DIN CLC/TS 50537-4:2011-04

This Technical Specification deals with gas and liquid actuated (Buchholz) relays for liquid immersed transformers and reactors with conservator for rail vehicles. The device is intended to detect: - gas release from the unit to be protected, - cooling liquid surge from the protected unit to the conservator, - complete loss of the cooling liquid in the conservator. This Technical Specification gives consideration to both technical and normative requirements of the railway environment and restricts the variety in particular provided by the industry standard EN 50216-2. It specifies requirements and tests enabling the interchangeability of Buchholz relays by defining the following interfaces: - mechanical interface, for example, flanges for pipe connection, dimensions; - electrical interface, for example, supply voltage for making and breaking capability; - functional interface, for example, protective operational behaviour. It is not applicable to flameproof relays. Different liquids may be used, which are typically used for both cooling and insulating. Furthermore, operating conditions are described. The responsible Committee is Subcommittee UK 351.1 "Fahrzeuge" ("Rolling stock") of the DKE (German Commission for Electrical, Electronic and Information Technologies) at DIN and VDE.