ORES

ORES is the distribution grid operator for most of Wallonia and part of the Brussels periphery. The Voltmasters EMS supports DSO RTU with ORES for producer sites, following the ORES specification OPM-080-ST09, the complement to the C2/112 connection prescription.

In short

• Safety decoupling does not run over this link. The ORES points carry no emergency stop and no decoupling command. Decoupling on a grid fault is the autonomous C10/21 protection in the installation, entirely outside the EMS. Do not wire or commission anything on the assumption that ORES can stop the installation through the EMS.
• Every value ORES writes is a real instruction. There is no value that means "produce freely": 0 MW means produce nothing. Before ORES has written anything, nothing is imposed at all, which is a different state from a received 0.
• Absolute setpoints, enforced at the connection point. ORES writes an absolute power; the EMS turns it into an injection ceiling, so charging the battery satisfies the ceiling just as curtailing the PV would.
• Five minutes before an instruction takes effect. Every active power setpoint carries a five-minute validity delay, including one that loosens the limit. The reactive setpoint, an absolute kVAr target per production block, takes effect straight away.
• A watchdog in each direction. By default they ride on the link itself and need nothing; hardwired, they run through interposing relays on the IO module.
• On a watchdog alarm the site falls back to its contractual permanent power. That can be looser than the standing setpoint.

Installation

ORES asks, the installation answers. The ORES 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 ORES cabinet into the customer's cabinet.

The connection diagram

Everything on this diagram is the same from site to site: the link parameters are fixed in the ORES specification and in the controller, so there is nothing to enter. The two watchdogs only appear on it when they are hardwired.

What you need

The first three lines are always needed. The rest only when the watchdog pair is hardwired; if it rides on the link itself, no extra material is involved.

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: the ORES RTU 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 contacts through interposing relays

This only applies when the watchdog pair is hardwired. If it rides on the link itself, there is nothing to wire.

ORES drives its watchdog contact with 48 VDC or 230 VAC, and the watchdog circuit it expects the installation to close runs at 48 VDC. The IO module can take neither directly: its digital inputs accept 10 to 30 VDC and its relay outputs are rated for 30 VDC. Each direction therefore passes through an interposing relay, so that the module only ever sees its own local 24 VDC.

Both relays are energised in normal operation and the contact in use is closed while all is well. Use the contact that closes when the coil is energised, so that a relay dropping out opens the circuit. That carries the logic of ST09 all the way to the wire: a loss of supply, a loss of communication or a fault in the controller de-energises the relay, the contact opens and a watchdog alarm follows, without anything having to act.

Configuration

1. Under Configuration → Grid & market → DSO RTU settings, set the provider to ORES.
2. If the watchdog pair is hardwired, assign the two contacts; if it rides on the link itself, leave them empty. See Assigning the watchdog contacts below.
3. Check that the project's grid export access power matches the contractual permanent power in the ORES connection contract. That value is the watchdog fallback.

Everything else about the link is fixed in the controller and matches the ORES validation form. There is nothing per site to transcribe, and therefore nothing to mistype.

Assigning the watchdog contacts

The two contacts sit under ORES watchdogs in the DSO RTU settings. They must be carried by an IO module:

Leave a side empty when it is not wired. A configured contact overrides the watchdog that rides on the link, for that direction.

How an active power instruction is applied

ORES splits a producer site into blocks. The site's PV sits in the first production block; storage is not a production for ORES and therefore carries no setpoint of its own.

An absolute ceiling on injection

ORES writes an absolute power, negated: a production limitation carries a minus sign on the wire. ST09 §17.4.5.4.4 allows that instruction to be enforced either on the production itself or on injection at the connection point, and the EMS takes the connection point:

injection ceiling = setpoint − site consumption calculated at the moment the instruction was received

This is the path that lets a site comply without throwing energy away. If the setpoint is 4 MW and the site consumes 1 MW, the installation may still produce 5 MW, because only 4 MW reaches the grid. Charging the battery with surplus PV satisfies the ceiling just as curtailing the PV would, and keeps the energy.

The consumption term is pinned at the moment of reception, not tracked live, because that is how ORES's own compliance check works: the calculated consumption is frozen at the instruction's arrival, so the ceiling must not drift with the load afterwards.

Five minutes before it bites

ST09 §17.4.5.4.3 gives every setpoint a validity delay: an instruction becomes valid five minutes after it is received and stays valid until five minutes after the next one arrives. Compliance at any moment is judged against the setpoint received five minutes earlier.

The EMS follows that rule exactly, which means an instruction that loosens the limit only takes effect after five minutes. Do not read the delay as a fault during commissioning: it is the specification.

No instruction, and a lost link

Reactive power

ORES steers reactive power as an absolute kVAr target per production block, not as a band and not as a power factor. The EMS applies it as the PV target of its reactive control and dispatches it open-loop across the PV inverters, respecting each inverter's apparent-power rating. ORES reads the ordered VAr back from the production block, not from the connection point.

• A received 0 is a real order: hold unity power factor.
• No target received yet leaves reactive control on its local behaviour.
• The reactive setpoint carries no validity delay and no consumption term, so it takes effect on the next control cycle.

The watchdogs

ST09 §17.4.5.5 defines a watchdog in each direction: one the operator drives toward the installation, and one the installation owes the operator in return. In both cases the signal is held active while all is well, so that losing the equipment, the wire or the power supply is itself the alarm. Losing the signal is the fault.

Over the link by default, contacts optionally

By default both watchdogs ride on the ORES link itself: the EMS sends a sign of life every second and expects one back from ORES every second. Ten seconds without one is the fault. This needs no configuration at all and no extra wiring.

ST09 also allows the pair to be hardwired as potential-free contacts. See Wiring the contacts through interposing relays for the wiring and Assigning the watchdog contacts for the setting.

When the input is trusted

Because losing the signal is the alarm, an unreadable input is treated as an alarm rather than as "no news":

The output side needs no incident of its own: if it becomes unreachable, the relay de-energises and ORES reads the alarm, which is the design working as intended.

What the alarm does

ST09 says the watchdog must be treated as a setpoint, so a change of state carries the same five-minute delay: the alarm bites five minutes after it appears and instructions resume five minutes after it clears. An alarm that comes and goes inside that window changes nothing.

While the alarm is in force, ORES's instructions are set aside entirely, whatever their value, and the site falls back to its contractual permanent power at the connection point. The EMS takes that value from the project's grid export access power, before any safety margin, so there is nothing extra to configure.

Independently of all this, the EMS keeps holding injection to the grid limits configured for the project on every control cycle, so the connection is protected whether the watchdog is up or down.

What ORES sees of the site

Every setpoint ORES sends is reported straight back to it, so its RTU can confirm the instruction landed.

A PV inverter that does not report reactive power is published as 0 VAr and raises a warning, because the reactive telemetry then understates what the installation is doing.

Issues the controller reports

Not part of this integration

• Emergency stop, decoupling and breaker position. Absent from the ORES point list. Decoupling is the autonomous C10/21 protection.
• The connection point metered by ORES itself. ORES can supply its own connection-point metering instead of reading ours. The EMS reports its own grid energy meter, which is the natural fit because the project always has one.
• A setpoint on storage. The first production block carries the site's PV; the battery is steered by the EMS to comply with the injection ceiling, not by an ORES setpoint of its own.

Next steps

• How DSO RTU works for the general control model.
• RTU connection for the on-site connection and network requirements.
• IO module for the module that carries the hardwired watchdog contacts.
• Commissioning & certification for the validation process.