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Smart Grids

Contact Prof. Dr. rer. nat. Volker Turau
Staff Amine Youssfi

Project Description

Smart grids are modern electricity grids comprehensively applying communication networks for acquiring data as well as for controlling and optimizing grid operation and attached generators and loads. It is seen as an important contribution to Germany’s energy turnaround, as the fluctuating power from wind and solar farms, which is injected to the grid in many locations, requires new concepts for the grids. Traditionally electricity grids were developed to distribute the electricity of few large-scale power plants. Communication networks for monitoring and control were available in high-voltage grids while medium and low-voltage grids were essentially passive. However, the injection of power into medium-voltage grids (e.g. by wind farms) and low-voltage grids (e.g. by solar farms) may lead to reverse power flows requiring monitoring and control also in these voltage levels. In addition, controlling loads gains importance to stabilize and optimize the usage of the grid and to increase energy efficiency (demand response).

The institute’s focus on smart grid research is the optimized usage of low-voltage grids and the application of domestic devices (e.g. water heaters, waterbeds) for demand response. The huge number of instances requires low costs for devices, installation, configuration, and operation. Having communication networks to power customers including private households also raises questions about privacy, security and new safety risks jeopardizing electricity grids.

Subprojects

Publications

Tobias Lübkert, Marcus Venzke and Volker Turau. Calculating retail prices from demand response target schedules to operate domestic electric water heaters. Energy Informatics, 1(1):31, October 2018.
@Article{Telematik_EI_2018, author = {Tobias L{\"u}bkert and Marcus Venzke and Volker Turau}, title = {Calculating retail prices from demand response target schedules to operate domestic electric water heaters}, pages = 31, journal = {Energy Informatics}, volume = {1}, number = {1}, day = {10}, month = oct, year = 2018, }
Abstract: The paper proposes a demand response scheme controlling many domestic electric water heaters (DEWHs) with a price function to consume electric power according to a target schedule. It discusses at length the design of an algorithm to calculate the price function from a target schedule. The price function is used by the control of each DEWH to automatically and optimally minimize its local heating costs. It is demonstrated that the resulting total power consumption approximates the target schedule. The algorithm was successfully validated by simulation with a realistic set of 50 DEWHs assuming perfect knowledge of parameters and water consumption. It is shown that the algorithm is also applicable to clusters of large numbers of DEWHs with statistical knowledge only. However, this leads to a slightly higher deviation from the target schedule.
Tobias Lübkert, Marcus Venzke, Nhat-Vinh Vo and Volker Turau. Understanding Price Functions to Control Domestic Electric Water Heaters for Demand Response. Computer Science - Research and Development, 81–92, February 2018.
@Article{Telematik_Demand_Response_DEWH_2017, author = {Tobias L{\"u}bkert and Marcus Venzke and Nhat-Vinh Vo and Volker Turau}, title = {Understanding Price Functions to Control Domestic Electric Water Heaters for Demand Response}, pages = {81-92}, journal = {Computer Science - Research and Development}, volume = {}, month = feb, year = 2018, }
Abstract: A well-known mechanism for demand response is sending price signals to customers a day ahead. Customers then postpone or advance their usage of electricity to minimize cost. Setting up price functions that adapt the customers' load to availability is a big challenge. This paper investigates the feasibility of finding day-ahead price functions to induce a desired load profile of Domestic Electric Water Heaters (DEWHs) minimizing their electricity cost for demand response. Bilevel optimization is applied for a single DEWH using a simplified linear model and full knowledge. This leads to a solvable bilevel problem and allows understanding optimality of price functions and resulting heating profiles. It is shown that with the resulting price functions the DEWH may select many significantly different heating profiles leading to the same cost. Thus the price does not uniquely induce the desired heating profile. The acquired knowledge forms the basis for a procedure to create price functions for controlling the load profile of many DEWHs.
Tobias Lübkert, Marcus Venzke and Volker Turau. Appliance Commitment for Household Load Scheduling Algorithm: A Critical Review. In 2017 IEEE International Conference on Smart Grid Communications (SmartGridComm), October 2017, pp. 527–532. Dresden, Germany.
@InProceedings{Telematik_SGC_2017, author = {Tobias L{\"u}bkert and Marcus Venzke and Volker Turau}, title = {Appliance Commitment for Household Load Scheduling Algorithm: A Critical Review}, booktitle = {2017 IEEE International Conference on Smart Grid Communications (SmartGridComm)}, pages = {527-532}, day = {23-26}, month = oct, year = 2017, location = {Dresden, Germany}, }
Abstract: The paper analyzes the behavior of two demand response algorithms, both claiming to minimize the energy cost regarding time-varying prices in an optimal way by iteratively scheduling heating phases of water heaters considering hot water consumption. Four issues of the well known algorithm by Du and Lu are identified, which lead to suboptimal behavior. Proposed enhancements lead to an algorithm similar to the second, recently published, method of Shah et al. The effect of each enhancement and its combinations are analysed simulatively reducing the costs.
Tobias Lübkert, Marcus Venzke and Volker Turau. Impacts of Domestic Electric Water Heater Parameters on Demand Response. Computer Science - Research and Development, 32:49–64, 2017.
@Article{Telematik_Demand_Response_DEWH_2016, author = {Tobias L{\"u}bkert and Marcus Venzke and Volker Turau}, title = {Impacts of Domestic Electric Water Heater Parameters on Demand Response}, pages = {49-64}, journal = {Computer Science - Research and Development}, volume = {32}, year = 2017, }
Abstract: This paper analyzes the impact of the high dimen- sional parameter space of domestic electric water heaters (DEWH) for demand response (DR). To quantify the con- sumer comfort a novel metric is introduced considering a stochastic distribution of different water draw events. Incor- porating three control algorithms from literature, it is shown that all considered parameters of a DEWH except the heat conductivity have a significant impact on consumer satisfac- tion. The effect on DR is mainly influenced by the temper- ature range and the planning horizon, but also by the heat conductivity and the volume. In contrast, the rated power of the heating element and the nominal temperature have no significant impact on the effect on DR. The impacts are an- alyzed by varying these parameters in a simulation of 1000 DEWHs considering three different controllers: a common thermostat, an exchange price dependent nominal temper- ature changing mechanism and an energy scheduling algo- rithm proposed by Du and Lu.
Volker Turau and Christoph Weyer. Cascading Failures Caused by Node Overloading in Complex Networks. In Proceedings of the Joint Workshop on Cyber-Physical Security and Resilience in Smart Grids, April 2016, pp. 1–6. Vienna, Austria.
@InProceedings{Telematik_CPSR-SG2016_SmartGrid, author = {Volker Turau and Christoph Weyer}, title = {Cascading Failures Caused by Node Overloading in Complex Networks}, booktitle = {Proceedings of the Joint Workshop on Cyber-Physical Security and Resilience in Smart Grids}, pages = {1-6}, day = {12}, month = apr, year = 2016, location = {Vienna, Austria}, }
Abstract: It is well known that complex networks are vulnerable to the failure of hubs in terms of structural robustness. An as yet less researched topic is dynamical robustness, which refers to the ability of a network to maintain its dynamical activity against local disturbances. This paper analyzes the impact of overload attacks in complex networks and gives a precise definition of this type of attack using the load redistribution model. The main contribution is a greedy algorithm to select a small number of candidates for an overload attack maximizing the impact with respect to the number of failed nodes and load increase. The quality of the algorithm is analyzed for a real power grid network.
Marcus Venzke and Volker Turau. Simulative Evaluation of Demand Response Approaches for Waterbeds. In Proceedings of the 2016 IEEE International Energy Conference (ENERGYCON), April 2016. Leuven, Belgium.
@InProceedings{Telematik_EnergyCon_2016_SimulationDemandResponseWaterbed, author = {Marcus Venzke and Volker Turau}, title = {Simulative Evaluation of Demand Response Approaches for Waterbeds}, booktitle = {Proceedings of the 2016 IEEE International Energy Conference (ENERGYCON)}, pages = , day = {4-8}, month = apr, year = 2016, location = {Leuven, Belgium}, }
Abstract: This paper quantitatively compares five demand response (DR) approaches for waterbeds using simulation. The approaches enable privacy by design with a local control and contribute to the planning phase of the electricity network’s balancing process. Approaches are assessed by their energy consumption, their ability to shift power consumption to times of high availability, and the effort of realization and configuration. Load steps were identified as a risk for power network stability. A classification of DR methods, based on the position of their contribution within the electricity network’s balancing process, is used to distinguish our approach from the DR approaches found in the literature.
Marcus Venzke and Volker Turau. A demand response approach locally implementable for waterbeds. In Proceedings of 1st Workshop on Middleware for a Smarter Use of Electric Energy (MidSEE’15), March 2015, pp. 1–6. Cottbus, Germany.
@InProceedings{Telematik_VT_2015_DemandResponseWaterbed, author = {Marcus Venzke and Volker Turau}, title = {A demand response approach locally implementable for waterbeds}, booktitle = {Proceedings of 1st Workshop on Middleware for a Smarter Use of Electric Energy (MidSEE’15)}, pages = {1-6}, day = {12}, month = mar, year = 2015, location = {Cottbus, Germany}, }
Abstract: The paper presents a demand response scheme for waterbeds that can be implemented in practice today. It balances the requirements of saving energy and shifting power to times with higher power availability by planning heating phases to minimize costs according to a virtual electricity tariff derived from trading prices of an electricity exchange. The approach was successfully validated with a real waterbed under real conditions.
Martin Ringwelski, Christian Renner, Andreas Reinhardt, Andreas Weigel and Volker Turau. The Hitchhiker's Guide to Choosing the Compression Algorithm for Your Smart Meter Data. In Proceedings of the IEEE International Energy Conference and Exhibition (EnergyCon'12), September 2012. Florence, Italy.
@InProceedings{Telematik_RRWRT_2012_CompressionGuide, author = {Martin Ringwelski and Christian Renner and Andreas Reinhardt and Andreas Weigel and Volker Turau}, title = {The Hitchhiker's Guide to Choosing the Compression Algorithm for Your Smart Meter Data}, booktitle = {Proceedings of the IEEE International Energy Conference and Exhibition (EnergyCon'12)}, day = {9-12}, month = sep, year = 2012, location = {Florence, Italy}, }
Abstract: Smart meters are increasingly penetrating the market, resulting in enormous data volumes to be communicated. In many cases, embedded devices collect the metering data and transmit them wirelessly to achieve cheap and facile deployment. Bandwidth is yet scarce and transmission occupies the spectrum. Smart meter data should hence be compressed prior to transmission. Here, solutions for personal computers are not applicable, as they are too resource-demanding. In this paper, we propose four lossless compression algorithms for smart meters. We analyze processing time and compression gains and compare the results with five off-the-shelf compression algorithms. We show that excellent compression gains can be achieved when investing a moderate amount of memory. A discussion of the suitability of the algorithms for different kinds of metering data is presented.
Christian Renner, Sebastian Ernst, Christoph Weyer and Volker Turau. Prediction Accuracy of Link-Quality Estimators. In Proceedings of the 8th European Conference on Wireless Sensor Networks (EWSN'11), February 2011. Bonn, Germany. Acceptance rate 20%.
@InProceedings{Telematik_REWT_HoPS, author = {Christian Renner and Sebastian Ernst and Christoph Weyer and Volker Turau}, title = {Prediction Accuracy of Link-Quality Estimators}, booktitle = {Proceedings of the 8th European Conference on Wireless Sensor Networks (EWSN'11)}, day = {23-25}, month = feb, year = 2011, location = {Bonn, Germany}, note = {Acceptance rate 20%}, }
Abstract: The accuracy of link-quality estimators (LQE) is mission-critical in many application scenarios in wireless sensor networks (WSN), since the link-quality metric is used for routing decisions or neighborhood formation. Link-quality estimation must offer validity for different timescales. Existing LQEs describe and approximate the current quality in a single value only. This method leads to a limited accuracy and expressiveness about the presumed future behavior of a link. The LQE developed in this paper incorporates four quality metrics that give a holistic assessment of the link and its dynamic behavior; therefore, this research is an important step to achieving a higher prediction accuracy including knowledge about the short- and long-term behavior.