Appendix C:
Delta MV Transformer and Auxiliary Power transformer
Application Note
A. Technical requirement of MV transformer
A.1 The required insulation voltage of low voltage winding in MV transformer should be,
- To endure the pulse mode voltage of inverter with a maximum 1400V to earth.
- To endure the maximum RMS voltage to earth is 700V
- To capable of voltage gradient dv/dt up to 500V/μS.
- The earthed shielding plant should be added between windings of high voltage and of
low voltage to serve as filter for dv/dt.
Vag Va
1500
1 00
500
0
-500
0.4 0.405 0.41 0.415
Time (s)
0.42 0.425 0.43
82
Appendix C: Delta MV Transformer and Auxiliary Power transformer Application Note