Bridging Power Grids of Different Frequencies

If memory serves, Japan has both 50 Hz and 60 Hz power systems. Find out how they bridge them (or if they chose not to) and you'll have some good clues.

I believe they use High Voltage DC as an intermediat step. HVDC has other advantages see here...

Every day I buy AC and convert it to DC for conversion to other frequencies. Transmission-line losses are certainly higher for AC than DC, but conversion costs are about equal.

Perhaps the purchaser countries plan to do the conversion.....? If the cost of conversion is less than the cost of building new generation plants, particularly to bridge peak power periods, there would be encouraging economics.

Don

convert it to DC.

there used to exist exist rotory converters which consisted of a 3 phase transformer with moving take-off points that would rotate at the difference in frequencies... but these days I think it's all done electronically.

in New Zealand the power cable between the two main islands is DC and both islands use the same frequency, it's just that power travels long distances more conveniently as DC (no skin effect, no inductive or capaciitative losses)

Bye. Jasen

My thanks to all who provided good answers. I don't know when 60 HZ power distribution began in North America, but there were a number of other line frequencies used in this part of the world. I believe that the Niagara Falls area used 20 HZ for some time and Southern California had 50 HZ at 120 volts before about 1930 according to the Pasadena Water and Power web site. I guess, if you think about it, in the 1920's, it wouldn't have mattered much what the line frequency was since most uses for electricity then were applications that weren't particularly frequency critical such as resistance heating and incandescent lighting. Even electric fans and other motorized devices of the day probably didn't cause much trouble if built for 60 and run at 50 HZ. I don't really know when synchronous motors became common in clocks and phonographs, but that definitely would have been something that mattered.

Reason for lower frequencies was for motor use. The development of low hysteresis steels had not started yet, and these losses go up with frequency. So 25 Hz was a popular frequency for systems where motor power was to be big use for system. Motors had BIG coil cores. Transformer and motor steels were pretty fancy metallurgy.