Basic patterns for arrangement of electric power systems for steel mills

The steel mill power systems to be discussed in this paper may be as small as about 15,000 kw installed capacity and may approach or even exceed a capacity of 200,000 kw. If the steel mill has blast furnaces and coke ovens with waste fuel available, part of this capacity will be from turbine generators. Where possible there will be a tie to the electrical utility; and in many mills all of the electric power is provided by the electrical utility. The utilization voltages for the steel mill usually will include 440 volts, 2,300 volts, and 6,600 or 13,200 volts for the large motors or furnaces. Generation will usually be at 6,900 or 13,800 volts, although some older 2,300-volt machines are still in service. Formerly there was only limited use of voltages above 6,900 but there is an increasing need for higher transmission voltages. These include 22, 33, and 69 kv.