European grids can be linked

Prof. Jan Popczyk

CENTREL

Your article “HVDC converter station links European grid” (September/ October 1994, page 19) stated that “Power grids in Western and Eastern Europe cannot be directly linked because of the frequency fluctuations.” From our point of view (CENTREL), this statement is injurious.

The European Union has already made the distinction between Central and Eastern Europe. CENTREL group countries, namely Hungary, the Czech Republic, the Republic of Poland and the Slovak Republic, being associated with European Union are officially classified as Central Europe.

CENTREL group of power systems has a well-defined time schedule for its interconnection with the Union for the Coordination of Production and Transmission of Electricity (UCPTE). This interconnection will take place not later than 1997.

The German VEAG power system has not been interconnected with the UCPTE system yet as shown in your map. CENTREL power systems currently operate synchronously with VEAG system.

In September 1993, the CENTREL power systems and VEAG power system demonstrated their autonomous operation during a test in which the interconnected grid operated synchronously with the load at 51,907 MW.

The frequency was maintained in the range of 50 plus or minus0.02 Hz. During transient operations, the frequency was in the range of 50 plus or minus0.08 Hz but restored to 50 plus or minus0.02 Hz in six minutes with secondary regulation.

Since April 1994, CENTREL power systems and VEAG system have operated autonomously. In this period, the quality of frequency control is comparable to the quality maintained in UCPTE.

(Editor`s note: The detailed results of the frequency test will be published in a future article.)