Active power losses in Estonian power transmission networkAinsaar, Karin Maria; Ülavere, Eero; Tammoja, Heiki; Valtin, Juhan14th International Symposium "Topical problems in the field of electrical and power engineering. Doctoral school of energy and geotechnology. II" : Pärnu, Estonia, January 13-18, 20142014 / p. 112-117 : ill