Case C-31/18: Judgment of the Court (Fifth Chamber) of 17 October 2019 (request for a preliminary ruling from the Administrativen sad Sofia-grad — Bulgaria) — ‘Elektrorazpredelenie Yug’ EAD v Komisia za energiyno i vodno regulirane (KEVR) (Reference for a preliminary ruling — Directive 2009/72/EC — Internal market in electricity — Article 2(3) to (6) — Concepts of electricity transmission system and electricity distribution system — Distinguishing criteria — Voltage — Ownership of installations — Article 17(1)(a) — Independent transmission operator — Articles 24 and 26 — Distribution system operator — Article 32(1) — Free third-party access — Access to medium-voltage electricity — Interconnection points between transmission and distribution systems — Discretion of the Member States)