IEC 60870-5-103:1997

Overview

IEC 60870-5-103:1997 is an IEC companion standard for the informative interface of protection equipment. It specifies transmission protocols for protection relays and other protection devices that use coded bit serial data transmission to exchange information with control systems in substations. Built on the IEC 60870-5 series, the standard focuses on enabling interoperability between protection equipment and control-system devices while preserving the protection function (the informative interface does not affect protection decisions). IEC 60870-5-103 is highly relevant to Smart Grid and substation automation projects.

Key topics and technical requirements

• Scope & objective: Applies to protection equipment with coded bit serial transmission; defines companion semantics and specific uses of IEC 60870-5 primitives for protection-device interfaces.
• Enhanced Performance Architecture (EPA): Uses a three-layer EPA model (physical, link, application) for faster response of critical information with some service limitations.
• Physical layer options: Supports fiber optic and copper (EIA RS-485) interfaces for binary symmetric, memoryless transmission.
• Link layer: Selects and extends link transmission procedures and frame formats from IEC 60870-5-1 and -2; uses explicit Link Protocol Control Information (LPCI).
• Application layer: Defines ASDUs (Application Service Data Units), application functions, and data structures drawn from IEC 60870-5-3 and -4. Note: explicit APCI is not used - APCI semantics are implicit in ASDU identifiers and the chosen link services.
• Two information-exchange methods:
  • Predefined, standardized ASDUs and application procedures (mandatory use where applicable).
  • Generic services to cover broader or vendor-specific protection data when standardized messages do not apply.
• Interoperability rules: Clause 8 defines required subsets for specific applications; private ranges exist for backward compatibility but are not recommended for future use.
• Informative annexes: Examples for generic functions, directories and ASDUs to aid implementation.

Applications and users

• Primary use: substation automation, protection-relay data exchange, disturbance recording and monitoring (informative interface only).
• Who uses it: protection-relay manufacturers, substation automation engineers, utility protection & control teams, system integrators and Smart Grid solution providers seeking standardized communication between relays and control systems.

Related standards

• IEC 60870-5 series: Part 1 through Part 5 (frame formats, link procedures, application structure, information elements, basic functions)
• IEC 60050(371), IEC 60794, IEC 60874 (fibre optics), ISO/IEC 7498-1 (OSI model), EIA RS-485

Keywords: IEC 60870-5-103, telecontrol, transmission protocols, protection equipment, ASDU, RS-485, fibre optic, substation interoperability, Smart Grid, substation automation.