Impact and benefits of distributed wind generation on quality and security in the case of the Cretan EPS

During the last five years substantial growth in wind generation took place in the autonomous Electric Power System (EPS) of Crete. The high penetration of wind power resulted in benefits while in the beginning it brought about numerous operational problems. There was a difficult period during 1999-2000. There were observed incidents of swings in wind generation due to sudden wind speed variations. There was little tolerance in the voltage deviations and the frequency deviations affecting the wind farms. Most system faults and transients caused problems in the wind farm operation. A total blackout of the system was experienced in 2001 (with a 7-hr restoration period) for which the wind farms contributed because of their low tolerance in under-frequency. There have been also serious communication problems between the dispersed wind generation and the system control center. A brief but concise presentation of the system and related operational problems is made and an analysis resulting in useful conclusions.