scholarly journals A Distributed and Robust Optimal Scheduling Model for an Active Distribution Network With Load Aggregators

2021 ◽  
Vol 9 ◽  
Author(s):  
Jidong Wang ◽  
Qiuming Xu ◽  
Huiling Su ◽  
Kaijie Fang
Keyword(s):  
Power Flow ◽  
Distribution Network ◽  
Optimization Methods ◽  
Distribution Networks ◽  
Optimal Scheduling ◽  
Economic Optimization ◽  
Voltage Security ◽  
Distributed Modeling ◽  
Scheduling Model ◽  
Flexible Loads

Increasing penetration of distributed generation (DG) has brought more uncertainty to the operation of active distribution networks (ADNs). With the reformation of the power system, increasingly more flexible loads access to distribution network through load aggregators (LAs), which becomes an effective way to solve these issues. Since LAs and ADNs are separate entities with different interests, the traditional centralized and deterministic optimization methods fail to meet the actual operational requirements of ADNs. Based on the linear power flow model, a robust optimal dispatching model of ADNs considering the influence of renewable DG’s uncertain output on voltage security constraints is established. Then, an independent optimal scheduling model for LAs is modeled based on the analysis of the composition and characteristics of flexible load in LAs. LAs and ADNs, as two different stakeholders, use a distributed modeling method to establish different economic optimization goals. The optimization problem is solved by decoupling the coupling exchanging power between LAs and ADNs into virtual controllable loads and virtual DGs. Finally, with the case study of a modified IEEE 33-bus system, the correctness and effectiveness of the proposed method are verified. The effects of the robust level and demand response incentive on the results are also analyzed.

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.

Research on the Voltage Influence of Active Distribution Network with Distributed Generation Access

2014 ◽  
Vol 668-669 ◽  
pp. 749-752 ◽  
Author(s):  
Xiao Yi Zhou ◽  
Ling Yun Wang ◽  
Wen Yue Liang ◽  
Li Zhou
Keyword(s):  
Distributed Generation ◽  
Power Distribution ◽  
Distribution System ◽  
Power Flow ◽  
Distribution Network ◽  
Distribution Networks ◽  
Power Distribution Network ◽  
Active Distribution Network ◽  
Novel Approach ◽  
Active Distribution Networks

Distributed generation (DG) has an important influence on the voltage of active distribution networks. A unidirectional power distribution network will be transformed into a bidirectional, multiple power supply distribution network after DGs access to the distribution network and the direction of power flow is also changed. Considering the traditional forward and backward substitution algorithm can only deal with the equilibrium node and PQ nodes, so the other types of DGs should be transformed into PQ nodes, then its impact on active distribution network can be analyzed via the forward and backward substitution algorithm. In this paper, the characteristics of active distribution networks are analyzed firstly and a novel approach is proposed to convert PI nodes into PQ nodes. Finally, a novel forward and backward substitution algorithm is adopted to calculate the power flow of the active distribution network with DGs. Extensive validation of IEEE 18 and 33 nodes distribution system indicates that this method is feasible. Numerical results show that when DG is accessed to the appropriate location with proper capacity, it has a significant capability to support the voltages level of distribution system.

scholarly journals Integration of Electric Vehicles in Low-Voltage Distribution Networks Considering Voltage Management

Energies ◽  
2020 ◽  
Vol 13 (16) ◽  
pp. 4125
Author(s):  
Miguel Carrión ◽  
Rafael Zárate-Miñano ◽  
Ruth Domínguez
Keyword(s):  
Power Systems ◽  
Electric Vehicles ◽  
Power Flow ◽  
Optimal Power Flow ◽  
Low Voltage ◽  
Distribution Network ◽  
Planning Horizon ◽  
Distribution Networks ◽  
Mixed Integer ◽  
Distribution Grid

The expected growth of the number of electric vehicles can be challenging for planning and operating power systems. In this sense, distribution networks are considered the Achilles’ heel of the process of adapting current power systems for a high presence of electric vehicles. This paper aims at deciding the maximum number of three-phase high-power charging points that can be installed in a low-voltage residential distribution grid. In order to increase the number of installed charging points, a mixed-integer formulation is proposed to model the provision of decentralized voltage support by electric vehicle chargers. This formulation is afterwards integrated into a modified AC optimal power flow formulation to characterize the steady-state operation of the distribution network during a given planning horizon. The performance of the proposed formulations have been tested in a case study based on the distribution network of La Graciosa island in Spain.

scholarly journals Active Distribution Network Modeling for Enhancing Sustainable Power System Performance; a Case Study in Egypt

2020 ◽  
Vol 12 (21) ◽  
pp. 8991
Author(s):  
Ali A. Radwan ◽  
Ahmed A. Zaki Diab ◽  
Abo-Hashima M. Elsayed ◽  
Hassan Haes Alhelou ◽  
Pierluigi Siano
Keyword(s):  
Power Systems ◽  
Electricity Market ◽  
System Performance ◽  
Power Flow ◽  
Electrical Power ◽  
Distribution Network ◽  
Distribution Networks ◽  
Western Desert ◽  
Distribution Transformers

The remarkable growth of distributed generation (DG) penetration inside electrical power systems turns the familiar passive distribution networks (PDNs) into active distribution networks (ADNs). Based on the backward/forward sweep method (BFS), a new power-flow algorithm was developed in this paper. The algorithm is flexible to handle the bidirectional flow of power that characterizes the modern ADNs. Models of the commonly used distribution network components were integrated with the developed algorithm to form a comprehensive tool. This tool is valid for modeling either balanced or unbalanced ADNs with an unlimited number of nodes or laterals. The integrated models involve modeling of distribution lines, losses inside distribution transformers, automatic voltage regulators (AVRs), DG units, shunt capacitor banks (SCBs) and different load models. To verify its validity, the presented algorithm was first applied to the unbalanced IEEE 37-node standard feeder in both passive and active states. Moreover, the algorithm was then applied to a balanced 22 kV real distribution network as a case study. The selected network is located in a remote area in the western desert of Upper Egypt, far away from the Egyptian unified national grid. Accordingly, the paper examines the current and future situation of the Egyptian electricity market. Comparison studies between the performance of the proposed ADNs and the classical PDNs are discussed. Simulation results are presented to demonstrate the effectiveness of the proposed ADNs in preserving the network assets, improving the system performance and minimizing the power losses.

scholarly journals Multi-Time-Scale Optimal Scheduling in Active Distribution Network with Voltage Stability Constraints

Energies ◽  
2021 ◽  
Vol 14 (21) ◽  
pp. 7107
Author(s):  
Tianhao Song ◽  
Xiaoqing Han ◽  
Baifu Zhang
Keyword(s):  
Time Resolution ◽  
Time Scale ◽  
Voltage Stability ◽  
Renewable Energy Sources ◽  
Stability Index ◽  
Distribution Networks ◽  
Optimal Scheduling ◽  
Coarse Grained ◽  
Scheduling Model ◽  
Network Losses

The uncertainty associated with loads and renewable-energy sources affects active distribution networks in terms of the operation and voltage stability on different time scales. To address this problem, a multi-time-scale voltage stability constrained optimal scheduling framework is proposed, which includes a day-ahead model with a coarse-grained time resolution and an intra-day model with a fine-grained time resolution. The day-ahead economic-scheduling model maps out a scheme to operate different types of devices with the aim of minimizing the network losses. Following the scheme, the intra-day corrective-adjustment model based on model predictive control is proposed to regulate the flexible devices, such as the energy storage systems and the photovoltaic converters. In particular, the proposed optimal scheduling framework embeds a voltage stability constraint which is constructed by using a novel index, defined based on the Distflow model Jacobian. As the index at each bus is a linear function of the locally measurable power flow variables, the proposed constraint does not introduce additional computational burdens. Simulation results demonstrate the necessity and effectiveness of the proposed multi-time-scale voltage stability constrained optimal scheduling model. The results also show that the variation trend of the proposed index is consistent with that of the commonly used voltage stability index.

scholarly journals BIBC Matrix Modification for Network Topology Changes: Reconfiguration Problem Implementation

Energies ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2738
Author(s):  
Ayşe Aybike Şeker ◽  
Tuba Gözel ◽  
Mehmet Hakan Hocaoğlu
Keyword(s):  
Network Topology ◽  
Power Flow ◽  
Distribution Network ◽  
Flow Analysis ◽  
Distribution Networks ◽  
Load Flow ◽  
Normal Operation ◽  
Algorithm Efficiency ◽  
Matrix Modification ◽  
Network Losses

The topology of a distribution network can be represented by a bus injection to branch current (BIBC) matrix. It has been introduced and used for load flow analysis of distribution networks. In this paper, a method for BIBC matrix modification is developed to use in applications which require a topology change representation. Proposed method that reflects the changes in configuration in the system BIBC matrix is implemented in distribution network reconfiguration problem. With providing potential solutions for network operational and planning requirements such as necessitate changes in configurations to transfer the loads to a different substation, ease the loading of equipment, conduct planned maintenance and reduce network losses during the normal operation with renewables, storage and other uprising technologies, reconfiguration may also be useful for emergencies, accidents, attacks and weather-related disasters. The BIBC modification process provides the knowledge of possible switches to open and the direction of power flow without any need to further radiality or continuity check. The proposed method needs only initial network topology information that makes it suitable to apply on any distribution network and to use with any search method or heuristic/meta-heuristic optimization algorithm. Efficiency of the method is investigated on systems with voltage dependent and time varying loads.

scholarly journals Optimal dispatching of integrated energy system considering flexible load

2021 ◽  
Vol 2076 (1) ◽  
pp. 012014
Author(s):  
Jinrui Guo ◽  
Zhijun Zhang ◽  
Lei Xu ◽  
Hao Wang ◽  
Hui Wang ◽  
...  
Keyword(s):  
Energy System ◽  
Optimal Scheduling ◽  
Scheduling Model ◽  
Alternating Direction ◽  
Proposed Model ◽  
Integrated Energy System ◽  
Flexible Loads ◽  
The Stability ◽  
The Mathematical Model ◽  
Protection Costs

Abstract Demand response, as an effective dispatching method, has been widely used in the optimization research of integrated energy system (IES). In this article, first, the mathematical model of flexible loads including shiftable electric, heat, and cooling load are established in line with their characteristics. Second, an optimal scheduling model of the IES is built, where the minimum sum of system operation and maintenance and the environmental protection costs comprise the objective function. Furthermore, the alternating direction multiplier method is used to solve the optimal scheduling model in a fully distributed manner. Finally, simulation results show that the proposed model and algorithm can efficiently solve the IES optimal dispatching problem, reduce the peak-valley difference, and improve the stability of the system.

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