ER G7/4 or IEC 60909? 1

[ijl]

I browsed a new book on fault analysis at a bookstore. It discusses also the relevant standards and recommended practices, among them the UK Engineering Recommendation ER G7/4. What is the role or status of this recommendation? If I were going to carry out fault analysis for a UK customer (not likely), what should I follow, the IEC 60909-standard, or the ER G7/4? Does any software recognize it?

 

[Marmite]

You can obtain the ER G74 document from

http://2008.energynetworks.org/,

but it will cost you £55. It sets out an outline procedure for a computer-based method for calculating circuit breaker short-circuit making and breaking currents in three-phase ac power systems having a nominal voltage range 380V to 400kV.The recommended procedure is also applicable for the calculation of short-circuit currents for other purposes, such as the determination of protection relay settings or the calculation of mechanical forces arising form short-circuit currents.
The Electricity Networks Association is the trade body of the UK power industry. ER G74 was developed by the industry to provide an alternative method of calculation to that presented in IEC60909 for use where higher precision is required. The perception was that IEC60909 gives conservative results with sufficient accuracy. All of the UK Distribution Companies and the transmission Company are members of the ENA, and contribute to the various documents it produces, therefore if you were to work for one of them, the likelyhood is that they would expect you to comply with the relevant ENA document.
Regards
Marmite