The document discusses various tests performed on transformers, including insulation resistance, open circuit, short circuit, vector group confirmation, magnetic balance, winding resistance, tan delta, and SFRA tests. It provides details on the purpose and procedures for each test, such as calculating the polarization index from insulation resistance measurements, determining magnetizing current and voltage ratios in open circuit tests, and verifying magnetic balance between phases. Setup and measurement fundamentals are covered for SFRA testing, and examples of normal and abnormal SFRA signatures are shown.

1. TESTING OF TRANSFORMER
BY
MANISH N PANDYA
Director, MECPL - VADODARA

2. LIST OF TEST PERFORMED IN
TRANSFORMER
• INSULATION RESISTANCE AND POLARIZATION INDEX
• OPEN CIRCUIT TEST
• SHORT CIRCUIT TEST
• VECTOR GROUP CONFIRMATION
• MAGNETIC BALANCE TEST
• WINDING RESISTANCE
• TAN DELTA TEST
• SFRA TEST

3. IR VALUE AND PI CALCULATION
USE OF TEST : 1) FINDING HEALTHINESS OF INSULATION
CALCULATION OF POLARIZATION INDEX IS MOST IMPORTANT IT IS A RATIO OF
INSULATION RESISTANCE VALUE OF 1 MIN TO 10MIN

4. OPEN CIRCUIT TEST
USE OF TEST : 1) FIND MAGNETIZING CURRENT 2) VOLTAGE RATIO

5. SHORT CIRCUIT TEST
USE OF TEST : 1) FIND SHORT CIRCUIT IMPEDANCE 2) CURRENT RATIO
% Z =
𝑀𝐸𝐴𝑆𝑈𝑅𝐸𝐷 𝑉𝑂𝐿𝑇𝐴𝐺𝐸 𝑋 𝑅𝐴𝑇𝐸𝐷 𝐶𝑈𝑅𝑅𝐸𝑁𝑇 𝑋 𝐹𝑅𝐸𝑄 𝑅𝐴𝑇𝐸𝐷
𝑅𝐴𝑇𝐸𝐷 𝑉𝑂𝐿𝑇𝐴𝐺𝐸 𝑋 𝑀𝐸𝐴𝑆𝑈𝑅𝐸𝐷 𝐶𝑈𝑅𝑅𝐸𝑁𝑇 𝑋 𝐹𝑅𝐸𝑄 𝑀𝐸𝐴𝑆𝑈𝑅𝐸𝐷

6. VECTOR GROUP TEST
USE OF TEST : VERIFICATION OF VECTOR GROUP

7. VECTOR GROUP COMBINATION

8. MAGNETIC BALANCE
USE OF TEST : VERIFICATION OF MAGNETIC BALANCE OF CORE

9. MAGNETIC BALANCE
R PHASE Y PHASE B PHASE
100% 60% to 80% 40% to 20%
50% 100% 50%
40% to 20% 60% to 80% 100%
MEASURED VOLTAGE PERCENTAGE

10. WINDING RESISTANCE

11. TAN DELTA TEST OF WINDING

12. TAN DELTA TEST OF BUSHING
SHORT LINK

13. TAN DELTA TEST OF WINDINGS

14. SFRA (SWIFT FREQUENCY RESONANCE ANALYSIS) TEST

15. SFRA TEST KIT SETUP

16. SFRA TEST MEASUREMENT FUNDAMENTAL

17. SFRA TEST SIGNATURE WITHOUT PROBLEM

18. SFRA TEST SIGNATURE WITH PROBLEM