Abstract :
ENERGY from the Safe Harbor development was first received in Baltimore during December 1931, and at once took an important place in the energy supply of this city. Baltimore has both 25-cycle and 60-cycle loads, the maximum 25-cycle load recorded being 125,400 kw, the maximum 60-cycle load being 104,800 kw, and maximum simultaneous load on both frequencies being 188,200 kw. The 25-cycle frequency was originally chosen for industrial purposes and for the operation of rotary converters, although in recent years growth on this frequency has been held back. Shortly after completion of the Safe Harbor-Westport transmission line the frequency at Baltimore was changed from the former value of 621 / 2 cycles to 60 cycles, and the older frequency changers were shut down. One 30,000-kw frequency changer at Westport now takes care of all energy interchanged between these 2 systems. The characteristics and control of this frequency changer are described in the paper
