(Updates with fire put out, adds details, impact)
SARAJEVO May 16 (Reuters) - Firefighters managed to put out a fire in Serbia's Kolubara coal-fired power plant complex, utility Elektroprivreda Srbije (EPS) said on Friday, which flared while the plant was already closed due to floods and did not cause any injuries.
"The fire was caused by the circuit breaker accident and has affected three power transformers but caused no damage to power generation capacities," an EPS spokeswoman told Reuters.
The more than 1,300 megawatt (MW) complex has been shuttered since Thursday after the worst floods in 120 years swept through the Balkans, killing at least four people and leaving more than 230,000 households without electricity in Serbia and Bosnia.
The nearby Kolubara river has flooded the coal depots that feed Serbia's coal-fired plants and made power generation more difficult. The floods have resulted in a 10 percent cut in EPS output.
Some 135,000 consumers in Serbia and close to 100,000 in neighbouring Bosnia are cut off from power, mainly due to the flooding and landslides, but also as a precaution, power utilities in the two Balkan countries said.
Bosnian power utility Elektroprivreda RS (EPRS) said it would increase power sales to neighbouring Serbia's EPS utility and sell 180 MW of power per day from May 17 to May 19 to EPS. .
Flooding boosted Serbian and Hungarian power prices on Friday, while Czech and Slovak prices fell.
In the over-the-counter market, Hungarian power for Monday rose to 41 euros per megawatt-hour (MWh), while Serbian day ahead prices rose by as much as 2 euros to 36 euros per MWh due to the floods, traders said. (Reporting by Maja Zuvela; editing by Jane Baird)