OUREL - Optimal Utilization of Renewable Energies in Low Voltage Distribution Grids

 

Project description

The decentralization of electricity generation on one hand and the electrification of e.g. the heat and mobility sectors on the other hand are important cornerstones of the energy transition. Their realization implies that a multitude of Decentral Energy Resources (DER), i.e. generation, consumption and storage units, have to be integrated into existing low-voltage distribution grids. To optimally utilize the potential of renewable energies, new grid operation concepts are required that include all the flexible DERs. The high degrees of decentralization and the high volatility of electricity generation from renewables pose substantial challenges for such concepts. Within the OUREL project, we develop a distributed operation management method for low-voltage grids with a high share of controllable DERs. It aims at optimizing the injected and consumed powers with regard to a utility measure that considers all participating units. This concept has been thoroughly investigated in the communication network domain and is transformed to electric power grids here. In doing so, we especially focus on a high update rate and the resulting tradeoff between enabling model reduction on one hand, and increasing communication demand on the other hand. The ieet scope covers modelling of the electric low-voltage grid including the connected passive loads and DERs, with a focus on photovoltaic power plants, electric vehicles and heat pumps. Furthermore, we develop the algorithms to estimate the grid state based on data from different sources. With regard to the optimization algorithms, we contribute our expertise to develop methods on how to consider grid constraints like voltage and current limits.

Tools

In the OUREL project, we use Matlab and Simulink to model the low-voltage grids and to develop and simulate the grid state estimation and optimization algorithms. To consider realistic communication network characteristics, we utilize co-simulations using a communication network emulator that was developed at the TUHH (FlowEmu) . We complement the software simulations with controller-hardware-in-the-loop (CHiL) simulations, where the developed algorithms are implemented on actual controller hardware and tested under real-time conditions using the OPAL real-time digital simulator of the PHiLsLab.

Contact

Hanko Ipach

Project duration

01.10.2019 till 30.09.2022

Funding

Project partners

Institute of Communication Networks (TUHH)

Publications

[155783]
Title: A Modified Branch-Current Based Algorithm for Fast Low Voltage Distribution Grid State Estimation using Smart Meter Data Tagungsband ETG-Kongress 2021
Written by: Ipach, H.; Stock, S.; Becker, C.
in: Mai 2021 2021
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[BibTex]

Note: ourel

Abstract: We present a modified version of the branch-current based weighted-least-squares (WLS) state estimation for application in three-phase low-voltage power distribution grids with a single transformer connection to the superordinate medium-voltage level. In our approach, voltage magnitude measurements are utilized to estimate the slack node voltage in a backward-sweep procedure separated from the WLS loop. As a result of excluding the voltage measurements from the WLS loop, the measurement functions are linear in the state variables as long as only power and power flow measurements are considered besides voltage measurements. Therefore, the computational complexity is significantly reduced compared to the straightforward way of including the nonlinear voltage magnitude measurement equations in the WLS loop. The proposed method is numerically evaluated in time-series simulations using various low-voltage benchmark grids. The results in terms of accuracy and speed are compared to the nonlinear node voltage based WLS approach as well as to a linear sensitivity-based method. It is shown that our algorithm yields an accuracy similar to the nonlinear WLS approach while requiring significantly less computation time.