In the numericals based on transmission line, the wording is like this-" A transmission line feeds power to a load at 132kV, 0.8 pf lagging and so on." In practice, are pf and current really constant? Doesn't it depend on the load? I mean, every minute someone is switching something on and something off. If the current waveform for a minute is plotted, how will it look? Will the pf be constant? By pf , I mean transmission line pf.