In 1948, Ognenova began working at the Regional Museum of History in Shumen, as a curator. She conducted excavations with Vera Mavrodinova and Ivanka Zhandova, preparing an inventory of artifacts found at Madara and Preslav, which led to her publication in 1950 of an article Рисунки на конници върху вътрешната крепост на Преслав (Drawings of horsemen on the inner fortress of Preslav). By the end of the year, she accepted a position in the antiquities department of the National Archaeological Museum in Sofia. Assigned to a team to research the site of Sevtopolis under the direction of professor Dimitar P. Dimitrov (), Ognenova honed her skill becoming an expert in Thracian research. Sevtopolis, also known as Seuthopolis, was discovered during the construction of the Koprinka Reservoir near Kazanlak in the 1940s and completely unearthed between 1948 and 1954. Though the ancient city was the only Thracian site to ever be fully researched and excavated, the communist regime of the People's Republic of Bulgaria allowed the artificial lake created by the dam to cover the site when excavation was completed. In addition to Ognenova, others on the team included Anna Balkanska, Gergana Canova, Mariya Chichikova and Dimitar Nikolov. In 1957, Ognenova discovered a Thracian religious complex near Babyak, when a television tower was being erected atop Bendida Peak.