DAWG Database 1998

`January 1, 1998 - December 31, 1998`

No.	Date	Time	Region	Utilities	Type	MW	Customers	Restored
1	01/06-10/98	-	NPCC - HQ	Hydro- Québec	INT, PA, DR	-	1,300,000	Initial: Final:
Cause: Severe Ice Storm Comments: Late in the evening of Monday, January 5, freezing rain started to fall on the southwest (Outaouais Region), south (Greater Montreal Region), and southeast areas (Monteregie Region) of Québec. Precipitation continued during the next five days resulting in a total accumulation of about four inches (100 mm) of water equivalent in the form of freezing rain, frozen snow, and snow. In the early hours of January 6, distribution and subtransmission lines started to fail due to fallen tree limbs and accumulation of ice on the conductors. At 1222 EST, the 735 kV Nicolet- Boucherville line faulted and opened because seven towers collapsed due to ice loading. The loss of this line, however, did not affect the transmission system's ability to serve customer loads. On January 7, many other distribution and transmission lines (120 & 230 kV) faulted. The local and regional control centers and the grid system control center went into emergency operation mode due to the severity of the events and the forecasts of more freezing rain for the next three days. By Saturday morning, January 10, a little less than 1,500,000 customers were without electric service. The transmission system stayed intact in most of the rest of the province and was able to supply customer needs except for the south shore of Montreal, the greater Montreal area, and southeastern Québec. In the Montreal area, most of the 735 kV transmission loop around Montreal was out of service (more than 120 tower were down), most of the underlying 315 kV and 230 kV circuits were affected (200 towers down), The Beauharnois generating station was isolated from the Montreal load center, and transmission lines to New York, Ontario, and Sandy Pond (HVDC) were out of service. The Highgate-Bedford HVDC line was out of service because the Highgate converter did not have a voltage source to support the conversion process. The ties to New Brunswick remained in service. Restoration of electric service began shortly after service failures began to occurred. By the end of Sunday, January 11, however, about 1 million customers were still out of service. Hydro- Québec was aided in its restoration process by private contractors and utility crews from other parts of Canada and the United States. During the storm and again during the restoration effort, Hydro-Québec issued public appeals for customers to minimize their use of electricity; it also had to resort to load shedding at times to balance the supply of power to customer demand. Service was restored to all customers by February 8. All facilities are expected to be returned to service by mid March. Hydro Québec is developing a plan to rebuild and upgrade transmission facilities in the affected area.

No.

Date

Time

Region

Utilities

Type

Customers

Restored

01/06-10/98

NPCC - HQ

Hydro- Québec

INT, PA, DR

1,300,000

Initial:
Final:

Cause:
Severe Ice Storm

Comments:
Late in the evening of Monday, January 5, freezing rain started to fall on the southwest (Outaouais Region), south (Greater Montreal Region), and southeast areas (Monteregie Region) of Québec. Precipitation continued during the next five days resulting in a total accumulation of about four inches (100 mm) of water equivalent in the form of freezing rain, frozen snow, and snow. In the early hours of January 6, distribution and subtransmission lines started to fail due to fallen tree limbs and accumulation of ice on the conductors. At 1222 EST, the 735 kV Nicolet- Boucherville line faulted and opened because seven towers collapsed due to ice loading. The loss of this line, however, did not affect the transmission system's ability to serve customer loads.

On January 7, many other distribution and transmission lines (120 & 230 kV) faulted. The local and regional control centers and the grid system control center went into emergency operation mode due to the severity of the events and the forecasts of more freezing rain for the next three days.

By Saturday morning, January 10, a little less than 1,500,000 customers were without electric service. The transmission system stayed intact in most of the rest of the province and was able to supply customer needs except for the south shore of Montreal, the greater Montreal area, and southeastern Québec. In the Montreal area, most of the 735 kV transmission loop around Montreal was out of service (more than 120 tower were down), most of the underlying 315 kV and 230 kV circuits were affected (200 towers down), The Beauharnois generating station was isolated from the Montreal load center, and transmission lines to New York, Ontario, and Sandy Pond (HVDC) were out of service. The Highgate-Bedford HVDC line was out of service because the Highgate converter did not have a voltage source to support the conversion process. The ties to New Brunswick remained in service.

Restoration of electric service began shortly after service failures began to occurred. By the end of Sunday, January 11, however, about 1 million customers were still out of service. Hydro- Québec was aided in its restoration process by private contractors and utility crews from other parts of Canada and the United States. During the storm and again during the restoration effort, Hydro-Québec issued public appeals for customers to minimize their use of electricity; it also had to resort to load shedding at times to balance the supply of power to customer demand. Service was restored to all customers by February 8. All facilities are expected to be returned to service by mid March. Hydro Québec is developing a plan to rebuild and upgrade transmission facilities in the affected area.

No.	Date	Time	Region	Utilities	Type	MW	Customers	Restored
2	01/08-12/98	-	NPCC-OH	Ontario Hydro	INT	-	-	Initial: Final:
Cause: Severe Ice Storm Comments: Several short-term disturbances occurred in the province of Ontario during a severe ice storm that also affected Québec, and northern New England. The first disturbance occurred on January 8 at 0134 EST when freezing rain and heavy ice build up on Ontario Hydro transmission lines resulted in the automatic removal from service of three 115 kV and seven 230 kV circuits. The loss of these circuits resulted in the loss of electric service to about 60,000 customers (300-400 MW) and the loss of about 250 MW of generation. That night at 1750 EST, two 230 kV transmission lines connecting Ontario Hydro (OH) to the eastern part of the New York Power Authority (NYPA) were opened to facilitate restoration of service to some customers in Québec. The OH-NYPA interconnection was restored about an hour later. No customers were affected by this switching operation. On January 11, OH was supplying electricity to Hydro-Québec (HQ) customers in the Laurentides Region using a radial 230 kV connection originating at its Chats Falls generating station. At 1712 EST, the line opened in Québec due to the weather resulting in OH serving an electrical island with more generation (92 MW) than customer load (40 MW), and frequency rose from 60.4 to 61.7 Hz. The electrical connection was reestablished in less than 30 minutes. No equipment was damaged during the disturbance. A similar disturbance recurred the next morning at 0847 EST. During this disturbance the frequency went from 59.6 to 62.3 Hz; no equipment was damaged. On January 12, OH was supplying electric power via two 230 kV radial lines to a portion of the H-Q system that had about 445 MW of H-Q generation and 700 MW of customer load . One of the OH lines was providing 115 MW of generation from Chats Falls and the other line was providing 140 MW from another source. At 1629 EST, a 115 kV circuit was removed from service when it came in contact with an underlying 25 kV system. This event resulted in the formation of an electrical island served by Chats Falls, which was connected to 43 MW of customer load. The frequency of the island fluctuated between 61.2 and 61.6 Hz and circuit voltage on the remaining 230 kV line rose to 252 kV. Power flow on the other radial OH line went from 140 MW into H-Q to 78 MW into OH. Chats Falls generation was reduced to 37 MW to bring the island frequency to 60 Hz. At 1638 EST, the Laurentides system operator reclosed the open line without approval of the Clarkson System Control Center or the H-Q System Control Center (SCC). The H-Q SCC instructed the Laurentides operator about the proper procedures to be followed. Chats Falls generation was returned to 115 MW at 1643 EST. About 215 MW of H-Q generation and 500 MW of HQ load were interrupted by this event.

No.

Date

Time

Region

Utilities

Type

Customers

Restored

01/08-12/98

NPCC-OH

Ontario Hydro

INT

Initial:
Final:

Cause:
Severe Ice Storm

Comments:
Several short-term disturbances occurred in the province of Ontario during a severe ice storm that also affected Québec, and northern New England.

The first disturbance occurred on January 8 at 0134 EST when freezing rain and heavy ice build up on Ontario Hydro transmission lines resulted in the automatic removal from service of three 115 kV and seven 230 kV circuits. The loss of these circuits resulted in the loss of electric service to about 60,000 customers (300-400 MW) and the loss of about 250 MW of generation.

That night at 1750 EST, two 230 kV transmission lines connecting Ontario Hydro (OH) to the eastern part of the New York Power Authority (NYPA) were opened to facilitate restoration of service to some customers in Québec. The OH-NYPA interconnection was restored about an hour later. No customers were affected by this switching operation.

On January 11, OH was supplying electricity to Hydro-Québec (HQ) customers in the Laurentides Region using a radial 230 kV connection originating at its Chats Falls generating station. At 1712 EST, the line opened in Québec due to the weather resulting in OH serving an electrical island with more generation (92 MW) than customer load (40 MW), and frequency rose from 60.4 to 61.7 Hz. The electrical connection was reestablished in less than 30 minutes. No equipment was damaged during the disturbance. A similar disturbance recurred the next morning at 0847 EST. During this disturbance the frequency went from 59.6 to 62.3 Hz; no equipment was damaged.

On January 12, OH was supplying electric power via two 230 kV radial lines to a portion of the H-Q system that had about 445 MW of H-Q generation and 700 MW of customer load . One of the OH lines was providing 115 MW of generation from Chats Falls and the other line was providing 140 MW from another source. At 1629 EST, a 115 kV circuit was removed from service when it came in contact with an underlying 25 kV system. This event resulted in the formation of an electrical island served by Chats Falls, which was connected to 43 MW of customer load. The frequency of the island fluctuated between 61.2 and 61.6 Hz and circuit voltage on the remaining 230 kV line rose to 252 kV. Power flow on the other radial OH line went from 140 MW into H-Q to 78 MW into OH. Chats Falls generation was reduced to 37 MW to bring the island frequency to 60 Hz. At 1638 EST, the Laurentides system operator reclosed the open line without approval of the Clarkson System Control Center or the H-Q System Control Center (SCC). The H-Q SCC instructed the Laurentides operator about the proper procedures to be followed. Chats Falls generation was returned to 115 MW at 1643 EST. About 215 MW of H-Q generation and 500 MW of HQ load were interrupted by this event.

No.	Date	Time	Region	Utilities	Type	MW	Customers	Restored
3	01/27/98	1000 EST	SERC-VACAR	Carolina Power & Light Company	INT	150	80,000	Initial: N/A Final: N/A
Cause: Snow storm Comments: A winter snow storm, resulting in accumulations of 12 to 24 inches, caused downed trees and power lines and interruption of service to about 80,000 customers. At various times, the storm caused interruptions, which were generally of short duration, to four transmission lines. It also caused extensive outages of distribution lines. Early restoration efforts were hampered by continuing wet snowfall and wind. Restoration work continued and as of 1030 EST, January 30, about 11,000 customers were still without service.

No.	Date	Time	Region	Utilities	Type	MW	Customers	Restored
4	02/02/98	1800 EST	FRCC	Florida Power & Light Company	INT	400	500,000	Initial: 1800 EST Final: N/A
Cause: Severe weather Comments: Extreme weather occurred in the Florida Power & Light Company (FPL) service area. Winds exceeded 100 mph (104 mph at Miami International Airport) and some tornados were confirmed. Extensive damage was done to the distribution system. Hardest hit areas were Miami-Dade and Broward counties.

No.	Date	Time	Region	Utilities	Type	MW	Customers	Restored
5	02/26/98	About 0900 CST	SPP	Central Louisiana Electric Company	INT	N/A	10,000	Initial: N/A Final: N/A
Cause: Tornado Comments: A tornado struck and destroyed the building that housed the Central Louisiana Electric Company (CLECO) Control Center. No one was killed in the incident. Most of the computer control systems were relocated to another part of the facilities at the site and were expected to become operational a few days later.

No.	Date	Time	Region	Utilities	Type	MW	Customers	Restored
6	03/09-10/98	0830 CST	MAIN	ComEd	INT	900	290,000	Initial: 0830 CST, 03/09/98 Final: N/A
Cause: Winter Storm Comments: A snow storm with strong winds moved through the ComEd service area causing transmission and distribution outages during the two-day period.

No.	Date	Time	Region	Utilities	Type	MW	Customers	Restored
7	03/31/98	1339 AST	NPCC - Maritime	New Brunswick Power Corp.	UO	0	0	Initial: N/A Final: 1421 AST
Cause: Human error Comments: New England personnel inadvertently opened the 345 kV Keswick, NB-Orrington, ME transmission line while testing the line's system protection at the Maine terminus. The line was at "full export flow" of 720 MW from New Brunswick. Opening of the line resulted in "islanding" of the Maritimes Area (3,000 MW total demand) and a rapid rise in system frequency. At 60.3 Hz, the special protection system at Keswick activated a preselected generation rejection scheme that resulted in shutting down the fully loaded Mactaquac Nos. 2, 3, 4, & 6 (436 MW) and Beechwood No. 2 (32 MW) units and the "runback" of the Eel River HVDC Circuit No. 2 tie to Hydro-Qu�bec from 104 MW to 62 MW. These actions halted the frequency rise at 60.37 Hz. Governor action stabilized the frequency at 60.23 Hz. The Maritime Area was resynchronized to the Eastern Interconnection at 1421 AST.

No.	Date	Time	Region	Utilities	Type	MW	Customers	Restored
8	12/8/98	0815 PST	WSCC-Calif	Pacific Gas & Electric Co.	INT	600	375,000	Initial: 0948 PST Final: 0948 PST
Cause: Human error Comments: The No. 1 230 kV Contra Costa-San Mateo line was out of service for scheduled maintenance. The No. 5 230/115 kV transformer bank and No.2 115 kV bus section were cleared for scheduled maintenance. Hunter Point generating unit No. 4 was generating at 75 MW and in the process of being removed from service due to a boiler-tube leak. At 0815 PST, a human error - failure to remove a ground connection put in place for safety reasons during maintenance - resulted in the Potrero (207 MW) and Hunters Point (195 MW) generating units tripping out of service. Five 115 kV lines tripped at the San Mateo switching station and electric service to 12 115 kV substations was interrupted. Frequency ranged from 60 Hz before the disturbance to a maximum of 60.05 Hz. Service was restored to all customers by 1430 PST.

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