Telecontrol technology · Glossary

Telecontrol technology refers to the technical equipment and communication procedures used to measure, monitor and control geographically remote installations. In the power system, it connects operating equipment with a control centre, for example switchgear, substations, local distribution substations, generation plants, storage systems or larger consumers. Measured values, switching states, fault messages, warnings and control commands are transmitted over this connection. The international standards series IEC 60870 is titled "Telecontrol equipment and systems". It describes telecontrol as the monitoring and control of geographically widely distributed processes.

Telemetering, remote signalling, remote control

The term covers three basic functions. Telemetering supplies values such as voltage, current, active and reactive power, frequency or temperature. Remote signalling transmits states, for instance whether a circuit breaker is open or closed or whether a protection pick-up is present. With remote control, the control centre issues commands: it switches a bay, changes a setpoint or limits an infeed. In addition, meter readings are usually transmitted as well. In practice, these functions come together in telecontrol devices, substation automation, communication networks and control systems. The control system is often referred to as a SCADA system.

Distinction from control technology, protection technology and smart meters

Telecontrol technology is a part of control technology, but is not identical to it. Control technology is the broader framework for the monitoring, management and automation of installations and networks. Within it, telecontrol technology mainly forms the transmission link between remote installations and the operational management level. The user interface and data processing in the control centre, that is, the SCADA system, uses this link. Telecontrol technology must also be distinguished from protection technology. Protection devices detect short circuits, earth faults or impermissible operating states and trip locally within milliseconds. Telecontrol technology can forward protection messages and support switching operations. However, it does not replace a protection function that has to work autonomously and very fast.

Telecontrol technology is often confused with smart meters. An smart metering system primarily records and transmits consumption and feed-in data at metering points. Telecontrol technology in grid operation, by contrast, serves the operational management of technical installations. It must report states promptly, transmit commands securely and remain as available as possible even during disturbances. However, the boundary is not entirely rigid. In Germany, the law increasingly provides for the smart metering system with a control unit as a communication path for controlling smaller generation plants and controllable consumers. A meter alone still does not make an installation an operating unit integrated via telecontrol. Conversely, a switchgear installation with a telecontrol connection can be operated entirely without a smart metering system.

Technical structure and protocols

Telecontrol technology consists of on-site devices, communication paths, protocols and systems in the control centre. On site, measurement transformers, sensors, protection devices and field devices capture the information. Telecontrol devices, also called Remote Terminal Units (RTU), collect the data, add time stamps and send them to the control system. They pass commands from the control centre on to the installation. In modern digital substations, field and protection devices perform many of these tasks themselves. Transmission paths include optical fibre, copper lines, radio and mobile networks, and network operators' own wide-area networks.

In Europe, the following protocols are particularly widespread: IEC 60870-5-101 for serial connections and IEC 60870-5-104. The IEC describes IEC 60870-5-104 as network access for IEC 60870-5-101 using standard transport profiles. In practice, this means transmission over TCP/IP. The current consolidated version is edition 2.1 of 2016. The IEC 61850 standards series, by contrast, is primarily a communication standard with a data model for the substation. However, it is now also used for connections between substation and control centre. The protocols define how measured values, messages, time stamps and commands are structured, addressed and acknowledged. This makes interoperation of devices from different manufacturers possible.

Significance for grid operation and the distribution grid

Power grids must be operated continuously within technical limits. Voltage, loading and switching states are therefore operating variables, not abstract planning variables. A network operator who does not know whether a switch is open, how much an installation is feeding in or whether a line is overloaded can assess the grid state only incompletely. Telecontrol technology turns distributed installations into installations that can be operationally managed. Its measured values are also the basis for methods such as state estimation, which computationally fills in missing measurement points.

This becomes particularly important in the distribution grid. In the past, many distribution grids were hardly observed. Power flowed predominantly from the higher voltage levels to consumers. Many local distribution substations had no continuous measurement, and switching was done on site when needed. With photovoltaics, wind energy, heat pumps, charging infrastructure and battery storage, this is changing. Feed-in and consumption fluctuate more, power can change direction, and voltage problems or bottlenecks occur more locally. Telecontrol technology is the prerequisite for detecting such states and intervening in a targeted way.

Remote controllability of distributed installations in Germany

For renewable energy and CHP installations in Germany, § 9 EEG 2023, in the version currently published, governs how remotely controllable they must be. As a basic principle, operators must ensure the technical state of their installation so that two things are possible: The metering point operator can install smart metering systems and control units. Network operators or other authorised parties can retrieve the actual feed-in at any time and remotely control the feed-in power, either fully or, as soon as technically possible, in steps or continuously. Small plug-in solar devices of up to 2 kilowatts module capacity and 800 volt-amperes inverter capacity behind a withdrawal point are exempt.

Until the smart metering system with control unit is installed and controllability has been successfully tested for the first time, transitional obligations apply. They depend on the installed capacity:

From 100 kilowatts: The network operator must be able to retrieve the actual feed-in at any time and to fully or partially remotely control and reduce the feed-in power.
From 25 and below 100 kilowatts: The network operator must be able to remotely control and reduce the feed-in power. Installations with a feed-in tariff or tenant electricity surcharge must additionally limit the active power feed-in at the grid connection point to 60 percent of the installed capacity, or they choose this limitation as an alternative.
Below 25 kilowatts: For installations with a feed-in tariff or tenant electricity surcharge, as well as for small CHP installations, the 60 percent limitation at the grid connection point applies. Under the transitional provisions, it does not apply to all existing installations.

It follows that technical controllability, legal authority and economic incentive are different levels. In redispatch, a network operator may, under defined rules, adjust feed-in in order to avoid grid bottlenecks. With market-based flexibility, by contrast, an installation changes its output on the basis of prices or contracts, for example on behalf of a direct marketer. The same interface can be used in both contexts, but the access rights differ. Who may see which data, who may control, and what priority a grid security command has over a market schedule are decided by energy law, technical connection rules, grid connection contracts, and data protection and IT security requirements. The technology creates options for action; which use is permissible follows from these rules.

Telecontrol is not the same as automation

A common mistake is to equate telecontrol technology with full automation. A telecontrol connection initially only means that data and commands can be transmitted. Whether this becomes an automatic process depends on the rules in the control system, on approvals, responsibilities and safety checks. Many switching operations deliberately remain subject to human decisions because the safety of people and installations is at stake. Automation can make sense, for example in fault location, switchover after a fault or voltage regulation. For this, measurement quality, data model, communication and operational responsibility must fit together.

Data quality, costs and benefits

Telecontrol technology is always also data management. Measured values must be plausible, carry the correct time and be located at the right place in the network model. A wrong switching state in the control system can lead to wrong decisions. A delayed measured value can conceal an overload. If the installation model is incomplete, a control command may not have the expected effect. The physical installation, its digital representation and the operating processes must therefore match.

Economically, telecontrol technology is double-edged. It costs money for devices, communication connections, parameterisation, data maintenance, servicing, cybersecurity and integration into the control centre. In return, it can avoid or postpone grid expansion, narrow down faults more quickly, shorten restoration times and make better use of existing operating equipment. The benefit rarely arises from a single device, but only when many installations are reliably observed and the data feed into grid operation, planning and fault handling.

IT security

Telecontrol technology does not merely transmit information. It can trigger real switching operations and change power values. IT security is therefore central: communication paths must be protected, access restricted, commands traceable and systems secured against manipulation. Unlike in office IT, availability and operational safety come first, because a grid cannot simply be switched off to fix a software problem. For operators of electricity and gas networks in Germany, § 11 para. 1a EnWG requires adequate protection of the telecommunications and IT systems necessary for safe network operation. The Bundesnetzagentur has specified this in the IT Security Catalogue, which requires a certified information security management system. According to the Bundesnetzagentur, the existing catalogues continue to apply until a new catalogue is published. In addition, standardised security extensions under IEC 62351 exist for IEC 60870-5-101 and -104.

Classification

Telecontrol technology is a technical foundation for what is often called the smart grid. This term remains imprecise as long as it is unclear which measurement points are captured, which installations are controllable, which processes are automated and who may access them. Telecontrol technology describes the concrete level at which visibility and options for intervention arise. It solves neither grid bottlenecks nor coordination problems on its own. But it shows how operating equipment is loaded and which interventions are technically possible.

Strictly speaking, telecontrol technology therefore refers neither to digitalisation in general, nor to mere measurement data acquisition, nor to the free remote control of arbitrary installations. It is the operational link between remote electrical installations and grid control. It matters because a power system with many decentralised, fluctuating and flexible elements can be managed only incompletely without reliable measuring, signalling and control.

Sources

Gesetz für den Ausbau erneuerbarer Energien (EEG 2023), § 9 Technische Vorgaben — Bundesministerium der Justiz / Bundesamt für Justiz (gesetze-im-internet.de); unbekannt (am 2026-11-11 abgerufene Fassung). § 9 Abs. 1, 2 und 2a EEG 2023
IT-Sicherheit im Energiesektor — Bundesnetzagentur; unbekannt. Einleitung der Seite
IEC 60870-5-104:2006+AMD1:2016 CSV – Telecontrol equipment and systems – Part 5-104 — International Electrotechnical Commission (IEC), TC 57; 2016-06-07. Produktseite, Titel und Metadaten; ergänzend Seite zur Ausgabe 2006 (webstore.iec.ch/en/publication/3746)
IT-Sicherheitskatalog gemäß § 11 Absatz 1a Energiewirtschaftsgesetz — Bundesnetzagentur; 2015-08. Abschnitte B und E (laut Suchergebnis)

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Edited by eCMS on 11.11.2026 19:47