Grid Stability: Price Signals & HEMS in the Grid Simulation

Network stability needs smart price signals: SECProMo creates a grid model from real data, simulates dynamic grid charges and HEMS reactions for load shifting. The AEP.DataHub links measurement, analysis and (in future via AEP.API) control.

The energy transition brings with it a constant field of tension: more flexibility and decentralized generation on the one hand, and growing demands for grid stability and planning security on the other. In order to realistically assess this balance, research and practice rely on grid simulations that map real data, consumption profiles and tariff models in virtual simulations.

On January 1, 2023, the SECProMo research project, which is funded by the Federal Ministry of Economics, was launched. The SECProMo project group includes company representatives from Arvato Systems, smartOPTIMO, Osnabrück University of Applied Sciences, items, Stadtwerke Bielefeld, Power Plus Communications and three other associated partners. In addition to secure communication via the SMGw infrastructure, the central aim of SECProMo is to create a realistic network model based on data from a specific network area. The data comes from TAF9, TAF10 and TAF14 power measurements with a 15-minute resolution, which are recorded by 17 systems and selectively supplemented by minute values. In addition, there is information on the grid topology (transformer stations, lines, house connections), installed PV systems, wallboxes and controllable consumers such as heat pumps.

This creates a data framework that includes both technical parameters (line cross-section, load capacity, voltages) and energy parameters (active energy, feed-in). This model enables a precise load flow calculation, which forms the basis for evaluating different tariff and control concepts.

One approach to optimizing energy use is the use of dynamic tariffs and time-variable network charges. If designed correctly, these price signals can optimize self-consumption (e.g. PV electricity for e-cars or heat pumps), reduce costs for consumers and relieve the grid at the same time.

In modern energy concepts, so-called Home Energy Management Systems (HEMS) play a central role. A HEMS monitors, controls and optimizes the energy flow in the household - e.g. PV generation, battery, heating, e-car or other flexible loads - ideally on the basis of tariff, weather or forecast information. In combination with intelligent metering systems and dynamic grid charges are opening up new potential for load shifting and grid stabilization. They are seen as the key to shifting consumer loads in a targeted manner.

An important point here is the unnatural simultaneity: If many HEMS systems in a grid area react to price signals at the same time (e.g. start or end of a low-price center), this can lead to bundled load peaks that burden the grid instead of relieving it if there is a lack of differentiation. The SECProMo team of experts hypothesizes that dynamic tariffs can thus reduce individual load peaks, but create a new peak as a whole if all systems switch at the same time. This results in shifted peaks instead of smoothing. To counteract this, stochastic elements and individual parameters for HEMS are integrated into simulations.

The simulation of dynamic grid charges is intended to answer the question of how the charges must be designed so that they are economically attractive for end customers and at the same time avoid grid congestion.

This involves, among other things:

• the correct granularity (hourly vs. quarter-hourly prices).
• the amount of the price spread between high and low tariffs,
• the definition of meaningful network cells in which the charges apply
• and the reaction of the HEMS to these price signals.

At Arvato Systems, all measurement and simulation data flows into the AEP.DataHub, which manages and visualizes them and makes them available for further analysis and feedback. The result is an integrated view: HEMS react to price signals, the grid model simulates the effects and the AEP.DataHub combines data, analysis and control feedback. This turns pure measured values into a decision-relevant basis that supports energy suppliers, grid operators and customers.

In the AEP.DataHub, threshold values can still be defined that automatically trigger actions when they are exceeded. In future, Arvato Systems plans to be able to send control commands directly to customers' properties via the AEP.API product, the BDEW Web API service. This combines simulation not only with analysis and forecasting, but also with concrete actionability in grid operation.