IEC 60870-5-101

IEC 60870-5-101
Name	IEC 60870-5-101
Title	IEC 60870-5-101
Developer	International Electrotechnical Commission
Type	Telecontrol protocol
Os	Embedded systems, RTUs
First	1991
Latest	2003

IEC 60870-5-101 is a telecontrol protocol standard developed by the International Electrotechnical Commission for supervisory control and data acquisition in electrical power systems. It defines serial line communication profiles and application layer services used by remote terminal units, master stations, and substations. Widely adopted alongside other standards in power system automation, the protocol interacts with equipment from multiple vendors and fits within broader regulatory and technical frameworks.

Overview

IEC 60870-5-101 was standardized by the International Electrotechnical Commission and aligns with frameworks used by European Committee for Electrotechnical Standardization, CENELEC-affiliated utilities, and national grid operators such as Réseau de Transport d'Électricité, National Grid (Great Britain), and TenneT. The standard complements international schemes like IEC 61850, DNP3, and Modbus in substations and distribution automation employed by entities such as Siemens, ABB, Schneider Electric, General Electric, and Hitachi Energy. Its serial-oriented design reflects deployment patterns documented by transmission system operators including E.ON, Enel, and Iberdrola.

Protocol Architecture and Functions

The architecture maps application services to link-layer mechanisms familiar to implementers at companies like Schweitzer Engineering Laboratories and SEL-equipped utilities, and to conformance testing bodies such as Underwriters Laboratories and DEKRA labs. Functional roles—control station (master) and controlled station (slave/RTU)—mirror testing approaches used by labs collaborating with organizations like TÜV Rheinland and VDE. Use cases include remote protection, telemetering, and command execution in environments managed by grid operators such as National Grid ESO and distribution companies like Pacific Gas and Electric Company.

Communication Services and Data Types

The standard defines balanced sets of interrogation, spontaneous reporting, and clock synchronization services that support time-tagged events, single-point and double-point information, measured values with quality descriptors, and commands with confirmation. Data types correspond to measurements and statuses used by manufacturers such as ABB and Schneider Electric and are comparable to information models in IEC 61850 and service sets referenced by utilities including RWE and EnBW. Interrogation commands and command confirmation procedures are relevant to protection schemes applied by system operators like TenneT and transmission planners at organizations such as ENTSO-E.

Frame Formats and Link Layer

At the link layer, IEC 60870-5-101 specifies variable and fixed length frames, control field sequences, and a character-oriented transmission using start/stop bits over serial media such as RS-232 and RS-485. Frame structure and error control mechanisms are conceptually similar to those examined in standards committees involving ITU-T and testbeds run by institutions like Fraunhofer Society and Électricité de France. Implementations must manage sequence numbers, acknowledgements, and retransmission logic compatible with serial modem equipment and multiplexers from vendors like Hirschmann and Belden used in substations.

Interoperability and Implementations

Interoperability efforts involve conformance testing, certified devices from vendors such as ABB, Siemens, and Schneider Electric, and integration projects led by utilities including E.ON and Enel. Gateways that map between IEC 60870-5-101 and TCP/IP-based variants or other protocols—designed by firms like CCTR, Kithara Software, and specialist integrators—enable coexistence with systems using IEC 60870-5-104, DNP3, and proprietary SCADA protocols deployed by operators such as National Grid and PG&E. Academic studies from institutions like Technical University of Munich and Czech Technical University in Prague examine interoperability, while industry consortia and certification events organized by IEC and regional bodies validate multi-vendor setups.

Security Considerations

Originally designed for closed serial links, the protocol lacks intrinsic modern cryptographic protections; field deployments therefore rely on physical isolation, secure serial concentrators, and network-level controls provided by vendors including Cisco Systems, Palo Alto Networks, and Fortinet. When mapped over IP or used with serial-to-IP gateways, mitigations reference standards and practices advocated by NIST, ENISA, and national cybersecurity centers such as CERT-EU and US-CERT. Hardening involves access control, integrity checks implemented by device manufacturers like Schneider Electric and GE Grid Solutions, and operational procedures promoted by grid operators including ERCOT and ENTSO-E to defend against intrusion, replay, and manipulation threats.

Category:Telecontrol protocols