Excitation Systems for Hydroelectric Power Plants on the Vltava Cascade, Czech Republic
The Vltava (Moldau) is the longest river in the Czech Republic, running north from its source in Šumava Mountains through Český Krumlov, České Budějovice, and Prague (Praha), merging with the Elbe (Labe) at Mělník. It is 430 km long and has a catchment area of 28,090 km2. Many people know Vltava as a name from the world of music. The best-known is the classical Czech composer Bedřich Smetana’s set of six symphonic poems Má vlast ("My Fatherland") called Vltava (or The Moldau), and is a musical depiction of the river’s course through Bohemia. From the premier of this poem in 1875 the river changed as well as our entire world. The nine dams were built to protect towns and villages around the river against annual floods whilst providing a renewable source for production of electricity.
Excitation System Upgrade
PRISMIC® excitation systems, which are operated in Vltava cascade by leading national electricity operator ČEZ a.s., are digital followers of original analogue excitation systems. The first PRISMIC® excitation system that was commissioned in the cascade was in Lipno power station in 1993. In 2006 ČEZ a.s. started a new process of upgrading the excitation systems in which BRUSH participates. In 2009 BRUSH has been awarded the orders for replacement of original systems at power plants in Vrané, Hněvkovice, Kamýk and Lipno.
An order received for the Lipno Power plant is for the replacement of static excitation cubicles of PRISMIC DCP-S5P.AD type used with two 60MW hydrogenerators. Having been installed in Lipno in 1993, these cubicles were the first PRISMIC DCP type in operation. They will be replaced with up-to-date Brush PRISMIC A50-S7.1D systems; one cubicle is scheduled for 2009 and second for 2010.
PRISMIC® A50 Excitation systems are capable of providing specific diagnostics required with hydrogenerators, such as diagnostics of the generator shaft current. They also are designed to support hydrogenerators special operating modes, for example:
- Black starts of unit
- Electrical braking of unit
- Pumping operation of unit (in pumping storage plants)