scholarly journals Utility-based operation management for low voltage distribution grids using online optimization

2021 ◽  
Author(s):  
Hanko Ipach ◽  
Leonard Fisser ◽  
Christian Becker ◽  
Andreas Timm-Giel
Keyword(s):  
Distribution System ◽  
Power Flow ◽  
Optimal Power Flow ◽  
Optimization Problem ◽  
Low Voltage ◽  
The State ◽  
Operation Management ◽  
Distributed Energy ◽  
System Operator ◽  
Distribution Grids

AbstractWe present an operation management controller for low voltage (LV) grids that coordinates a multitude of distributed energy resources (DER) in real time to maximize the utilization of renewable energy production. It utilizes an LTE radio network that connects the DERs to the distribution system operator. In our approach, utility functions are assigned to the DERs, and the utility maximization is formulated as an optimization problem. The optimization problem is solved by an iterative algorithm that performs incremental updates of the DER power set values to achieve the optimum. In order to take the state of the grid in the optimization process into account, the state of the grid is estimated. During the simulation of a use case, we demonstrate the applicability and identify the benefits of our approach compared to an established optimal power flow (OPF) method. Particular emphasis is put on evaluating the communication delay and feasibility of the required communication network, as the iterative approach leads to a high communication load.

scholarly journals Smart charging for electric vehicles to minimise charging cost

2017 ◽  
Vol 231 (6) ◽  
pp. 526-534 ◽  
Author(s):  
Yue Wang ◽  
David Infield ◽  
Simon Gill
Keyword(s):  
Electric Vehicle ◽  
Electric Vehicles ◽  
Distribution System ◽  
Power Flow ◽  
Optimal Power Flow ◽  
Low Voltage ◽  
Wholesale Price ◽  
Heuristic Method ◽  
Domain Model ◽  
Smart Charging

This paper assumes a smart grid framework where the driving patterns for electric vehicles are known, time variations in electricity prices are communicated to householders, and data on voltage variation throughout the distribution system are available. Based on this information, an aggregator with access to this data can be employed to minimise electric vehicles charging costs to the owner whilst maintaining acceptable distribution system voltages. In this study, electric vehicle charging is assumed to take place only in the home. A single-phase Low Voltage (LV) distribution network is investigated where the local electric vehicles penetration level is assumed to be 100%. Electric vehicle use patterns have been extracted from the UK Time of Use Survey data with a 10-min resolution and the domestic base load is generated from an existing public domain model. Apart from the so-called real time price signal, which is derived from the electricity system wholesale price, the cost of battery degradation is also considered in the optimal scheduling of electric vehicles charging. A simple and effective heuristic method is proposed to minimise the electric vehicles’ charging cost whilst satisfying the requirement of state of charge for the electric vehicles’ battery. A simulation in OpenDSS over a period of 24 h has been implemented, taking care of the network constraints for voltage level at the customer connection points. The optimisation results are compared with those obtained using dynamic optimal power flow.

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 Local Market for TSO and DSO Reactive Power Provision Using DSO Grid Resources

Energies ◽  
2020 ◽  
Vol 13 (13) ◽  
pp. 3442
Author(s):  
Fábio Retorta ◽  
João Aguiar ◽  
Igor Rezende ◽  
José Villar ◽  
Bernardo Silva
Keyword(s):  
Real Time ◽  
Distribution System ◽  
Power Flow ◽  
Optimal Power Flow ◽  
Reactive Power ◽  
Time Interval ◽  
Local Market ◽  
Distribution Grid ◽  
Power Profile ◽  
System Operator

This paper proposes a near to real-time local market to provide reactive power to the transmission system operator (TSO), using the resources connected to a distribution grid managed by a distribution system operator (DSO). The TSO publishes a requested reactive power profile at the TSO-DSO interface for each time-interval of the next delivery period, so that market agents (managing resources of the distribution grid) can prepare and send their bids accordingly. DSO resources are the first to be mobilized, and the remaining residual reactive power is supplied by the reactive power flexibility offered in the local reactive market. Complex bids (with non-curtailability conditions) are supported to provide flexible ways of bidding fewer flexible assets (such as capacitor banks). An alternating current (AC) optimal power flow (OPF) is used to clear the bids by maximizing the social welfare to supply the TSO required reactive power profile, subject to the DSO grid constraints. A rolling window mechanism allows a continuous dispatching of reactive power, and the possibility of adapting assigned schedules to real time constraints. A simplified TSO-DSO cost assignment of the flexible reactive power used is proposed to share for settlement purposes.

scholarly journals Reactive Power Management Considering Stochastic Optimization under the Portuguese Reactive Power Policy Applied to DER in Distribution Networks

Energies ◽  
2019 ◽  
Vol 12 (21) ◽  
pp. 4028 ◽  
Author(s):  
Abreu ◽  
Soares ◽  
Carvalho ◽  
Morais ◽  
Simão ◽  
...  
Keyword(s):  
Power Management ◽  
Distribution System ◽  
Power Flow ◽  
Optimal Power Flow ◽  
Reactive Power ◽  
Renewable Energy Sources ◽  
Distribution Network ◽  
Real Data ◽  
Distribution Networks ◽  
System Operator

Challenges in the coordination between the transmission system operator (TSO) and the distribution system operator (DSO) have risen continuously with the integration of distributed energy resources (DER). These technologies have the possibility to provide reactive power support for system operators. Considering the Portuguese reactive power policy as an example of the regulatory framework, this paper proposes a methodology for proactive reactive power management of the DSO using the renewable energy sources (RES) considering forecast uncertainty available in the distribution system. The proposed method applies a stochastic sequential alternative current (AC)-optimal power flow (SOPF) that returns trustworthy solutions for the DSO and optimizes the use of reactive power between the DSO and DER. The method is validated using a 37-bus distribution network considering real data. Results proved that the method improves the reactive power management by taking advantage of the full capabilities of the DER and by reducing the injection of reactive power by the TSO in the distribution network and, therefore, reducing losses.

scholarly journals An Optimal Power Flow Algorithm for the Simulation of Energy Storage Systems in Unbalanced Three-Phase Distribution Grids

Energies ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1623
Author(s):  
Lukas Held ◽  
Felicitas Mueller ◽  
Sina Steinle ◽  
Mohammed Barakat ◽  
Michael R. Suriyah ◽  
...  
Keyword(s):  
Energy Storage ◽  
Power Flow ◽  
Optimal Power Flow ◽  
Low Voltage ◽  
Phase Distribution ◽  
Storage Systems ◽  
Optimal Power ◽  
Three Phase ◽  
Flow Algorithm ◽  
Distribution Grids

An optimal power flow algorithm for unbalanced three-phase distribution grids is presented in this paper as a new tool for grid planning on low voltage level. As additional equipment like electric vehicles, heat pumps or solar power systems can sometimes cause unbalanced power flows, existing algorithms have to be adapted. In comparison to algorithms considering balanced power flows, the presented algorithm uses a complete model of a three-phase four-wire low voltage grid. Additionally, a constraint for the voltage unbalance in the grid is introduced. The algorithm can be used to optimize the operation of energy storage systems in unbalanced systems. The used grid model, constraints, objective function and solver are explained in detail. A validation of the algorithm using a commercial tool is done. Additionally, three exemplary optimizations are performed to show possible applications for this tool.

scholarly journals TSO-DSO Operational Planning Coordination through Surrogate Lagrangian Relaxation

2021 ◽  
Author(s):  
Mikhail Bragin ◽  
Yury Dvorkin
Keyword(s):  
Distribution System ◽  
Cost Efficiency ◽  
Power Flow ◽  
Operational Planning ◽  
Planning Problem ◽  
Distributed Energy ◽  
Coordination Problem ◽  
Lagrangian Multipliers ◽  
Ac Power ◽  
System Operator

With the proliferation of distributed energy resources (DERs), located at the Distribution System Operator (DSO) level, uncertainties propagate from Transmission System Operator (TSO) to DSOs and vice versa. Therefore, to enable interoperability, while ensuring higher flexibility and cost-efficiency, both systems need to be efficiently coordinated to operate in sync. Moreover, because of the intermittency of renewable generation, voltages exhibit fluctuations thus necessitating the inclusion of AC power flow. Difficulties behind creating such TSO-DSO coordination include the combinatorial nature of the operational planning problem involved at the transmission level as well as the nonlinearity of AC power flow within both systems. These considerations significantly increase the complexity even under the deterministic setting. In this paper, a deterministic TSO-DSO operational planning coordination problem is considered and a novel decomposition and coordination approach is developed. Within the new method, the problem is decomposed into TSO and DSO subproblems, which are efficiently coordinated by updating Lagrangian multipliers. The nonlinearities at the TSO level caused by AC power flow constraints are resolved through a novel dynamic linearization. Numerical results based on the coordination of 118-bus TSO system with 32 DSO 34-bus systems indicate that both systems benefit from the coordination.<br>

scholarly journals New Dispatching Paradigm in Power Systems Including EV Charging Stations and Dispersed Generation: A Real Test Case

Energies ◽  
2020 ◽  
Vol 13 (4) ◽  
pp. 944
Author(s):  
Fabio Cazzato ◽  
Marco Di Clerico ◽  
Maria Carmen Falvo ◽  
Simone Ferrero ◽  
Marco Vivian
Keyword(s):  
Power Flow ◽  
Optimal Power Flow ◽  
Low Voltage ◽  
Renewable Energy Sources ◽  
Electricity Production ◽  
Transport Sector ◽  
Distribution Grid ◽  
New Paradigm ◽  
Charging Stations ◽  
Distribution Grids

Electric Vehicles (EVs) are becoming one of the main answers to the decarbonization of the transport sector and Renewable Energy Sources (RES) to the decarbonization of the electricity production sector. Nevertheless, their impact on the electric grids cannot be neglected. New paradigms for the management of the grids where they are connected, which are typically distribution grids in Medium Voltage (MV) and Low Voltage (LV), are necessary. A reform of dispatching rules, including the management of distribution grids and the resources there connected, is in progress in Europe. In this paper, a new paradigm linked to the design of reform is proposed and then tested, in reference to a real distribution grid, operated by the main Italian Distribution System Operator (DSO), e-distribuzione. First, in reference to suitable future scenarios of spread of RES-based power plants and EVs charging stations (EVCS), using Power Flow (PF) models, a check of the operation of the distribution grid, in reference to the usual rules of management, is made. Second, a new dispatching model, involving DSO and the resources connected to its grids, is tested, using an Optimal Power Flow (OPF) algorithm. Results show that the new paradigm of dispatching can effectively be useful for preventing some operation problems of the distribution grids.

scholarly journals A Master/Slave Approach to Power Flow and Overvoltage Control in Low-Voltage Microgrids

Energies ◽  
2019 ◽  
Vol 12 (14) ◽  
pp. 2760 ◽  
Author(s):  
Guido Cavraro ◽  
Tommaso Caldognetto ◽  
Ruggero Carli ◽  
Paolo Tenti
Keyword(s):  
Power Systems ◽  
Distribution System ◽  
Power Flow ◽  
Low Voltage ◽  
Point Of View ◽  
Operating Conditions ◽  
Energy Resources ◽  
Distributed Energy Resources ◽  
Distributed Energy ◽  
Systematic Analysis

This paper proposes a technique to control distributed energy resources in low-voltage microgrids aiming at (i) allowing power flow control at the point of connection with the upstream grid, (ii) keeping voltage profiles within the operational limits. The first feature is crucial in smart low-voltage power systems. In fact, it enables both demand-responses, which is extremely valuable from the point of view of distribution system operators and for energy trading, and the autonomous operation of the microgrid. The latter can be achieved by regulating to zero the power exchanged with the main grid. The second feature allows to limit voltage increases due to active power injection by distributed energy resources and, thus, to limit stresses on the electrical infrastructure and the served loads, which is a concrete issue as renewables become widely deployed in the low-voltage scenario. The proposed approach is firstly described in detail, then a systematic analysis of its local and global properties is reported. All the obtained results are verified considering the IEEE 37 test feeder in realistic operating conditions.

scholarly journals TSO-DSO Operational Planning Coordination through "l1-Proximal" Surrogate Lagrangian Relaxation

2021 ◽  
Author(s):  
Mikhail Bragin ◽  
Yury Dvorkin
Keyword(s):  
Distribution System ◽  
Cost Efficiency ◽  
Power Flow ◽  
Operational Planning ◽  
Planning Problem ◽  
Distributed Energy ◽  
Coordination Problem ◽  
Lagrangian Multipliers ◽  
Ac Power ◽  
System Operator

The proliferation of distributed energy resources (DERs), located at the Distribution System Operator (DSO) level, bring new opportunities as well as new challenges to the operations within the grid, specifically, when it comes to the interaction with the Transmission System Operator (TSO). To enable interoperability, while ensuring higher flexibility and cost-efficiency, DSOs and the TSO need to be efficiently coordinated. Difficulties behind creating such TSO-DSO coordination include the combinatorial nature of the operational planning problem involved at the transmission level as well as the nonlinearity of AC power flow within both systems. These considerations significantly increase the complexity even under the deterministic setting. In this paper, a deterministic TSO-DSO operational planning coordination problem is considered and a novel decomposition and coordination approach is developed. Within the new method, the problem is decomposed into TSO and DSO subproblems, which are efficiently coordinated by updating Lagrangian multipliers. The nonlinearities at the TSO level caused by AC power flow constraints are resolved through a dynamic linearization while guaranteeing feasibility through ``l1-proximal'' terms. Numerical results based on the coordination of the 118-bus TSO system with up to 32 DSO 34-bus systems indicate that the method efficiently overcomes the computational difficulties of the problem.<br>

scholarly journals TSO-DSO Operational Planning Coordination through Surrogate Lagrangian Relaxation

2021 ◽  
Author(s):  
Mikhail Bragin ◽  
Yury Dvorkin
Keyword(s):  
Distribution System ◽  
Cost Efficiency ◽  
Power Flow ◽  
Operational Planning ◽  
Planning Problem ◽  
Distributed Energy ◽  
Coordination Problem ◽  
Lagrangian Multipliers ◽  
Ac Power ◽  
System Operator

With the proliferation of distributed energy resources (DERs), located at the Distribution System Operator (DSO) level, uncertainties propagate from Transmission System Operator (TSO) to DSOs and vice versa. Therefore, to enable interoperability, while ensuring higher flexibility and cost-efficiency, both systems need to be efficiently coordinated to operate in sync. Moreover, because of the intermittency of renewable generation, voltages exhibit fluctuations thus necessitating the inclusion of AC power flow. Difficulties behind creating such TSO-DSO coordination include the combinatorial nature of the operational planning problem involved at the transmission level as well as the nonlinearity of AC power flow within both systems. These considerations significantly increase the complexity even under the deterministic setting. In this paper, a deterministic TSO-DSO operational planning coordination problem is considered and a novel decomposition and coordination approach is developed. Within the new method, the problem is decomposed into TSO and DSO subproblems, which are efficiently coordinated by updating Lagrangian multipliers. The nonlinearities at the TSO level caused by AC power flow constraints are resolved through a novel dynamic linearization. Numerical results based on the coordination of 118-bus TSO system with 32 DSO 34-bus systems indicate that both systems benefit from the coordination.<br>

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