Platform

MiCOM C264 and PACiS: The Substation Layer We Know Bay by Bay

A bay control unit is where substation automation stops being software and starts being the switchgear. We have installed and tested ninety C264 units at a single TRANSCO grid station, and that experience is the substance of this page.

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The platform

What the C264 and PACiS actually are

The MiCOM C264 is a bay control unit: one hardened controller per switchgear bay, reading every switch position, measuring the electrical quantities, enforcing the interlocking that decides whether an operation is permitted, and timestamping events at the bay itself rather than at a server. PACiS is the substation automation system those units historically live inside, the Schneider Electric lineage that runs a large share of Abu Dhabi's transmission and distribution stations, with EcoFIT as the retrofit path that modernises those systems while the station stays energised.

This layer of a substation has a property that shapes all work on it: it cannot simply be switched off and replaced. A grid station keeps feeding its load while its control system is renewed, which turns an equipment swap into a discipline of sectioning, temporary measures, testing and staged cutover, bay by bay.

Almafor has delivered exactly this in Abu Dhabi: substation control and monitoring system replacement on live 400 kV to 11 kV stations for TRANSCO and AADC, including ninety C264 bay control units supplied, installed and tested at the Mussafah 220/33/11 kV grid station MOSG, with redundant gateways to the load dispatch centre, the emergency control centre and the distribution management system.

The work

What we do on this platform

Bay control unit replacement

Supplying, installing, configuring and testing C264 units bay by bay on stations in service. Ninety at one station is our documented record, one unit per bay, so no single controller failure can blind the whole station.

PACiS and EcoFIT retrofits

Modernising the legacy PACiS estate through the EcoFIT retrofit path: new station-level hardware and gateways on the existing switchgear, keeping the asset owner's investment in the primary plant.

Control centre integration

Redundant gateways from the station to the load dispatch centre, emergency control centre and DMS, with the point mapping, testing and sign-off the network operator's procedures demand.

MiCOM relay integration

The protection layer and the control layer meet at the bay. We integrate MiCOM protection relays with the bay control units and the station bus, including the IEC 61850 engineering between them.

Time synchronisation and SOE

GPS station clocks, synchronised timestamps at the bay, and sequence-of-events records that hold up in a fault investigation, the discipline our field notes cover on other platforms too.

Fibre and station LAN

The fibre backbone, LAN switches and communications cabinets the bay layer depends on, delivered and terminated by the same team, on the same programme.

Before you tender

What to check on a bay-level replacement

Whether the station must stay in service during the works, because that decides the entire methodology, not just the programme
How many bays, and whether the replacement is one-for-one or a re-engineering of the bay-level functions
The interlocking philosophy: enforced where, tested how, and signed off by whom
Gateway redundancy to the control centres, and what happens at the dispatch desk during each cutover stage
Time synchronisation end to end, so events across ninety bays can be laid on one timeline
IEC 61850 conformance where the specification demands it, and the engineering tooling to prove it
The factory and site acceptance test regimes, bay by bay and station-wide
Who owns the as-built configuration, and in what tool, when the last bay is handed over

Track record

Where we have delivered it

Live-station SCMS replacement for TRANSCO and AADC, documented with the rest of the project record.

TAQA TRANSMISSION- Mussafah Substation

TAQA Transmission

Date2023-02-10

CategoryAutomation, Panel Building

TAQA DISTRIBUTION - ALKHAZNA substation 33 KV - 11 KV

TAQA Distribution

Date2025-03-25

CategoryAutomation, Panel Building

Upgrading and replacement of GE SCMS, TAQA Transmission

TAQA - Transmission

Date2022-01-16

CategoryAutomation, Panel Building

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Common questions

Questions we are asked about this

What does a C264 bay control unit do?

It is the controller for one switchgear bay: it reads every switch position in the bay, measures currents and voltages, enforces the interlocking that decides whether an operation is allowed, executes commands from the station level or the control centre, and timestamps everything it sees at the bay itself. One unit per bay means a single failure affects one bay's visibility, never the whole station's.

Can bay control units be replaced while the substation stays live?

Yes, and on transmission stations it is usually the only acceptable way. The work is staged bay by bay with sectioning and temporary measures, each bay is tested and returned to service before the next is touched, and the control centres keep visibility of the station throughout. Our ninety-unit replacement at a 220/33/11 kV TRANSCO station was delivered exactly this way.

What is PACiS, and what is EcoFIT?

PACiS is the Schneider Electric substation automation system, with Alstom and AREVA heritage, that runs a large share of the existing stations in the region. EcoFIT is the retrofit path for that estate: renewing the station-level system and gateways while the switchgear and much of the field wiring stay, which is how an asset owner modernises without rebuilding the station.

Do you work with IEC 61850?

Yes. The station bus engineering between bay control units, protection relays and the station level is part of the delivery, to the network operator's specification, and it is tested rather than assumed: conformance on paper and behaviour on the bus are checked separately.

Which network operators have you delivered this for?

Substation control and monitoring replacement for TRANSCO on live grid stations from 400 kV down, and for AADC on the distribution side, including the ninety-bay MOSG station in Mussafah and the Al Khazna grid station. The project pages carry the scope of each.