Case StudyGrid Simulation

Proving voltage-rise compliance for new power plants — without redrawing the low-voltage grid

Elektrizitätswerk Schwyz AG · Schwyz, Switzerland

In Switzerland, connecting a new solar panel or wind farm to the grid isn't just a technical milestone — it's a compliance requirement. Under the “Technical Rule for the Assessment of System Perturbations” (DACHCZ), utilities must prove that the resulting voltage rise across an entire low-voltage grid stays within defined limits before a new power plant can go live.

Challenge: Proving voltage-rise compliance for new power-plant connections without manually redrawing the low-voltage grid for every simulation.
Solution: A direct GIS-to-NEPLAN data translation interface that carries existing attribute data straight into NEPLAN's calculation package.
Results: Confidence in network specifications, clear visibility on reinforcement needs, and savings on costs — without manual redraws.

01Challenge

For Elektrizitätswerk Schwyz AG (EWS), meeting that requirement meant one thing: a full, accurate load flow simulation of its network in NEPLAN — something that had traditionally meant rebuilding the grid model by hand.

NEPLAN's calculation engine needs the complete network — every transformer, every attribute, correctly represented — and historically, that meant painstakingly redrawing sections of the low-voltage grid by hand whenever a simulation was needed.

02How the data flows

01
GIS
Low-voltage grid with all attribute data
02
SEPM NEPLAN interface
Tap positions, limiting currents, fuse values
03
NEPLAN calculation package
Load flow simulation of the full network
04
DACHCZ voltage-rise check
Is reinforcement genuinely necessary?

03Solution

A direct link between GIS and NEPLAN

Working with SEPM, EWS connected its GIS directly to NEPLAN using SEPM's data translation interface. The interface was configured to carry over values already stored in the GIS straight into NEPLAN's calculation package, with no manual re-entry:

Transformer tap positions
Limiting currents
Fuse values

Low-voltage grid of Elektrizitätswerk Schwyz AG in the GIS — EWS's low-voltage grid as maintained in its GIS — the source of the attribute data the NEPLAN interface carries over automatically.

From manual project to routine check

Today, whenever EWS needs to assess a new power plant connection request, the network model is already there in NEPLAN — nothing needs to be redrawn.

Simulations show, with confidence, whether the grid's specifications hold and whether reinforcement is genuinely necessary, turning a compliance obligation into a routine check instead of a manual project.

Network schema in the NEPLAN calculation package with voltage-rise check points — NEPLAN's calculation package, showing the network with automatically transferred attribute data and highlighted voltage-rise check points.

“The grid network information no longer needs to be entered manually into NEPLAN. The data is stored centrally in our GIS database and then transferred using the SEPM NEPLAN interface. The days of unnecessarily repetitive and error-prone database maintenance are long gone.”

Mario SchulerLeiter Messtechnik, Elektrizitätswerk Schwyz AG