Stepped Event Analysis

Stepped event analysis is one of the important additions in the upcoming V11 release of OneLiner™. A stepped event simulation begins an initiating short circuit defined by the user. The stepped-event logic then simulates subsequent relay-tripping and line-reclosing events until no further events are forthcoming.

Volumn 3

Winter 2008

 

 

Increasingly, the Industry is having to deal with the consequences of performance drivers seeking both high reliability levels and the minimization of outage times. In the case of power transformers, best practice currently is initially to take an oil or Buchholz gas sample and send it to a laboratory for dissolved gas analysis and reporting.

The move toward an exemplary Industry-driven stewardship of SF6 gas in the power industry is a major concern to the Industry internationally, especially as greenhouse gas issues have rapidly elevated in public awareness over the past year. Although only responsible for managing some 1.5% of the world’s SF6 gas resource, the power industry cannot operate without this gas. Other uses of the gas (such as blanketing magnesium and aluminium castings) have been widely noted for wastage and caused already an unbelievable level of environmental damage which the power industry is racing to distance itself from.

Ergon Energy in Queensland is committed to environmental responsibility in serving its customers and the community. As operator of Australia’s largest and most diverse electricity distribution network infrastructure, Ergon has an international ISO 14001 environmental certification and has been a signatory to the Australian Greenhouse Challenge since 1997.
Aware of the major potential greenhouse impact following any losses of the switchgear insulant gas, SF6, Ergon Energy have long-established gas management practices that seek to minimise and track and loses of the gas. Such initiatives pre-date much of the SF6 gas tightness and handling initiatives from the European sector of the Industry, only now being finalised as Cigre Guidelines under Committee B3 AA2 WG18.

Volume 1

2007

 

 

 

For your information, Morgan Schaffer has released a new version of their “Calisto Access” software.

This version is installed on all Calistos leaving the factory and we thus recommend that you download and install it on your computers.

By M. Duval

Dissolved gas analysis (DGA) is widely used to monitor the condition of transformers and other pieces of oil-filled equipment in service. Wrong diagnoses may be drawn, however, if the DGA results coming from the lab are not accurate. For instance, an electrical fault may be mistaken as a thermal fault, which may have serious consequences for the equipment. Several CIGRE and IEC round robin tests (RRTs) have shown that the repeatability (precision) of DGA labs is generally good, but that their accuracy (deviation from true value) is often poor.