Swiss DSO telecontrol and curtailment

In Switzerland, a distribution system operator (DSO) may require an installation to react to remote grid-control commands. Depending on the project, these commands can arrive as relay contacts from a ripple-control receiver (Rundsteuerempfänger) or through a local or cloud gateway.

This guide explains both approaches and, most importantly, where the standard configuration ends and a project-specific telecontrol integration begins.

Choose the correct integration path

Standard ripple-control configuration

The SmartgridOne Controller provides two standard Swiss DSO external-signal strategies. Both read one or two digital input devices and apply a configurable percentage of nominal active power.

You can add both strategies at a mixed site when the DSO must control solar production and controllable consumption. Configure and test the applicable assets separately.

Digital input encoding

With one digital input, the strategy provides binary control:

With two digital inputs, four states are available:

This supports a common four-stage requirement such as 100% / 60% / 30% / 0%, but the order must come from the DSO's truth table. Enter the permitted-power percentage for each asserted state exactly as approved by the DSO. Do not assume that every receiver uses the same contact order or polarity.

Hardware and wiring

The OM1 controller has two onboard digital inputs. They accept 5–50 Vdc. A passive dry contact can be wired using the controller's 12 V wetting supply as shown in the digital-input wiring guidelines.

If the controller has no available onboard inputs, use a supported external input module such as the dS1242 Ethernet relay module. The module or channel must appear as an eligible External Input in the commissioning wizard.

Do not assume that a generic smart relay is a drop-in replacement. It can only be used when its input channels are supported and appear as selectable External Input devices in the commissioning interface.

Step 1: add the digital input devices

1. Open the commissioning interface.
2. Open Devices and select Start device wizard.
3. For an onboard input, choose Energy Meter → Generic → Relay → Digital Input Device and select the connected controller input.
4. Repeat this for the second input when four-state control is required.
5. For an external module, add that module first and verify that each required input channel is visible as an External Input device.
6. Change the receiver contacts one at a time and verify that the displayed input states follow the approved truth table.

Step 2: add the Swiss DSO external signal

1. Open External Signals and select Start wizard.
2. Choose Distribution system operator / grid operator.
3. Select provider SwissDSO.
4. Select Swiss DSO Solar Peak Limiter for PV curtailment or Swiss DSO Power Limiter for batteries, EV chargers and heat pumps.
5. Select Digital input 1 and enter the permitted-power percentage for limit level 1.
6. Enable the second digital input when four states are required. Select Digital input 2 and enter the percentages for levels 2 and 3.
7. Select all controllable devices to which the signal must apply.
8. Finish the wizard and confirm that the external signal reports a connected state.

The selected devices must be controllable and must have their nominal power configured. The strategy derives each power limit from that nominal value.

Step 3: commission every state

Coordinate the acceptance test with the installer and, where required, the DSO.

1. Activate every receiver state separately.
2. Confirm the two digital input values in the commissioning interface.
3. Confirm that the external-signal status shows the expected percentage.
4. Verify the resulting active-power command and the response of every selected asset.
5. Return the receiver to its no-limit state and verify that normal control resumes.
6. Interrupt the receiver or input-module connection and verify the agreed fail-safe behaviour.
7. Record the accepted truth table, polarity, limit values and test result in the commissioning dossier.

Active power versus reactive power

The standard Swiss DSO Solar Peak Limiter and Swiss DSO Power Limiter control active power only. Additional relay contacts do not automatically add reactive-power control.

If the DSO requires Q, cos φ, power-factor setpoints or a larger command matrix, first verify that the inverter or other controlled asset supports the required reactive-power commands. The interface must then be designed as a project-specific telecontrol integration. The required protocol, input hardware and feedback path depend on the DSO data-point list and the capabilities of the controlled devices.

Project-specific gateway integration

A DSO gateway or SCADA connection is not configured through the standard Swiss relay wizard. Possible architectures include a local Modbus TCP or IEC 60870-5-104 connection, or a cloud connection through API or MQTT. The actual choice, protocol role and data points must be agreed for each project.

Before the technical review, collect:

• the DSO's complete command and feedback data-point list;
• the required active- and reactive-power functions;
• protocol and role on both sides, for example Modbus client/server;
• register addresses, data types, byte order, scaling, units and valid ranges;
• network addressing, VLAN and firewall requirements;
• command validity, acknowledgement, watchdog, timeout and fail-safe behaviour;
• the exact brands, models and communication protocols of the controlled assets;
• the controller model and serial number;
• the planned commissioning date and responsible technical contacts.

The current intake asks you to confirm a telecontrol-capable controller with two onboard Ethernet ports, such as an applicable OM1 telecontrol, OM2 or Ultra model. Submit the Telecontrol Request before fixing the commissioning date. Eniris will review device support, reactive-power capability, protocols and planning.

Troubleshooting

No digital input is available in the Swiss DSO wizard

Add the onboard input or external input module through the device wizard first. The Swiss DSO wizard only lists devices that are registered as eligible External Input devices.

The wrong limit is applied

Check all of the following:

• whether the configured value is permitted power, not reduction percentage;
• the DI1/DI2 state and receiver polarity;
• the DSO truth table and the configured value for each level;
• the nominal power configured on every controlled asset.

A selected device does not react

Verify that the device is online, controllable, included in the external signal and supports the requested active-power command. An EV charger without a connected vehicle may correctly report that no limit can currently be applied.

Reactive power does not change

This is expected with the standard Swiss DSO relay strategies: they control active power only. Use the project-specific gateway process when Q or cos φ must also be controlled.

Normal operation does not resume

Verify that the receiver has returned to the configured no-limit state and that both digital inputs display the expected values. Then check the external-signal status before investigating the local control strategy.