In a statement on Tuesday, Interior Minister Yazid Zarhuni said the blast at the Hamma power station just outside Algiers was "apparently accidental" and that none of the main installations were destroyed.
It was up to an inquiry to determine the exact circumstances of the explosion, he said.
Nur al-Din Butarfa, president and managing director of the state electricity and gas company Sonelgaz, said "the network remains interconnected and only an auxiliary network was slightly damaged".
The Hamma power station feeds other power plants in the country.
The emergency services confirmed 11 people were injured, four of them seriously, when windows of nearby buildings were blown out.
State television said the blast, heard all over the capital, was the result of a technical fault that caused fuel tanks to explode.
In February 2003 much of Algeria was plunged into darkness for several hours due to a power cut caused by a breakdown in the country's principal power station.