BS EN 60255-121:2014 - Measuring relays and protection equipment. Functional requirements for distance protection
BSI Shop is currently experiencing technical issues. Any orders with HardCopy items are not being processed. We are working to resolve these as soon as possible. Please return later to place any HardCopy orders. We apologise for any inconvenience caused.

BS EN 60255-121:2014

Measuring relays and protection equipment. Functional requirements for distance protection

Status : Current   Published : July 2014



IEC 60255-121:2014 specifies minimum requirements for functional and performance evaluation of distance protection function typically used in, but not limited to, line applications for effectively earthed, three-phase power systems. This standard also defines how to document and publish performance tests. This standard covers distance protection function whose operating characteristic can be defined on an impedance plane and includes specification of the protection function, measurement characteristics, phase selection, directionality, starting and time delay characteristics. The test methodologies for verifying performance characteristics and accuracy are included in this standard. The standard defines the influencing factors that affect the accuracy under steady state conditions and performance characteristics during dynamic conditions. It also includes the instrument transformer requirements for the protection function. The general requirements for measuring relays and protection equipment are defined in IEC 60255-1.

Standard NumberBS EN 60255-121:2014
TitleMeasuring relays and protection equipment. Functional requirements for distance protection
Publication Date31 July 2014
Normative References(Required to achieve compliance to this standard)EN 61850, EN 60255-1, IEC 60255-1, IEC 61869-5:2011, IEC 60050, EN 61869-5:2011, IEC 61869-2:2012, IEC 61850, EN 61869-2:2012
Informative References(Provided for Information)No other standards are informatively referenced
International RelationshipsEN 60255-121 (IEC 60255-121:20,IEC 60255-121:2014
Draft Superseded By10/30215568 DC
DescriptorsTransient response, Length, Instrument transformers, Electromagnetic compatibility, Measuring relays, Electrical protection equipment, Voltage regulators
Title in FrenchRelais de mesure et dispositifs de protection. Exigences fonctionnelles pour protection de distance
Title in GermanMessrelais und Schutzeinrichtungen. Funktionsanforderungen für den Distanzschutz
ISBN978 0 580 70318 8
File Size2.943 MB

 Your basket
Your basket is empty

Multi-user access to over 3,500 medical device standards, regulations, expert commentaries and other documents


The faster, easier way to work with standards

Worldwide Standards
We can source any standard from anywhere in the world

Tracked Changes

Understand the changes made to a standard with our new Tracked Changes version