Direct Current – Power flOws in megawatt-scale Energy gRids

Project Information

DC-POWER

Grant agreement ID: 101135828

DOI

10.3030/101135828

EC signature date 20 November 2023

Start date 1 January 2024

End date 31 December 2027

Funded under

• Climate, Energy and Mobility

Total cost

€ 8 452 854,15

EU contribution

€ 7 136 536,50

Coordinated by

COMMISSARIAT A L ENERGIE ATOMIQUE ET AUX ENERGIES ALTERNATIVES
France

Periodic Reporting for period 1 - DC-POWER (Direct Current – Power flOws in megawatt-scale Energy gRids)

Reporting period: 2024-01-01 to 2025-06-30

Summary of the context and overall objectives of the project

DC-POWER proposes a local medium voltage direct current distribution bus architecture for the local electricity distribution to power industrial applications in the Megawatt level. DC-POWER builds on previous work done on low voltage DC distribution grids —suited for lower power levels— and extends this into the medium voltage range. This architecture is envisioned to manage electric power distribution on industrial sites or buildings, powering high-power loads while smoothly integrating local energy generation and storage. This will be demonstrated in two operational pilots: in a data centre and in an industrial application.
Main objective is to show that medium voltage direct current grids for local electricity distribution operating at bipolar ±1.5 kV—with a significant local, fluctuating generation through RES—lead to at least a 50% reduction of distribution energy losses, at least a 50% reduction in the copper used in conductors, and at least a 50% reduction of down-time compared to a standard 400V 3-phase AC local distribution grid.

Work performed from the beginning of the project to the end of the period covered by the report and main results achieved so far

During the first 18 months, efforts focussed on the specification and the development of the six key components of a local medium voltage direct current distribution bus, which we call D3-Bus (Dual DC Distribution Bus), which are shown in the diagram above and which are:

* The active frontend is connected to the medium voltage AC grid and provides power from the utility to the DC bus

* The appliance driver powers the appliances or loads, such as the electrolyser stack or a server rack in a data centre. It is a DC/DC converter with galvanic isolation. The appliance driver is powered at 3kV to reduce the currents needed to power MW scale appliances. There are two versions to adapt the voltage level of the D3-Bus (3kV) to the voltage level of the appliances of this project: one for the server racks and the other for the electrolyser.

* The photovoltaic system converter adjusts the PV system voltage to the so called maximum power point and converts this voltage for the injection of the PV energy into the distribution bus. By this way, the appliances are directly powered with green energy. The PV arrays feed each leg of the D3-Bus with a separate photovoltaic system converter to keep the PV system voltages within the low voltage limit of 1.5kV.

* The battery storage system with their corresponding DC/DC converters, which stabilize each leg of the D3-Bus separately to keep the batteries within the low voltage limit of 1.5kV.

* The power management system assures system stability, manages the battery, and assures that a maximum of PV power is used for the appliances.

* An electrical system protection designed to work at 3kV DC.

At month M18, the system and component specifications have been concluded, and heavy development efforts were made for the six key components mentioned above, and concrete designs are available. Laboratory prototypes will be delivered in M22 with a delay of four months, the final versions are expected in M30 if the delay of four months can be recovered.

The definition of the data center pilot has been concluded in a deliverable, for the electrolyser pilot the efforts are still ongoing.

Progress beyond the state of the art and expected potential impact (including the socio-economic impact and the wider societal implications of the project so far)

The first result is a system concept for the local medium voltage direct current distribution bus, which we call D3-Bus (Dual DC Distribution Bus). To our knowledge, this is the first system concept for medium voltage DC grids for industrial applications. Profit has been made from the concept published by the Open Direct Current Association (OCDA) which is limited to low voltage DC system.
Other results concern the 6 key components of the D3Bus system listed above, for which detailed specifications have been elaborated and which are today in a design and development phase and where the laboratory prototypes are expected in month M22 (October 2025). Prototypes for pilot sites are currently expected for month M30 (June 2026), and the test of pilots is expected to last until M45.

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