Distribution System Congestion Management Based on Local Flexibility Market

2021 ◽  
Author(s):  
Rui Liu ◽  
Xiuli Wang ◽  
Hongyang Zhao ◽  
Yifei Wang
Keyword(s):  
Distribution System ◽  
Congestion Management ◽  
Local Flexibility

Optimization problem for meeting distribution system operator requests in local flexibility markets with distributed energy resources

2018 ◽  
Vol 210 ◽  
pp. 881-895 ◽  
Author(s):  
Pol Olivella-Rosell ◽  
Eduard Bullich-Massagué ◽  
Mònica Aragüés-Peñalba ◽  
Andreas Sumper ◽  
Stig Ødegaard Ottesen ◽  
...  
Keyword(s):  
Distribution System ◽  
Optimization Problem ◽  
Energy Resources ◽  
Distributed Energy Resources ◽  
Distributed Energy ◽  
Local Flexibility ◽  
System Operator

scholarly journals Sparse Measurement-Based Coordination of Electric Vehicle Charging Stations to Manage Congestions in Low Voltage Grids

Smart Cities ◽  
2020 ◽  
Vol 4 (1) ◽  
pp. 17-40
Author(s):  
Daniel-Leon Schultis
Keyword(s):  
Electric Vehicle ◽  
Distribution System ◽  
Low Voltage ◽  
Congestion Management ◽  
Load Flow ◽  
Detection Accuracy ◽  
System State ◽  
Electric Vehicle Charging ◽  
Vehicle Charging ◽  
Charging Stations

The increasing use of distributed generation and electric vehicle charging stations provokes violations of the operational limits in low voltage grids. The mitigation of voltage limit violations is addressed by Volt/var control strategies, while thermal overload is avoided by using congestion management. Congestions in low voltage grids can be managed by coordinating the active power contributions of the connected elements. As a prerequisite, the system state must be carefully observed. This study presents and investigates a method for the sparse measurement-based detection of feeder congestions that bypasses the major hurdles of distribution system state estimation. Furthermore, the developed method is used to enable congestion management by the centralized coordination of the distributed electric vehicle charging stations. Different algorithms are presented and tested by conducting load flow simulations on a real urban low voltage grid for several scenarios. Results show that the proposed method reliably detects all congestions, but in some cases, overloads are detected when none are present. A minimal detection accuracy of 73.07% is found across all simulations. The coordination algorithms react to detected congestions by reducing the power consumption of the corresponding charging stations. When properly designed, this strategy avoids congestions reliably but conservatively. Unnecessary reduction of the charging power may occur. In total, the presented solution offers an acceptable performance while requiring low implementation effort; no complex adaptations are required after grid reinforcement and expansion.

OS4ES – Open System for Energy Services

2015 ◽  
Vol 63 (11) ◽  
Author(s):  
Martin Zanner ◽  
Andrea Schröder ◽  
Christoph Kahlen
Keyword(s):  
Open System ◽  
Distribution System ◽  
Service System ◽  
Field Tests ◽  
Electrical Energy ◽  
Congestion Management ◽  
Management Service ◽  
Energy Services ◽  
Open Service ◽  
Reliability And Robustness

AbstractToday, mass presence of distributed energy resources (DERs) connected to the grid is often seen as having adverse effects on grid reliability and robustness. The apprehension is that it complicates or even compromises network management by distribution system operators (DSOs).The central aim of the Open System for Energy Services (OS4ES) project is to provide a solution that closes the current information, communication and cooperation gap between DERs and energy market actors. To this end, the OS4ES project delivers an innovative Open Service System that enables dynamic cooperation between these two parties. A Distributed Registry for DERs offers to involved actors the opportunity to reserve the aggregated flexibility of DERs as a grid management service in order to improve Smart Grid robustness and reliability. OS4ES will be based on standardized and interoperable communication interfaces, as well as generic interfaces among components producing, consuming or storing electrical energy.The OS4ES Open Service System includes laboratory and field tests under different service scenarios such as congestion management, energy trading, imbalance risk reduction and Volt/VAR optimization. An OS4ES User Group has been established to allow interested parties to gain a broader insight in the project and to actively contribute to the work packages of interest. Besides, standardization proposals will be prepared and submitted to the respective standardization committees.

scholarly journals On the Sensitivity of Local Flexibility Markets to Forecast Error: A Bi-Level Optimization Approach

Energies ◽  
2020 ◽  
Vol 13 (8) ◽  
pp. 1959
Author(s):  
Delaram Azari ◽  
Shahab Shariat Torbaghan ◽  
Hans Cappon ◽  
Karel J. Keesman ◽  
Madeleine Gibescu ◽  
...  
Keyword(s):  
Distribution System ◽  
Large Scale ◽  
Optimization Problem ◽  
Distribution Networks ◽  
Second Order ◽  
Optimization Approach ◽  
Second Order Cone ◽  
Local Flexibility ◽  
Level Problem ◽  
Relaxation Error

The large-scale integration of intermittent distributed energy resources has led to increased uncertainty in the planning and operation of distribution networks. The optimal flexibility dispatch is a recently introduced, power flow-based method that a distribution system operator can use to effectively determine the amount of flexibility it needs to procure from the controllable resources available on the demand side. However, the drawback of this method is that the optimal flexibility dispatch is inexact due to the relaxation error inherent in the second-order cone formulation. In this paper we propose a novel bi-level optimization problem, where the upper level problem seeks to minimize the relaxation error and the lower level solves the earlier introduced convex second-order cone optimal flexibility dispatch (SOC-OFD) problem. To make the problem tractable, we introduce an innovative reformulation to recast the bi-level problem as a non-linear, single level optimization problem which results in no loss of accuracy. We subsequently investigate the sensitivity of the optimal flexibility schedules and the locational flexibility prices with respect to uncertainty in load forecast and flexibility ranges of the demand response providers which are input parameters to the problem. The sensitivity analysis is performed based on the perturbed Karush–Kuhn–Tucker (KKT) conditions. We investigate the feasibility and scalability of the proposed method in three case studies of standardized 9-bus, 30-bus, and 300-bus test systems. Simulation results in terms of local flexibility prices are interpreted in economic terms and show the effectiveness of the proposed approach.

scholarly journals Local Markets for Flexibility Trading: Key Stages and Enablers

Energies ◽  
2018 ◽  
Vol 11 (11) ◽  
pp. 3074 ◽  
Author(s):  
Simone Minniti ◽  
Niyam Haque ◽  
Phuong Nguyen ◽  
Guus Pemen
Keyword(s):  
Electricity Markets ◽  
Distribution System ◽  
Market Access ◽  
Renewable Energy Sources ◽  
Energy Transition ◽  
Support Tool ◽  
Value Stream ◽  
Electricity System ◽  
A Value ◽  
Local Flexibility

The European energy transition is leading to a transformed electricity system, where Distributed Energy Resources (DERs) will play a substantial role. Renewable Energy Sources (RES) will challenge the key operational obligation of real-time balancing and the need for flexibility will consequently increase. The introduction of a local flexibility market (LFM) would allow the trading of flexibility supplied by both producing and consuming units at the distribution level, providing market access to DERs, a support tool for Distribution System Operators (DSOs) and a value stream for energy suppliers. Aggregators and DSOs for different reasons can enhance the valuation of flexible DERs. Several research papers have assumed aggregators fully interacting with the electricity markets and DSOs contracting services with power system actors. These interactions are still not allowed in many European countries. This article aims to analyze the European regulation to identify the most important enablers and pave the way towards the full exploitation of DER flexibility, culminating in the establishment of an LFM. Therefore, three main stages, emerging from the progressive withdrawal of the current regulatory and market barriers, are identified: (1) enabling the aggregator’s trading, (2) evolution of the DSO’s role, and (3) key-design challenges of an LFM.

scholarly journals Lifetime Assessment of PILC Cables with Regard to Thermal Aging Based on a Medium Voltage Distribution Network Benchmark and Representative Load Scenarios in the Course of the Expansion of Distributed Energy Resources

Energies ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 494
Author(s):  
Martin Zapf ◽  
Tobias Blenk ◽  
Ann-Catrin Müller ◽  
Hermann Pengg ◽  
Ivana Mladenovic ◽  
...  
Keyword(s):  
Thermal Aging ◽  
Distribution System ◽  
Reference Data ◽  
Extreme Values ◽  
Distribution Network ◽  
Congestion Management ◽  
Energy Resources ◽  
Distributed Energy Resources ◽  
Distributed Energy ◽  
Medium Voltage

The decentralized feed-ins from distributed energy resources (DER) represent a significant change in the manner in which the power grid is used. If this leads to high loads on electrical equipment, its aging can be accelerated. This applies in particular with regard to the thermal aging of older generations of power cables, namely paper insulated lead covered (PILC) cables. This type of power cable can still be found frequently in medium voltage (MV) networks. If aging of these cables is significantly accelerated in the presence of DER, distribution system operators (DSO) could face unplanned premature cable failures and a high replacement demand and costs. Therefore, this paper investigates the thermal aging of PILC cables in a MV distribution network benchmark for different load scenarios, using standardized load profiles and representative expansion scenarios for wind power and photovoltaics plants in particularly affected network areas in Germany. A main objective of this paper is to present a methodology for estimating the thermal degradation of PILC cables. An approach is used to draw simplified conclusions from the loading of cables to their conductor or insulation temperature. For this purpose, mainly Joule losses are considered. In addition, thermal time constants are used for the heating and cooling processes. Based on the insulation temperature, thermal aging is determined using the Arrhenius law or the Montsinger rule. However, it is important to note that there is an urgent need for research on reference data in this area. For this reason, the results of the lifetime estimation presented in this paper should only be considered as an approximation if the selected reference data from the literature for the aging model are actually applicable. The lifetime assessment is performed for a highly utilized line segment of the network benchmark. Accordingly, extreme values are examined. Different operational control strategies of DSO to limit cable utilization are investigated. The results show that the expansion of DER can lead to a short but high cable utilization, although the average utilization does not increase or increases only slightly. This can lead to significantly lower cable lifetimes. The possible influence of these temporarily high loads is shown by comparing the resulting cable lifetime with previous situations without DER. It is also shown that DSO could already reduce excessive aging of PILC cables by preventing overloads in a few hours of a year. In addition to these specific results, general findings on the network load due to the influence of DER are obtained, which are of interest for congestion management.

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