BS EN IEC 61869-9:2019

What is BS EN IEC 61869‑9 - Digital interface for instrument transformers about? 

BS EN IEC 61869‑9 is a safety standard on the digital interface for instrument transformers. 

BS EN IEC 61869‑9 is a product family standard applicable to instrument transformers with digital output. The product standard is composed of IEC 61869-1 and IEC 61869-6, in addition to this standard and the relevant product-specific standards in the IEC 61869 series (Part 7, Part 8, Part 12, Part 13, Part 14, and Part 15).  

BS EN IEC 61869‑9 defines requirements for digital communications of instrument transformer measurements. BS EN IEC 61869‑9 is based on the IEC 61850 series, UCA international users group document. Implementation guideline for digital interface to instrument transformers using IEC 61850-9-2, and the relevant parts of IEC 60044-8 that are replaced by this standard. 

BS EN IEC 61869‑9 includes additional improvements including the IEC 61588 network-based time synchronization. 

Who is BS EN IEC 61869-9 - Digital interface for instrument transformers for?  

BS EN IEC 61869‑9 on the digital interface for instrument transformers is relevant to: 

• Electrical engineers 
• Electromagnetic engineers 
• Electricians and other officials of the electrical department 
• Testing authorities 
• Manufacturers of instrument transformers 
• Manufacturers of electrical and electronic measurement devices 

Why should you use BS EN IEC 61869‑9 - Digital interface for instrument transformers? 

BS EN IEC 61869‑9 is a product family standard for instrument transformers. 

BS EN IEC 61869‑9 provides an application of the standard series IEC 61850, which details layered substation communication architecture in the world of instrument transformers. 

By providing tutorial material such as examples and explanations, BS EN IEC 61869‑9 also provides access for instrument transformer, protective relay, and meter experts to concepts and methods applied in the IEC 61850 series. BS EN IEC 61869‑9 defines information models for the substation automation system. These information models include both the models of the instrument transformers and other process equipment (like circuit-breakers and disconnectors), and the models of the substation automation system (like protection relays and meters).  

The IEC 61869-9 standard: 

• Replaces the IEC 60044-8 digital solution 
• Provides a product standard for instrument transformers with a digital interface according to the IEC 61850 series; similar to what IEC 62271-3 offers for switchgear 
• Includes backward compatibility for the UCA International Users Group Implementation 
• Guideline for Digital Interface to Instrument Transformers Using IEC 61850-9-2 
• Uses IEC 61588 based time synchronization in accordance with IEC/IEEE 61850-9-3, with an option for 1PPS (pulse per second) 

With regard to accuracy classes, instrument transformers with digital output shall be classified in two groups: 

• Measuring instrument transformers 
• Protection instrument transformers 

To make the best use of the dynamic range enabled by the 32-bit message format specified in BS EN IEC 61869‑9, all protection instrument transformers and protection capable SAMU channels are specified with dual accuracy class ratings. Dual rating is intended to precisely document the measuring and protection accuracy class applicable to a given channel. 

Overall, BS EN IEC 61869‑9 is useful as has the ability of instrument transformers with digital output to meet their published accuracy specification depending on time synchronization. Merging units have the capability to accept an external synchronizing signal so that their sampling can be synchronized both to other merging units and to an external time reference. 

What’s changed since the last update? 

BS EN IEC 61869‑9:2019 is identical to IEC 61869‑9:2016. Together with BS EN 61869‑6:2016, BS EN IEC 61869‑9:2019 supersedes BS EN 60044‑8:2002, which will be withdrawn upon publication of BS EN 61869‑8.