12 Transformer is tested and also to get optimal test
results, the Voltage Transformer connection is disconnected.
D. Data Collection
Various data collection is carried out. At this stage, data
is collected from the transformer manufacturer and
transformer specifications BAT.12 PLTGU Priok.
E. Identification Of Problems
Based on historical fault data in the Maximo record, there
are several disturbances indicating damage to the transformer
fan cooling system, failure of excess gas content of ethane
and water content and temperature differences in the
bushings.
In the two disturbances in 2017 the transformer
experienced the same problem where the cooling of the
transformer could not be operated due to an abnormality in
the transformer commond fan system. This will result directly
in reducing the quality of the insulation resistance of
transformers that are damaged due to overheating.
In this study, the focus was on testing equipment that had
experienced the effects of previous disturbances. So it is
necessary to test the insulation resistance of the transformer,
tan delta, and dielectric frequency response.
F. Insulation Resistance Test
Figure 3.1 HV Ground Insulation Resistance Test Range
Insulation resistance testing is carried out with a voltage
injection of 5KV and a short circuit on the HV and LV
windings of the transformer.
G. Tangent Delta Test
Primary side voltage injection
Figure 3.2 Connection ICH + ICHL [17]
OS1-B6
OS1-B6

3. Ssecondary side voltage injection
Figure 3.3 Connection CL + CHL [17]
The Tan Delta test was carried out with Omicron CP 100
and CP TD 1. The test method is by injection of voltage on
the primary and secondary sides by short circuiting the HV
and LV side windings of the transformer.
H. Dielectric Frecuency Respone Test
Figure 3.4 Logarithmic analysis flow chart [18]
Frequency Response Dielectric Testing was carried out
with the Omicron Dirana Analyzer. The test method is by
short circuiting the winding on the HV and LV sides of the
transformer. The results of the test are in the form of a power
dissipation curve against frequency.
IV. RESULT AND ANALYSIS
A. Insulation Resistance and Polarity Indeks
Table 4.1 BAT.12 index polarization test results
Table 4.2 BAT.12 Insulation Resistance test results
Table 4.3 PI Standard IEEE C57.125 – 2013 [20]
By using the IEEE C57.125 – 2013 standard, the
provisions for the measurement results are as follows: The
polarization index value is 2.37 in the very good category.
Rmin : Minimum insulation resistance in MΏ
C : Constant 1.5 for transformer at 20°C
30 for no description.
E(KV) : Working Voltage (F-F if connected to delta and F-
N if connected to star)
KVA : Transformer Rating Capability
(Reference IEEE C57.125)
Rmin = 1,5 x 155∕ √(177000)
= 0,552 MΏ
This value is the minimum insulation resistance when
measured in oil temperature conditions of 20°C, because the
oil temperature conditions are at 30°C, the BAT.12
transformer maintenance manual standardization table is used.
Based on the transformer maintenance guide BAT.12 in
Appendix III that the minimum measurement results at a
lubricating oil temperature of 30ºC are 200 MΏ or 0.2 GΏ,
with these standards the insulation resistance of the HV-LV
transformer is still in good condition.
B. Tan Delta Test
In the tan delta injection test on the primary side, the
injected voltage is 10 KV constant with a constant frequency
of 50 Hz. Calculation of tan delta manually can be calculated
using the following equation:
S =
𝑉2
𝑍
…………………………. (1)
Z =
𝑉2
𝑆
…………………………. (2)
Xc =
𝑉2
𝑄
…………………………. (3)
To Determine Xc :
Xc =
1
𝑊𝐶
…………………………. (4)
So that the formula Xc is obtained as follows :
Q =
𝑉2
𝑋𝑐
…………………………. (5)
Q =
𝑉2
1
𝑊𝐶
…………………………. (6)
Q = 𝑉2
𝑊𝐶 .…………………………. (7)
Dimana W = 2ℼf
Then the Tan delta formula is as follows :
tan 𝛿 =
𝑃
𝑄
…………………………. (8)
Table 4.4 Tan delta test results on the primary injection
BAT.12 transformer
Based on equation (8), manual calculations can be
performed as a calculation factor correction, as follows:
 CH + CHL
tan𝛿=
2,50474
(90002)(2𝑥3,14𝑥50)(28875,2𝑥10−12)
x100%
= 0,2762%
Measured Value = 0,2761
Calculated Value = 0,3410
Deviation = 0,649
OS1-B6
OS1-B6

4. power factor measurement is rounded to the value of CH
+ CHL = 0.3
 CL
tan𝛿=
1,58749
(90002)(2𝑥3,14𝑥50)(18754,3𝑥10−12)
x100%
= 0,3328%
Measured Value = 0,2694
Calculated Value = 0,3328
Deviation = 0,6340
power factor measurement is rounded to the value of CL
= 0.3
 CLH
Sfaslna
tan𝛿=
0,92553
(90002)(2𝑥3,14𝑥50)(10121,2𝑥10−12)
x100%
= 0,3595%
Measured Value = 0,2911
Calculated Value = 0,3595
Deviation = 0,6840
power factor measurement is rounded to the value of CLH
= 0.3
Table 4.5 ((IEEE C.57 2013) maximum DF on transformer
winding [20]
Table 4.6 (IEEE std 62 - 1995) Criteria for standard DF
values of transformer windings [21]
Based on data comparison both in measurement and
calculation with IEEE standards, the tan delta value in
condition 1 (≤0.5%) with the assessment results is still in
good condition.
Meanwhile, if the measured and calculated data will be
applied to standard measurements based on the
manufacturer's maintenance manual in Appendix III, namely
with a temperature of 30ºC, then the minimum value in the
good category is 5/100 = 0.05. However, this standard cannot
be used as a reference considering the condition of BAT.12
is not a new transformer. So that the author's recommendation
for the results of measuring the tan delta of the BAT.12
transformer is still in good condition.
C. Dielectric Frecuency Respone Test
Figure 4.1 Dielectric Frequency Response test results on
CHL
Figure 4.2 The results of the Dielectric Frequency
Response test on CH
Figure 4.3 Dielectric Frequency Response test results on
CL
Moisture content in the CHL transformer cellulose inter
winding in the "dry" category was 1.2% and the oil
conductivity in the "good" category was 6.7 pS/m. In the CH
inter winding test the moisture content in cellulose was 1.5%
thus CH inter winding was included in the "dry" category.
And for oil conductivity of 6.7 pS/m it is in the "good"
category. And in the inter winding CL moisture content test
on cellulose of 1.0%, thus CL inter winding is included in the
"dry" category. And for oil conductivity of 6.3 pS/m it is in
the “good” category.
OS1-B6
OS1-B6

5. By comparing the measurement results with the standards
used, namely IEC 60422 and IEC 61620, the winding
insulation quality from the dielectric frequency response test
is good.
ACKNOWLEDGMENT
The author would like to thank all parties, especially
Trisakti University and PT PLN Indonesia Power, who have
provided advice and support so that this research can be
carried out.
REFERENCES
The template will number citations consecutively within
brackets [1]. The sentence punctuation follows the bracket [2].
Refer simply to the reference number, a
[1] Basic Power Factor Theory and Apparatus Testing, Doble Engineering
Company, 2003
[2] Rickley, A.L, Clark, R.E, Power Factor versus Temperature
Characteristics of Modern power-Transformer Insulation, Doble
Engineering Company
[3] [3.] I Made Indra Wijaya. Characteristics of the corona and breakdown
voltage of insulating oil on needle-plate electrode configurations. 2008.
ITS.[Online].Available:http://lodien33.blogspot.com/2012/06/kartuist
ik-korona-dantangan.html
[4] Gilbert, Norbert E, Power Factor versus Temperature Relationships for
Oil-Filled Power Transformers, Doble Engineering Company.
[5] Bushing Diagnostic and Conditioning, ABB.
[6] “Center Tapped Transformer,“ components 101, 2018. [Online].
Available : https://components101.com/transformers/12-0-12-center-
tapped-transformer
[7] Harlow I, James H, Electrical Power Transformer Engineering, 2004,
CRC Press LLC.
[8] Maintenance Manual Transformer, Tj. Priok CCCP, Marubeni
Corporation.
[9] "Types of Transformers (Transformers), " Electronics Engineering.
[On line]. Available : https://teknikelektronika.com/tipe-tipe-
transformer-trafo/
[10] Kind, Deter 1993. Introduction to high voltage experimental
techniques: ITB Bandung.
[11] “Determination of Rating Current Transformer (CT), “ Tharus Blog,
2014.[Online].Available.https://cetarus.wordpress.com/2014/09/30/pe
nentuan-rating-current-transformer-ct/
[12] “Voltage Transformers,” Aria Theonata, 2010. [Online]. Available :
http://ariyatheonata.blogspot.com/2010/06/transformer-tetangan.html
[13] M. Koch, S. Tenbohlen, M. Krüger and M.Puetter.2011, “Advanced
Insulation Diagnostic byDielectric Spectroscopy” , Ljubljana,
Slovenia.
[14] M. A. Muzar and M. Syukri, "Analysis of the Influence of Temperature
Due to Loading on the Age Loss of Power Transformers at Lambaro
Substations," vol. 3, p. 8. 2018.
[15] L. Abidin, "Dissipation Factor Testing on Transformers with Jumpers
and without Jumper Bushings," Electrical Energy, vol. 11, no. 2, p.
189–196, Dec 2019, doi: 10.33322/energi.v11i2.762.
[16] "safe work instructions for operating CPC 100 for testing tan delta
winding transformers," PT. Citra Wahana Sekar Clothing.
[17] "Measurement of Factor Dissipation (tan d), " PT.PLN (Persero),
Maintenance Officer TrainingPT PLN (Persero) Distribution and Load
Control Center Java Bali, 2003.
[18] “Transformer Diagnostic Measurment, ” Omicron Demonstration ,
2012.
[19] PT. PLN, “MANAGEMENT GUIDEBOOK FOR POWER
TRANSFORMERS,” Attachment to the Decree of the Board of
Directors. PT. PLN, 2014.
[20] T. C. of the I. P. Energy Society, “IEEE Guide for Diagnostic
FieldTesting of Fluid-Filled PowerTransformers, Regulators,
andReactors,” 2013, IEEE.
[21] Power System Instrumentation and Measurements Committee of the
IEEE Power Engineering Society, “IEEE Guide for Diagnostic Field
Testing of Electric Power ApparatusÑ Part 1: Oil Filled Power
Transformers, Regulators, and Reactors,” prsented on IEEE, 1995.
OS1-B6
OS1-B6