Fala power plant: the oldest plant, now with renewed power
The Fala HPP is the oldest power plant in the Slovene section of the Drava River. Its construction began in 1913, with the first five units commissioned as early as 1918.
Due to the increasing demand for electric power, a sixth unit was built in 1925 and then a seventh was completed in 1932. When construction of all the other power plants on the Drava River was completed, the plant’s turbine discharge proved low in comparison and this led to the construction of an eighth unit in 1977 using a Kaplan turbine with the capacity of 17 MW. After the extensive refurbishment at the end of the nineteen nineties, the power plant now operates using only the three newer units which make use of the 14,6 m available head and have a net capacity of 58 MW, and can generate 260 million kWh of electricity annually.
The damming of the Drava River gave rise to a reservoir with a length of 8,6 km which extends up to the Ožbalt HPP further upstream. The reservoir contains 4,2 million m3 of water, of which 0,9 million m3 can be used for the generation of electric power. The dam was originally built as a structure with five spillways each with a width of 15 m allowing for the complete raising of individual groups of spillway gates. The spilling capacity of the five spillways together amounted to 5600 m3/s. A more precise calculation of the maximum possible flow of the Drava River however, showed that it couldn't surpass 4500 m3/s. Due to the requirements for the increase of the turbine discharge, an additional generation unit with a vertical Kaplan turbine was built in 1977 in one of the spillways, lowering the spilling capacity to 4800 m3/s. All the spillway plates were replaced during 1991 to 1994 and the turbine of the eighth unit was replaced in 1995 with a new one with better technical characteristics and a higher rated discharge. Two units with vertical Kaplan turbines and generators installed above them were constructed in the new machine house. With an installed flow of 175 m3/s and a total capacity of 40 MW, they have now replaced the seven older generating units. The powerhouse also has a pre-assembly hall for major overhaul works. A special characteristic of the power plant is that the 110 kV and 10 kV switchyards are located in a separate building whose construction was completed prior to the Fala HPP commencing operations. The 110 kV switchyard is made up of double busbars, three line bays and three generator bays.
Within the dam structure complex, the old power house being an important item of technical heritage has been preserved. Its units, comprising double horizontal Francis turbines and generators on the same shaft, were closed down in stages as a result of the construction of the new powerhouse. Today the old powerhouse is an interesting vantage point for visitors allowing them to become acquainted with both the old and current methods of operating the power plant.