The number of IEC 61850 projects in the world is increasing year by year, and most of these projects involve retrofit and expansion of current substations.

Because pro­tec­tion relays are being main­ly cho­sen by its reli­a­bil­i­ty per­form­ing its pro­tec­tive func­tions, many already installed relays can­not be replaced. And still, many pro­tec­tion relays cur­rent­ly being sold in the mar­ket, or cur­rent­ly cer­ti­fied by util­i­ties do not sup­port IEC 61850. These facts com­pro­mise the upgrade/expand of old sub­sta­tions to IEC 61850 sub­sta­tion automa­tion sys­tems, main­ly in High Voltage.

iGrid T&D iGW allows these relays to con­nect to the IEC 61850 net­work, as if they were anoth­er IEC 61850 relay. iGW com­mu­ni­cates with the IED through any of most com­mon­ly used pro­to­cols in ener­gy sec­tor such as IEC 60870–5‑101, IEC 60870–5‑103, IEC 60870–5‑104, DNP3.0, Profibus, Pro­come and Modbus.

iGW collects all information from relays and maps it to IEC 61850 Logical Nodes.


iGW sup­ports any kind of Log­i­cal Node(LN) and Com­mon Data Class (CDC), both stan­dard and cus­tomized. All this infor­ma­tion is avail­able through IEC 61850 with all required features:

  • Read and discovery.
  • Gen­er­al Interrogation
  • Report­ing
    • Buffered Report Con­trol Blocks (BRCB)
    • Unbuffered Report Con­trol Blocks (URCB)
  • Dynam­ic dataset and report con­trol block creation.
  • Log ser­vices
  • Any IEC 61850 con­trol mod­el is sup­port­ed, regard­less of the con­trol mode used by the IED.
  • SCL files support
  • IEC 61850 Edi­tion 1 and Edi­tion 2 full support
  • Con­fig­u­ra­tion of RFC 1006 lay­er parameters
  • GOOSE pub­lish­ing

Some IEC 61850 data can­not be obtained direct­ly from the IED, and need to be cal­cu­lat­ed by the iGW :

  • Sta­tus points. Some inputs in the IED must be com­bined into a sin­gle sta­tus point in IEC 61850. Such us the phys­i­cal capa­bil­i­ties of the break­er to oper­ate ‘CBOp­Cap’, which reflects the switch­ing ener­gy as well as addi­tion­al block­ing due to some local problems.
  • Mea­sures cal­cu­la­tion. iGW can com­plete IEC 61850 data mod­els cal­cu­lat­ing new mea­sures based on the ones pro­vid­ed by the IED.
  • IEC 61850 spe­cif­ic data. There are some spe­cif­ic IEC 61850 attrib­ut­es that need to be com­put­ed also, such us ‘Beh’, ‘Health’, dead­band and others.

Sev­er­al IEDs can be added to the same IEC 61850 serv­er iGW by means of Log­i­cal Devices (LD), where each LD rep­re­sents a phys­i­cal IED. In any case, any oth­er mod­el struc­ture is also possible.

Note that though iGW can pro­vide GOOSE pub­lish­ing, this may not be suit­able for all pro­tec­tion schemes. Because, if com­mu­ni­ca­tion with IED is being done by ser­i­al links with low band­width, this would com­pro­mise time respons­es to be fast enough to meet some pro­tec­tion scheme tim­ing requirements.

iGW is the best way to inte­grate an exist­ing relay into an IEC 61850 net­work as any oth­er IEC 61850 relay. The iGW adds to the IED a com­plete set of IEC 61850 fea­tures addi­tion­al­ly to the cur­rent­ly pro­tec­tive func­tions offered by the relay. This allows these relays to be includ­ed into new IEC 61850 projects while extend­ing their live cycle, and with­out com­pro­mis­ing IEC 61850 deploy­ment inside the utility.