ETIP Photovoltaics

Roadmap 5

Interoperability in communication and operation of RES smart grids

Rationale for Support

Due to the lack of common rules, country specific grid codes, standards and interconnection rules, different com- munication approaches and protocols are used and there- fore quite often installation/energy application is different. The design and engineering effort therefore is quite high. Also, the scalability of such solutions suffers, calling for modifications and adaptation with added complexity and cost.

The following main problems exists today related to ICT solutions for Smart Grids with a high share of DER:

  • Missing common application modelling concepts for power and energy systems,
  • No existing model-based engineering concepts for energy applications in heterogeneous, distributed environments,
  • Scalability and openness in Smart Grid solutions with a high share of DER components only partly addressed,
  • Lack of common and open communication interfac- es in Smart Grids impede scalable and distributed automation solutions,
  • Missing possibilities to update and extend DER functions and ancillary services,
  • Available proprietary automation solutions in Smart Grids prevent efficient reuse of control software, thus the engineering costs exceed admissible costs by far,
  • Lack of cyber-security of DER devices (i.e. cyber-se- curity protection means are partly missing)


Currently, the availability of ancillary services (e.g., local voltage and frequency control) provided by DERs (e.g., PV-inverters) enables local energy control. For instance, lo- cal voltage control using reactive power is commonly avail- able. If active, such a local voltage control function tries to keep the voltage at the Point of Common Coupling (PCC) at a level usually specified by a characteristic curve. Most of the PV-inverter manufacturers provide some kind of interface to their inverters (mainly proprietary protocols and data models) where the characteristics of the control can be specified and/or adapted.

If the local DER control is active, the area of influence voltage (and many other physical parameters) can be controlled in the power distribution grid. However, with- out coordination, the operation of the whole grid may be sub-optimal. In order to achieve a global optimum, a coor- dinated distributed function is necessary.

Targets, Type of Activity and TRL

The massive deployment of distributed generators from renewable sources in recent years has led to a fundamen- tal paradigm change in terms of planning and operation of the electric power system and its grid. Smart Grids are one of the most promising solutions to use the existing grid in a more efficient way, thus allowing higher penetration levels of renewables. To capture the benefits of such in- telligent power grids, it will be necessary to develop new information and communication solutions, automation architectures and control strategies. That opens the abil- ity to effectively manage the large numbers of dispersed generators and to utilise their “smart” capabilities. How- ever, up to now a common and formal modelling concept for energy applications used in Smart Grids and distributed energy resources is still missing. Moreover, the scalability and openness of today’s utility automation systems that handle a high number of distributed generators needs to be improved due to the lack of common and open inter- faces as well as the usage of a huge number of different protocols.

Future inverter systems need to be interoperable from the automation/control and communication point of view and they should provide advanced services including auto-con- figuration of PV plant components.

There is still a lack in the harmonization of PV plant con- trol and the access of power grid operators since domain standards like Modbus/Sunspec or IEC 61850 for remote control are partly implemented by vendors. Another issue is that vendors usually use proprietary solutions for mon- itoring. Moreover, an ICT framework to model and imple- ment local but also distributed/remote control strategies in an easy manner is also not possible. Therefore, changing grid codes, standards, interconnection rules for DER and changing requirements cannot be quickly addressed in a complex, distributed Smart Grid system environment.

Digitalisation can provide architectures, concepts and methods for the creation of a truly open and interoperable information and automation solution for the integration of renewable energy sources into Smart Grids. Moreover, it can also help to define a kind of an access management for distributed energy resources, which takes different user roles in the Smart Grid into account and therefore make such a system more robust and resilient against cyber-at- tacks.

Based on the above outlined shortcomings and open is- sues of currently available approaches, the following top- ics need to be tackled

Develop interoperability on inverter level for fully integrated and connected systems.
Develop connectivity with various communication protocols to allow for appropriate functionalities in different system applications (not all protocols have the same level of complexity and functionality, such as Modbus/Sunspec or IEC 61850).
Integration of 3rd party applications on inverter platforms, allow for additional software components, e.g., forecasting, energy trading functions, remote controllable functions and services.
Develop cybersecurity schemes for interconnected and controlled PV systems.
Develop reliable and redundant communication systems for mission critical applications.
Planned activities for developing the required inter- operable smart grid systems with trustful communi- cation systems are the following:
  • Action 1: Technical development of interopera- ble control systems of inverter-based solutions moving TRL from 6 to 8 by 2025
  • Action 2: Technical development of communica- tion protocol connectivity of system applications moving TRL from 6 to 8 by 2027.
  • Action 3: Technical development of for the inter- operable integration of third-party applications in the inverter platforms moving TRL from 6 to 8 by 2030.


Possible KPIs that can be utilised for capturing progress in the above identified R&I fields are:

KPITarget Value
Build a resilient, open automation and control architecture for
inverter-based DER

By 2025 to be operational

Develop accessible source-based reference implementation of
an open automation architecture

By 2025 to be operational

Develop a role-based access management for inverter-based
By 2025 to be operational
Fully interoperable advanced (remote controllable) inverter
services with standardized and safe/resilient communication
By 2027 to be operational