Baum on 220,000 volt power line

Standard Insulators May Be Used on 220,000-Volt Lines, Says Frank G. Baum

TRANSMISSION at 220,000 volts is now assured, according to a statement made this week to the ELECTRICAL WORLD by Frank G. Baum, who asserted that he had now the solution to the insulation problem. Mr. Baum, who is consulting hydro-electric engineer for the Pacific Gas & Electric Company and under whose supervision the design of the Pit River development is being carried out, is now in the East inspecting most of the equipment for this project, but particularly with the object of working out the 220-kv. insulator manufacturing details.

With Prof. Harris J. Ryan of Leland Stanford Junior University he has been conducting experiments on insulators working under a pressure of 220,000 volts and over, and with proper shielding of a type recently worked out experimentally he has demonstrated that standard insulators can be used at these higher voltages.

"However, engineers would be making a mistake," Mr. Baum asserted, "to go to these higher voltages just because they are higher. The economics of engineering development must play the heaviest part.

"This thought goes even further. In the great hydroelectric development of the country that is coming engineers must not be encouraged to build the highest dams, the largest plants, lines of the highest voltage, just because they are record-breaking.

Conservatism and good economics must rule. Furthermore, engineers ought to be honest and make honest estimates—not a million-dollar estimate where it is known the job ultimately will cost two millions. If the engineers do not act conservatively and honestly, there will once more be hydro-electric failures and loss of public confidence. "In the Pit River development we are going to transmit energy at 220,000 volts, not because it is a record, but because it costs less. At the lower voltages the regulation was poorer and more circuits were needed. We expect to transmit 150,000 kva. per circuit, each circuit having a cross-section of 500,000 circ.mil."

Another important problem on which Mr. Baum is working in connection with this development is that of close regulation of long high-tension lines. He stated that he is planning to secure on the Pit River lines practically uniform voltage and operation. From the plant to the first substation is 200 miles, and from this station to the second substation is 260 miles.