scholarly journals Evolutionary Priority-Based Dynamic Programming for the Adaptive Integration of Intermittent Distributed Energy Resources in Low-Inertia Power Systems

Eng ◽  
2021 ◽  
Vol 2 (4) ◽  
pp. 643-660
Author(s):  
Pavlos Nikolaidis ◽  
Andreas Poullikkas
Keyword(s):  
Dynamic Programming ◽  
Power Systems ◽  
Optimal Power Flow ◽  
Unit Commitment ◽  
Renewable Energy Sources ◽  
Minimum Cost ◽  
Energy Resources ◽  
Distributed Energy Resources ◽  
Distributed Energy ◽  
Priority List

The variability and uncertainty caused by the increased penetrations of renewable energy sources must be properly considered in day-ahead unit commitment, optimal power flow, and even real-time economic dispatch problems. Besides achieving minimum cost, modern generation schedules must satisfy a larger set of different complex constraints. These account for the generation constraints in the presence of renewable generation, network constraints affected by the distributed energy resources, bilateral contracts enclosing independent capacity provision, ancillary power auctions, net-metering and feed-in-tariff prosumers, and corrective security actions in sudden load variations or outage circumstances. In this work, a new method is presented to appropriately enhance the integration of distributed energy resources in low-inertia power grids. Based on optimal unit commitment schedules derived from priority-based dynamic programming, the potential of increasing the renewable capacity was examined, performing simulations for different scenarios. To ameliorate the expensive requirement of computational complexity, this approach aimed at eliminating the increased exploration-exploitation efforts. On the contrary, its promising solution relies on the evolutionary commitment of the next optimum configuration based on priority-list schemes to accommodate the intermittent generation progressively. This is achieved via the collection of mappings that transform many-valued clausal forms into satisfiability equivalent Boolean expressions.

scholarly journals Cybersecurity Considerations for Grid-Connected Batteries with Hardware Demonstrations

Energies ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 3067
Author(s):  
Megan Culler ◽  
Hannah Burroughs
Keyword(s):  
Power Systems ◽  
Network Connectivity ◽  
Energy Resources ◽  
System Stability ◽  
Distributed Energy Resources ◽  
Distributed Energy ◽  
Defense Strategies ◽  
Storage Devices ◽  
Attack Surface ◽  
Area Of Concern

The share of renewable and distributed energy resources (DERs), like wind turbines, solar photovoltaics and grid-connected batteries, interconnected to the electric grid is rapidly increasing due to reduced costs, rising efficiency, and regulatory requirements aimed at incentivizing a lower-carbon electricity system. These distributed energy resources differ from traditional generation in many ways including the use of many smaller devices connected primarily (but not exclusively) to the distribution network, rather than few larger devices connected to the transmission network. DERs being installed today often include modern communication hardware like cellular modems and WiFi connectivity and, in addition, the inverters used to connect these resources to the grid are gaining increasingly complex capabilities, like providing voltage and frequency support or supporting microgrids. To perform these new functions safely, communications to the device and more complex controls are required. The distributed nature of DER devices combined with their network connectivity and complex controls interfaces present a larger potential attack surface for adversaries looking to create instability in power systems. To address this area of concern, the steps of a cyberattack on DERs have been studied, including the security of industrial protocols, the misuse of the DER interface, and the physical impacts. These different steps have not previously been tied together in practice and not specifically studied for grid-connected storage devices. In this work, we focus on grid-connected batteries. We explore the potential impacts of a cyberattack on a battery to power system stability, to the battery hardware, and on economics for various stakeholders. We then use real hardware to demonstrate end-to-end attack paths exist when security features are disabled or misconfigured. Our experimental focus is on control interface security and protocol security, with the initial assumption that an adversary has gained access to the network to which the device is connected. We provide real examples of the effectiveness of certain defenses. This work can be used to help utilities and other grid-connected battery owners and operators evaluate the severity of different threats and the effectiveness of defense strategies so they can effectively deploy and protect grid-connected storage devices.

scholarly journals Methods for Aggregation and Remuneration of Distributed Energy Resources

2018 ◽  
Vol 8 (8) ◽  
pp. 1283 ◽  
Author(s):  
Pedro Faria ◽  
João Spínola ◽  
Zita Vale
Keyword(s):  
Power Systems ◽  
Energy Resource ◽  
Energy Resources ◽  
Distributed Energy Resources ◽  
Virtual Power ◽  
Distributed Energy ◽  
Distributed Energy Resource ◽  
Technical Operation ◽  
Made In

Distributed energy resource integration in power systems has advantages and challenges in both the economic and the technical operation of the system. An aggregator, as in the case of a Virtual Power Player, is essential in order to support the operation of these small size resources. Innovative approaches capable of supporting the decisions made in terms of resource scheduling, aggregation and remuneration are needed. The present paper addresses a methodology capable of managing resources through the activities of an aggregator, providing different choices of aggregation and remuneration strategies. The methodology is validated in a case study regarding a 21-bus network, composed of 20 consumers and 26 producers.

scholarly journals A Horizon Optimization Control Framework for the Coordinated Operation of Multiple Distributed Energy Resources in Low Voltage Distribution Networks

Energies ◽  
2019 ◽  
Vol 12 (6) ◽  
pp. 1182 ◽  
Author(s):  
Konstantinos Kotsalos ◽  
Ismael Miranda ◽  
Nuno Silva ◽  
Helder Leite
Keyword(s):  
Optimal Power Flow ◽  
Low Voltage ◽  
Distribution Networks ◽  
Heat Pumps ◽  
Energy Resources ◽  
Distributed Energy Resources ◽  
Distribution Grid ◽  
Distributed Energy ◽  
Control Framework ◽  
Optimization Control

In recent years, the installation of residential Distributed Energy Resources (DER) that produce (mainly rooftop photovoltaics usually bundled with battery system) or consume (electric heat pumps, controllable loads, electric vehicles) electric power is continuously increasing in Low Voltage (LV) distribution networks. Several technical challenges may arise through the massive integration of DER, which have to be addressed by the distribution grid operator. However, DER can provide certain degree of flexibility to the operation of distribution grids, which is generally performed with temporal shifting of energy to be consumed or injected. This work advances a horizon optimization control framework which aims to efficiently schedule the LV network’s operation in day-ahead scale coordinating multiple DER. The main objectives of the proposed control is to ensure secure LV grid operation in the sense of admissible voltage bounds and rated loading conditions for the secondary transformer. The proposed methodology leans on a multi-period three-phase Optimal Power Flow (OPF) addressed as a nonlinear optimization problem. The resulting horizon control scheme is validated within an LV distribution network through multiple case scenarios with high microgeneration and electric vehicle integration providing admissible voltage limits and avoiding unnecessary active power curtailments.

scholarly journals Harmony Search Algorithm Based Management of Distributed Energy Resources and Storage Systems in Microgrids

2020 ◽  
Vol 10 (9) ◽  
pp. 3252 ◽  
Author(s):  
Oğuzhan Ceylan ◽  
Mustafa Erdem Sezgin ◽  
Murat Göl ◽  
Maurizio Verga ◽  
Riccardo Lazzari ◽  
...  
Keyword(s):  
Low Voltage ◽  
Search Algorithm ◽  
Renewable Energy Sources ◽  
Harmony Search ◽  
Energy Resources ◽  
Test Facility ◽  
Distributed Energy Resources ◽  
Optimization Approach ◽  
Distributed Energy ◽  
Islanded Operation

Microgrids are composed of distributed energy resources (DERs), storage devices, electric vehicles, flexible loads and so on. They may either operate connected to the main electricity grid (on-grid operation) or separated from the grid (islanded operation). The outputs of the renewable energy sources may fluctuate and thus can cause deviations in the voltage magnitudes especially at islanded mode. This may affect the stability of the microgrids. This paper proposes an optimization model to efficiently manage controllable devices in microgrids aiming to minimize the voltage deviations both in on-grid and islanded operation modes. RSE Distributed Energy Resources Test Facility (DER-TF), which is a low voltage microgrid system in Italy, is used to verify the algorithm. The test system’s data is taken through an online software system (REDIS) and a harmony search based optimization algorithm is applied to control the device parameters. The experimental results show that the harmony search based optimization approach successfully finds the control parameters, and can help the system to obtain a better voltage profile.

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