How to improve smart grid interoperability – ISGAN

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A community-driven management approach is recommended to address the complexity of interoperability in the smart grid.

The perennial challenge of interoperability in the smart grid is once again highlighted in a new discussion paper from the International Smart Grid Action Network (ISGAN).

The challenge is not the lack of adequate technical standards but the absence of governance of processes, the paper states, highlighting the lack of a central stakeholder which prevents the development of holistic and system-independent solutions and the difficulty to find a consensus between the stakeholders beyond the lowest common denominator.

Furthermore, no technical standard or key concept alone can guarantee ‘perfect’ interoperability. For example, the Common Information Model or IEC 61850 describe suitable information models for their individual scope but they do not define a context and, therefore, do not guarantee so-called ‘pragmatic’ interoperability.

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Case studies and experience from the healthcare sector show that these individual methodologies complement each other and in combination are able to improve interoperability significantly utilising concepts addressing different levels of interoperability, the paper states.

In order to achieve interoperability between the individual systems, a common understanding of the technical (syntax), informational (semantic) and the organisational (pragmatic) levels needs to be achieved.

The paper points to the suitability of a community-driven management approach involving users, vendors and other stakeholders, citing the ‘Integrating the Energy System’ (IES) Austria initiative, which in turn drew on the ‘Integrating the Healthcare Enterprise’ initiative that has established itself as a driver for interoperability in the health sector.

The IES methodology, which appears similar to that advocated by the US National Institute of Standards and Technology (NIST) in its February 2021 release 4.0 of its smart grid framework, is said to provide a transparent, manufacturer-neutral and cooperative process to define interoperability profiles and perform interoperability testing of ICT systems.

The methodology is based on four phases:

  1. Identify use cases where interoperability is an issue and specify these by identifying the system borders and requirements.
  2. Jointly identify how interoperability issues can be prevented and specify the requirements normatively as an Integration Profile.
  3. Test independent prototype solutions against each other in an annual plugfest and iteratively improve the Integration Profile.
  4. Publish interoperability test results for each participant/vendor.

The paper notes the need for the integration profiles – which are essentially similar to the basic application profiles of IEC 61850 – to be published in a freely accessible way for third party access.

Once a system has successfully passed all necessary tests, an ‘Integration Statement’ can be published specifying the use cases and integration profiles a given system is designed to support.

The NIST document notes the need for proper development of interoperability profiles, stating the basic set of elements to include the asset description and associated physical performance specifications, communication protocol and information model.

The NIST also advocates the need for the development of open-source test harnesses to eliminate barriers to entry for interoperability testing efforts, and facilitate a rapid expansion of interoperability focused formalised testing and certification programmes.