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Elektro internationaal dc grid 05

how the Ei•dcgrid works 

The Ei•dcgrid is a microgrid that runs entirely on DC (Direct Current) and is made up of components that are Current/OS compliant.

1. AFE (Active Front End)

The AFE is the bidirectional Interlink converter that ensures DC grid stability in the microgrid. In addition, the AFE provides galvanic isolation between the AC and DC grid.


A collection of batteries that serves as support for delivering the desired power when it is not available from renewables.

3. Battery chargers

The DC battery chargers are connected to the Battery Management System of the Battery Racks. These chargers provide communication with the batteries about the state of charge and charging / discharging.

4. Optional DC busbar

DC busbar system to which all power sources and consumers can be connected. Distribution boxes with DC protection can be installed on this busbar system.

5. Current Routers

The CRN are the solid state protection components that protect each individual (group) of consumers against short circuits, overloads, and ground faults. The tripping time of the CRN is less than 8µs.

6. PV optimizers

These connections between the generated solar power and the DC microgrid ensure that the voltage of the PV panels is fed into the DC grid without too much disruption.

Droop rates replace expensive software

Unlike an AC microgrid, the Ei•dcgrid operates without complicated software but through voltage-level control, called droops. The nominal voltage levels for this system are set at 700Vdc/350Vdc. Voltage limits are specified within these levels. The voltage within these limits is crucial, as it informs the various circuits about the available power within the system. Assuming the system operates at 700Vdc, we can state the following:

Emergency range:
between 500Vdc and 630Vdc


Normal operating range:
between 640Vdc and 760Vdc


Overvoltage range:
between 770Vdc and 1080Vdc.

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Voltage range scenarios

If the system enters a voltage range of 700 to 750Vdc, this means that the grid is overfed, meaning more energy is generated than consumed. This voltage level encourages loads to operate as actively as possible, to store as much energy as possible in the BESS, to consume it, or to feed it back to the grid. When the voltage level is below 700Vdc in a range up to 640Vdc, this means that the grid is underfed. This results in the BESS charging being cut off, the charging capacity to the EV being reduced, and the BESS being discharged to feed the grid. The droop settings (voltage levels) are determined and transmitted to all loads via the AFE (Active Front End). Based on these settings, the entire system will be self-regulating. The droop settings can be linked to a weather forecast.

Safety of the DC microgrid

Among electricians, there is a prevailing idea that DC applications bring more safety issues. This is often the result of mixed AC/DC solutions and the use of electromagnetic circuit breakers or fuses. In the Ei•dcgrid, we use the specialized and advanced components of DC Systems. They have developed security equipment as a pioneer in the DC world based on Solid State technology: the Current Routers (CRN). This technology provides ultra-fast tripping and an ultra-limited short-circuit current in the installation. Benefits of Solid State technology include:


Short-circuit protection is much simpler and faster.


No gas emissions during the disconnection of a short circuit (unlike AC protections).


Built-in capabilities for measurement, communication, and local computing power. In AC systems, these are optional components that are more expensive to purchase.

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High impedance safety cable

Because in the DC microgrid all power sources and consumers are connected to the same ring, it is very important that all power sources are disconnected during work on the grid. For maintenance purposes, a patented high impedance 48V safety cable is used. This safety cable serves as auxiliary power for all sources, converters, and CRN. When this cable is de-energized, the system will not be turned on. If the system is live and the voltage of the safety cable drops, all CRN and sources will be switched off.


More information about DC and voltage level control (with tables) and about leakage or stray currents? Leave your details and download our whitepaper:
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Want to learn more about the possibilities of your own DC microgrid?

LOGO Ei dcgrid diap

Reliable and sustainable direct current microgrid solutions for a changing energy landscape.

Ei•dcgrid is Current/OS compliant

The DC microgrid of Elektro Internationaal follows the open protocol for direct current applications.

Ei•dcgrid is powered by

Elektro Internationaal B.V.
Pompmolenlaan 17
3447 GK  Woerden
The Netherlands

+31 348 420540

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