Sept. 2, 2008
Entergy preparations began early last week, well in advance of Hurricane Gustav. Entergy is nationally recognized as a leader in the industry at restoring major damage safely and quickly.
Transmission System Severely Damaged
Entergy’s transmission system has sustained extremely severe damage from Hurricane Gustav, damage that could make power restoration a difficult and slow process, especially in southeastern Louisiana.
The transmission damage across the Entergy system includes 191 transmission lines and 210 substations out of service.
Entergy’s preparations made in advance of the storm to protect its system contributed directly to the power that is still on in New Orleans. Without the planning to isolate some generators there, this transmission damage would have interrupted power everywhere in the New Orleans area. Entergy’s Waterford 1, Nine Mile Point and Little Gypsy plants are now supplying all the power available in this area.
Thirteen of the 14 transmission lines serving the New Orleans metropolitan area are out of service due to the storm. This creates a situation where the New Orleans metropolitan area and a corridor along the Mississippi River between New Orleans and Baton Rouge have become essentially an island, no longer electrically connected to the rest of the Entergy system and the electricity grid for the eastern United States. This “island” is south of Lake Pontchartrain and includes Orleans, Jefferson, St. Bernard, St. James, St. John the Baptist, St. Charles and upper Plaquemines parishes, which are sometimes referred to as the “river” parishes.
Transmission lines in the Baton Rouge area that are needed to tie the “island” back to the system are out of service due to storm damage there, which was particularly severe.
Entergy is therefore continuing to carefully manage the restoration process in the affected area because adding more load could create an imbalance and trip the system, putting all the lights out.
Part of the difficulty is that there are no transmission lines to the south of New Orleans area because of the Gulf of Mexico. Transmission lines to the north, east and west are out of service.
Entergy’s first choice to relieve the islanding issue was to use its 500,000-volt transmission line, but that line is damaged at the substation and will take several days to repair. The alternate is to use several 230,000-volt lines to tie in the system. Several lines would be needed to assure the stability of the island and avoid an outage that would affect the entire region. Assessment continues and the time needed to repair the 230,000-volt lines could still take several days.
Entergy has experienced extensive distribution system damage, as well. This damage will be repaired in parallel with the transmission repairs so distribution will be ready as soon as possible when the transmission system repairs are made.
Entergy continues restoring service to emergency facilities in the affected area. Other restoration continue, but energizing of completed repairs will be delayed until the area can be tied back to the rest of the system. Continued bad weather also is preventing damage assessment by helicopter at this time.
Generation
Entergy’s River Bend nuclear plant in St. Francisville, La., was taken out of service Monday afternoon to help keep the electricity transmission grid in balance due to reduced demand. Entergy’s other Louisiana nuclear plant – Waterford 3 at Taft near New Orleans – completed a controlled shutdown on Sunday night in anticipation of the heavy winds forecast for Monday morning.
Entergy’s Waterford 3 Nuclear Plant near New Orleans completed a controlled shutdown on Sunday night in accordance with procedure at approximately 10:30 p.m. in anticipation of the heavy winds that were forecast for Monday morning.
River Bend Nuclear Station was brought offline on Monday evening due to loss of demand caused by extensive outages in the region.
Personnel at both plants are performing site assessments this morning and working closely with the Nuclear Regulatory Commission and Federal Emergency Management Agency to determine a timeline for restart.
Bringing the plants online will be closely coordinated with utility company personnel to maintain the reliability of the power grid.