Converter-based generation is increasingly producing renewable clusters in which several hybrid wind-battery plants operate in parallel at a shared grid connection point. While a single hybrid plant's dynamics are well studied, multiple independently controlled hybrid plants at a common point of common coupling (PCC) respond to the same disturbance through their own local controllers, unaware of their neighbours, with no guarantee that individually well-behaved plants combine into well-coordinated system-level behaviour. This thesis investigates whether, where, and by how much coordinated dynamic control improves the disturbance response of such a cluster, using a case inspired by a Finnish hybrid renewable project studied in collaboration with DNV, in which three wind farms (129, 149, and 102 MW) and two battery energy storage systems (30 MW, 60 MWh each) inject into a shared 110 kV connection point.

An RMS model of the five-unit system is developed in DIgSILENT PowerFactory: all units are aggregated grid-forming converters based on the REGFM_A1 droop model, extended with a Frequency Sensitive Mode (FSM) block for the grid-code-required primary frequency response and, for the wind units, a dispatch-anchored active-power limit that blocks sustained upward power. The coordinated design separates two time scales: a fast primary layer, whose droop and FSM parameters are tuned by an Optuna-based optimisation within physically bounded, per-technology search spaces, and a slow supervisory layer that measures only the PCC and restores its frequency and voltage through deadbanded integral loops allocated to the converters by participation factors. A four-configuration ablation evaluates the layers separately and in combination across four grid-code-oriented disturbances: active load steps in both directions, a reactive load step, and a short-circuit.

The uncoordinated grid-forming baseline already arrests every disturbance in a stable, well-damped, and complementary manner: the feared inter-plant control conflicts do not materialise, because droop control is itself a decentralised sharing mechanism. On this baseline, the tuned primary layer reduces the load-step frequency excursions and the supervisory layer removes the residual steady-state deviations and returns the PCC voltage towards nominal; the two contributions are additive, with no interference between the layers, directly validating time-scale separation as the architectural principle. Restoration is structurally asymmetric between the load-step directions, because the wind units cannot realise upward corrections, demonstrating that the allocation of restoration effort is a genuine design variable.

The central conclusion is differentiated: grid-forming control substantially reduces the need for explicit inter-plant coordination in the disturbance time frame; the measurable value of a coordination layer lies instead in secondary restoration of the connection point, in deliberately allocating that effort, and in operational and governance functions no local controller can provide. Requiring only one measurement point and one slow correction channel per converter, and degrading gracefully to stable uncoordinated behaviour if disconnected, the supervisory layer is practically feasible as a retrofit across plants that share neither an owner nor a control room.
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This report focuses on the USB implementation subgroup of the Wrepair Powerstation Project, which aimed to design and develop a versatile USB powerstation capable of supporting both high-power delivery and data transfer through USB Type-C ports. The implementation involved integrating advanced charging protocols, real-time measurements, and power control capabilities into a modular system that can seamlessly fit into existing Wrepair stations. This integration enables the powerstation to feature dynamic power allocation and visualisation of charging performance.

Key tasks of this project included selecting appropriate power delivery integrated circuits (ICs), designing a high-speed USB data hub, and developing control hardware to manage power and data flow efficiently. The USB charging station is designed to support up to 100W per port, with a total available power budget of 300W, distributed across six USB Type-C ports. The powerstation also incorporates safety features to protect against overcurrent, overheating, and short circuits, ensuring user safety and device protection.

The report details the design process, including the selection of components, system integration, and validation procedures. The design process involved evaluating different power delivery systems, including development boards, PD modules, and stand-alone chips, to select the most suitable solution for the project requirements. The chosen solution, the IP2368 PD (Power delivery) module, was initially tested but was found to be inadequate, leading to the exploration of alternative modules such as the SW2303 and MAX25430 development boards.

Furthermore, the design includes a USB data hub sub-module to facilitate high-speed data transfer and connectivity. This hub supports multiple devices and allows for real-time data logging and display, enhancing user interaction and monitoring capabilities. The validation and evaluation phase involved rigorous testing of the USB implementation submodule, including power delivery, measuring and controlling capabilities, and overall system integration.

The results demonstrate that the USB implementation meets the required specifications, ensuring efficient power distribution and data handling for multiple devices. This work contributes to the overall Wrepair Powerstation Project by providing a robust and scalable USB solution that enhances the functionality and utility of Wrepair stations. ... Read more