Low-Voltage A-C. Networks of the Standard Gas and Electric Company´s Properties

The low-tension a-c. network utilizing secondary network protectors has been adopted by five properties of the Standard Gas and Electric Company for service in areas of high-load density. The system has been applied to cities of the second class and smaller, although load density in certain cases is high. Each individual installation was made after a specific study of conditions involved. Underlying principles on which all of the designs are based are: (1) Primary supply at generator voltage (11 kv. or 13 kv.), (2) Omission of feeder regulators, (3) Simplified transformer vault design with barrier wall between primary and secondary equipment, (4) High-reactance transformers, usually inherent, (5) Use of secondary network protectors, (6) Three-phase four-wire secondaries, (7) Use of 250,000 cir. mil. secondary mains (or smaller) forming a solid grid without fuses. The operating experience of the installations made thus far has justified their application. The use of the system in other areas will be considered in future planning.