According to CIGRE A2.34, the dynamic resistance measurement or DRM (OFFLINE) is a test that offers diagnostics for several diverter or selector switch malfunctions such as: contact problems, broken springs, broken transition resistors, poor contact pressure, inadequate transition time, momentary open circuit, and synchronism motion issues.
Zensol’s DRM principle
Tap windings are powered with a DC voltage source. The current fluctuations are recorded during the switching process. The schematic below shows the principle of the...
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...
Dissolved gas analysis (DGA) in transformers is a very successful periodic screening method to identify transformers that may be having problems. It is a symptom-based assessment of health, rather than a condition-based assessment. That is because the gases themselves do not cause failure, but are...
According to the annual Emerging Markets Smart Grid: Outlook 2015 study by the Northeast Group, LLC, the world loses US$89.3 billion annually to electricity theft, with the top 50 emerging market countries losing $58.7 billion annually compared with $30.6bn in the rest of the world, including...
INTRODUCTIONIn 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...
The utilization of online dissolved gas analysis monitoring has proven to be one of the most effective predictors of overall transformer health and condition. A wide range of monitoring systems are available, offering multiple costs, features, and benefit combinations. Hydrogen MonitoringSingle or...
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...
IntroductionContinuous online monitoring of bushings provides real-time information which can result in the early detection of a possible failure. Challenge: A Major AlarmA prominent U.S. utility was looking for a way to improve system reliability for their 138kV assets. They researched and...
By Chris Rutledge, Product Manager, Dynamic Ratings, Inc. 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. A wide range of monitoring systems are available, offering multiple...
By R.W. Hurst, Editor A distribution transformer is a critical component of the electrical power system, used to reduce the voltage of electrical energy for electric power distribution to end-users. It plays a vital role in voltage regulation and load management, ensuring the efficient and reliable...
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...
