Table of Contents
What are the benefits of transformer oil?
Transformer oil is used to insulate high-voltage electrical infrastructure such as transformers, capacitors, switches and circuit breakers. Transformer oils are designed to operate effectively at very high temperatures, cooling, insulating, and stopping corona discharges and arcing.
How does the oil temperature indicator of a transformer work?
This device measures top oil temperature with the help of sensing bulb immersed in the pocket by using liquid expansion in the bulb through a capillary line to operating mechanism. A link and lever mechanism amplifies this movement to the disc carrying pointer and mercury switches.
What is the transformer oil temperature?
Liquid-filled transformers come in standard rises of 55C and 65C. These values are based on a maximum ambient temperature of 40C. That means, for example, that an 80C rise dry transformer will operate at an average winding temperature of 120C when at full-rated load, in a 40C ambient environment.
What is the advantage of using transformer oil rather than air?
Regardless of the type of liquid used, oil and liquid-type transformers offer better cooling than dry types, because liquid is a more thorough medium for cooling applications. Highly efficient cooling mechanisms also translates to a smaller, more compact unit.
What is the importance of transformer oil in transformer?
Transformers are used by the electrical industry to transfer electrical energy from one circuit to another. The oil surrounding the coils in a power transformer provide cooling, insulation and protection against corona and arcing.
Why do we use mineral oil in transformers?
Naphthenic mineral oil has long been the most preferred insulating liquid for power transformer insulation because it has a good pouring point at low temperatures, good thermal cooling capacity, low cost, high efficiency and availability on the transformers market [1, 2, 3, 7].
What is WTI and OTI in transformer?
The WTI means winding temperature Indicator and OTI means Oil Temperature Indicator which indicates the winding temperature & oil temperature of the transformer and operates the alarm, trip, and cooler control contacts. This instrument operates on the principle of thermal imaging and it is not an actual measurement.
Why bushing is used in transformer?
The bushings used for the low voltage winding(s) of a transformer are often solid type with a porcelain or epoxy insulator. Their purpose is to control the voltage field around the center conductor so that the voltage distributes more uniformly across the surrounding insulation system in the bushing.
What is the reason for temperature rise in transformer?
The temperature rise of a transformer is due to the power loss dissipated by the transformer in the form of heat. The power loss of a transformer consists of core loss and of winding coil losses, and can be predicted accurately.
What happens when a transformer overheats?
When a transformer overheats through overcurrent, the copper windings heat first. Eventually, the wire will reach a temperature at which the insulation begins to degrade, to lose mechanical strength, to smoke and char, to catch fire, to melt (not necessarily in that order).
What are the advantages and disadvantages in using oil cooled transformer?
It has the advantages of fast heat dissipation, uniform conduction and recoverable insulation performance of the oil. However, the oil itself has the disadvantages of low heat resistance, flammability and aging, so there are many specific requirements in the use of transformer oil as a cooling medium.
What is the purpose of transformer oil testing?
Transformer oil testing is important to: Determine the essential electrical properties of transformer oil. Identify if a certain oil is suitable for future use. Detect whether regeneration or filtration is needed.