Parts of Nyanza, Central Rift and North Rift were without electricity from Saturday morning owing to a technical hitch.
The firm said the interruptions were occasioned by system interference on its distribution line between Nakuru and Eldoret.
"We are experiencing a power system disturbance after losing a main line between Nakuru and Eldoret main stations this morning. Parts of Nyanza, Central Rift and North Rift are affected," Kenya power said in a tweet.
The firm apologised to residents in the affected areas and said power restoration was in progress.
However, hours later, residents said power is yet to be restored.
@DJ_ARNOLD_KENYA said, "Till now, not sorted guys. It's a weekend we got businesses to handle..quicken up things," he said.
The tweet came four hours after Kenya Power said it was working to restore supply.
Other than decrying the effect it had on their businesses, residents said the lack of power also cost them the opportunity to watch Mashujaa Day festivities live on TV.
"Seriously you decided that I will not witness the historical Mashujaa Day at my neighbouring county? And have been waiting, you have to compensate me," @SeremAlvin said.
"Even some parts of Kakamega no power. Yall will not see heaven," added @MMarrisah.
Kenya Power reiterated that it was working to restore the power.
"Kindly bear with us as our technical team attends to the problem," it said.
