Flexible Power Flow Algorithm for Distribution Network Including Second-Order Items

2014 ◽  
Vol 521 ◽  
pp. 440-443 ◽  
Author(s):  
Ning Zhou ◽  
Ru Si Chen ◽  
Tao Lin ◽  
Qiang Li ◽  
Xiang He ◽  
...  

For intelligent distribution system including Distributed Generations, we take the generator and load static characteristic into account and propose a flexible power flow algorithm for distribution network including second-order items. First, this algorithm modifies the distribution network power flow equations including second-order items in order to meet the static characteristic of generator and load. Moreover, we use the fsolve function of MATLAB to solve the power flow equations. This algorithm makes full use of the characteristic of high accuracy of the distribution network flow equations including second-order items and good convergence of the fsolve function. Compared with conventional distribution power flow algorithm, it does not need to set the trend flexible node type of each one. Not only the voltage amplitude, phase information of each node and the system frequency information can be calculated, as well as the actual power of generator and loads. The result of the algorithm is more in line with the practical electric power system engineering. Improved IEEE33 node system is chosen to verify the correctness of the algorithm.

Author(s):  
Jieyun Zheng ◽  
Shiyuan Ni ◽  
Pengjia Shi ◽  
Guilian Wu ◽  
Ri’an Wang ◽  
...  

Considering the fault "N-1" checksum and the power flow, the single-phase power flow model is further transformed into a three-phase power flow model, and the asymmetry of the three-phase power flow is measured by the three-phase unbalance factor. The calculation model is linearized by the second-order cone relaxation and the Big-M method. At the same time, the load response and distribution network reconstruction are used to improve the reliability of the power supply network to cope with the power failure. The relationship between power supply capability and power flow constraints, main transformer capacity and distributed power parameters is analyzed by IEEE 33-node three-phase power distribution system. The feasibility of the proposed model and the accuracy of the second-order cone relaxation are verified by numerical examples, which provides a technical reference for distribution network planning.


2014 ◽  
Vol 986-987 ◽  
pp. 377-382 ◽  
Author(s):  
Hui Min Gao ◽  
Jian Min Zhang ◽  
Chen Xi Wu

Heuristic methods by first order sensitivity analysis are often used to determine location of capacitors of distribution power system. The selected nodes by first order sensitivity analysis often have virtual high by first order sensitivities, which could not obtain the optimal results. This paper presents an effective method to optimally determine the location and capacities of capacitors of distribution systems, based on an innovative approach by the second order sensitivity analysis and hierarchical clustering. The approach determines the location by the second order sensitivity analysis. Comparing with the traditional method, the new method considers the nonlinear factor of power flow equation and the impact of the latter selected compensation nodes on the previously selected compensation location. This method is tested on a 28-bus distribution system. Digital simulation results show that the reactive power optimization plan with the proposed method is more economic while maintaining the same level of effectiveness.


Energies ◽  
2015 ◽  
Vol 8 (8) ◽  
pp. 8391-8405 ◽  
Author(s):  
Haifeng Liang ◽  
Xiaoling Zhao ◽  
Xiaolei Yu ◽  
Yajing Gao ◽  
Jin Yang

2014 ◽  
Vol 672-674 ◽  
pp. 1175-1178
Author(s):  
Guang Min Fan ◽  
Ling Xu Guo ◽  
Wei Liang ◽  
Hong Tao Qie

The increasingly serious energy crisis and environmental pollution problems promote the large-scale application of microgrids (MGs) and electric vehicles (EVs). As the main carrier of MGs and EVs, distribution network is gradually presenting multi-source and active characteristics. A fast service restoration method of multi-source active distribution network with MGs and EVs is proposed in this paper for service restoration of distribution network, which takes effectiveness, rapidity, economy and reliability into consideration. Then, different optimal power flow (OPF) models for the service restoration strategy are constructed separately to minimize the network loss after service restoration. In addition, a genetic algorithm was introduced to solve the OPF model. The analysis of the service restoration strategy is carried out on an IEEE distribution system with three-feeder and eighteen nodes containing MGs and EVs, and the feasibility and effectiveness are verified


2014 ◽  
Vol 484-485 ◽  
pp. 655-659
Author(s):  
Jing Wen Xu

In the planning and operation of distribution network, flow calculation and optimal flow is the hot issue for many experts and scholars to study. In network reconfiguration, service restoration and capacitor configuration, it needs hundreds even thousands times of power flow calculation. So it is very important to propose a suitable optimization algorithm. Based on the three-phase model we proposed hybrid particle swarm algorithm to calculate the three-phase power flow. The method uses the superposition principle. The distribution network is divided into two network models, one is the pure radial network without cyclic structure, and another is the pure cyclic network without radiation structure. We do iterative calculation respectively using hybrid particle algorithm, getting the calculation results. The hybrid algorithm is a new reference for the future optimization of power flow calculation in this paper.


Energies ◽  
2019 ◽  
Vol 12 (21) ◽  
pp. 4028 ◽  
Author(s):  
Abreu ◽  
Soares ◽  
Carvalho ◽  
Morais ◽  
Simão ◽  
...  

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.


2020 ◽  
Vol 10 (20) ◽  
pp. 7199
Author(s):  
Fernando García-Muñoz ◽  
Francisco Díaz-González ◽  
Cristina Corchero

This article presents a method based on a mathematical optimization model for the scheduling operation of a distribution network (DN). The contribution of the proposed method is that it permits the configuration and operation of a DN as a set of virtual microgrids with a high penetration level of distributed generation (DG) and battery energy storage systems (BESS). The topology of such virtual microgrids are modulated in time in response to grid failures, thus minimizing load curtailment, and maximizing local renewable resource and storage utilization as well. The formulation provides the load reduced by bus to balance the system at every hour and the global probability to present energy not supplied (ENS). Furthermore, for every bus, a flexibility load response range is considered to avoid its total load curtailment for small load reductions. The model has been constructed considering a linear version of the AC optimal power flow (OPF) constraints extended for multiple periods, and it has been tested in a modified version of the IEEE 33-bus radial distribution system considering four different scenarios of 72 h, where the global energy curtailment has been 27.9% without demand-side response (DSR) and 10.4% considering a 30% of flexibility load response. Every scenario execution takes less than a minute, making it appropriate for distribution system operational planning.


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