© EPS Stromversorgung in 2022, this information is subject to change without notice
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30000800_manual_psb_10000_4u_30kw_en_04
2.3.2.2
Additional measure for energy recovering devices
All models of this series are so-called recuperating devices, at least when they’re working in sink mode. In this is mode they
feed back a specific amount of energy into the local or public grid. The devices can’t work sink mode without this function
-
ality. The goal is to consume the recovered energy completely in the local power grid of a company or plant. In case it can
occur that more energy is recuperated than consumed, the excess will be fed back into the public grid which usually isn’t
allowed without further precautions.
The operator of the device must,owing to circumstances, contact the local electric utility and clarify what’s allowed and if a
so-called network & system protection is required to be installed. There are several different international provisions or stan-
dard, such as the german VDE-AR-N 4105/4110 or the british ENA EREC G99 which regulate this situation.
The device itself provides a basic protection and would shut down energy feed back in case it can’t work, but a full protec-
tion against frequency shift or voltage deviation can only be accomplished by such an NS protection device, which will also
prevent isolation operation.
We offer NS protection solutions. They already fulfill the german AR-N 4105 and 4410, as well as the italian CEI 0-21 or the
british G59/G98/G99.
Concept of an NS protection system:
Supervision
Device
L1
L2
L3
PE
N
GRID
Figure 9 - Principle of an NS protection network
2.3.2.3
Installation concept for energy recovering devices
A PSB 10000 device recovers energy and feeds it back into the local power grid of a company or big electric plant. The re-
covered current adds to the grid current (see schematic below) and this can lead to an overload of the existing electric instal-
lation. Considering any two outlets, no matter of what type they are, there is usually no extra fusing installed in between. In
case of a defect in the AC part (i.e. short-circuit) of any consumer device or when there are multiple devices connected which
could take a higher power, the total current could flow across wires which are not laid out for this higher current. It could lead
to damage or even fire in the wires or connection points.
In order to avoid damages and accidents, the existing installation concept must be taken into regard before installing such
recovering devices. Schematic depiction with 1 recovering device and consumers:
PSB/ELR 10000 4U
<61 A
63 A
Grid
Consumer 2
Consumer 2
Consumer 1
Consumer 1
up to 124 A
When running a higher number of recovering, i. e. energy backfeeding units on the same leg of the installation, the total cur-
rents per phase increases accordingly.
