Group operation of systems having different frequencies

The group operation of high-tension transmission systems having different frequencies has been successfully accomplished in Southern California during the past seven years. Some of the outstanding advantages of power interchange are emphasized and the value of the frequency changer for this purpose is shown. The metering of the interchanged power and the method of loading a frequency-changer offer somewhat unusual problems. With a liberal field design a synchronous frequency changer is of value as a means of power factor correction. Certain troubles with the starting winding and the bearings of some of the machines have developed as a result of severe operating conditions but the frequency-changer has proved to be a reliable and satisfactory means of interchange of power between large systems.