Czech grid operator ČEPS tests black start involving Tušimice 2 power plant

On Tuesday, 3 October 2023, a test of the Black Start ancillary service provided by the Orlík hydroelectric power plant was successfully completed. Its aim was to energize the auxiliary systems at the Tušimice 2 coal-fired power plant and synchronize it with the grid. It was an extended test involving the startup of one unit at the power plant.

Following a successful Black Start test in May this year, when the Orlík power plant supplied power to the auxiliary systems at the Prunéřov 2 power plant and the startup of several drives there was verified, ČEPS and ČEZ decided to test the route between the Orlík and Tušimice 2 power plants. This time, the extended test involved starting up an entire power plant unit with an installed capacity of 200 MW. The last test of a similar scope took place in 2008 on the Orlík–Chvaletice route.

„Although the Czech Republic’s transmission grid is very robust, ČEPS is constantly looking for new ways to increase the security of its operation. That is why it is prepared to restore the grid completely even in the worst-case scenario, a system blackout. Using several hydroelectric power plants, we can restore the power supply to selected system power plants, which can then deliver electricity to other customers as well,“ says Miroslav Šula, director of ČEPS’s Dispatching Operations Division.

„The gradual transformation of the Czech energy sector will require not only the construction of new zero-emission capacity, led by nuclear power plants and renewable sources, but also stronger links between the individual elements of the grid. We are pleased that our power plants have once again passed the test this year, demonstrating their readiness to restore power supply to key parts of the energy infrastructure. This also reflects the ongoing investment in fast-starting hydroelectric power plants, which has amounted to more than 3.5 billion crowns over the past 15 years,“ adds Jan Kalina, member of the board and director of ČEZ’s Renewable and Conventional Energy Division.

A separate route between the Orlík and Tušimice 2 power plants was set aside for the test and de-energized to simulate a system blackout. The route ran over 220 kV lines (operated by ČEPS) and 110 kV lines (operated by ČEZ Distribuce). Electricity generated at the Orlík hydroelectric power plant was then supplied along it to the auxiliary systems at Tušimice 2, where a shut-down unit was subsequently started up. During the test, key system parameters—especially voltage and frequency—were measured and evaluated, along with the dynamics of transient phenomena caused by changes in load as Tušimice’s auxiliary equipment was switched on. The test was successfully completed when the started-up unit at Tušimice 2 was synchronized with the grid at the Hradec substation.