D7.3 Innovative approaches for rig testing in wave energy report

The present deliverable releases the results regarding the novel dual-Hardware-In-the-Loop (Dual HIL) approach, methodologies and metrics proposed in the IMPACT project. It does so in order to facilitate their implementation in future testing practices for the development of wave energy technologies. Section 2 provides an overview of the IMPACT project, including its structure, implementation, motivation, project partners and objectives.
The definition of the test rig parameters and mechanical specifications is intrinsically linked with a detailed understanding of the loading environment that a Wave Energy Converter (WEC) will be subject to during its lifetime. In the initial phase of the IMPACT project, four research areas - mechanical/structural, electrical, techno-economic and environmental – were addressed in parallel to inform the baseline test rigs developments, namely their requirements and specifications. In Section 3, the definition of a WEC database to characterize the parameters of different WEC types and modes of operation is described, from which was made a selection of WEC target deployment sites and relevant environmental conditions, in order to characterize the range of environmental conditions that WECs can be exposed to. This was followed by the creation of numerical models for the selected WECs to simulate various design situations and define the mechanical specifications for the test rigs needed to satisfy the combination of WEC types. Section 3 compiles the test rigs specifications and discusses associated limitations and assumptions.
The demonstration of survivability and reliability are at the core of WEC design and underpin the success of a future wave energy industry. Section 4 identifies testing methodologies and metrics that support the development of WECs, specifically under three evaluation areas: performance, reliability, and survivability. The proposed novel testing framework aims at ensuring the survival of a WEC over the full range of Design Load Conditions and demonstrating its reliability for the duration of its design life. The critical aim here was to accelerate technology development and provide test-based inputs to key design drivers, leading to shorter development pathways to the market. Specifically: a) the rigs specifications were harmonized to be made compliant with different testing approaches; b) a methodology for the accelerated testing of WEC design situations to demonstrate the survivability and reliability of a WEC was defined; and c) several novel metrics to demonstrate the survivability and reliability of a WEC and its key subsystems were defined.
Based on input data from the project, the Dual HIL testing platform was designed and activities were divided into: a) designing, manufacturing, assembling of the drivetrain test rig; b) designing, manufacturing, assembling of the structural components test rig; c) execution of the acceptance tests of the two test rigs; d) integration of the two Hardware-In-the-Loop (HIL) test rigs to develop the Dual HIL testing platform. Section 5 describes the design of the test rigs and the Dual HIL platform. Namely the architecture, testing capabilities, final specifications, the assembly of the units, and the Internet-of-Things (IoT) framework including digital twins of the rigs and Device-Under-Test (DUT) for monitoring and analysing the key test results.
Section 6 provides an overall description of the tests carried out in the project with the rigs and discusses the applicability of the novel testing methodology. It includes a brief explanation of the selection process for the case studies and the approach for test and risk management. It summarises the testing campaign management activity, which aimed to select candidate devices for testing on the IMPACT rigs and manage the corresponding testing campaigns. In particular, it addresses the relevant test procedures and documentation, including applicable details related to the planning, execution and post-test phases, i.e. pre-processing, processing and post-processing considerations. In fact, the completion of both HIL and Dual HIL tests in the IMPACT rigs can be seen as a demonstration of their capabilities, bringing new a new testing approach to the ocean energy sector.
Finally, Section 7 lists several key conclusions about the project, focusing on further recommendations for using the IMPACT testing platform after the end of the project and for establishing Dual HIL as a best practice to accelerate the development pathway of the ocean energy technologies.