National transmission systems use the high-voltage lines to get interconnected in order to achieve more secure, reliable and stable operation thus enabling a power exchange among them. Those were the reasons because of which the power system of the then Socialist Federal Republic of Yugoslavia got interconnected with the West Europe interconnection system in the 1970’s.

With deregulation of the energy sector, which started in the last decade of the 20th century, coordination of the transmission system operators (TSOs) actions has been since attracting more and more importance, mainly because of intensive cross border electricity trading. It provoked a need for creation of common standards and criteria for operation of a system in all parts of Europe, and resulted, on the basis of a European regulation, in cessation of the work of TSOs associations in respective synchronous areas (UCTE, NORDEL, ATSOI, BALTSO and UKTSOA), as well as of ETSO (European Transmission System Operators) and transfer of its tasks and responsibilities to ENTSO-E (European Network of Transmission System Operators for Electricity, webpage: www.entsoe.eu), with EMS JSC as one of its full members.

The working structure of ENTSO-E is governed by the following committees:

• System Operation Committee
• System Development Committee
• Market Committee
• Research & Development Committee
• Digital Committee

Legal and Regulatory Group (LRG) supports the operation of the committees.

The committees consist of functional working groups (dedicated to specific technical issues), regional groups (with their subgroup(s)), and ad-hoc teams and project groups.