Oil transformer on site tests (Turns ratio & Dielectric ) testsاختبارات المحول الزيتي فى الموقع

Oil transformer on site tests
The electrical device which can transfer electrical energy from one circuit to another circuit (without any connection) by means of mutual induction between the windings, is called a transformer. It works on the principle of electromagnetic induction. The transformer consists of the primary winding and secondary winding. It is used to increase or decrease the voltage levels of a circuit. In the entire electrical distribution system, the transformer is the main part. If the transformer doesn’t work properly, then the entire distribution system may get damaged and there will be no chance of transferring electrical energy. The electrical circuit can get damaged due to mechanical failures, electrical damage, thermal damage, and winding deformity. So, the functioning of the transformer should be checked by using the transformer testing process to avoid failures. The transformer testing can be done to determine the specifications, and performance of an electrical transformer. To meet the specific design and specifications, transformer testing should be done during the manufacturing process.
Transformer Testing Done at the Site
The transformer tests done at the site include the following.
Pre-commissioning tests of the transformer include,

Operational checking of the protection system
Insulation resistance (IR) measurement
Measurement of capacitor bushings
Measurement of voltage ratio (turns ratio)
Measurement of vector group or polarity of the transformer
Measuring of winding resistance
Measurement of vibration of the transformer
Test of the magnetic balance of the transformer
A measure of Frequency Balance Response (FRA) of the transformer
Measurement of floating neutral point
The measure of short-circuit impedance and magnetizing current of the transformer
Operational measurement on OLTC’S
Measurement of stability of differential, REF of transformer
Measurement of bushing current transformers (BCT’S)