The dissolved gas analysis (DGA) is an effective method for detecting incipient faults in immersed oil power transformers. In this paper, we investigate the DGA methods and employ the ANSI/IEEE C57.104 standards (guidelines for the interpretation of gases generated in oil-immersed transformers) and IEC Basic Gas Ratio method to design a heuristic power transformer fault diagnosis tool in practice. The proposed tool is implemented by a MATLAB program and it can provide users a transformer diagnosis result. The user keys in the data of H2, CH4, C2H2, C2H4, and C2H6 gases dissolved from the immersed oil transformer’s insulating oil measured by ASTM D3612. The analyzed results will be represented in texts and figures. The real measured data of the transformer oil were taken from Taiwan Power Company substations to verify the validation and accuracy of the developed diagnosis tool.
Immersed-oil power transformers in the power system play an important role as voltage conversion. The transformer’s insulating oil can cool the transformer down and strengthen the ability of power supply. A transformer fault will cause electricity interruption and may result in a serious problem. Therefore, detection of transformer’s fault is very important task. The insulating oil gas analysis (DGA) is a good way to diagnose the transformer fault and has been widely used by many power companies in the world. This is because that the insulating oil analysis can predict incipient faults via the analysis of the gases generated from the insulating oil. If the transformer’s fault can be diagnosed accurately, and then the transformer will be well maintained, the electricity interruption caused by transformer’s fault can be avoided.
The insulating oil measurement is via chromatography instrument (ASTM D3612). The measured data of nine kinds of gas, namely Ethane (C2H6), Hydrogen (H2), Methane (CH4), Carbon Dioxide (CO2), Ethylene (C2H4), Acetylene (C2H2), Carbon Monoxide (CO), Nitrogen (N2), and Oxygen (O2) can be obtained [
Total Combustible Gases are made up of H2, CH2, C2H6, C2H4, C2H2 and CO, and its definition as follows, is shown in formula (1) (unit ppm):
The immersed oil transformer’s insulating oil along with the transformer operating time and the measured of the cyclical time has made vital relations with its life-span, however its increase value on IEEE C57.104 standard, as shown in formula (2):
where, R is increase of the TCG value (a milliliter/day), ST is testing value, SO is previous value, V is measured from the transformer’s volume as well as T is measured from the duration of days. So the quantity of the TCG, rely on the R’s value which is classified “Normal”, “Attention”, “Abnormal”, and “Danger” etc., four kinds of symptom shown in
Be based on Dissolved Gas Analysis (DGA), the value of insulating oil has been diagnosed either normality or abnormality in the body of transformer. In recent years, a lot of techniques have been developed to predict diagnosis for the transformer latent failure points by the gas content, such as the Key Gas method, Duval triangle method as well as Dornenberg method, Roger method, Liner SVM diagnosis etc., this paper took the Diagnosis of IEC Basic Gas Ratio method and ANSI/IEEE Standard Rule to design a Transformer Fault Diagnosis Tool by the MATLAB program which described next sections below.
The IEC Basic Gas Ratio method uses 3 sets gas ratios C2H2/C2H4, CH4/H2, and C2H4/C2H6 as base to engage in diagnosis. Each ratio is distinguished 6 fault’s conditions such as Partial discharges, Discharge of low energy, Discharge of high energy, Thermal fault t < 300˚C, Thermal fault 300˚C < t < 700˚C, and Thermal fault t > 700˚C. The result according to IEC method is shown in
According to the Diagnosis of Specification for ANSI/IEEE C57.104 Standard, the anomalous properties values
Case | TCG | Increase | Again Measures Duration | Suggestion |
---|---|---|---|---|
Case 1 | ≤720 | >30 | Month | Normal |
10 - 30 | Season | Normal | ||
<10 | Year | Normal | ||
Case 2 | 721 - 1920 | >30 | Month | Attention |
10 - 30 | Month | Attention | ||
<10 | Season | Attention | ||
Case 3 | 1921 - 4630 | >30 | Week | Abnormal |
10 - 30 | Week | Abnormal | ||
<10 | Month | Abnormal | ||
Case 4 | >4630 | >30 | Day | Danger |
10 - 30 | Day | Danger | ||
<10 | Week | Danger |
Case | Characteristic Fault | C2H2/C2H4 | CH4/H2 | C2H4/C2H6 |
---|---|---|---|---|
PD | Partial Discharges | NS1 | <0.1 | <0.2 |
D1 | Discharge of Low Energy | >1 | 0.1 - 0.5 | >1 |
D2 | Discharge of High Energy | 0.6 - 2.5 | 0.1 - 1 | >2 |
T1 | Thermal Fault t < 300˚C | NS1 | >1 but NS1 | <1 |
T2 | Thermal Fault 300˚C < t < 700˚C | <0.1 | >1 | 1 - 4 |
T3 | Thermal Fault t > 700˚C | <0.22 | >1 | <4 |
Note: NS1 stand for No Significance.
from decomposition of the insulating oil were shown in
The diagnosis tool of insulating oil can be diagnosed by well usage of different method and specification after incorporating some kinds of human experience. The flow chart of the proposed diagnostic method is shown in
For more simple, precise, and effective to diagnose, I read lots of diagnosis’s approach of transformer’s insulating oil which were such good paper as “Support Vector Machine-Based Fault Diagnosis of Power Transformer” [
The accuracy of interpretable plots by concept of digital rule establishes during implementation after input the concentration of H2, CH4, C2H6, C2H4, and C2H2. This paper designs a set of highly fast way to diagnose of transformer incipient fault by IEC Basic Gas Ratio and the Standard of ANSI/IEEE C57.104 diagnosis method. From the report’s from the obtained texts of the ANSI/IEEE C57.104 standard diagnosis and the figure of IEC Basic Gas Ratio to judge what was in body of transformer.
Name | Content Value | Property | Name | Content Value | Property |
---|---|---|---|---|---|
H2 | >1801 | Danger | CH4 | >1001 | Danger |
>701 | Abnormal | >401 | Abnormal | ||
>101 | Attention | >121 | Attention | ||
<100 | Normal | <120 | Normal | ||
C2H6 | >151 | Danger | C2H4 | >201 | Danger |
>101 | Abnormal | >101 | Abnormal | ||
>66 | Attention | >51 | Attention | ||
<65 | Normal | <50 | Normal | ||
C2H2 | >35 | Danger | C2H2 | >2 | Attention |
>10 | Abnormal | < 1 | Abnormal |
On March 22nd, 2012 Taiwan Power Company Ba Dou D/S # 4DTr’s insulating oil, inspected these gas component content Hydrogen, Methane, Ethane, Ethylene, and Acetylene data are described (in
Keeping in mind when computers work on digital gate that high or low voltage is considered as 1 or 0. So that using these high or low data is represented for 1 or 0. Electronic circuits must be designed to manipulate these
Date | H2 | CH4 | C2H6 | C2H4 | C2H2 |
---|---|---|---|---|---|
2012.03.22 Before Repair | 100 | 149 | 41 | 401 | 5.3 |
2012.05.21 After Repair | 7 | 6 | 44 | 18 | 0 |
Diagnosis for ANSI/IEEE C57.104 Standard |
---|
**H2 == Normal |
**CH4 == Attention |
**C2H2 == Normal |
**C2H4 == Danger |
**C2H6 == Normal |
Diagnosis for IEC Basic Gas Raito |
**C2H2/C2H4 == Normal |
**CH4/H2 == Discharge of High Energy |
**C2H4/C2H6 == Temperature Fault > 700˚C |
Name/Ratio | Result of Diagnosis | Digital Symbol | Result of Diagnosis | Digital Symbol |
---|---|---|---|---|
H2 | Danger | 1 | Abnormal, Attention, Normal | 0 |
CH4 | Danger | 1 | Abnormal, Attention, Normal | 0 |
C2H6 | Danger | 1 | Abnormal, Attention, Normal | 0 |
C2H4 | Danger | 1 | Abnormal, Attention, Normal | 0 |
C2H2 | Danger | 1 | Abnormal, Attention, Normal | 0 |
C2H2/C2H4 CH4/H2 C2H4/C2H6 | Partial Discharges | 1 | ||
Discharge of Low Energy | 1 | |||
Discharge of High Energy | 1 | |||
Thermal Fault t < 300˚C | 1 | |||
Thermal Fault 300˚C < t < 700˚C | 1 | |||
Thermal Fault t > 700˚C | 1 |
positive and negative pulses into meaningful logic (in
To ensure power supply stable quality and safety, the gases of the insulating oil was shown by Truth
Taking some case (in
As we know that, how to detect the transformer fault quickly and accurately is not an easy job. In this paper, we have investigated the DGA methods and developed a quick method to diagnose the malfunction of power transformers by using ANSI/IEEE C57.104 diagnosis specification and IEC Basic Gas Ratio method. We have developed the transformer fault diagnosis tool by a MATLAB program. The real measured data of the transformer oil taken from Ba Dou D/S # 4DTr transformer of Taiwan Power Company are used to verify the validation and accuracy of the developed diagnosis tool. This tool will be useful for engineers and technicians who are in charge of transformer’s maintenance.
Date | H2 | CH4 | C2H6 | C2H4 | C2H2 | C2H2/C2H4 | C2H4/C2H6 | CH4/H2 | OUT |
---|---|---|---|---|---|---|---|---|---|
2012.3.22 | 0 | 0 | 0 | 1 | 0 | 0 | 1 | 1 | 1 |
2012.5.21 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 1 | 0 |
Diagnosis for ANSI/IEEE C57.104 Standard |
---|
**H2 == Normal |
**CH4 == Normal |
**C2H2 == Normal |
**C2H4 == Normal |
**C2H6 == Normal |
Diagnosis for IEC Basic Gas Raito |
**C2H2/C2H4 == Normal |
**CH4/H2 == Discharge of Low Energy |
**C2H4/C2H6 == Partial Discharge |
Date | H2 | CH4 | C2H6 | C2H4 | C2H2 | CO | TCG |
---|---|---|---|---|---|---|---|
C1 (2007.05.10) | 44 | 41 | 88 | 7 | 10.1 | 57 | 247 |
C2 (2010.09.05) | 140 | 54 | 79 | 21 | 53.8 | 35 | 388.1 |
C3 (2011.08.03) | 181 | 74 | 84 | 58 | 51.4 | 171 | 619 |
C4 (2011.12.26) | 935 | 271 | 116 | 330 | 420 | 128 | 2200 |
C5 (2012.05.10) | 239 | 346 | 78 | 787 | 24 | 312 | 1786 |
C6 (2012.07.08) | 48 | 694 | 356 | 1077 | 0.4 | 36 | 2211 |
C7 (2013.09.23) | 133 | 211 | 66 | 384 | 1.9 | 411 | 1207 |
Case/Name | Diagnosis for ANSI/IEEE C57.104 | Diagnosis for Program out | Repair State | |||||||
---|---|---|---|---|---|---|---|---|---|---|
H2 | CH4 | C2H6 | C2H4 | C2H2 | C2H2/C2H4 | C2H4/C2H6 | CH4/H2 | |||
C1 | 0 | 0 | 0 | 0 | 0 | 1 | 0 | 1 | 0 | N |
C2 | 0 | 0 | 0 | 0 | 1 | 1 | 1 | 1 | 1 | Ac |
C3 | 0 | 0 | 0 | 0 | 1 | 1 | 1 | 0 | 1 | Ac |
C4 | 0 | 0 | 0 | 1 | 1 | 1 | 1 | 1 | 1 | Pd |
C5 | 0 | 0 | 0 | 1 | 0 | 0 | 1 | 1 | 1 | Ac |
C6 | 0 | 0 | 1 | 1 | 0 | 0 | 1 | 1 | 1 | Pd |
C7 | 0 | 0 | 0 | 1 | 0 | 0 | 1 | 1 | 1 | Pd |
Symbols: N (Normal), Ac (Arc), Pd (Partial Discharge). 1 (Program out for 1), 0 (Program out for 0), C1 (Case1), C2 (Case2), C3 (Case3), C4 (Case4), C5 (Case5), C6 (Case6), C7 (Case7).
The author would like to thank that the relevant information of this paper was provided by the department of the supply, Tai Pei branch supply, and Research Institute of Taiwan Power Company.