Grid compliance · Belgium
DSO-RTU compliance for solar and battery installations: everything you need to know
Remote grid control lets the Belgian grid operator remotely measure and regulate your installation during grid congestion. From certain power levels it is mandatory for every new or modified grid connection. The Voltmasters EMS handles the full connection and guides certification.
What is DSO-RTU compliance?
DSO-RTU compliance (remote grid control) is the system by which the grid operator, whether that is Fluvius, Sibelga, ORES or RESA, can remotely measure and regulate your installation. Via a standardised communication protocol (IEC 60870-5-104) the grid operator sends setpoints to your energy management system: how much power your inverters or batteries may maximally inject or consume.
The goal is to prevent grid congestion. As more solar parks and batteries connect to the distribution grid, certain zones become overloaded. With remote grid control the grid operator can locally and in real time adjust the load without physically going on site or having to carry out costly grid reinforcements immediately.
For you as an installer or project developer, DSO-RTU compliance means concretely: your EMS must be able to receive, process and execute the signals from the grid operator, and correctly report back the current state of the installation. The grid operator validates this live before commissioning.
What the grid operator can request
- Limit active power: P-setpoint for the maximum power to inject or consume
- Regulate reactive power: Q-setpoint or cos φ for voltage support
- Activate emergency stop: immediate disconnection of all injection via a hardware contact
- Receive status reporting: current power values and alarms per asset category
Important: remote grid control does not give the grid operator access to your business processes or other systems. It can only adjust the energy parameters of your decentralised sources, nothing more.
When is DSO-RTU compliance mandatory?
The obligation applies to every new or modified grid connection. If you add extra PV capacity or a battery to an existing installation, the grid operator recalculates whether the combined capacity exceeds the threshold.
Inverter capacity (kVA): when does the obligation apply?
PV and battery capacity are added together. In congestion zones the 400 kVA threshold also applies to PV.
Fluvius
Flanders- ≥ 250 kVA Battery storage (BESS)
- ≥ 400 kVA In congestion zones
- ≥ 1 MVA All decentralised sources
PV and battery capacity are added together. In congestion zones (Fluvius determines this via a grid analysis) the lower threshold of 400 kVA applies.
Sibelga
Brussels-Capital Region- ≥ 250 kVA Battery storage (BESS)
- ≥ 1 MVA All decentralised sources
Sibelga largely follows the same logic as Fluvius. The exact thresholds and validation procedure are aligned per project.
ORES
Wallonia- ≥ 1 MW Remote grid control always required
- > 250 kVA If ORES imposes it
- < 250 kVA Provisions on motivated request
ORES follows the federal C10/11 prescription and the Walloon technical regulation. Above 250 kVA remote control is not automatic: the grid operator has to impose it. Batteries count as a production unit.
RESA
Wallonia (Liège)- ≥ 1 MW Remote grid control always required
- > 250 kVA If RESA imposes it
- < 250 kVA Provisions on motivated request
RESA is the grid operator in the province of Liège and follows the same Walloon rules as ORES. Below 250 kVA, RESA can require the installation to be prepared for a remote control cabinet on motivated request, approved by CWaPE.
Unsure whether your project falls under the obligation? Take the total inverter capacity of PV and battery combined, add them up and compare with the thresholds for your region. We help you do the calculation and prepare the application.
How does DSO-RTU compliance work technically?
The grid operator installs an RTU cabinet on your site. At Fluvius this is the Netflex 5 cabinet. Your EMS acts as the Customer RTU that receives the signals from that cabinet and translates them to your assets.
DSO-RTU signal chain
SCADA
Grid operator
IEC 60870-5-104
RTU Cabinet
By grid operator
Ethernet
Voltmasters EMS
Customer RTU
Modbus · SunSpec
Your assets
PV · Battery
Grid operator sends setpoint
Via the RTU cabinet a P or Q setpoint arrives at your EMS. This can happen at any time of day, including outside business hours.
EMS processes and controls
The Voltmasters EMS calculates how the setpoint is distributed across your inverters and batteries, taking site limits and safety margins into account.
EMS reports back
The current power values, availability per category and any alarms are sent back via IEC 60870-5-104 to the grid operator's SCADA.
The control loop, visualised
The grid operator commands, the controller regulates, the site reports back
The grid operator sets a power limit over the IEC 60870-5-104 protocol. The Voltmaster Controller ramps the assets down in a controlled way and feeds the measurements back in real time, with an independent hardware emergency stop that the controller executes through its IO extension as a safety net.
Voltmasters EMS: certified for DSO-RTU compliance
The Voltmasters EMS has the IEC 60870-5-104 server built in and has been validated by Fluvius. We handle the full remote grid control connection, from the initial cabling to the certification session.
- Built-in IEC 60870-5-104: no extra gateway needed, the RTU cabinet connects directly to the Voltmasters Controller
- IO extension for dry contacts: P-setpoint, Q-setpoint, emergency stop and status feedback per asset category correctly wired
- Internal simulation before validation: we test all signals internally so the session with the grid operator succeeds first time
- No conflict with energy trading: DSO-RTU priority is always respected, energy trading resumes as soon as the restriction is lifted
- Fluvius, Sibelga, ORES and RESA: support for the four largest Belgian grid operators with their specific requirements
- Certification in a single session: thanks to preparation and experience across dozens of Belgian projects, validation is typically completed in one day
Fluvius specific
Netflex 5: the Fluvius RTU cabinet in detail
Is your project subject to Fluvius? Read everything about the Netflex 5 cabinet: thresholds, signals, certification process and how the Voltmasters EMS handles the connection.
Getting DSO-RTU compliance sorted for your installation?
Tell us the total inverter capacity and location. We assess the obligation, handle the connection and guide certification with the grid operator.
FAQ
Frequently asked questions about DSO-RTU compliance
What is remote grid control at Fluvius?
Remote grid control is the system by which Fluvius can remotely measure and regulate your installation via the Netflex 5 cabinet. Via the IEC 60870-5-104 protocol, Fluvius sends power setpoints (P and Q) to your EMS. Your controller translates these to the inverters and batteries and reports the current state back.
From how many kW is DSO-RTU compliance mandatory?
At Fluvius (Flanders) remote grid control is mandatory for battery storage (BESS) from 250 kVA, in congestion zones from 400 kVA, and for all decentralised sources from 1 MVA. PV and battery capacity are added together. Sibelga applies comparable thresholds. In Wallonia (ORES and RESA) the federal C10/11 prescription applies: remote grid control is always required from 1 MW, and above 250 kVA as soon as the grid operator imposes it.
Does DSO-RTU compliance also apply to solar panels without a battery?
Yes, for large PV installations. Without a battery the obligation only applies from 1 MVA inverter capacity. If you add a battery, the capacities are added together and the lower battery thresholds apply (250 kVA).
What is the difference between DSO-RTU compliance and Netflex 5?
Remote grid control (DSO-RTU compliance) is the umbrella term for the system of remotely measuring and regulating decentralised sources. Netflex 5 is the specific version of the Fluvius RTU cabinet that Fluvius installs at your installation. Sibelga, ORES and RESA have comparable systems with their own names.
Can my installation still do energy trading when DSO-RTU compliance is active?
Yes. When the grid operator is not sending an active setpoint, your installation has full freedom for energy trading. If Fluvius does send a setpoint, the Voltmasters EMS automatically adjusts the trading strategy so the setpoint is respected. As soon as the restriction is lifted, trading resumes.
How long does DSO-RTU certification take?
With good preparation, the validation session with the grid operator is completed in a single day. Voltmasters tests all signals internally before the session. Expect 2 to 6 weeks lead time for the full procedure, including application and scheduling with the grid operator.
Sources
Official sources and standards
This page is based on the grid operator and standards documents below. Always check the most recent version at the publisher.
Looking for the technical details and step-by-step configuration? You will find them in our documentation.
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