Examining the Properties of Neem Oil, Sunflower Oil and Mahua Oil with Antioxidants and Nano Powders for Power Transformer

In the newfangled world, electrical energy is the most important thing, and we cannot live without it. The recent research has predominated that petroleum by-products are available only for a few hundred years. This paper is especially clear to meet out that. After some years, the mineral oil in the transformer needs to be changed due to its degradation of insulation. The mineral oil used in the transformer acts as insulation as well as cooling purpose. The used mineral oil can be recycled by adding some additives for reuse purpose. In this paper, the oil chosen is neem oil, sunflower oil and mahua oil and it is treated with antioxidants and nano powders. “Breakdown voltage, flash point, fire point, acidity, and viscosity are measured in consonance with standards”. To reduce the oxidation stability natural and synthetic antioxidants are preferred, and Nano powders are also used for improving the properties of the oil. Synthetic antioxidants such as Beta Carotene and TBHQ and selenium are preferred as natural antioxidants. Selenium is used. Before and after the addition of antioxidants and nano powders the measurements were done. By doing this analysis, the transformer oil is used for reuse purpose and it has a longer lifetime. After antioxidants and Nano powders are added, the property of the transformer oil is increased.


Background
Transformer oil is used for insulation purpose. It is obtained by petroleum by-products and so it is named 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 that is it acts as a coolant. It also helps in another two reasons, one to preserve the core and winding as these are fully immersed inside oil, and next preventing the direct contact of atmospheric oxygen [1].
In the transformer there are two types of transformer oil are used. They are i. Paraffin-based transformer oil ii. Naphtha-based transformer oil Naphtha oil gets more easily oxidized than Paraffin oil. Sludge formation present in the naphtha oil is more when compared to paraffin oil [2]. Thus sludge is not formed in the bottom of the transformer and does not disturb the cooling system of the transformer. But in the case of Paraffin oil although the oxidation rate is lower. Although Paraffin-based oil has a disadvantage because we use it because of its easy availability. High pour point problem is found in paraffinic oil due to the wax content, but this does not affect its use due to warm climate condition of India [3][4][5].
degeneration is stated to have been caused by harmful molecules called free radicals. Free radicals are molecular fragments having one (or) more unpaired electrons [6][7][8].

Nanopowders
Nanopowders are defined as powdered materials with individual particles having sizes fewer than 100 nanometers. The particles present in the nanopowders are very smaller when compared with the wavelength of visible light [9,10]. The smaller size of nanopowders gives them an extremely high surface area to volume ratio that results in extraordinary properties like extreme strength. Below formula is used to calculate the number of nanoparticles to be added with the oil for preparation of nanofluids: Weight of the nanoparticles density * Volume / Volume Fraction (1) The above euation A represents the equation for calculating the nano power weight added to the oil samples.

Methodology
The methodology includes standards, measurements, sample description and sample preparation. Sample description and sample preparation are done for neem oil, sunflower oil and mahua oil.

Standards
The measurement of oil properties like Viscosity, Breakdown Voltage, Acidity, Flash and Fire pointis carried out according to IEC and ASTM standards [11][12][13]. The method standard used and standard values are given in Table 1.

Measurement of Breakdown Voltage
The dielectric strength of transformer oil is also known as the Breakdown voltage of transformer oil. The low value of BDV indicates the presence of moisture content and conducting substance in the oil. In BDV kit, oil is kept in a pot in which one pair of the electrode is fixed with a gap of 2.5mm between them [14]. By raising the voltage measurement is taken 3 to 5 times in the same sample of oil. The breakdown Voltage testing kit is shown in Figure 1.

Measurement of Viscosity
Technically the viscosity of the oil is a measure of the oil resistance to shear. Viscosity is more commonly known as resistance flow. The measurement of viscosity the resistance to flow between the individual layers [15]. A high viscosity implies high resistance to flow while a low viscosity indicates a low resistance to flow. Viscosity varies inversely with temperature [21]. The Redwood viscometer is shown in Figure 2.

Measurement of Flash and Fire Point
Flashpoint of a volatile liquid is the lowest temperature at which it can vaporize to form an ignitable mixture in air. Measuring a liquid's flashpoint requires an ignition source [16]. The flash point is often used as one descriptive characteristic of liquid fuel, but it also used to describe liquids that are not used intentionally as fuels [22].
The temperature at which the vapor continues to burn after being ignited is called fire point. It is the lowest temperature at which, on further heating beyond the flash point the sample will support combustion for 5 seconds. The Pensky Martins Closed Cup apparatus is shown in Figure 3.
Uma Devi Sankarasubbu and Senthil Kumar Suburaj: Examining the Properties of Neem Oil, Sunflower Oil and Mahua Oil with Antioxidants and Nano Powders for Power Transformer

Measurement of Acidity
The acidity is calculated by using colour chart method. The colour code for determining the acidity is shown in figure 4. 1.1mlof the oil sample and 1ml of ethyl alcohol are mixed and after shaking well 1ml of sodium carbonate is added [17]. After re shaking well 5 drops of universal indicator solution is added and mixed well. By using the colour chart acid content in oil sample is found in KoH/g.

Sample Description
The vegetable oil is mixed in different proportions like neem oil, sunflower oil and mahua oil with different antioxidants and nanopowders [18][19][20]. Samples prepared using neem oil with antioxidants and nanopowders are shown in Table 2. Samples prepared using sunflower oil with antioxidants and nanopowders are shown in Table 3. Table 3. Sample Combination Using Sunflower Oil.

Sample Preparation
The neem oil, sunflower oil and mahua oil of 500 ml is mixed with the single and combination antioxidants like TBHQ, selenium and beta carotene and nanopowders like aluminium nitride and carbon nanopowder and mixed using magnetic stirrer unit for 20 to 30 minutes under 750 RPM.

Result and Discussion
The results are obtained from the combination of neem oil, sunflower oil and mahua oil blended with regenerative materials. The critical parameters of the samples are improved by using this.

The Blending of Neem Oil with Regenerative Materials
The results are obtained from the experiment are presented here in Table 5. The evaluation of critical parameters of Neem Oil by way of different proportions through the addition of regenerative materials like TBHQ, Selenium, Beta Carotene, Aluminium Nitride and Carbon Nanopowder were made.             Figure 10 shows the comparison graph of Acidity for different samples using neem oil.
From the Investigations of the Acidity values of the neem oil sample the following inference were made: 1. The acidity of the oil sample gets reduced from 0.6KoH/g to 0.05KoH/g. 2. The acidity value for Sample 10 that is when carbon nano powder is low.

The Blending of Sunflower Oil with Regenerative Materials
The results are obtained from the experiment are presented here in Table 6. The evaluation of critical parameters of Neem Oil by way of different proportions through the addition of regenerative materials like TBHQ, Selenium, Beta Carotene, Aluminium Nitride and Carbon Nanopowder were made.   Figure 11 shows the comparison graph of breakdown voltage for different samples using sunflower oil.
From the Investigations of the breakdown Voltage of the sunflower oil sample the following inference were made: 1. Breakdown Voltage of the sunflower oil sample increases when Antioxidants and nano powders are added.

When Carbon nano powder is added the Breakdown
Voltage (Sample 10) is higher when compared with other. 3. The breakdown voltage is increased from 21.3kV to 41kV.           Figure 16 shows the comparison graph of Acidity for different samples using sunflower oil.
From the Investigations of the Acidity values of the sunflower oil sample the following inference were made: 1. The acidity of the oil sample gets reduced from 0.7KoH/g to 0KoH/g. 2. The acidity value for Sample 4, 5 and 11 that is when beta carotene, selenium and beta carotene andwhen carbon and aluminium nano powder is added is low.

The Blending of MahuaOil with Regenerative Materials
The results are obtained from the experiment are presented here in Table 7. The evaluation of critical parameters of Neem Oil by way of different proportions through the addition of regenerative materials like TBHQ, Selenium, Beta Carotene, Aluminium Nitride and Carbon Nanopowder were made.              Figure 22 shows the comparison graph of Acidity for different samples using mahua oil.
From the Investigations of the Acidity values of the mahua oil sample the following inference were made: 1. The acidity of the oil sample gets reduced from 0.6KoH/g to 0.05KoH/g. 2. The acidity value for Sample 3 and 9 that is when selenium and when beta carotene, selenium and TBHQ is added is low.

Regenerative Materials
The evaluation of critical parameters of the three oils by way of different proportions through the addition of regenerative materials like TBHQ, Selenium, Beta Carotene, Aluminium Nitride and Carbon Nanopowder were made are discussed below.  From the Investigations of the breakdown Voltage of the three oil sample the following inference were made: 1. Breakdown Voltage of the sunflower oil when mixed with carbon nano powder is high. 2. For all the oils the breakdown voltage is higher when antioxidants and nano powder is added.        Figure 27 shows the comparison graph of Viscosity for different samples using three oils at 90°C.
From the Investigations of the Viscosity values of the three oil sample the following inference were made: 1. At 40°C, the sample 10 when carbon nano powder is added the viscosity value reduces. 2. At 90°C, the sample 10 when carbon nano powder is added the viscosity value reduces. 3. Usually lower the viscosity value gives the better oil sample.  Figure 28 shows the comparison graph of Acidity values for different samples using three oils.
From the Investigations of the Acidity values of the three oil sample the following inference were made: 1. The acidity of the oil sample of 4, 5 and 11 is very low for sunflower oil. 2. Usually sunflower oil has lower acidity value.

Conclusion
Transformers are the most important component in the electrical power system. The analysis is used to establish the reclamation of vegetable oil. Moreover, the combination of antioxidants (TBHQ, Selenium and Beta Carotene) and Nano Powders (Aluminium Nitride and Carbon Nano Powder) is a proven technique for enhancing the properties of vegetable oil. The important features of using antioxidants and nanopowders combination during experimentation apart from enhancement property are very less carbon content during the breakdown. After the addition of regenerative materials, the parameters such as BDV, Viscosity, Flash point and Fire point gets increased. This approach is also useful in avoiding harmful disposal of used transformer oil to the environment. The overall investigation concludes that the enhanced oils using regenerative materials, nanopowders and antioxidant is an appropriate solution for potential reuse in power transformer.