Nickelodeon didn't (& usually doesn't) give reasons WHY they cancel shows, but it can be assumed it was canceled for the same reason most shows get canceled. The ratings did not justify the cost of producing new episodes.
Cuban Power ended in 1968.
Civilian Power ended in 2008.
Washington Power ended in 2002.
Una Power ended in 2008.
Popular Power ended in 2001.
Parramatta Power ended in 2004.
Power Symphony ended in 2005.
Amiga Power ended in 1996.
Sega Power ended in 1997.
National Power ended in 2001.
power source
If you get to the end of the power plant zapdos will be there.