scholarly journals Breakdown Voltage Characteristic Of Mineral Oil In Power Transformer 16 Mva Updl Semarang

Author(s):  
Setyo Adi Nugroho ◽  
Setyo Aji Priambodo

The transformer is one of the most important equipment in the electric power system, which is to distribute power from power plants to the load centers by step-up or step down the voltage. Transformer is expect to have a high level of reliability. One of the causes of damage to the power transformer is its insulation system. Mineral oil is an insulator that is widely used in power transformers. One of the important parameters in oil type insulation is the breakdown voltage value, the greater breakdown voltage value, as better the insulation quality. In this research, a breakdown voltage test is carried out on a Shell Diala B transformer oil type regarding the IEC 60156-95 standard. The results showed a breakdown voltage in the power transformer oil at UPDL Semarang of 49.2 kV. These results have met the feasibility standard of transformer oil, based on the IEC standard the value of breakdown voltage of liquid type insulation is 30 kV.

Author(s):  
Dayyala Ravi

Power transformer plays a significant role in the entire power transmission network; thus, transformer protection requires more attention for fault free electric supply. when the mineral oil and insulation inside the transformer is subjected to high thermal and electrical stresses, gases are created by the decay of mineral oil and cellulose. Different gases create different faults, Identification of faults inside the power transformer before they occur reduces its failure rate during its service period. For Knowing the fault condition of power transformer, Dissolved Gas Analysis (DGA) is proven to be as accurate method based on combination of concentration of gases like CO, CO2, H2, C2H6, C2H4, C2H2 etc., Dissolved gas analysis is the most important test in determining the fault condition of a transformer and it is the first indicator of a problem and can identify deteriorating insulation and oil, overheating hot spots, partial discharge and arcing. For developing this DGA Techniques, the MATLAB GUIDE interface can be used for making easy interaction between the user and software developed. This software is designed using some conditional statements and logical functions to get the type of faults in transformers based on the concentration of gases in transformer oil. The faults in transformer using dissolved gases analysis are detected using methods such as key gas, Roger’s methods, IEC ratio, Doernenburg ratio, Duval triangle and the Combined DGA methods. In this paper, these four methods of dissolved gas analysis (DGA) are presented and explained briefly.


2018 ◽  
Vol 2 (2) ◽  
pp. 25
Author(s):  
A.A.N. Amrita ◽  
W.G. Ariastina ◽  
I.B.G. Manuaba

Power transformer is very important in electric power system due to its function to raise or lower the voltage according to its designation. On the power side, the power transformer serves to raise voltage to be transmitted to the transmission line. On the transmission side, the power transformer serves to distribute the voltage between the main substations or down to the distribution voltage. On the distribution side, the stresses are channeled to large customers or lowered to serve small and medium customers. As the power transformer is so importance, it is necessary to protect against disturbance, as well as routine and periodic maintenance, so that the power transformer can operate in accordance with the planned time. Some factors that affect the duration of the power transformer is the ambient temperature, transformer oil temperature, and the pattern of load. Load that exceeds the maximum efficiency of the transformer which is 80% of its capacity will cause an increase in transformer oil temperature. Transformer oil, other than as a cooling medium also serves as an insulator. Increasing the temperature of transformer oil will affect its ability as an isolator that is to isolate the parts that are held in the transformer, such as iron core and the coils. If this is prolonged and not handled properly, it will lead to failure / breakdown of insulation resulting in short circuit between parts so that the power transformer will be damaged. PLN data indicates that the power transformer is still burdened exceeding maximum efficiency especially operating in the work area of PLN South Bali Area. The results of this study, on distribution transformers with different loads, in DS 137, DS 263 and DS 363, show that DS 363 transformer with loading above 80% has the shortest residual life time compared to DS 263 and DS 137 which loading less than 80%.


Author(s):  
Muhammad Bin Yahya ◽  
Fatin Amirah Binti Amirrazli

<p>This paper investigates the suitability of vegetable oils to replace mineral oil based on its AC breakdown voltage, partial discharge and viscosity. The purpose of the study is to analyze the effect of the nanofluids containing SiO<sub>2</sub> nanoparticle in vegetables oils; namely, Coconut oil and Palm oil. A nanofluid is a fluid containing nanoparticles. However, the precise effects on the electrical properties is still uncertain. For decades, transformers use petroleum-based mineral oil because of its good dielectric properties and cooling capability. Coconut oil (CO) and Palm oil (PO) are thought to be   suitable alternatives to replace mineral oil as transformer oil as they are sustainable and available in plenty as natural resources.  It was obtained in this study that the breakdown voltages of these raw oils have fulfilled the standard specifications of good insulating liquid. However, the addition of SiO<sub>2</sub> did not improve the AC breakdown voltage and viscosity of coconut oil and palm oil at different temperatures. However, the addition of SiO<sub>2</sub> gave positive results in the values of partial discharges in which the presence of the nanoparticles has greatly reduced the mean volume of partial discharges for both coconut oil and palm oil.</p>


Author(s):  
Imran Sutan Chairul ◽  
Sharin Ab Ghani ◽  
Norazhar Abu Bakar ◽  
Mohd Shahril Ahmad Khiar ◽  
Aminur Hazieq Zulkefli ◽  
...  

This paper described in-laboratory oil regeneration process of aged transformer oil using adsorbent; Fuller’s earth. The niche of this paper is the usage of real aged transformer oil taken from an 11kV/433V in-service power transformer made by ACEC Transformer in 1986. The regeneration process is achieved by forcing a mixture of aged transformer oil and Fuller’s earth through a filter paper with the aid of a vacuum pump, hence producing reclaimed transformer oil. This oil was then inserted in an amber glass bottle, blanketed with nitrogen, tightly sealed, and labelled. To test the effectiveness of Fuller’s earth as adsorbent, parameters of Dissolved Decay Product (DDP) were measured using UV-Visible Spectrophotometer (UV-Vis) by referring to ASTM D6802. In addition, Total Acid Number (TAN) and Breakdown Voltage (BdV) measurement were carried out complying the ASTM D974 and ASTM D1816 respectively. Results of UV-Vis indicated that Fuller’s earth can adsorbed 25.24% of DDP in aged transformer oil. As the DDP decreased, TAN is 84.62% reduced while BdV increased 50%. These findings are parallel with the breakdown voltage mechanism due to acidity emergence. It is proved that Fuller’s earth is effective adsorbent for oil regeneration process.


2021 ◽  
Vol 16 (3) ◽  
pp. 387-394
Author(s):  
Yang Su ◽  
Ming-Hui Liu ◽  
Xu-Hui Kong ◽  
Chen-Jun Guo ◽  
Jiang Zhu ◽  
...  

Power transformer is regarded as one of the crucial part of electrical power transmission and distribution system. The quality of transformer oil can directly affect the operation of the power transformer, and breakdown voltage (BDV) and water content are the two main parameters of transformer oil quality. Monitoring the BDV and water content of transformer oil is considered as an important method to evaluate the safe operation of power systems. This work proposes the measurement of BDV and water content in transformer oil using multi frequency ultrasonic and generalized regression neural network (GRNN). The BDV and water content of all 210 samples were firstly tested according to the traditional testing methods and the multi frequency ultra-sonic technology, separately. And then the 210 samples were randomly divided into training sets and test sets. The obtained multi frequency ultrasonic data were set as the input of GRNN, and the BDV and water content as the output of GRNN. Moreover, the 20-fold-cross-validation was incorporated to obtain the best smoothing factor δ for GRNN. Finally, the GRNN model was trained by the training sets with δ =4.54 and was evaluated with the test sets. All results show that the lower BDV or the higher water content of the sample will cause greater ultrasonic sound attenuation, and the prediction accuracy of the prediction model for BDV and water con-tent in oil is up to 95%. It provides a new method for evaluating the health of transformer oil.


2020 ◽  
Vol 62 (4) ◽  
pp. 222-231
Author(s):  
C Ranga ◽  
A Kumar ◽  
R Chandel

In the present work, a new electrothermal combined stress test cell has been designed and fabricated to conduct accelerated electrothermal ageing. The fabricated test cell includes all possible real working conditions of the transformers. The effects of accelerated electrothermal ageing on the performance of power transformers with thermally upgraded Kraft (TUK), Nomex-910 and Nomex-410 solid dielectrics in conjunction with mineral oil have been investigated. The accelerated electrothermal ageing has been performed for a temperature range of 100°C to 220°C, along with 10 kV electrical stress. Subsequently, several electrical, thermal, mechanical and chemical properties of transformer oil and different paper dielectrics have been determined. It has been observed from the diagnostic test results that Nomex impregnated mineral oil samples have better electrothermal performance as well as oxidation stability when compared to the thermally upgraded Kraft oil samples. Therefore, Nomex insulating materials in conjunction with mineral oil are suggested as alternative solid dielectrics for power transformers in order to achieve better oxidation stability, improved thermal performance for long service runs and reduced operating and maintenance costs. It is envisioned that the present experimental study will be very beneficial to utility managers and end-users of power transformers.


Author(s):  
I. H. Zakaria ◽  
M. H. Ahmad ◽  
Y. Z. Arief ◽  
N. A. Awang ◽  
N .A. Ahmad

Trends in the field of nanomaterial-based transformer oil show most of the conducted works have focused only on the transformer oil-based nanofluids but limited studies on the stability of transformer oil-based nanofluids. Since mineral oil-based nanofluids still can produce the sedimentation, thus the cold-atmospheric pressure plasma method is proposed to functionally modify the Silicon Dioxide (SiO<sub>2</sub>) nanofiller in order to enhance the electrical properties of the mineral oil-based nanofluids. The AC breakdown strength oil samples before and after modification were measured. It was found that the plasma treated nanofluids have higher AC breakdown voltage compared to pure oil and untreated nanofluids. Also, Fourier Transform Infrared (FTIR) Spectroscopy has been used in this study to analyse the physical changes of oil samples. It is envisaged that the added silica nanofiller has significant effect on electrical properties of the transformer oil-based nanofluids which would enable to the development of an improved class of liquid dielectric for the application of power transformer.


2015 ◽  
Vol 1119 ◽  
pp. 175-178 ◽  
Author(s):  
Wittawat Saenkhumwong ◽  
Amnart Suksri

Transformer is one of the major component, which is the most important device in power system. Their lifetime depends upon liquid insulation that help transfer the heat out of its winding inside of transformer. Transformer oil uses mineral oil that is the most commonly used has very slow process on decomposition and non-biodegrade. This paper presents the investigation on breakdown voltage of two types of natural ester oils, including palm oil and soy bean based-on ZnO nanofluids. Nanofluids that use nanoparticles modified by use of surfactant that are suspended by process of sonication. Different fraction of nanoparticles were investigated from 0.1% - 0.5% by weight. The breakdown voltage were measured according to ASTM D877. The voltage breakdown strength increased significantly when nanoparticles were added in oils. The obtained results will enable transformer industry to develop liquid insulation dielectric for use in transformer in the future.


Author(s):  
Siti Sufiah Abd Wahid ◽  
Mohd Fikri Hilmi Mohd Taib ◽  
Yanuar Z. Arief ◽  
Mohd Hafizi Ahmad ◽  
Noor Azlinda Ahmad ◽  
...  

Insulation is one of the most important parts in high voltage apparatus such as power transformer. Most power transformer use liquid insulation material, known as power transformer oil. Petroleum-based oil so called mineral oil has been used for many years as power transformer oil. This is due to its high dielectric field strength, low dielectric loses and good long-term performance. This research work has been carried out to investigate the effect of thermal accelerated ageing on electrical properties for several vegetative-based oils. The oil samples that have been used in this research work are soy bean-based oil (FR3) and commercial palm-based oil (PFAE). As comparison, Hyrax mineral oil has also been investigated. The results revealed that vegetative-based oils have as well as dielectric strength compared with mineral oil.  It was found that the dielectric strength for all oil samples decreased when undergo the thermal accelerated ageing process.


Sign in / Sign up

Export Citation Format

Share Document