(Information below provided to Jackson Miss. media, December, 2006)

New Autotransformer Most Recent Project to Boost Reliability for Entergy Mississippi Customers

Entergy is installing a new 500kV/230kV autotransformer at the company’s Ray Braswell substation 8.5 miles west of Jackson.  The device will better serve the area’s growing power demands.

The autotransformer weighs approximately 715,000 pounds and when fully assembled is approximately 67 feet long, 69 feet high and 81.3 feet wide.

An autotransformer moves power from a higher voltage to a lower voltage for distribution to retail consumers.

The Ray Braswell substation is part of the power network that supplies electricity to thousands of Mississippi residents.

Manufactured by Asea Brown Boveri at that company’s manufacturing facility in Varennes, Canada,, and delivered by rail to Jackson and by heavy-duty trailer to the Entergy substation, the autotransformer not only improves reliability of service for Entergy Mississippi customers, but bolsters the reliability of the entire Entergy transmission system which covers more than 15,000 miles in four states and in New Orleans and serves approximately 2.7 million customers.

Autotransformer One Piece of a Bigger Reliability Picture

Installation of the new autotransformer at the substation west of Jackson adds another element in a series of transmission expansions and upgrades that benefit present and future Entergy Mississippi customers.

Last summer, Entergy completed a project that relieved overloading of the Amite to Fernwood transmission line, part of the transmission system tie between Entergy Mississippi and Entergy Louisiana.

The entire transmission line is approximately 32 miles long, with 15 miles in Mississippi and 17 miles in Louisiana.

Prior to its rebuilding and upgrading, if part of this region’s extreme high voltage transmission network were to fault and trip while heavily loaded, this line would have overloaded until Entergy was able to redispatch generation to relieve the overload. The rebuilding and upgrading eliminates this situation.

New Entergy Transformer Serves Summer Peak Demand

The third part of the series of expansions and upgrades was the new transformer that went into service last June at Entergy's Twinkletown substation in Walls, Mississippi.

Located in DeSoto County, near the intersection of Highway 61 and Church Road, the substation where the new transformer was installed is on the company's 230kv transmission line that runs between its Freeport and Robinsonville substations.

Installing the transformer enhances reliability of service to Entergy Mississippi customers during peak summer demand for power.

In addition to the transformer, the project included construction of a 230kV line into and out of the substation, three Entergy feeders and one feeder serving the Coahoma Electric Power Association.

Completion of this project created the option to add a third transmission line eastward that could ultimately connect to the company's Getwell substation near Hernando in DeSoto County, thereby providing service to distribution substations located along that transmission line, should demand grow.