Power Transformers

Electrical Transformers

Leakers, What a Mess!

Electric Substation apparatus, transformers and circuit breakers, are the workhorses of the electric transmission grid. Our focus in this article is on the issue of dielectric media leaks. Specifically, oil in large power transformers and oil or SF6 gas in power circuit breakers. Oil and gas leaks...

Transformer Testing & Maintenance

Advantages of Headspace Hydrogen Monitoring for Network Transformers

INTRODUCTION The utilization of online dissolved gas analysis monitoring has proven to be one of the most effective predictors of overall transformer health and condition. Monitoring can vary greatly from nine gas to single gas systems to best suit the customers application when considering...

Transformer Monitoring

Dielectric Voltage Testing – Standard Methods

There are two standard methods from ASTM International: D877, Standard Test Method for Dielectric Breakdown Voltage of Insulating Liquids Using Disk Electrodes, and D1816, Standard Test Method for Dielectric Breakdown Voltage of Insulating Oils of Petroleum Origin Using VDE Electrodes. VDE stands...

Dielectric Fluids

Advancements in Dissolved Gas Analysis: CO/CO2 Ratio

For DGA interpretation, faults identified using hydrocarbon gases are considered more serious if they appear to affect paper insulation. That is made explicit in CIGRE technical brochure 771[1]. Production of hydrocarbon gases from the oil by electrical or thermal stress does not significantly...

Transformer Protection

Prevent Transformer Shutdown

Power transformers seldom shutdown; however, if a shutdown occurs, the effects would be immediate and devastating to utility operations. According to “An Analysis of Transformer Failures” by William H. Bartley, P.E., on behalf of the Hartford Steam Boiler Inspection and Insurance Company, the...

Transformer Software & Technologies

Grounding Transformers Explained

By R. W. Hurst, Editor Grounding transformers are used to provide a path to ground for unbalanced load current and for fault currents on systems where a suitable ground is otherwise not available. Grounding transformers are normally constructed with one of the two configurations: Zig-Zag (Zn) with...

Home Transformation Power Transformers

Protection of Electrical Power Transformers

INTRODUCTION
In most large electrical systems, generators and power transformers are the two most expensive pieces of equipment. In addition to the capital cost of purchase, these two key devices are also the most critical to continuous and reliable operation of the system.
Consider, for example, the main incoming power transformer of a large industrial plant. Failure of that transformer can result in production losses reaching millions of dollars. If the transformer requires repair or...