Realtime Interface (RTI)

Why is Netbeheer Nederland introducing the Realtime Interface?

Netbeheer Nederland: “With the energy transition, a large-scale emergence of sustainable generation installations in the distribution networks of regional grid operators is visible. This development ensures the return of large powers to grid parts that were not originally designed for this. This has already led to congestion problems and transport restrictions in many places. The purpose of the interface is to enable collaboration between generators and grid operators to increase and better utilize transport capacity and safely maintain the electricity network.”

For which systems is the RTI mandatory?

The RTI is mandatory for all new feed-in generation connections or existing connections requesting a capacity increase, with a capacity between 1 and 50 MW. This is category B of the European Regulation Requirement for Generators (RfG). That also include energy storage systems.
At a later stage, the RTI will apply to other categories (A, C and D) and to existing connections. However, you can already voluntarily request an RTI.

Can the grid operator switch off my installation?

Under certain circumstances, such as acute grid congestion, the grid operator can switch off a generating installation.
If it happens, there is a compensation for this.

What functionalities should the RTI have?

The generator must install a customer endpoint able to receive and process the control signal from the grid operator in accordance with IEC-61850.
As a connected party, it is desirable (but not mandatory) that this functionality is combined with the additional control signals in order to participate in TenneT’s balancing markets.

What does a customer endpoint consist of?

The customer endpoint consists of:
• A controller (such as the Teleport) to receive the signal from the grid operator, process it and send it to the generation plant(s).
• A metering system to be able to measure the load at the transfer point.
• Connectivity, so that mandatory cybersecurity updates can be performed.

What is the legal basis for the RTI?

Article 14.2, part B, of the European RfG legislation:
“Type B power-generating modules shall fulfill the following requirements in relation to frequency stability: the relevant system operator shall have the right to specify the requirements for further equipment to allow active power output to be remotely operated.”

Who is responsible for the RTI?

The grid operator is responsible for the DSO endpoint. The customer is responsible for the customer endpoint and the cable to the DSO endpoint.

Who pays for the RTI?

All equipment from the grid up to the connection transfer point is owned by the grid operator (including the DSO endpoint). Everything from this point within the connection is owned by the generator (connected party). Thus, the generator is responsible for providing a functioning customer endpoint and the Ethernet cable.

How do I install the Teleport as a client endpoint?

The Teleport can handle over 300 asset protocols, including the most commonly used PV park controllers, wind turbine systems and battery systems. See the full list of compatible assets here.
To get your Teleport, contact us.

Where do I install the client endpoint?

In a logical and safe place for the connected person from which a connection can be made to the DSO endpoint. At the closed part of the MS room.

Who will install this for me?

The affiliate must take care of the purchase and installation of the customer endpoint. In some cases the grid operator will have to take care of this.

How do I see that the RTI has been activated by the network operator?

The Teleport automatically creates a log of all activations performed by the network operator. If there is a data forwarding link between the Teleport and the systems of the connected party and/or the energy trader, those logs will also be available in those systems.

How does switching by the grid operator compare to switching for other things such as TenneT balancing markets?

These things are separate from each other. However, direct switching by the grid operator has priority over any other switching action. The Teleport as a customer endpoint can clearly distinguish this.

Will I be reimbursed if I am disconnected?

The generator will be compensated when the grid operator uses the RTI. The extent and manner depend on the application framework.

What does the reimbursement process look like?

The connected party must provide an overview of the missed electricity generated and lost income. The Teleport can generate the necessary source data for this.

How do I make existing generation facilities suitable for the RTI?

Many PV inverters, even very old ones, are already set up to be controlled by a centralized control system. They provide a standard communication protocol with registers that can receive commands. Please check compatibility in the product manual or in the document describing the communication protocol. The Teleport is already linked to dozens of brands and hundreds of types.

What about a site with multiple generation facilities (solar, wind, battery combined), how does the customer endpoint handle that?

The grid operator sends a power framework to the connection. How that is realized is up to the connected party. For example, whether solar is curtailed or battery charged. The Teleport as customer endpoint can differentiate this according to the customer’s requirements. During commissioning, the parameters are determined.

May the customer endpoint be accessible via the Internet?

The customer endpoint may not be directly accessible via the internet, only via secure access.

How is cybersecurity ensured?

• Passwords must be unique and strong based on section 5 NIST SP 800-63B.
• There must be a process to implement security updates remotely on the Realtime interface. The following must be monitored: vulnerability lists, manufacturer notifications and new release notes. Patches and updates should be implemented immediately after compatibility testing.
• Cybersecurity training must be followed by the administrators of the customer endpoints.
• The Teleport and the processes meet these requirements

What other security requirements are needed?

ISO 27001 is desirable for data protection and additional requirements as set out by the European Network for Cybersecurity (ENCS).

What should the time accuracy be?

A maximum deviation of 10 seconds is allowed.

Where can I find the specifications for the RTI?

Because it is a national standard, the specifications are published on the Netbeheer Nederland website.

How does the customer endpoint control the generation facilities?

The functionality of the real-time interface is based on reading the powers and voltages at the transfer point and the possibility of sending control signals (set points). In most cases communication will take place using a protocol such as Modbus RTU or Modbus TCP. The Teleport as a customer endpoint already has most protocols of commonly used generation installations in its asset library.

How does the grid operator obtain measurement data?

The measurement data is requested by the DSO endpoint and sent to the grid operator. If the generation installation is close to the transfer point (taking cable resistances into account) and there is little self-consumption (impact on power), the measurement data from the generation installation can be used directly (if they meet the correct measurement class).

What class should the measurement data have?

Measurement data must have a class 1 accuracy in line with IEC-61869.

Can the client endpoint for the real-time interface also be used without separate measurement devices?

The customer endpoint for the real-time interface can also be used without separate measuring equipment if the generation installation meets the measuring class and is representative of the behavior at the transfer point.

What about liability of measurement data?

The grid operator and the generator are each individually liable for the quality of the measurement data and any resulting damage.

What type of control commands (setpoints) should the client endpoint be able to process?

• Maximum generated power in % and as absolute value [MW] and the maximum consumed power in absolute value [MW].
• Reactive power in [MVAr].
• The reason why a setpoint was sent.

What metrics should the client endpoint be able to read?

Current power in MW, Current reactive power in MW, Current voltage on all phases in kV, Current current on all phases in A.

What happens when the connection is lost (safe-mode)?

A fail-safe logic is implemented to prevent unnecessary curtailment of the installation:
• If communication is no longer possible between the customer endpoint and the DSO endpoint after a set period, the generated power must be switched back. The established period and the safe-mode setpoint are determined in advance.
• The grid operator can remotely read and set these safe-mode setpoints in MW and %.
• When communication is restored, the 15 minute average, minimum and maximum power values of the past 8 hours must be sent.

Should measurements be forwarded immediately?

The grid operator determines the frequency with which measuring signals are automatically sent (integrity reports). In addition, the grid operator can set it to receive measurements when there is a change in measurements (for example when power or voltage is lost) (data change).

What is the availability of the client endpoint?

The customer endpoint must have an availability of at least 99% of the time measured over a period of 6 months in accordance with IEC-60870-4 class A1. In addition, the DSO must be able to retrieve the status of the customer endpoint.

What are the response times required?

Communication between the endpoints may not take more than 4 seconds. The maximum response time between the asset and the customer endpoint varies per use case. For the first use cases (acute congestion), the response times inherent to Modbus RTU and Modbus TCP protocols comply, among other things. The time to start up after different types of interruptions may take a maximum of 3 minutes.