AVO New Zealand

What's in the name...?

For over 100 years, Megger has been a premier provider of test equipment and measuring instruments for electrical power applications. The Megger trademark was first registered in May 1903 and is closely guarded by the company. Although Megger is best known for its world-famous range of insulation testers, the company provides a full service solution to meet all electrical test and measurement needs. Megger products provide testing solutions for the most critical maintenance areas, including cable fault location, protective relay and circuit breaker testing, and power quality testing. With such a diverse product offering, Megger is the single source for electrical test and measuring instruments.

Abstract:

Measuring a transformer's winding (DC) resistance from one external terminal to another can reveal a great deal of information about the transformer. In addition to the obvious faulted winding (i.e., an open winding), more subtle problems can be detected. The DC current, in addition to flowing through the winding, must also flow through the off-load ratio adjusting switch (De-Energized Tap Changer or DETC) and the on-load ratio adjusting switch (Load Tap Changer or LTC), as well as numerous welded and mechanical connections. Hence, the integrity of all these components can be verified.

Authors note: Specific aspects of safety are addressed herein; however comprehensive procedures are not detailed. It is assumed the operator has sufficient knowledge of electrical theory and safe working practices to use the test instrument in a safe and responsible manner.

A Practical Technique FOR Battery Condition Assessment and Capacity Monitoring.

ABSTRACT:

The management of the condition assessment of standby lead acid battery systems using impedance methods is now a highly regarded and mature technology delivering an accepted compliment to load discharge methods. Offering the significant attributes of being a non-invasive diagnostic method implemented at modest per-cell costs to in-service battery systems, impedance testing may be applied both to absolute or trended ( CBM ) condition assessment philosophies. Given the often sudden nature of battery failure mechanisms, the success of failure prediction is proportional to sampling intervals. Studies have expanded the scope of impedance technology to the determination of deterioration in battery capacity.

Often just viewed as a form of ‘insurance’, an appropriate on-line monitor can not only provide a timely detection of main tank issues but also provide, arguably, an even more signifi cant contribution in the subsequent management of the event with the transformer remaining energised throughout.

Sherlock SF6 gas imaging and analysis video camera as tested at PG&E facilities in California

Presented at the EPRI Substation Equipment Diagnostics Conference XV

ABSTRACT

A new technology developed for remote imaging and quantification of gases has been developed using state-of-the-art diffractive optics and image processing algorithms. This technology was developed and patented by Pacific Advanced Technology for the US Defense Department1. The technology has been applied to remote gas leak imaging and quantification for the oil, gas, chemical and power industries. Gas Imaging Technology, LLC (GIT) has been granted the world wide exclusive license to market the Sherlock® for this purpose. This paper describes the Sherlock® imaging spectrometer, theory of operations, and applications in the power industry to
find sulfurhexafluoride (SF6) gas leaks from circuit breakers and gas insulated switch gear (GIS).

Abstract

Utility companies worldwide are striving to reduce the life cycle costs of their medium voltage distribution systems in response to economic and environmental drives. The use of tree retardant XLPE insulation has allowed utilities to achieve long cable service life under severe operating conditions. This has lead to improved life cycle economics and minimized social and environmental issues resulting from cable replacement activities.

This paper will discuss the multitude of accelerated cable aging tests, implications and current global trends for both the TR-XLPE and the Copolymer XLPE insulations. It will review the experience with TR-XLPE in North America, experience with Copolymer XLPE and TR-XLPE in Europe as well as the growing interest and usage of TR-XLPE in Asia. As the long life performance expectations for the MV underground cable system increase, movtivation towards using TR-XLPE as the insulation of choice to achieve these objectives is increasing.

Keywords - crosslinked polyethylene, tree-retardant XLPE, copolymer XLPE, accelerated wet cable testsI.

A series of mini papers

The latest Cigre News and perspective on transformers. Current cigre activity including discussion at the Paris session august 2006