TRANSFORMER OIL classifications and specifications
- 3. A transformer is a static device which is used to step up or step down voltages at constant frequency It consists of two coils, that are electrically isolated but magnetically linked The primary coil is connected to the power source and the secondary coil is connected to the load Voltage is stepped up or stepped down proportional to turns ratio The turn’s ratio is the ratio between the number of turns on the secondary (Ns)to the number of turns on the primary (Np). Working principle
- 5. Transformer classification Based on construction Core type Shell type Berry type Based on application Power transformer Distribution transformer Based on cooling Oil filled self cooled Oil fill water cooled Air blast type
- 6. Transformers types based on construction
- 7. Transformers types based on application
- 8. Based on number of turns in the primary and secondary windings and the induced emf. Step-up transformer Step down transformer Step up and Step down Transformer
- 11. Transformer OEMS 11 1. ABB India Corporate Office – Bangalore, Karnataka | Establishment – 1889 2. Siemens India Corporate Office – Mumbai, India | Establishment – 1867 3. Alstom T&D India Corporate Office – Noida, India | Establishment – 1911 4. Transformers & Rectifiers India Ltd Corporate Office – Gujarat, India | Establishment – 1994 5. Kirloskar Electric Company Limited Corporate Office – Bangalore, Karnataka | Establishment – 1946 6. Gujarat Transformers Pvt. Ltd Corporate Office – Gujarat, India | Establishment – 1974
- 12. Transformer Insulating system To provide dielectric strength of the transformer insulation system. To provide efficient cooling. To protect the transformer core and coil assembly from chemical attack. To prevent the build up of sludge in the transformer To quench the arc produced while operation
- 13. Transformer oil classifications NAPTHANIC OIL PARAFFINIC OIL SILICON OIL Transformer Oil Mineral Oil (petroleum product ) Synthetic Oil (Chemical Product)
- 14. Oxidation Inhibitor in mineral oil Mineral insulating oil undergo oxidative degradation process in the presence of oxygen to form acid & sludge. To prevent these process , oxidation inhibitor is used for interrupting process of oxidation and thereby minimize oil deterioration and extend the operating life of the transformer the oil. Depending on the presence of oxidation inhibitor, mineral insulating oil is categorized as – 1. Uninhibited oil 2. Inhibited oil 1. Uninhibited oil New insulating oil as normally refined contains small amounts of certain chemical compounds that act as oxidation inhibitors. 2. Inhibited oil To increase the oxygen inhibitor beyond its natural limit, oxygen inhibitor is added in the oil
- 15. TRANSFORMER OIL SPECIFICATIONS NEW OIL: An unused mineral insulating oils intended to use in transformers for insulation and cooling purpose. IS-335/2018 TYPE I – Specification for Naphthenic new insulating oils. IS-335/2018 TYPE II – Specification for Paraffinic new insulating oils. IEC -60296/2003 – Specification for unused mineral insulating oils for transformers and switchgear. This standard cover both uninhibited and inhibited oils. ASTM – D3487/2000- Standard Specification for Mineral Insulating Oil used in Electrical apparatus. This standard also covers both uninhibited and inhibited oils.
- 17. HP TRANSFORMER OIL SPECIFICATIONS IS:335-2018 TYPE II UNINHIBITED (New Oil) • Appearance ------------ • Density at 29.5˚C (Max) • Kinematic Viscosity (Max) 1) at 0˚C (Max)--------- 2) at 40˚C (Max)----------- • IFT at 27˚C (Min) --------- • Flash Point (Min) --------- • Pour Point (Max) --------- • Corrosive Sulphur ------- • PCA Content % (Max) • PCB Content, mg/kg • Clear and transparent • 0.89 g/cm2 • 1800 cSt • 15 cSt • 0.04 N/m (old, NA) • 135˚C • -10˚C • Non-corrosive • 3 • Non Detectable (<2)
- 18. TRANSFORMER OIL SPECIFICATIONS IS:335-2018 TYPE II UNINHIBITED (New Oil) • Electric Strength (BDV) 1) New unfiltered Oil(Min) 2) After filtration (Min) • Dielectric dissipation factor (tan δ)at 90˚C(max) • Oxidation Stability 1) Total Acidity (max) 2) Sludge (max) • DBDS, mg/kg • Metal Passivator additive • 2 Furfurals & related compound, mg/kg • 30 KV (rms) • If the above value is not attained, the oil shall be filtered to 60 KV (rms) • 0.005 • 1.2 mg KOH/gm • 0.8 % by weight • Non detectable (<5) • Non detectable (<5) • Non detectable (<0.05)
- 19. PHYSICAL PROPERTIES OF OIL Physical Properties Effects Appearance Decreases the Electrical strength, IFT value etc., Density Since density is inversely proportional to temperature , heat dissipation capacity of the oil decreases with the decrease of temperature Kinematic Viscosity Heat removal capacity from windings increases with Low viscosity at low temperature and prevent localized overheating. Interfacial Tension Oil with lower IFT reduces the cooling effect due to presence of sludge & oil decay product
- 20. PHYSICAL PROPERTIES OF OIL 20 Physical Properties Effects Flash point Low value to the specified value – Risk of fire in transformer Pour point Low value to the specified value – transformer oil stop flowing. Sludge & Sediments Reduces the electric strength and hinder heat transfer.
- 21. CHEMICAL PROPERTIES OF OIL Chemical Properties Causes Effects Neutralizatio n Number or Acidity Oxidation of insulating oil due to aging Corrosion of various parts of transformer, Lower the electric strength and causes Insulation degradation Oxidation Stability Moisture Metal corrosion which minimizes the life of the transformer Moisture By breathing action, Chemical reaction Decreases electric strength (BDV) Electric dissipation factor (Tan Delta) Resistivity Dissolved Gases Thermal degradation Arcing, Partial discharge H2 = Partial discharge H2,CH4 = Low energy discharge CH4 = Low temp hot spot H2, C2H2 = Arcing C H = High temp
- 22. ELECTRICAL PROPERTIES OF OIL Electrical Properties Definition Causes Effects Dielectric Strength It is the minimum voltage that oil can withstand due to its dielectric strength Solid impurities Water content , Fiber Conductive particles Higher the value, Higher the purity Resistivity The resistivity of a liquid is a measure of its electrical insulating properties under prescribed conditions. High resistively reflects low content of free ions and ion- forming particles and normally indicates a low count ratio of conductive contaminants. Moisture , Acidity Solid contamination Higher the value , better the condition of the oil Dielectric Dissipation Factor / Tan Delta PF = Cos φ = Cos ((90-∂) = Sin ∂ = Tan ∂ Heat dissipation in the insulator due to leakage Current = OA x OB Tan ∂ (Watt) Since heat dissipation in the insulator increases With increase of PF / Cos φ / Tan ∂ - this factor is known as dielectric dissipation factor and should be Soluble varnishes, resins , Moisture Increased value causes in increase in temperature, increase in corrosion (Applied voltage V) O Φ = (90-∂) ∂ A B C Capacitive current Actual current
- 26. Storage and Handling Transformer Oils 26 • Contamination of any kind is highly detrimental to the quality and performance of transformer oil • Storage tanks are normally made of mild steel or stainless steel. • An oil resistant Epoxy coating is necessary on the walls of the tank. • Water content greatly affects the insulation properties. A silica gel breather is can be used in humid areas. • It is vital to keep the tank(s) completely separate, dedicated for use with transformer oil. This applies of course to all piping and lines that are used to transport oil to loading stations.
- 27. THANK YOU
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Editor's Notes
- #2: Our Presentation will cover the various aspects of Transformer oil starting with some insights on the working of transformer oil, Various Classifications of Transformers, Types of Transformer oil, regulation compliances needed for transformer oil. We will also talk about the testing parameters and their significance. In the end we will cover the various documents and certificates needed for major Transformer oil customers.
- #3: One of the main reasons that we use alternating AC voltages and currents in our homes and workplace’s is that AC supplies can be easily generated at a convenient voltage. This is done through a Transformer. The transformer uses Mutual induction between two or more windings (coils) allows for electrical energy to be transferred between circuits. Power transformer range from 11 to 765 kV and account for over 70-75% of total transformer Industry Volume in India while the distribution transformer account for the balance market share i.e. 25-30%.
- #5: If there are more turns on the primary coil than the secondary coil than the voltage will decrease (step down). If there are less turns on the primary coil than the secondary coil than the voltage will increase (step up).
- #7: In core type transformer, the winding encircles the core, whereas, in shell type transformer, the core encircles the winding of the transformer. he core type transformer is also called cylindrical or core winding transformer because their windings are arranged as the concentric coil. In shell type transformer, the low voltage winding and the high voltage winding are put in the form of the sandwich, and hence it is called the sandwich or disc winding transformer. The losses in a core type transformer are more as compared to shell type transformer because the core type transformer consists two magnetic circuits. Berry Type of transformers are kept in tightly fitted sheet metal tanks which are constructed of specific high quality steel plate cut formed and welded into the rigid structures.
- #8: There are various types of transformer used in the electrical power system for different purposes, like generation, distribution and transmission and utilization of electrical power. Based on application they are diffeciated in the following ways:
- #9: Step-up transformer transforms a low voltage, high current AC into a high voltage, low current AC system In this type of transformer the number of turns in the secondary winding is greater than the number of turns in the primary winding. If (V2 > V1) the voltage is raised on the output side and is known as Step-up transformer
- #10: Step-up transformer transforms a low voltage, high current AC into a high voltage, low current AC system In this type of transformer the number of turns in the secondary winding is greater than the number of turns in the primary winding. If (V2 > V1) the voltage is raised on the output side and is known as Step-up transformer
- #11: This type of transformer has lower ratings like 11 KV, 6.6 KV, 3.3 KV, 440 V and 230 V. They are rated less than 200 MVA and used in the distribution network to provide voltage transformation in the power system by stepping down the voltage level where the electrical energy is distributed and utilized at the consumer end.
- #12: ABB is a leading Transformer Manufacturer in India and headquartered in Bangalore, Karnataka. It offers a wide range to Power and distribution Transformers; and liquid field and dry type Transformers. ABB have delivered more than 14,500 power transformers till date. Siemens Group comprises of total 13 companies in India and has more than 21 manufacturing plants. The company is a world leader in electronics and electrical equipment; and it operates in more than 100 countries and supplies various types of transformers all across the globe. Alstom is a global leader in the field of Transformer Manufacturing. It was established in 1911 in Kolkata, West Bengal. Alstom is having a rich experience in Transformer manufacturing and has supplied numerous Transformers to national and international customers. The company is reliable and trusted name in transformer industry in India with production capacity of 130000 MVA. It has marketing offices in all the metro cities of India. T&R, A well known name in the transformer industry and one of the leading transformer manufacturers in India. Established in 1994 in the field of Transformer manufacturing and has over 30 years of experience in Design and manufacturing of Transformers & rectifiers. The company’s branches and marketing offices offices are located in all major cities of the country. Kirloaskar, Established in 1946 and reputed name in Indian transformer industry. It produces more than 70 products under more than 8 product groups. It has 9 manufacturing units and 34 sales offices spread from corner to corner in India. Their acquisition of Lloyd Dynamowerke in Berman, Germany, has strengthened their core businesses with world class products and skilled workers. More than 15000 Transformers products have been so far supplied in India. Gujarat Transformers Private limited is an old powerhouse and among the top 10 transformer manufacturers in India which has total 40 years of experience in design & manufacturing of distribution and power Transformers. They have capability to manufacture Distribution Transformer upto 3000KVA, Power Transformer upto 10,000KVA, Dry type up to 2500KVA and Cast Resign up to 5000KVA.
- #13: The oil in the transformer is used for Cooling Insulating the windings Protecting from the moisture Transformer oil acts a dielectric medium in oil filled transformers to cool and insulate the transformer windings and core. Transformer Windings and core, which are highly stable at high temperature, are fully immersed in the oil as they prevent contact of atmospheric oxygen with cellulose paper insulation of windings, which are prone to oxidation.
- #14: NAPTHANIC OIL Naphtha oil is 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 bottom of the transformer. Hence it does not obstruct convection circulation of the oil, means it does not disturb the transformer cooling system PARAFFINIC OIL Oxidation rate of Paraffin oil is lower than that of Naphtha oil But the oxidation product or sludge is insoluble and precipitated at bottom of the tank and obstruct the transformer cooling system. It has high pour point due to the wax content In India it is generally used because of its cheaper and easy availability. SILICON OIL Fire retardant, hence it is used only for fire prone area. Lower heat dissipation capacity and high moisture absorbing capacity Costlier than mineral oil
- #15: 1. Uninhibited oil New insulating oil as normally refined contains small amounts of certain chemical compounds that act as oxidation inhibitors. These naturally occurring materials retard oil oxidation until such time as they are expended. The rate at which the inhibitors in the oil are used up is dependent upon the amount of oxygen available, soluble contaminants in the oil, catalytic agents in the oil, and the temperature of the oil 2. Inhibited oil, To increase the oxygen inhibitor beyond its natural limit, oxygen inhibitor is added in the oil for reducing the rate of oxidation process in a view to increase the life expectancy of the transformer . Phenolic materials are quite good for this purpose and the two most commonly used inhibitors are 2,6-ditertiary- butylphenol (DBP) and 2,6-di-tertiary-butyl-4-methylphenol or 2,6-di-tertiary-butyl-paracresol (DBPC).
- #16: Transformer Oil standards in India are as per IS:3352018, Tyoe 1 for Napthenic and type 2 for paraffininc . IEC and ASTM specification are international Standards for Transformer oil.
- #20: Appearance The oils should be clear, transparent, and free from suspended matter. To determine the presence of moisture, sediments, carbon, fibers, dirt in the oil which changes the appearance of the oil, Density It measures the weight of oil with respect to the mass of an equal volume of pure water at the same temperature To ensure that the free water always remains at the bottom and oil can circulate easily due to lighter weight. (Lower the density better the heat transferring capacity ) Kinematic Viscosity It measures the resistance of the oil to continuous flow without the effect of external force To ensure the mobility of oil at low temperature since presence of sediments, moisture and aging of the oil increases the viscosity value. (Lower the viscosity better the oil quality & heat transferring capacity) Interfacial Tension It measures the molecular attractive force between water and oil molecule. To determine the presence of polar contaminates such as of sludge and other degrading products as a result of oxidation (Higher the IFT better the oil quality heat transferring capacity )
- #21: Flash point It is the lowest temperature at which oil vapour gets ignited. To determine the self ignition temperature of oil for safe operation and storing . (Higher the flush point safer the operation & storing hazards) Pour point It is the lowest temperature at which oil stops to flow due to solidification. To determine the lowest temperature at which oil stop flowing due to solidification. (Lower the flush point safer the operation & storing hazards) Sludge & Sediments Solid matter comprises insoluble in solvent. It can be determined by Centrifuge method Oxidation or degradation products of insulating materials, fibers of various origins, carbon, and metallic oxides etc., arise from the conditions of service of the equipment. (Good oil must be free form sludge & sediments )
- #22: Neutralization Number or Acidity It is the number of milligram of Potassium hydroxide required to neutralize completely the acids present in 1 gm of the transformer oil. Oxidation of insulating oil due to aging Oxidation Stability It the evolution of acid and sludge formation tendency of new mineral oil due to oxidation Moisture It measures in ppm the presence of moisture in the oil By breathing action, Chemical reaction Dissolved Gases It measures of dissolved Gases produced in the oil due to decomposition of oil Thermal degradation Arcing, Partial discharge
- #23: Dielectric Strength It is the minimum voltage that oil can withstand due to its dielectric strength Resistivity The resistivity of a liquid is a measure of its electrical insulating properties under prescribed conditions. High resistively reflects low content of free ions and ion-forming particles and normally indicates a low count ratio of conductive contaminants.
- #24: A number of Performance Reports collected form customers such as: Kerla State electricity Board Kayaka Parameshwari engineering Prathamesh transformers
- #25: Thota Coldecl Power Transformer Savio Electricals industries
- #26: Major Supplies were made to the following customers: Ajmer Vidyut Vitran Nigam Limited : 2000 KL Uttar Haryana Bijli Vitran Nigam: 200 KL Kerala State electricity Board : 100 KL MP State electricity board
- #27: One of the most important requirements to transformer oil, especially new oil just before it is put into a transformer, is its purity. Presence of water, gases and solid particles accelerates aging of oil and disrupts the insulation of the transformer.