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

Communication Protocols

IEC 61850

Grid & Substation Automation

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

An Intel­li­gent Elec­tron­ic Device (IED) is a term used in the elec­tric pow­er indus­try to describe micro­proces­sor-based con­trollers of pow­er sys­tem equip­ment, such as cir­cuit break­erstrans­form­ers and capac­i­tor banks.

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.

Communication Protocols

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. 

IEC 61850

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.

Communication Interfaces

Network Communication

Internet Protocols

Communication Interfaces

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.

Network Communication

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.)

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

Internet Protocols

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.

Cyber Security

Cyber Security

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…