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----- , -- ---- --- - , O 1997 Portland General Electric. All rights reserved. , Transforme~ Loading M Vaults `"""~ ~ ~ "~ ~ ` Transformers located in vaults cannot be loaded as high as the same units in open air. The following loading guides are from Standards Section LC-250-00-03 for oil-filled transformers. Submersible Oil-filled transformer loading is based on 175 percent of nameplate peak loading. For commercial use, see Standard STD. LC-245-00-01. Table 1. Submersible Oil-Filled Transformers , , y,y.~ , Vault Change out Loading Install Loading Transformer peak Month kWh (Rated kVA) ~ ) (Peak Month kWh) 15 I 8.000 0- 7,000 25 i S,CCC i,CCC - 14,000 , _ 3/-12 ~ 22,500 ; 14,000 - 21,000 50 30,000 21,000 - 26,500 ' 75 45,G00 ; 26,500 - 44,000 100 60,000 44,000 - 53,000 167 100,000 53,000 - 90,000 Structural Requirements and Fire Protection Oil-filled transformers installed indoors shall be housed in a vault which has a minimum fire resistance of three hours and compl~es with all local, state, and national codes. Local code interpretation should be obtained from the local fire marshal. Structura! Requirements The intent of three-hour fire construction is to contain an oil fire within the vault. Walls, ceilings, and self-supporting floors would require six inches of reinforced concrete or eight inches of concrete block to meet the three-hour requirement. All doors and vent openings shall be approved for a three-hour fire rating. All conduit penetrations shall be grouted. Conduits, doors, and vents should also be protected against fluid entry by four-inch sills if located at floor level. Structural floor strength requirements are determined by the total weight of the transformer, other equipment, and assumptions for typical growth. Structural strength of the walls should be sufficient to support equipment weighing 400 pounds. Ceiling structural strength should be sufficient to support cable trays, bus work, or conduits. Fire Protection The fire marshal may require water sprinklers to be installed in a vault containing oil- filled transformers. The intent of a sprinkler system is to extinguish a fire in the vault. It is not intended to protect the electrical equipment. The safety features incorporated in;o the sprinkler system protect personnel inside the vault from the action caused by water being sprayed into the vault. PGE PROPRIETARY MATERIAI - THIS INFO IS BASED ON ASSUMPTIONS & CRITERIA WHICH MAY NOT BE VALID OUTSIDE THE PGE ELEC7RIC SYSTEM - FOR IP(TERNAL IJSE ONLY UNDERGROUND BUILDING CLASS A X DESIGN CONSTRUCTION VAULTS T&D STANDARDS UNDERGROUND DATE 08-09-96 P.G.E. CO. STANDARD LD-310-07-04 ~ `a~ :Q Menu - Close -