Application of DSAPSO Algorithm in Distribution Network Reconfiguration with Distributed Generation

With the current integration of distributed energy resources into the grid,the structure of distribution networks is becoming more complex.This complexity significantly expands the solution space in the optimization process for network reconstruction using intelligent algorithms.Consequently,traditional intelligent algorithms frequently encounter insufficient search accuracy and become trapped in local optima.To tackle this issue,a more advanced particle swarm optimization algorithm is proposed.To address the varying emphases at different stages of the optimization process,a dynamic strategy is implemented to regulate the social and self-learning factors.The Metropolis criterion is introduced into the simulated annealing algorithm to occasionally accept suboptimal solutions,thereby mitigating premature convergence in the population optimization process.The inertia weight is adjusted using the logistic mapping technique to maintain a balance between the algorithm’s global and local search abilities.The incorporation of the Pareto principle involves the consideration of network losses and voltage deviations as objective functions.A fuzzy membership function is employed for selecting the results.Simulation analysis is carried out on the restructuring of the distribution network,using the IEEE-33 node system and the IEEE-69 node system as examples,in conjunction with the integration of distributed energy resources.The findings demonstrate that,in comparison to other intelligent optimization algorithms,the proposed enhanced algorithm demonstrates a shorter convergence time and effectively reduces active power losses within the network.Furthermore,it enhances the amplitude of node voltages,thereby improving the stability of distribution network operations and power supply quality.Additionally,the algorithm exhibits a high level of generality and applicability.

通信限制下多DG接入配网的新型电流差动保护

差动保护是解决分布式电源(distributed generation, DG)接入下配电网保护难题的有效手段,然而配网现有通信建设水平很大程度上制约了差动保护的构建。首先,融合电流相位与相量差动保护思想,同时将电流相位信息进行变换,实现通信信息降容。应用递推最小二乘法实现短路电流相位参数的快速估计,提出了短路电流相位修正策略,以应对CT饱和与直流分量对保护的干扰。最后,提出适用于含多DG配网的新型电流差动保护构建原则与保护判据。基于PSACD/EMTDC平台搭建仿真模型,验证了所提出的电流相位参数预测方法的精度与新型差动保护的性能。算例结果表明:所提电流相位参数预测方法速度快、精度高,具有良好的抗CT饱和能力;所提新型差动保护原理具有良好的性能。

Identification of Type of a Fault in Distribution System Using Shallow Neural Network with Distributed Generation

A distributed generation system(DG)has several benefits over a traditional centralized power system.However,the protection area in the case of the distributed generator requires special attention as it encounters stability loss,failure re-closure,fluctuations in voltage,etc.And thereby,it demands immediate attention in identifying the location&type of a fault without delay especially when occurred in a small,distributed generation system,as it would adversely affect the overall system and its operation.In the past,several methods were proposed for classification and localisation of a fault in a distributed generation system.Many of those methods were accurate in identifying location,but the accuracy in identifying the type of fault was not up to the acceptable mark.The proposed work here uses a shallow artificial neural network(sANN)model for identifying a particular type of fault that could happen in a specific distribution network when used in conjunction with distributed generators.Firstly,a distribution network consisting of two similar distributed generators(DG1 and DG2),one grid,and a 100 Km distribution line is modeled.Thereafter,different voltages and currents corresponding to various faults(line to line,line to ground)at different locations are tabulated,resulting in a matrix of 500×18 inputs.Secondly,the sANN is formulated for identifying the types of faults in the system in which the above-obtained data is used to train,validate,and test the neural network.The overall result shows an unprecedented almost zero percent error in identifying the type of the faults.

考虑DG无功调节和不确定性的配电网新能源消纳容量评估

为充分考虑分布式电源不确定性和控制多样性对配电网运行的影响,提出了一种考虑分布式电源无功调节和不确定性配电网新能源消纳容量的评估方法。首先分析了分布式电源对配电网电压分布的影响、分布式电源无功调节能力以及分布式电源出力的不确定模型;其次,以最大化新能源消纳容量和最小网损为优化目标,以计及分布式电源无功调节和不确定性的有功-无功作为重要约束,建立配电网新能源消纳容量评估模型;然后,以分布式电源和无功补偿装置的出力为优化变量,通过快速非支配排序遗传算法进行求解,实现了新能源消纳容量的准确评估;最后通过应用实例进行验证。结果表明,所提评估方法实现了配电网新能源消纳容量的可靠评估。

Economic Power Dispatching from Distributed Generations: Review of Optimization Techniques

In the increasingly decentralized energy environment,economical power dispatching from distributed generations(DGs)is crucial to minimizing operating costs,optimizing resource utilization,and guaranteeing a consistent and sustainable supply of electricity.A comprehensive review of optimization techniques for economic power dispatching from distributed generations is imperative to identify the most effective strategies for minimizing operational costs while maintaining grid stability and sustainability.The choice of optimization technique for economic power dispatching from DGs depends on a number of factors,such as the size and complexity of the power system,the availability of computational resources,and the specific requirements of the application.Optimization techniques for economic power dispatching from distributed generations(DGs)can be classified into two main categories:(i)Classical optimization techniques,(ii)Heuristic optimization techniques.In classical optimization techniques,the linear programming(LP)model is one of the most popular optimization methods.Utilizing the LP model,power demand and network constraints are met while minimizing the overall cost of generating electricity from DGs.This approach is efficient in determining the best DGs dispatch and is capable of handling challenging optimization issues in the large-scale system including renewables.The quadratic programming(QP)model,a classical optimization technique,is a further popular optimization method,to consider non-linearity.The QP model can take into account the quadratic cost of energy production,with consideration constraints like network capacity,voltage,and frequency.The metaheuristic optimization techniques are also used for economic power dispatching from DGs,which include genetic algorithms(GA),particle swarm optimization(PSO),and ant colony optimization(ACO).Also,Some researchers are developing hybrid optimization techniques that combine elements of classical and heuristic optimization techniques with the incorporation of droop control,predictive control,and fuzzy-based methods.These methods can deal with large-scale systems with many objectives and non-linear,non-convex optimization issues.The most popular approaches are the LP and QP models,while more difficult problems are handled using metaheuristic optimization techniques.In summary,in order to increase efficiency,reduce costs,and ensure a consistent supply of electricity,optimization techniques are essential tools used in economic power dispatching from DGs.

Comprehensive Benefit Evaluation of SZ Distributed Photovoltaic Power Generation Project Based on AHP-Matter-Element Extension Model

With the introduction of the“dual carbon goals,”there has been a robust development of distributed photovoltaic power generation projects in the promotion of their construction.As part of this initiative,a comprehensive and systematic analysis has been conducted to study the overall benefits of photovoltaic power generation projects.The evaluation process encompasses economic,technical,environmental,and social aspects,providing corresponding analysis methods and data references.Furthermore,targeted countermeasures and suggestions are proposed,signifying the research’s importance for the construction and development of subsequent distributed photovoltaic power generation projects.

含DG的配网系统中性点接地方式设计研究

电力系统中性点接地方式是一个重要的综合性问题,对于电网正常运行具有重要意义。在当前的技术背景下,配网系统中性点接地方式主要包括大电流接地、小电流接地两种,并不存在统一的标准,不同接地方式适用于不同工作需求。文章通过对相关文献进行查阅,以含分布式电源(Distributed Generation,DG)的配网系统中性点接地为研究对象,设计含DG的配网系统中性点接地方式。为证实研究的有效性,结合仿真软件进行中性点接地方案仿真建模。最终发现,文章研究内容可以在架空线路、电缆线路2个场景中发挥出较为优越的技术效果,具有一定的实际应用价值。

基于多Agent的含DG智能配电网差动保护自愈方法

含DG智能配电网中的潮流方向随分布式发电的变化而变化,导致配电网故障自愈的效果难以保障,因此,提出基于多Agent的含DG智能配电网差动保护自愈方法。通过构建基于多Agent的MAS体系结构,将其应用于含DG智能配电网差动保护和自愈的控制,在MAS体系结构的数据处理层完成差动保护,并在MAS体系结构的协调控制层实现故障自愈。结果表明,该设计方法不仅可以恢复配电网故障区域的电力,而且在操作次数、线损及功率因数方面可达到较理想的效果。

城市配电网DG消纳能力曲线的计算方法与分析应用

为了完整描述城市配电网的分布式发电(DG)消纳能力(TAC),探究DG TAC曲线的提升措施,提出一种城市配电网DG TAC曲线的计算方法。介绍安全域和安全边界;建立考虑馈线负荷实际情况和电压约束的TAC曲线模型,该模型利用日负荷曲线确定状态空间,通过对边界点进行电压校验得到TAC曲线。算例验证了所提方法的有效性。通过分析TAC曲线的负荷影响因素发现,只有瓶颈馈线段(组)下游负荷对TAC曲线有影响,提出增加瓶颈馈线段(组)下游负荷和瓶颈馈线段(组)扩容2种TAC曲线提升措施。提出TAC曲线在指导DG和负荷接入、导线更换方面的应用方法。

Restraint of spatial distribution in high-order harmonic generation from a model of hydrogen molecular ion

The spatial distribution in high-order harmonic generation（HHG） is theoretically investigated by using a few-cycle laser pulse from a two-dimensional model of a hydrogen molecular ion. The spatial distribution in HHG demonstrates that the harmonic spectra are sensitive to the carrier envelope phase and the duration of the laser pulse. The HHG can be restrained by a pulse with the duration of 5 fs in the region from the 90 th to 320th order. This characteristic is illustrated by the probability density of electron wave packet distribution. The electron is mainly located near the nucleus along the positive-x direction from 3.0 o.c. to 3.2 o.c., which is an important time to generate the HHG in the plateau area. We also demonstrate the time-frequency distribution in the region of the positive-and negative-x direction to explain the physical mechanism.

Carrier envelope phase effect on the spatial distribution of high-order harmonic generation in asymmetric molecule

The spatial distribution in high-order harmonic generation（HHG） from the asymmetric diatomic molecule He H^（2＋） is investigated by numerically solving the non-Born–Oppenheimer time-dependent Schr？dinger equation（TDSE）. The spatial distribution of the HHG spectra shows that there is little contribution in HHG around the geometric center of two nuclei（z = 1.17 a.u.） and the equilibrium internuclear position of the H nucleus（z = 3.11 a.u.）. We demonstrate the carrier envelope phase（CEP） effect on the spatial distribution of HHG in a few-cycle laser pulse. The HHG process is investigated by the time evolution of the electronic density distribution. The time–frequency analysis of HHG from two nuclei in HeH^（2＋） is presented to further explain the underlying physical mechanism.

Evaluation of intermittent-distributed-generation hosting capability of a distribution system with integrated energy-storage systems

The penetration rate of distributed generation is gradually increasing in the distribution system concerned.This is creating new problems and challenges in the planning and operation of the system.The intermittency and variability of power outputs from numerous distributed renewable generators could significantly jeopardize the secure operation of the distribution system.Therefore,it is necessary to assess the hosting capability for intermittent distributed generation by a distribution system considering operational constraints.This is the subject of this study.An assessment model considering the uncertainty of generation outputs from distributed generators is presented for this purpose.It involves different types of regulation or control functions using on-load tap-changers(OLTCs),reactive power compensation devices,energy storage systems,and the reactive power support of the distributed generators employed.A robust optimization model is then attained It is solved by Bertsimas robust counterpart through GUROBI solver.Finally,the feasibility and efficiency of the proposed method are demonstrated by a modified IEEE 33-bus distribution system.In addition,the effects of the aforementioned regulation or control functions on the enhancement of the hosting capability for intermittent distributed generation are examined.

Power loss reduction of distribution systems using BFO based optimal reconfiguration along with DG and shunt capacitor placement simultaneously in fuzzy framework

In distribution systems,network reconfiguration and capacitor placement are commonly used to diminish power losses and keep voltage profiles within acceptable limits.Moreover,the problem of DG allocation and sizing is great important.In this work,a combination of a fuzzy multi-objective approach and bacterial foraging optimization(BFO) as a meta-heuristic algorithm is used to solve the simultaneous reconfiguration and optimal sizing of DGs and shunt capacitors in a distribution system.Each objective is transferred into fuzzy domain using its membership function.Then,the overall fuzzy satisfaction function is formed and considered a fitness function inasmuch as the value of this function has to be maximized to gain the optimal solution.The numerical results show that the presented algorithm improves the performance much more than other meta-heuristic algorithms.Simulation results found that simultaneous reconfiguration with DG and shunt capacitors allocation(case 5) has 77.41%,42.15%,and 56.14%improvements in power loss reduction,load balancing,and voltage profile indices,respectively in 33-bus test system.This result found 87.27%,35.82%,and 54.34%improvements of mentioned indices respectively for 69-bus system.

Optimal DG Placement in Distribution Networks Using Intelligent Systems

Distributed Generation (DG) unlike centralized electrical generation aims to generate electrical energy on small scale as near as possible to the load centers, interchanging electric power with the network. Moreover, DGs influence distribution system parameters such as reliability, loss reduction and efficiency while they are highly dependent on their situation in the distribution network. This paper focuses on optimal placement and estimation of DG capacity for installation and takes more number of significant parameters into account compare to the previous studies which consider just a few parameters for their optimization algorithms. Using a proposed optimal Genetic Algorithm, a destination function that includes the cost parameters (such as loss reduction, fuel price, etc.) has been optimized. This method is also capable of changing the weights of each cost parameter in the destination function of the Genetic Algorithm and the matrix of coefficients in the DIGSILENT environment. It has been applied and simulated on a sample IEEE 13-bus network. The obtained results show that any change in the weight of each parameter in the destination function of the Genetic Algorithm and in the matrix of coefficients leads to a meaningful change in the location and capacity of the prospective DG in the distribution network.

Mitigation of Distributed Generation Impact on Protective Devices in a Distribution Network by Superconducting Fault Current Limiter

Protection of radial distribution networks is widely based on coordinated inverse time overcurrent relays (OCRs) ensuring both effectiveness and selectivity. However, the integration of distributed generation (DG) into an existing distribution network not only inevitably increases fault current levels to levels that may exceed the OCR ratings, but it may also disturb the original overcurrent relay coordination adversely effecting protection selectivity. To analyze the potentially adverse impact of DG on distribution system protective devices with respect to circuit breaker ratings and OCR coordination fault current studies are carried out for common reference test system under the influence of additional DG. The possible advantages of Superconducting Fault Current Limiter (SFCL) as a means to limit the adverse effect of DG on distribution system protection and their effectiveness will be demonstrated. Furthermore, minimum SFCL impedances required to avoid miss-operation of the primary and back-up OCRs are determined. The theoretical analysis will be validated using the IEEE 13-bus distribution test system is used. Both theoretical and simulation results indicate that the proposed application of SFCL is a viable option to effectively mitigate the DG impact on protective devices, thus enhancing the reliability of distribution network interfaced with DG.

Impact of PV Distributed Generation on Loop Distribution Network

The rapid spreading of the Photovoltaic (PV) Systems as Distributed Generation (DG) in medium and low voltage networks created many effects and changes on the existing power system networks. In this work, two methods have been used and applied to determine the optimal allocation and sizing of the PV to be installed as DGs (ranging from 250 kW up to 3 MW). The first one is to determine the location according to the maximal power losses reduction over the feeder. The second one is by using the Harmony Search Algorithm which is claimed to be a powerful technique for optimal allocation of PV systems. The results of the two techniques were compared and found to be nearly closed. Furthermore, investigation on the effects on the feeder in terms of voltage levels, power factor readings, and short circuit current levels has been done. All calculations and simulations are conducted by using the MATLAB Simulation Program. Some field calculations and observations have been expended in order to substantiate the research findings and validation.

Optimal Placement of Distributed Generation for Reliability Benefit in Distribution Systems

A <st1:data language="0" startpos="3" context="A distributed generator is a small-scale active generating unit located on or near the site where it is to be used. Several benefits have been realized by installing DGs in the distribution network. Among them is a reduction in the system power loss if their locations and sizes are appropriately determined. For this reason, the main objective of this paper is to develop mathematical models and a technique based on tabu search for the optimal placement and sizing of DGs in a distribution system. Numerical results from tests on 12-, 33- and 13-bus distribution systems with different load distributions show that the system power loss with DGs can be significantly reduced when compared with that without the DGs. " w:st="on">distributed generator is <st1:data language="0" startpos="28" context="A distributed generator is a small-scale active generating unit located on or near the site where it is to be used. Several benefits have been realized by installing DGs in the distribution network. Among them is a reduction in the system power loss if their locations and sizes are appropriately determined. For this reason, the main objective of this paper is to develop mathematical models and a technique based on tabu search for the optimal placement and sizing of DGs in a distribution system. Numerical results from tests on 12-, 33- and 13-bus distribution systems with different load distributions show that the system power loss with DGs can be significantly reduced when compared with that without the DGs. " w:st="on">a small-scaled <st1:data language="0" startpos="42" context="A distributed generator is a small-scale active generating unit located on or near the site where it is to be used. Several benefits have been realized by installing DGs in the distribution network. Among them is a reduction in the system power loss if their locations and sizes are appropriately determined. For this reason, the main objective of this paper is to develop mathematical models and a technique based on tabu search for the optimal placement and sizing of DGs in a distribution system. Numerical results from tests on 12-, 33- and 13-bus distribution systems with different load distributions show that the system power loss with DGs can be significantly reduced when compared with that without the DGs. " w:st="on">active <st1:data language="0" startpos="49" context="A distributed generator is a small-scale active generating unit located on or near the site where it is to be used. Several benefits have been realized by installing DGs in the distribution network. Among them is a reduction in the system power loss if their locations and sizes are appropriately determined. For this reason, the main objective of this paper is to develop mathematical models and a technique based on tabu search for the optimal placement and sizing of DGs in a distribution system. Numerical results from tests on 12-, 33- and 13-bus distribution systems with different load distributions show that the system power loss with DGs can be significantly reduced when compared with that without the DGs. " w:st="on">generating <st1:data language="0" startpos="60" context="A distributed generator is a small-scale active generating unit located on or near the site where it is to be used. Several benefits have been realized by installing DGs in the distribution network. Among them is a reduction in the system power loss if their locations and sizes are appropriately determined. For this reason, the main objective of this paper is to develop mathematical models and a technique based on tabu search for the optimal placement and sizing of DGs in a distribution system. Numerical results from tests on 12-, 33- and 13-bus distribution systems with different load distributions show that the system power loss with DGs can be significantly reduced when compared with that without the DGs. " w:st="on">unit <st1:data language="0" startpos="65" context="A distributed generator is a small-scale active generating unit located on or near the site where it is to be used. Several benefits have been realized by installing DGs in the distribution network. Among them is a reduction in the system power loss if their locations and sizes are appropriately determined. For this reason, the main objective of this paper is to develop mathematical models and a technique based on tabu search for the optimal placement and sizing of DGs in a distribution system. Numerical results from tests on 12-, 33- and 13-bus distribution systems with different load distributions show that the system power loss with DGs can be significantly reduced when compared with that without the DGs. " w:st="on">located <st1:data language="0" startpos="73" context="A distributed generator is a small-scale active generating unit located on or near the site where it is to be used. Several benefits have been realized by installing DGs in the distribution network. Among them is a reduction in

Impacts of Electrical Line Losses Comprising Mul-ti-Distributed Generation in Distribution System

This paper proposes to study the impacts of electrical line losses due to the connection of distributed generators (DG) to 22kV distribution system of Provincial Electricity Authority (PEA). Data of geographic information systems (GIS) including the distance of distribution line and location of load being key parameter of PEA is simulated using digital simulation and electrical network calculation program (DIgSILENT) to analyze power loss of the distribution system. In addition, the capacity and location of DG installed into the distribution system is considered. The results are shown that, when DG is installed close to the substation, the electrical line losses are reduced. However, if DG capacity becomes larger and the distance between DG and load is longer, the electrical line losses tend to increase. The results of this paper can be used to create the suitability and fairness of the fee for both DG and utility.

A Reliability Impact and Assessment of Distributed Generation Integration to Distribution System

The main purpose of this paper is to study the reliability due to the employment of distributed generations (DG) integrated to distribution system. The system under this study is from Provincial Electricity Authority (PEA) that is a part of Thailand’s distribution system. Data of geographic information systems (GIS) including the distance of distribution line and location of load that are parameter of PEA is simulated using digital simulation and electrical network calculation program (DIgSILENT) to analyze the impact of reliability with the installing DG into the distribution system. The system average interruption frequency index (SAIFI), the system average interruption duration index (SAIDI) and interruption cost are assessed as index of reliability by comparing the SAIFI, SAIDI, and interruption cost between the base case (no DG) and the case that DG connected to the distribution system. The results can be summarized by focusing on location of DG, the capacity of DG, the size of load, and the distance of load which are factors able to impact to SAIFI, SAIDI, and interruption cost.

Analysis of Distribution Generation Influences on the Vol-tage Limit Violation Probability of Distribution Line

Considering the time-sequence characteristic and randomness of load and natural resources, ?this paper studies on the distributed generation (DG) impacts on voltage limit violation probability of distribution lines. The time-sequence characteristic and randomness of load, wind and photovoltaic (PV) generation are analyzed;the indices and risk levels of voltage limit violation probability of node and distribution line are proposed. By using probabilistic load flow based on semi-invariant method, the impact degrees of voltage limit violation are calculated with different distributed power penetration levels, different seasons, different time periods, different allocation ratio between the wind power and PV power. Voltage limit violation laws of distribution line, which are concluded by IEEE33 bus system simulation, are very helpful to guide the voltage?regulation of distribution line including distributed generation.