SCADAs, protocols, IEC standards, network redundancy… the Smart Guide Academy provides all you need to know about communication technology in energy applications.
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Communication Technology in Electrical Grids and Substations
Grid & Substation Automation
Grid & Substation Automation
- RTU — Remote Terminal Unit
- SCADA — Supervisory Control and Data Acquisition
- IED — Intelligent Electronic Device
- SER — SEQUENCE OF EVENTS RECORDING
RTU most commonly stands for Remote Terminal Unit, but is sometimes also used as an abbreviation for Remote Telemetry Unit or Remote Telecontrol Unit.
RTUs are devices that rely on microprocessors and communication interfaces to automatically monitor and control field devices and establish a bridge to the plant control or SCADA (supervisory control and data acquisition) systems.
Supervisory control and data acquisition (SCADA) systems collect, monitor and process real-time data to:
- Automate and control industrial processes remotely or locally
- Provide a human-machine interface (HMI) to directly interact with devices such as relays, sensors, generators, pumps, valves and others
- Record events and automate reporting
Sequence of events recording (SER) is performed by microprocessor based systems, which monitor collected data inputs and record the time and sequences of the changes.
Sequence of events recorders rely on external time sources such as GPS or radio clocks to record the exact time of state of each change.
IEC 60870–5 is a protocol standard for telecontrol, teleprotection, and other telecommunication functions for electric power systems.
IEC 60870–5‑104 (short IEC104) is a companion standard defining how to extend the IEC 60870–5‑101 protocol to gain network access using standard transport profiles.
DLMS/COSEM (or IEC 62056) is the main global standard for smart energy metering, control and management. It includes specifications for media-specific communication profiles, an object-oriented data model and an application layer protocol.
Modbus is a communications protocol based on master/slave (RTU) or client/server (TCP/IP) architectures that can operate on the 1st, 2nd, 7th level of the OSI Model.
Originally designed in 1979 by Modicon for its range of PLCs, it is now a de facto standard communications protocol in the industry, becomming the most widely available protocol for the connection of industrial electronic devices.
Distributed Network Protocol 3 (DNP3) is a set of communications protocols used between components for automation systems in electric, industrial and water sectors.
It is a key protocol in SCADA systems, where it is primarily used for communications between a master station and RTUs or IEDs.
ICCP (Inter-Control Center Communications Protocol) is a standard protocol for communications between control centers, which is part of the IEC 60870–6 standard under the name of TASE.2 Telecontrol Application Service Element 2.
It is being used around the world to exchange data over wide area networks (WANs) between grid operators, utilities, virtual power plants, regional control centers and other generators.
PROFIBUS (Process Field Bus) is an open standard for fieldbus communications in industrial automation systems that was first promoted in Germany in 1989.
The now most commonly found “Profibus DP” provides simple communications between Profibus masters and their remote I/O slaves.
The GOOSE (Generic Object Oriented Substation Event) protocol is a communication model defined by the IEC 61850 standard, which uses fast and reliable mechanisms to group any format of data (status, value) into a data set and transmit it through electrical networks within a time period of 4 milliseconds.
It is most commonly used for data exchanges between IEDs (IED – Intelligent Electronic Device) in electrical substations over Ethernet.
IEC 61850 MMS (Manufacturing Message Specification) is a client/server based protocol for communications between IEDs (IED – Intelligent Electronic Device) and higher level entities (such as RTUs and SCADAs) over Ethernet that is part of the IEC 61850 standard for communication technology in substations.
It is mapped onto TCP/IP and allows to access the server through its IP address in order to write/read data and exchange files.
The IEC 61850 standard for substation automation specifies a standardized Substation Configuration Language (SCL) to transfer device descriptions and communication parameters amongst different vendors/ manufacturers.
SCL files define several capability subsets for the IED to instantiate its capabilities.
The IED Capability Description (ICD) file is a specific type of SCL file, which are the configuration files defined by the IEC 61850 standard for modern substation automation.
It is usually supplied by manufacturers and defines the full capability range of an IED.
Logical nodes (abstract data objects) are the main elements of the virtual object-oriented IEC 61850 model, which consists of standardized data and data attributes.
They can represent switches in the grid, sensors, communication interfaces, or simply contain descriptions of devices.
- RS-232 — TIA/EIA-232
- RS-485 — TIA/EIA-485
- RS-422 — TIA/EIA-422
- 100BASE-FX Ethernet
- 100BASE-TX Ethernet
The RS-232 (Recommended Standard-232) or also known EIA-232 (Electronic Industries Alliance-232) is a standard for the serial transmission of data in industrial applications.
The standard defines the timing, electrical characteristics and meaning of signals as well as the physical size and pinout of connectors.
The RS-485 (Recommended Standard-485) or also known EIA-485 (Electronic Industries Alliance-485) standard defines the characteristics of an electrical interface for serial communications in industrial control systems.
In contrast to the older RS-232, it allows to balance electrical signals and connect multiple device to the network, which can stretch over longer distances and harsher environments.
The RS-422 (Recommended Standard-422) or also known EIA-422 (Electronic Industries Alliance-422) standard defines the characteristics of an electrical interface for serial communications in industrial control systems.
It was designed to replace the older RS-232C standard in order to provide higher speed (up to 10 Mb/s), better immunity from noise, and longer cable lengths (up to 1,500 meters).
100BASE-FX is a physical layer specification for Fast Ethernet over fiber optics using two multi-mode fiber optic strands for both links, reception and transmission.
The maximum length is 412 meters for half-duplex connections (to ensure that collisions are detected) or 2 kilometers for full-duplex.
100BASE-TX is the most common Fast Ethernet physical layer, transmitting data through two twisted wire-pairs (one for each direction), which provide full duplex operation with 100 Mbit/s of throughput in each direction.
Cabling distances are limited to 100 metres (328 ft) for each network segment.
- HSR — High-availability Seamless Redundancy
- PRP — Parallel Redundancy Protocol
- MAC — Medium Access Control
- VLAN — Virtual Local Area Network
- IEC 62439–3
- Network Redundancy
HSR (High-availability Seamless Redundancy) is a redundancy protocol for Ethernet networks requiring short reaction times and high availability, as for example protection systems at electrical substations.
Unlike common redundancy protocols like RSTP, HSR reacts to any network component failures seamlessly (without recovery time) and is invisible to the application.
PRP (Parallel Redundancy Protocol) is a redundancy protocol for Ethernet based networks requiring high availability and a short switchover time, as for example protection systems at electrical substations.
Unlike common redundancy protocols like RSTP, PRP reacts to any network component failures seamlessly (without recovery time) and is invisible to the application.
Ethernet is a family of wired computer networking technologies commonly used in local area networks (LAN) and also wide area networks (WAN).
Over time, Ethernet has largely replaced competing wired LAN technologies by providing higher bit rates, a greater number of nodes, and longer link distances and decent backward compatibility.
The Medium Access Control (MAC) sublayer provides flow control and multiplexing for the transmission medium to control the hardware that interacts with the wired, optic and also wireless transmission media in the IEEE 802 LAN/MAN data link layer.
The MAC is accompanied by the LLC sublayer, which provides flow control and multiplexing for the logical link (i.e. EtherType, 802.1Q VLAN tag etc.)
A Virtual Local Area Network (VLAN) is a is a subnetwork which can group together collections of devices that are connected to separate physical LANs.
VLANs allow network administrators to partition a single switched network in order to keep network applications separate despite being connected to the same physical network, without requiring new cabling or major changes in the current network infrastructure.
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Network redundancy is a method to ensure network availability, providing failover when a device or network path fails or becomes unavailable.
Redundancy is usually achieved by installing additional or alternative network devices, communication media or equipment within the network infrastructure
- ARP — Address Resolution Protocol
- FTP — File Transfer Protocol
- IP Routing
- TCP — Transmission Control Protocol
The Address Resolution Protocol (ARP) is a communication protocol used for discovering the link layer address (e.g. MAC address) that is associated with a given internet layer address, commonly IPv4.
The mapping function provided by ARP is critical to the Internet protocol suite and has been implemented with many combinations of network and data link layer technologies, such as IPv4, Chaosnet and DECnet using IEEE 802 standards, FDDI, X.25 and Frame Relay amongst others.
The File Transfer Protocol (FTP) standard defines an application layer network protocol to transfer files from a server to a client on a computer network.
FTP is based on a client-server model architecture using separate control and data connections between client and server.
The Hypertext Transfer Protocol (HTTP) is a standardized application layer protocol for distributed and collaborative, hypermedia information systems.
Alongside HTML, HTTP facilitated the development of original World Wide Web, the first interactive, text-based web browser.
IP routing encompasses different methodologies to route Internet Protocol (IP) packets within and across IP networks by determining a suitable path to transfer network packets between source and destination nodes in and across IP networks.
IP Routing protocols enable routers to build up a forwarding table that correlates final destinations with next hop addresses.
The Transmission Control Protocol (TCP) is one of the main protocols of the Internet protocol suite providing reliable, ordered, and error-checked byte stream deliveries between hosting applications communicating through an IP network.
Located in the Transport Layer of the TCP/IP suite, major internet applications such as the World Wide Web, email, SSL/TLS and file transfers rely on or run on top of TCP.
IEC 62351 is a standard developed to handle the security of TC 57 series of protocols including IEC 60870–5 series, IEC 60870–6 series, IEC 61850 series, IEC 61970 series & IEC 61968 series.
The different security objectives include the authentication of data transfer through digital signatures, prevention of eavesdropping and playback as well as spoofing, and intrusion detection.
IPsec (IP for “Internet Protocol” and sec for “secure”) is a group of protocols to ensure the integrity, confidentiality and authentication of data communications over an IP network.
IPsec is commonly used as a base for VPNs (Virtual Private Networks), encrypting the IP packets and authenticating the source where the packets come from.
Terminal Access Controller Access-Control System Plus (TACACS+) is a protocol developed by Cisco to handle authentication, authorization, and accounting (AAA) services and was released as an open standard beginning in 1993.
It is an extension of its predecessor TACACS, encrypting the full content of each packet and provides granular control (command by command authorization) whilst operating over TCP.
OpenVPN is a virtual private network (VPN) protocol and software for both client and server applications.
It implements techniques to create secure point-to-point or site-to-site connections in routed or bridged configurations and remote access facilities enabling peer authentication using pre-shared secret keys, certificates or usernames/passwords.
Public key infrastructure (PKI) refers to a range of technologies for authenticating users and devices in order to secure the digital transfer of information for a range of network activities such as e‑commerce, internet banking and confidential email.
It includes a set of roles, policies, hardware, software and procedures needed to create, manage, distribute, use, store and revoke digital certificates and manage public-key encryption.
iGrid Solutions and Applications
Automation with IEC 61850
The IEC 61850 standard is enabling new oportunities for vendor interoperability and advanced substation automation. Find out how you can take advantage of IEC 61850 with easy-to-use and adaptable solutions for a simple migration or retrofit.
HV Substation Automation
Powerful substation automation systems often handle numerous communication protocols and media within one network, which can result in expensive and complex projects. Avoid these problems with interoperable technology and smart configuration tools.
MV Distribution Grid Automation
It is often difficult to find the exact solution you need in a MV application, leading to higher costs than necessary. With our scalable and adaptable solutions you will be able to only pay for what you really need, without comprimising on quality or security.
Photovoltaic Power Station
Using an open and scalable SCADA system to monitor and control a PV plant comes with many benefits on several levels. Find out how advanced communication technology affects PV operation, maintenance, system design, investment security, profits…