Posters

Abstract

In this contribution, we propose a modelling framework specifically designed for the analysis and design of HVDC multi-terminal systems, see Figure 1. This framework accommodates both average modelling and Electromagnetic Transient (EMT) simulation approaches, each serving distinct purposes in system analysis. The proposed workflow follows an iterative process, beginning with the HVDC project requirements. The initial phase involves component selection, topology definition, and initial sizing, which may result from a techno-economic analysis that considers external incentives and supplier agreements. Next is the model build-up phase. For small-scale systems, this process is typically manual, while for largescale systems, it is often automated. At this stage, controller models are integrated into the system, see Figure 2 for different architectural variants. These models are usually provided by the Original Equipment Manufacturer (OEM) as black box modules with limited tuneable parameters and a list of setpoints serving as the main inputs. Integration of these black box models can be achieved through various methods, including the Functional Mock-up Interface (FMI) approach, which has recently gained wide acceptance in the industry. Following model integration, fault analysis is performed on either the DC or AC side. The fault occurrence time, duration (depending on the clearance mechanism), and location can be randomized to explore all probabilistically sound scenarios. This step helps in identifying potential issues and understanding system behaviour under different fault conditions. The final step is requirements validation, which typically involves impedance estimation to analyse potential oscillations and controller tuning to mitigate these oscillations. This step also helps identify critical scenarios that might necessitate architectural changes, such as switching from reactive power control to AC voltage control, especially in weak AC grid environments. The workflow can be repeated iteratively until all requirements are satisfactorily met.