19-04-2017, 09:22 PM
And the 25kV/6.25kV is all AC so the arc tends to quench at every zero crossing. Don't think there's any 6.25kV overhead now on UK railways.
HVDC switching is now possible:
https://en.wikipedia.org/wiki/High-volta...it_breaker
Even in the 100V to 1000V range DC switching isn't easy. On my solar PV system the DC isolator is a sort of kludge - 3 (4?) sections of standard AC isolator in series on a common shaft. It may have to break up to 700V from a series string of panels.
HVDC switching is now possible:
https://en.wikipedia.org/wiki/High-volta...it_breaker
Even in the 100V to 1000V range DC switching isn't easy. On my solar PV system the DC isolator is a sort of kludge - 3 (4?) sections of standard AC isolator in series on a common shaft. It may have to break up to 700V from a series string of panels.
www.borinsky.co.uk Jeffrey Borinsky www.becg.tv
