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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 instruction set from SIB25 CCLB E097.

In short

  • Safety decoupling does not run over this link. The decoupling breaker is the autonomous C10/21 protection relay. The EMS only reads its position and never drives it.
  • No emergency stop. The protocol carries none in either direction, so there is no emergency stop to configure for this operator.
  • Sibelga steers per production type. A limit applies to the PV or to the storage, never to the whole site: there is no instruction at the connection point.
  • The active power setpoint is a percentage of that type's maximum production, and 100 % means no control request.
  • The reactive setpoint is a cos φ target per production type.
  • An instruction outside its valid range is ignored and raises an incident. It is still echoed back as received, so Sibelga can see what arrived.

Installation

Sibelga asks, the installation answers. The Sibelga RTU reads the site's measurements and writes the setpoints to it; the EMS never initiates anything of its own. The link itself runs over RS-485, from the Sibelga cabinet into the customer's cabinet.

The connection diagram

Connection diagram of the Sibelga link: the Sibelga RTU runs over an RS-485 line to a gateway configured as a master on the serial side, and from there over Ethernet to the Voltmasters controller. The decoupling breaker, the C10/21 relay, and the back-up breaker each report their position through a potential-free auxiliary contact to a digital input of the IO module, per production type. The IO module sits on the same network as the controller.

The Sibelga link in the cabinet: one RS-485 line for the setpoints, and the two breaker positions on digital inputs of the IO module.

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

What you need

The first three lines are always needed. The rest only when you report the breaker positions; without them the EMS reports every breaker as in service.

Item What for
RS-485 to Ethernet gateway, as a master on the serial side Converts the Sibelga RS-485 line to Ethernet.
Shielded twisted-pair cable for A, B and GND The RS-485 line from the Sibelga RTU to the gateway.
Ethernet cable From the gateway to the Voltmasters controller.
Voltmasters IO module Carries the digital inputs for the breaker positions.
Potential-free auxiliary contacts on the breakers One per breaker and per production type: the decoupling breaker and the back-up breaker.
24 VDC power supply on DIN rail Powers the IO module.

The RS-485 gateway

The controller has no RS-485 port of its own, so a gateway sits in between that converts the serial line to Ethernet. That gateway must be configured as a master on the serial side: Sibelga issues the requests, the gateway forwards them to the controller, and the responses go back out on RS-485. This is the reverse of the usual setup, so it is worth double-checking during installation.

Wiring the 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.

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.

Configuration

  1. Under Configuration → Grid & market → DSO RTU settings, set the provider to Sibelga.
  2. Assign the breaker positions under Switch positions. See Assigning the breaker positions below.

Assigning the breaker positions

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 on the right type, and
  • a switch type: the decoupling breaker or the back-up breaker.

Leaving the list empty reports every breaker as in service.

What Sibelga instructs

Sibelga organises the installation by production type: PV, CHP and storage. The EMS controls no CHP, so that type is published as out of service with open breakers rather than left unanswered.

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 type steers the PV inverters, the storage type 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.

What Sibelga sees of the site

Point Source
Active power The production of that type. Storage is reported as discharge power; the telemetry 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 digital input, see Wiring the breaker positions.
Back-up breaker position Read from a digital input, see Wiring the breaker positions.

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.

Issues the controller reports

Incident Severity Meaning
Sibelga link down Critical The link is not open, 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.

Next steps