FROM A TO Z

The dictionary for communication between SCADA systems, controllers, other electrical devices and people. All entries from A to Z.


A
ARP — Address Resolution 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.
D
DLMS
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.
DNP3.0
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.
E
Encryption
Encryption, from ancient Greek Kryptós (“hidden”), is the art of hiding written messages by applying a given mathematical algorithm. Encryption seeks many objectives, such as;
- Confidentiality: the original message (“plain text”) should not be understood by anybody else than the legitimate destination
- Authentication; the receiver wants to make sure that the message comes from an authorised source. This is important, for example in a GOOSE message tripping a breaker (who sent it? Is the transmitter really authorised to trip a breaker or not?)
- Integrity: the receiver wants to make sure that the original message has not been modified by a man-in-the-middle attack
All encryption algorithms can be classified under the following two categories;
- Symmetrical encryption
- Asymmetrical encryption
Encryption for Smart Grids is defined in IEC62351 series (Substations), IEC 62056 (Smart Meters) and NERC-CIP, among others. Usually a combination of asymmetrical and symmetrical algorithms is used to benefit from the advantages of both categories.
Ethernet
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.
F
100BASE-TX — Fast Ethernet
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.
The cabling distance is limited to 100 metres (328 ft) for each network segment.
FTP — File Transfer Protocol
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.
FX100 Ethernet
Fast Ethernet is the name of the extension to 100 Mbit/s Ethernet network to 10 Mbit/s. This is the IEEE 802.3u working group that is at the origin. Access technique is the same as in the Ethernet Version 10 Mbit/s, but at a speed multiplied by 10. transported frames are identical. This increase in speed may conflict with the wiring system and the possibility or not there such important transit flows.
H
HTTP — Hypertext Transfer Protocol
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.
HTTPS — Hypertext Transfer Protocol Secure
HTTPS (Secure HTTP) is the cybersecured version of HTTP, Hyper Text Transfer Protocol. Its purpose is to encrypt the contents of a web page so that its transmission between client and server benefits from confidentiality, authentication and integrity. In fact HTTPS is HTTP (Application Layer) combined with TLS (Transport Layer Security), an encryption layer that makes uses of encryption algorithms.
HSR — High-availability Seamless Redundancy
Unlike common redundancy protocols like RSTP, HSR reacts to any network component failures seamlessly (without recovery time) and is invisible to the application.
I
ICCP/ TASE.2
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.
IEC 60870–5‑104 // IEC104
IEC 60870–5 is a protocol standard for telecontrol, teleprotection, and other telecommunication functions for electric power systems.
IEC 60870–5‑104 (short IEC-104) is a companion standard defining how to extend the IEC 60870–5‑101 protocol to gain network access using standard transport profiles.
IEC 61850 — BRCB/URCB — Buffered/Unbuffered MMS Reports
IEC 61850 distinguishes between buffered and unbuffered reporting. In unbuffered reporting events will not be logged and reported if the associated client for the unbuffered report control block is not connected. In the case of buffered reporting the events will be logged for a specific amount of time and sent later when the client is connected again
IEC 61850 — GOOSE
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 4 milliseconds.
It is most commonly used for data exchanges between IEDs (IED – Intelligent Electronic Device) in electrical substations over Ethernet.
IEC 61850 — ICD File
IED Capability Description (ICD) files are a specific type of Substation Configuration Language (SCL) file, containing a generic description of the whole capability range of a given device, including the functions and objects it can support.
The ICD file is usually supplied by the developer/manufacturer.
IEC 61850 — LN Logical Node
Logical nodes or LN (abstract data objects) are the main elements of the virtual object-oriented IEC 61850 model, which consists of standardized data and data attributes.
The abstract data objects can be mapped to any other protocol, as for example with the MMS or SMV protocol on an Ethernet data frame.
IEC 61850 — MMS Protocol
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.
IEC 61850 — SCL — Substation Configuration Language
The IEC 61850 standard for substation automation specifies a stadardized 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.
IEC 62439–3
IEC 62439–3:2016 defines the PRP and HSR standards, which provide seamless failover against failure of any single component in Ethernet networks.
PRP and HSR are application protocol independent, can be used by most Industrial Ethernet protocols in the IEC 61784 suite and have been integrated in the framework of IEC 61850 for substation automation.
IEC 62443
IEC 62443 is an International Standard dealing with cybersecurity in Industrial Automation and Control Systems (IACS). While IEC 62351 emphasizes on encrypting communications, IEC 62443 emphasizes on the device itself and introduces requirements such as a generalised definition of user (so that RBAC applies not only to humans but software processes as well); or the requirement that passwords be stored in hardware, which makes the use of TPM ICs necessary. From its very definition IEC 62443 applies naturally to RTUs and associated equipment.
IEC 62439–3
IEC 62439–3:2016 defines the PRP and HSR standards, which provide seamless failover against failure of any single component in Ethernet networks.
PRP and HSR are application protocol independent, can be used by most Industrial Ethernet protocols in the IEC 61784 suite and have been integrated in the framework of IEC 61850 for substation automation.
IEC 62351
IEC 62351 is a series of Standards dealing with Cybersecurity in electricity systems. Developed by IEC TC57 WG15, they aim at improving the different aspects of Cybersecurity in the different RTUs and IEDs deployed in substations, with parts dedicated to encryption and key exchange in telecontrol protocols (e.g. IEC 60870–5‑104 or DNP3.0), 61850, Smart Metering (DLMS-COSEM), RBAC (Role Based Access Control) and Conformance Testing among others.
IED — Intelligent Electronic Device
In the power sector, intelligent electronic devices (IED) are microprocessor based power system equipment, such as circuit breakers, transformers and capacitor banks, providing control and automation functions.
IEDs receive and process data from sensors and other equipment to issue control commands or adjust tap poisitions in order to prevent failures and maintain the desired voltage level.
IP Routing
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.
Interlocking (network protection scheme)
The interlock consists of one or more switches that prevent both main power and generator power from powering the dwelling simultaneously. Without this safeguard, both power sources running at once could cause an overload condition, or generator power back-feed onto the main could cause dangerous voltage to reach a lineman repairing the main feed far outside the building.
M
MAC — Medium Access Control
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.)
Modbus RTU & TCP
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.
Multi-drop Bus
In order to automate, monitor and control a substation and its intelligent devices in real time from a central monitoring station, the substation must be connected to a Supervisory Control and Data Acquisition (SCADA) system.
The SCADA provides grid operators with an HMI (Human Machine Interface) to visualize collected data and facilitate the substation maintenance and operation.
N
NERC CIP
North American Electricity Reliability Corporation (NERC), and its predecesor North American Electricity Reliability Council, is a non-profit organisation whose goal is to ensure the reliability of electricity supply across North America by developing technical standards for power system operation. NERC developed the so-called CIP (Critical Infrastructure Protection), a set of nine standards to implement cybersecurity in power systems. NERC-CIP standards cover technical and non-technical aspects, such as the use of encryption or personnel awareness and training, and have been adopted worlwide as a reference framework for cybersecurity in power systems.
Network Redundancy
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.
P
IEC 61131–3 — PLC
IEC 61131 is an international standard that describes Programmable Logic Controllers, a type of programmable industrial automation systems. IEC 61131 PLC systems embedded in RTUs allow the implementation of custom functions by processing different inputs and generating outputs.
Common examples are an RTU automatically connecting capacitor banks when the reactive power exceeds a threshold or performing load shedding when the frequency deviates. The program itself can be written in five different programming languages, described in part 3 of the standard.
PLC according to IEC61131‑3 is supported in all iGrid products, including the iRTU/iGW series and the iControl SCADA system.
Power Plant Controller — PPC
PPC (Power Plant Controller) is a control loop that regulates the amount of energy injected to the grid by a generation plant, to make sure that complies with both the setpoints and the grid codes dictated by the TSO. The PPC receives the setpoint from the TSO delegate office and receives feedback from a meter installed at the Point of Injection.
Profibus
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.
PRP — Parallel Redundancy Protocol
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.
R
RS-232 — TIA/EIA-232
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 electrical characteristics and timing of signals, the meaning of signals, and the physical size and pinout of connectors.
RS-422 — TIA/EIA-422
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).
RS-485 — TIA/EIA-485
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.
RTU — Remote Terminal Unit
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.
S
SAIDI/SAIFI
SAIDi and SAIFI are reliability indexes defined in IEEE 1366 and intended to measure the Quality of Service of electricity supply. SAIDI (System Average Interruption Frequency Index) measures how often electricity supply is interrupted and how many customers the interruptions affect. SAIDI (System Average Interruption Duration Index) measures the time duration of the interruptions. Very often SAIDI and SAIFI have to meet maximum values dictated by the regulator, and in some countries it is compulsory by Law that SAIDI/SAIFI calculation be supported by a SCADA system (e.g. Spain).
Sampled Values in IEC 61850
Sampled Values are one type of Ethernent message used in digital substations, used to transmit information of analogue nature in digital format. A typical application is measuring AC analogue currents and voltages; the current and voltage are measured with current/voltage transformers and delivered to a merging unit that will sample them at a given samplig rate and generate the corresponding Sampled Values messages. These sampled values messages are then published in a multicast Ethernet message in the process bus of the substation LAN so that all IEDs needing this information may subscribe to it and receive it (for example protection relays). Sampled values are described in detail in IEC 61850–9‑2 (“Sampled Values over ISO/IEC 802.3”) and IEC 61869–9 (“Digital Interface for Instrument Transformers”).
SCADA — Supervisory Control and Data Acquisition
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
Secure Boot
HTTPS (Secure HTTP) is the cybersecured version of HTTP, Hyper Text Transfer Protocol. Its purpose is to encrypt the contents of a web page so that its transmission between client and server benefits from confidentiality, authentication and integrity. In fact HTTPS is HTTP (Application Layer) combined with TLS (Transport Layer Security), an encryption layer that makes uses of encryption algorithms.
SER — SEQUENCE OF EVENTS (SOE) RECORDING
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.
SSH
Secure Shell is a secure client-server administration protocol which allows remote access to IEDs through an authentication mechanism. This protocol was created as a secure replacement for Telnet and makes use of both asymmetric and symmetric encryption algorithms with 128 bit keys. SSH is an essential component of cybersecurity and is implemented in all iRTU/iGW series for secure access to the devices.
T
TASE.2/ ICCP
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.
TCP — Transmission Control Protocol
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.
U
UDP
UDP (acronym for User Datagram Protocol) is a layer 4 transport protocol commonly used in IP networks. Unlike TCP (Transmission Control Protocol), UDP is a connectionless protocol, there is no connection setup or connection release. This makes it very adequate for the transport of short, urgent or spontaneous messages, like SNMP; or when retransmission is not feasible, like for example VoIP. UDP is used in some DNP3.0 profiles, specially in mobile networks, at the expense of less efficient handling of lost packets.
V
VLAN — Virtual Local Area Network
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.
VPN — Virtual Private Network
VPN (acronym for Virtual Private Network) is a communications technology that allows client-server secure communication over unsecure channels. A common example is remote access to a substation over an unsecure communications network, e.g. a public telecom operator. Both the client attempting to access and IED server at the substation must use a VPN software with embedded encryption algorithms that provide user authentication, data confidentiality and data integrity.
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…

Protocol Conversion
As communication networks grow in complexity, “plug and play” promises become harder to keep. Interoperable protocol converters and software solutions with state-of-the-art capabilities and funcitonalities can be the bridge to all the functions and flexibility your network needs.

Generation Dispatch Control Center
With a generation dispatch enter you can automatically control the generation of all power plants and make direct bids for ancillary services on one platform. Check out the most efficient communication path between generation sites, grid operators and the power market.

Smart Metering
A single device that collects, processes, transfers smart meter data and load curves from several meters in different protocols via serial or Ethernet, whilst providing advanced automation functions? Adaptable designs and a full communication protocol suite make it possible.

Switchgear & Transformers
Sometimes you have preferred gear for a project or it has already been installed, but it is lacking the communication capabilities to provide the automation functions you are looking for. With our software core iGComms any device can be as smart as you want it to be.