Owner's manual

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
• •