TenneT TSO is developing the NordLink interconnector with its consortium partners, the Norwegian TSO Statnett and Germany’s KfW IPEX-Bank on behalf of KfW. The Nordlink interconnector will run between Wilster in Schleswig- Holstein in Germany and Tonstad in the south-west of Norway. NordLink will be a bi-pole, high voltage, direct current (HVDC) interconnector comprising a pair of high voltage electricity cables. The exchange of power enabled by the interconnector will increase security of electricity supply in both countries, will contribute to increase production of renewable energy, and create an integrated and more efficient power market.
The consortium asked several suppliers to propose for the interconnector project. A control system for this Nordlink Interconnector is in the scope of this project. The quality of the control systems software is dependent on the supplier’s ability to develop and maintain protection and security software.
TenneT asked DNV GL – Energy Advisory services to conduct an assessment on the supplier’s capability to control software development and quality during all stages of the software life cycle. The objective was to assess the quality of the software development process, not the software itself. Because the outcome of the assessment was input for the overall decision, the assessments were performed within a small timeframe but amongst all the potential suppliers.
A team of DNV GL consultants developed a so called protocol based on international standards like the ISO/IEC 12207 on systems and software engineering and DNV GL best practices and complemented specific Nordlink requirements. The assessments were based on the protocol so the results of the assessments could be compared. The DNV GL team leads the assessments at the supplier sites while representatives of TenneT and Statnett witness the assessments. Because of the protocol which was send in advance to the suppliers it was possible to provide a structured feedback to the consortium at short notice.
The outcome of the assessment provided the consortium with a clear description of the approach of the software development process and the peculiarities of the suppliers. The consortium was able to estimate the risks related to software development and took this into account in their decision process.