Howard Substation Transformers User Manual
Page 5
Copyright © 2013 Howard Industries, Inc.
Howard Industries, Inc.
Laurel, MS 39440
www.howardtransformers.com
Document No. 2.4.18
Revision: 2
Issued: October, 2013
5
Medium Power Substation Transformers
34-10
Tests
Transformer Class
Class I (≤ 69 kV)
Class II (115-765 kV)
Standard
Optional
Standard
Optional
Winding resistance
•
•
Winding insulation resistance (Megger)
•
•
Core insulation resistance (Megger)
•
•
Ratio
•
•
Polarity and phase relation
•
•
Insulation power factor
•
•
Control (auxiliary) cooling losses
•
Single-phase excitation tests
•
•
No-load losses and excitation current
•
•
Impedance voltage and load losses
•
•
Zero-phase sequence impedance voltage
•
•
Temperature rise
•
•
Low frequency dielectric tests
•
•
Low frequency dielectric tests on auxiliary devices,
control, and current transformer circuits
•
•
Lightning impulse
•
•
Front of wave impulse
•
•
Switching impulse
•
•
Partial discharge
•
•
Audible sound level
•
•
Operational tests (all devices)
•
•
Dissolved gases in oil
•
•
Leak test
•
•