Development of Dielectric Strength Measuring Unit

Oils that combine a high flashpoint with high dielectric strength have long been used as an insulating medium in transformers, switchgear and other electrical apparatus. To ensure that the dielectric strength of the oil does not deteriorate however, proper maintenance is essential, and the basis of

2025-06-28 16:32:04 - Adil Khan

Project Title

Development of Dielectric Strength Measuring Unit

Project Area of Specialization RoboticsProject Summary

Oils that combine a high flashpoint with high dielectric strength have long been used as an insulating medium in transformers, switchgear and other electrical apparatus. To ensure that the dielectric strength of the oil does not deteriorate however, proper maintenance is essential, and the basis of proper maintenance is testing. Testing sequences and procedures are defined by various international standards. Testing consists of measuring breakdown voltage and other physical and chemical properties of samples of the oil. Thus, the dielectric quality of transformer oil is essential to secure operation of a transformer. As transformer oil deteriorates through aging and moisture ingress and transformer oil should depending on economics. Transformer duty and other factors to be tested periodically. Power utility companies have a vested interest in periodic oil testing since transformers represent a large proportion of their total assets. Through such testing, transformers' life can be substantially increased, thus delaying new investment of replacement transformer assets. The dielectric breakdown voltage of an insulating liquid is of importance as a measure of the liquid’s ability to withstand electric stress without failure. It serves to indicate the presence of contaminating agent such as water, dirt moisture, cellulosic fibers or conducting particles in liquids. To assess the insulating property of dielectric transformer oil, a sample of the transformer oil will be taken and its breakdown voltage will be measured. Break down voltage measured by observing at what voltage, sparking straits between two electrodes emerged in the oil, separated by specific gap. The lower the resulting breakdown voltage, the poor the quality of the transformer oil.

Project Objectives

Objectives:

To develop dielectric strength tester for transformer oil by building a coil to boost voltage up to 35kV.We boost 220V to 35kV by step up transformer and that voltage is supplied to electrodes dipped in transformer oil. The voltage at which spark occurs between two electrodes is breakdown voltage of oil. The lower the resulting breakdown voltage, the poor the quality of the transformer oil.

Industrial Objective:

In order to meet the residential, commercial and industrial energy requirements and ensure a smooth operation of power supply transformer plays an important role.  During transformer operation, transformers dissipate heat which can damage the system if not controlled. In order to achieve seamless operation of transformer by preventing from heat damage the oil are used. Transformer oil is used in oil-filled and submersible transformers to maintain temperature of transformers. Application of transformer oil can also be seen in high-voltage circuit breakers and switches. Since the oil is in constant contact with components it is therefore susceptible to chemical interaction. It is therefore essential to check for the quality of transformer oil at regular intervals since with continuous reaction the chemical composition of the oil may change and this may render it unfit for use. There are three types of transformer oil based on origin:  mineral oil-based, silicone oil-based, and bio-based. Though bio based transformer oil have gained attention due to stringent environmental issues but their usage is restricted due to limited advantage.

Project Implementation Method

Initially, the project components will be designed and selected for hardware implementation. The designed components will be connected to make complete schematic diagram. This schematic diagram will be tested on proteus software. Then components will be assembled to complete the hardware. On hardware, autotransformer will convert utility 220V AC from 0 – 220 V AC variable. Output of the autotransformer would be stepped up to 35 kV accordingly. Before step up transformer the Hall Effect sensor is connected and through protection fuse, the electrodes are connected to the step up transformer. We gradually increase the voltage up to 35kV between electrodes. At a certain point the spark occurs between the electrodes and the current produces and then sensor after detecting it sends the signal to microcontroller to trip the circuit and that voltage is breakdown voltage of oil. Microcontroller sends the trip signal to relay to trip the entire signal. The circuit will be tripped and the LCD connected with microcontroller displays our breakdown voltage of oil. If the breakdown voltage is less, the quality of oil is not good and the quality is good if the breakdown voltage is close to 35kV.  

Benefits of the Project

•    The transformer oil is hygroscopic in nature i.e it tends to absorb the moisture quickly. The dielectric strength of the oil gets deteriorated with the absorption of the moisture. That is why the breather filled with silica gel (Moisture absorbent material) is used in transformer so that external moisture during breathing can be trapped in silica gel. The reliability of the transformer can be ensured if all the parameters of the transformer oil are as per the standard.
•    The one very important parameter - Dielectric strength or breakdown voltage (BDV) of the oil must be periodically checked to ensure trouble-free operation of the transformer.

Technical Details of Final Deliverable

The final product will contain the step up transformer which step-up the voltage up to 35kV. This transformer have power rating is 300VA and current will be 7mA. And the HRC fuse is used in input and output side of the transformer. And low voltage protection scheme is used. Step-down transformer having 0.5A current that is used to operate the controller

Final Deliverable of the Project Hardware SystemType of Industry Energy , Manufacturing , Others Technologies Robotics, OthersSustainable Development Goals Affordable and Clean EnergyRequired Resources
Item Name Type No. of Units Per Unit Cost (in Rs) Total (in Rs)
Total in (Rs) 52570
Transformer Core Equipment140004000
Bobbin Equipment1500500
Copper Wire SWG:21 Equipment130003000
Copper Wire SWG:45 Equipment140004000
Brass Rod Equipment180008000
Acrylic Sheet Equipment120002000
Resistor Equipment1010100
Capacitors Equipment1025250
Electrical wire Equipment110001000
LCD Equipment1800800
Arduino UNO Equipment115001500
12V Transformer Equipment1300300
Heat sleeve Equipment520100
Auto Transformer Equipment11000010000
Relay Equipment1200200
HRC Fuse Equipment41040
Hall Effect Sansor Equipment25001000
Rectifier Equipment250100
Voltage Regulator Equipment260120
Transistors Equipment41560
Wood Sheet Equipment115001500
Transport Miscellaneous 130003000
Stationary Miscellaneous 120002000
Mechanical Fixing Miscellaneous 150005000
Fiber Sheet Equipment140004000

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