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Underground Distribution Serves Fair; Seattle City Light builds firmly to serve Fair's 22,600 kva after meeting difficulties with early load estimates by exhibitors HERALD GWILYM, Supervising Senior Engineer, Underground Distribution, Seattle City Light, Seattle, Wash. The perfect functioning of all electric equipment at the April 21 opening of Seattle's Century 21 Exposition was the result of three years of planning for an unfamiliar load by Seattle City Light engineers. First load estimates for the undertaking had a fantastic quality. These engineers' initial contacts were with promoters and exhibitors' representatives, who had little understanding of their own electrical needs. One large exhibitor asked for "3- million watts." A check put his actual requirement at 225 kw. In other instances, exhibitors added loads to those first estimated, and some exhibits were not started or even announced until six weeks before opening day. Total connected load finally proved to be 22,600 kva. Although past years' load diversity studies were an aid in estimating anticipated load, many commercial installations were reviewed on the basis of sq-ft area, connected load, and actual demand. The initial estimate of an 8,000-kva demand was raised to 10,000 kva as detailed information became available. Load checks in the first week of the Fair's operation disclosed an actual total of 10,833-kva demand at 90 pf. Consumption in the exhibit areas was computed at 8 w per sq ft. Underground distribution was planned from the beginning. This involved new supply lines to the Fair from the 120,000-kva Broad Street Substation, a few blocks west of the 74-acre site, and two 26-kv feeders passing through to districts beyond. An underground network replaced the overhead system in the 20-sq-block area between the Fair site and the downtown underground service area. Seattle City Light's engineers decided to provide 4,160-v service to the Fair, a decision based on facilities available at Broad Street Substation and the large stock of 4,160- v subway transformers released through a cutover to 13.5-kv. Hence four radial bus-regulated feeders supply the Fair's distribution system, and a paralleling fifth feeder can be switched to pick up the load of any failed feeder. Such switching is made practicable by load-break disconnecting oil switches at the outer ends of the four feeders and primary junction boxes. The latter have disconnect- HYDROELECTRIC POWER is represented at the Seattle Fair in Washington State. Consumer products are on display in by this exhibit which is sponsored by all the electric utilities nearby General Electric Pavilion 36 June 78, 1962 ELECTRICAL WORLD
Object Description
Description
Title | Page 36 |
File Format | image/jp2 |
Collection | Century 21 Digital Collection |
Contributing Institution | The Seattle Public Library |
Rights and Reproduction | For information about rights and reproduction, visit http://cdm16118.contentdm.oclc.org/cdm/rights |
Type (DCMI) | text |
Transcript | Underground Distribution Serves Fair; Seattle City Light builds firmly to serve Fair's 22,600 kva after meeting difficulties with early load estimates by exhibitors HERALD GWILYM, Supervising Senior Engineer, Underground Distribution, Seattle City Light, Seattle, Wash. The perfect functioning of all electric equipment at the April 21 opening of Seattle's Century 21 Exposition was the result of three years of planning for an unfamiliar load by Seattle City Light engineers. First load estimates for the undertaking had a fantastic quality. These engineers' initial contacts were with promoters and exhibitors' representatives, who had little understanding of their own electrical needs. One large exhibitor asked for "3- million watts." A check put his actual requirement at 225 kw. In other instances, exhibitors added loads to those first estimated, and some exhibits were not started or even announced until six weeks before opening day. Total connected load finally proved to be 22,600 kva. Although past years' load diversity studies were an aid in estimating anticipated load, many commercial installations were reviewed on the basis of sq-ft area, connected load, and actual demand. The initial estimate of an 8,000-kva demand was raised to 10,000 kva as detailed information became available. Load checks in the first week of the Fair's operation disclosed an actual total of 10,833-kva demand at 90 pf. Consumption in the exhibit areas was computed at 8 w per sq ft. Underground distribution was planned from the beginning. This involved new supply lines to the Fair from the 120,000-kva Broad Street Substation, a few blocks west of the 74-acre site, and two 26-kv feeders passing through to districts beyond. An underground network replaced the overhead system in the 20-sq-block area between the Fair site and the downtown underground service area. Seattle City Light's engineers decided to provide 4,160-v service to the Fair, a decision based on facilities available at Broad Street Substation and the large stock of 4,160- v subway transformers released through a cutover to 13.5-kv. Hence four radial bus-regulated feeders supply the Fair's distribution system, and a paralleling fifth feeder can be switched to pick up the load of any failed feeder. Such switching is made practicable by load-break disconnecting oil switches at the outer ends of the four feeders and primary junction boxes. The latter have disconnect- HYDROELECTRIC POWER is represented at the Seattle Fair in Washington State. Consumer products are on display in by this exhibit which is sponsored by all the electric utilities nearby General Electric Pavilion 36 June 78, 1962 ELECTRICAL WORLD |
Date created | 2012-03-20 |