
34-1
34.1 Case for Balanced Polyphase Power Systems
Electric power is transmitted from source to load in the circuit shown in Figure 34.1a, and is proportional
to the root mean square (RMS) voltage between conductors (V) and the RMS current (I). ere are certain
voltages determined by IEEE/ANSI standards from which one may choose. e selection is made for a
given application based on several factors, including availability, cost, power level, and safety. Given that
the voltage has been selected, the transmitted power is proportional to current; hence, the more power
to be delivered to the load, the greater the current. e upper limit on cu