Home » Transformer Services » Power Distribution Transformers

Power Distribution Transformers

Power Distribution Transformers Tests Includes:

• Condition Monitoring-Online
• Condition Monitoring-Offline

Thermography

Thermography is the use of Infrared photography to measure thermal energy from an object. Thermal energy shows us a new picture to us- the one which is not visible with naked eye

Benefits of Infrared Thermography

• Prevent -  In one step you can increase equipment efficiency and the safety of your facility- a potentially save your company cost of a major electrical malfunction
• Diagnose – by using thermographic photography, we can look inside at the performance of many different systems and make recommendations that will increase the performance of your business
• Repair -  NDL has been providing electrical maintenance and repair Since 1991.  Safety is our no. 1 priority, so you can assure your electrical Work is completed with all the safety standards

Oil Analysis

Faults can occur at any stage of your transformer’s life and evolve rapidly. Testing your transformers on a regular basis will allow you to detect any unforeseen change in the condition of your transformers.

The recommended tests in this package include:

• BIS 1866 (8 tests)*

*Water Content, Tan Delta, Resistivity, Acidity, IFT, Flash Point, Sludge, Dielectric Strength

Dissolved Gas Analysis

The use of DGA as a powerful diagnostic tool is a critical and important aspect of determining the condition and health of a transformer.

D.G.A. is a very reliable and proven technique to detect the internal faults in working transformers. The fault diagnosis by the gas chromatography is based upon the types & relative quantities of various hydrocarbon gases which can get dissolved in the oil under various faults.

D.G.A has proved to be reliable means of establishing the healthiness of a transformer which have tripped by suspected mal operation of differential protection (due to charging inrush or C.T Circuit problem) or Buchholz relay (due to air suction or control suction problem) can be returned to service with more confidence on the basis of D.G.A results. The accepted methods for performing this test are outlined in the ASTM D3612 and IEC 60567 standards.

Furan Analysis

A furan test should be included with yearly maintenance and trends developed to monitor the condition of the paper.

Furan Test is used to detect the thermal, oxidative and hydrolytic breakdown of paper insulation. This test, in conjunction with our dissolved fault gas analysis, gives you the best overview of the state of your transformer.

A rough approximation is that, for every 6° to 8° Celsius rise above normal operating temperatures, the life of the insulation is halved. Furans produced from these temperature build-ups are generated in two ways: the first being a localized area of high heat and paper damage, and the second being the general overall heating of the entire insulation system.

Early detection of paper insulation breakdown can prevent major damage or outright failure!

Insulation Resistance

It is desirable to have Insulation Resistance as high as possible consistent with acceptable mechanical, chemical and heat resisting properties.

This test is to detect the conductive impurities or mechanical imperfections in the dielectric which affect the quality of insulation which may be developed in the dielectric during the manufacturing process.

The insulation resistance test can detect if this connection is loose. It can also detect whether there are other, undesired and inadvertent, grounds. If the intentional core ground is intact, the resultant resistance should be very low. To check for unintentional core grounds, remove the intentional ground and Megger between the core and the grounded transformer tank. This test should produce very high resistance indicating that an unintentional ground is not present. This test is to supplement DGA that shows generation of hot metal gases (methane, ethane, and ethylene) and to indicate if a spurious, unintentional core ground is the problem. Experience can help locate the source of the problem.

Polarization Index

Polarization Index test that it can provide an indication of insulation quality in ten minutes for very large equipment that might take very long time to get fully charged.

Magnetic Balance

Magnetic Balance Test is performed on transformer to check whether the core and winding of the transformer is in balance position or not. Magnetic Balance is a test of Critical use as it helps us to enhance the efficiency and life of transformers

Magnetic Current

Magnetic Current Test is performed on transformer to check whether the core and winding of the transformer is in balance position or not. Magnetic Current is a test of Critical use as it helps us to enhance the efficiency and life of transformers

Inspection Stage: A team of our service engineers would visit you, to inspect and analyze the transformers. Inspection helps us to analyze customers requirements and transformers condition so we can plan for the future work which is to be done.

Overhauling Procedures: After the inspection and based upon the measured data, suitable course of Overhauling Procedure is recommended to improve the reliability & the Life of equipment. However, at least once in a decade, overhauling is essential to restore the health of equipment.

Commissioning Stage: All the Chemical & Electrical Tests are performed before commissioning of the equipment to ensure the Integrity and for obtaining the future reference values.