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DSO RTU

Sibelga

DSO RTU with Sibelga, the Brussels-Capital Region grid operator, over a Modbus producer link with a setpoint per production type.

Sibelga is the distribution grid operator for the Brussels-Capital Region. The Voltmasters EMS supports DSO RTU with Sibelga, following the Sibelga specification SIB24 CCLB 111, with the register map from its Bijlage 2 and the instruction set from SIB25 CCLB E097.

To use it, set the DSO RTU provider to Sibelga under Configuration → Grid & market → DSO RTU settings.

Connection

Sibelga's RTU is the Modbus master and the customer's equipment is the slave. The EMS plays that slave, the role the specification calls the Centraal PLC: it serves registers and answers the RTU's polls, and never initiates traffic of its own.

Parameter Value
Protocol Modbus, the EMS as slave
Slave address 10

The specification describes the link as Modbus RTU over RS-485. In our deployment the controller serves Modbus TCP and the link is bridged to RS-485 by a gateway, which must be configured as an RTU master on the serial side and a Modbus TCP client toward the EMS.

See RTU connection for the on-site connection and network requirements.

The register map

Sibelga organises the installation by production type, each with its own block of registers in an identical layout:

Block Base register Served
PV 100 Yes
CHP 200 Published as out of service
Storage 300 Yes

The EMS controls no CHP, so that block is published as out of service with open breakers rather than left unanswered.

What the EMS reports (Sibelga reads)

Point Source
Active power The production of that type. Storage is reported as discharge power; the register cannot carry the charging direction.
Reactive power The reactive power of the devices of that type.
Cos φ The power factor derived from the two above.
Production status Whether that production type is in service.
Decoupling breaker position Read from a breaker feedback input, see below.
Back-up breaker position Read from a breaker feedback input, see below.

What Sibelga instructs (Sibelga writes)

Point Meaning
Active power setpoint A cap on that production type, as a percentage of its maximum production. 100 % means no regulation demand.
Cos φ setpoint A power factor the installation must hold for that production type.

The EMS applies the setpoint to the matching assets: the PV block steers the PV inverters, the storage block steers the batteries. An instruction outside its valid range is ignored, never applied, and raises an incident; the EMS still echoes it back as received so Sibelga can see what arrived.

Sibelga steers per production type only. There is no instruction on the grid connection point and none on the assets as a whole, so a limit always applies to the PV or to the storage, never to the site as a whole.

Reactive power

Sibelga instructs reactive power as a cos φ target per production type. The EMS applies it as its power-factor control law and distributes the required reactive power across the capable devices of that type. When neither block carries a target, reactive control stays on its local behaviour.

Breaker positions

The two breaker positions the EMS reports are read from digital inputs on an IO module. This is feedback flowing out of the installation toward Sibelga; it is not how Sibelga sends instructions.

Configure them under Switch positions in the DSO RTU settings. Each entry maps one input port to:

  • a production type: PV or battery, so the position lands in the right register block, and
  • a switch type: the decoupling breaker or the back-up breaker.

Leaving the list empty reports every breaker as in service.

The decoupling breaker is the autonomous C10/21 protection relay. The EMS never drives it: it only reports the position of that relay as telemetry. Safety decoupling happens without the EMS and does not depend on it.

No emergency stop, no reason codes

The Sibelga protocol carries no emergency-stop command in either direction (SIB24 CCLB 111 §7.13.5), so there is no relay for the EMS to assert and no DSO RTU emergency stop to configure on this provider. Grid-fault decoupling is the C10/21 relay described above.

The instructions also arrive without a reason code: an active-power or cos φ setpoint states no cause.

Incidents

Incident Severity Meaning
Sibelga Modbus server is not listening Critical The slave is not serving, so Sibelga cannot reach the installation.
Reactive power unavailable (PV or storage) Warning A device of that type does not report reactive power. The missing value counts as zero, so the reported reactive power understates reality and the reported cos φ is biased toward unity.
Invalid cos φ setpoint Warning A received cos φ instruction lies outside its valid range and is therefore ignored.

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