IEC 61869-13:2021

Overview

IEC 61869-13:2021 is an international product standard developed by the International Electrotechnical Commission (IEC) that specifies additional requirements for stand-alone merging units (SAMUs) used in alternating current (AC) applications with rated frequencies ranging from 15 Hz to 100 Hz. SAMUs serve as critical digital interfaces that convert standardized analogue inputs from instrument transformers into digital outputs compliant with IEC 61869-9, facilitating advanced power utility communication architectures based on IEC 61850. This standard is intended to be used alongside IEC 61869-9:2016 and IEC 61869-6:2016, which provide digital interface and low-power instrument transformer requirements, respectively.

IEC 61869-13 focuses exclusively on SAMUs with analogue inputs such as 1 A, 5 A, 3.25 V/√3, or 100 V/√3, supplied by instrument transformers compliant with related standards including IEC 61869 parts 2 to 5, 7, 8, 10, 11, IEC 60044 series, IEC 60185, IEC 60186, and IEEE C57.13. Cybersecurity aspects are outside its scope and are covered by the IEC 62351 series.

Key Topics

• Scope and Applicability: Targets stand-alone merging units in AC power systems with a focus on standardized analogue inputs and their conversion to digital signals.
• Design and Construction: Sets guidelines for SAMU construction, ensuring compatibility with instrument transformers and operational reliability under normal and special service conditions.
• Accuracy and Performance: Defines measuring accuracy classes and limits for current and voltage channels of SAMUs, including limits for protection and metering purposes.
• Testing Requirements: Details comprehensive tests such as electromagnetic compatibility (EMC), environmental tests (heat, cold, humidity), and operational cycles to ensure device robustness and reliability.
• Safety: Outlines safety requirements to protect equipment, operators, and system integrity during normal operation and fault conditions.
• Integration with Other Equipment: Describes how SAMUs can be combined with switchgear controllers (IEC 62271-3) or Intelligent Electronic Devices (IEDs) per IEC 60255 to enhance system functionality.

Applications

IEC 61869-13:2021 plays a vital role in modern electrical power systems by enabling:

• Digital Substation Automation: SAMUs act as critical nodes converting analogue measurements to digital data for intelligent control and monitoring of substations.
• Enhanced Protection and Control: With precise and reliable signal conversion, SAMUs support accurate protective relaying and switchgear control functions.
• Improved Data Integration: Facilitates integration into IEC 61850-based digital communication networks, optimizing power system data exchange, fault analysis, and operational efficiency.
• Retrofit and Upgrade Projects: Assists utilities in upgrading existing instrument transformer setups with digital interface capabilities without comprehensive hardware changes.
• Low-Power Instrument Transformer Systems: Supports advanced measurement chains ensuring safer, efficient, and higher accuracy data acquisition.

Related Standards

• IEC 61869-1:2007 - General requirements for instrument transformers providing the foundational principles followed by IEC 61869-13.
• IEC 61869-6:2016 - Additional general requirements for low-power instrument transformers that complement stand-alone merging unit specifications.
• IEC 61869-9:2016 - Defines digital interface requirements for instrument transformers and standardizes digital output formats.
• IEC 62271-3 - Switchgear controller functionality which can be integrated with SAMU features to enhance digital substation roles.
• IEC 60255 - Covers IED functionality relevant to protection, monitoring, and controlling electrical power equipment.
• IEC 62351 series - Cybersecurity requirements applicable to power system communications and data integrity, complementing but not covered by IEC 61869-13.

IEC 61869-13:2021 establishes essential technical and performance criteria ensuring that stand-alone merging units operate reliably within digitalized power systems. By adhering to this standard, manufacturers and utilities can guarantee interoperability, accuracy, and safety in measurement and control functions critical to modern electrical grids.