Analysis and Power Quality Improvement in Hybrid Distributed Generation System with Utilization of Unified Power Quality Conditioner

This paper presents a comprehensive study that includes the sizing and power flow by series and parallel inverters in a distributed generation system(DGs)that integrates the system of hybrid wind photovoltaic with a unified power quality conditioner(UPQC).In addition to supplying active power to the utility grid,the system of hybrid wind photovoltaic functions as a UPQC,compensating reactive power and suppressing the harmonic load currents.Additionally,the load is supplied with harmonic-free,balanced and regulated output voltages.Since PVWind-UPQC is established on a dual compensation scheme,the series inverter works like a sinusoidal current source,while the parallel inverter works like a sinusoidal voltage source.Consequently,a smooth alteration from interconnected operating modes to island operating modes and vice versa can be achieved without load voltage transients.Since PV-Wind-UPQC inverters handle the energy generated through the hybrid wind photovoltaic system and the energy demanded through the load,the converters should be sized cautiously.A detailed study of the flow of power via the PV-Wind-UPQC is imperative to gain a complete understanding of the system operation and the proper design of the converters.Thus,curves that allow the sizing of the power converters according to the power flow via the converters are presented and discussed.Simulation results are presented to assess both steady state and dynamic performances of the grid connected hybrid system of PV-Wind-UPQC.This investigation is verified by simulating and analyzing the results with Matlab/Simulink.

SMO Algorithm to Unravel CEED Problem using Wind and Solar

This research proposes a more advanced way to address Combined Economic Emission Dispatch(CEED)concerns.Economic Load Dispatch(ELD)and Economic Emission Dispatch(EED)have been implemented to reduce generating unit fuel costs and emissions.When both economics and emission tar-gets are taken into account,the dispatch of an aggregate cost-effective emission challenge emerges.This research affords a mathematical modeling-based analyti-cal technique for solving economic,emission,and collaborative economic and emission dispatch problems with only one goal.This study takes into account both the fuel cost target and the environmental impact of emissions.This bi-inten-tion CEED problem is converted to a solitary goal function using a price penalty factor technique.In this case,a metaheuristic and an environment-inspired,intel-ligent Spider Monkey Optimization technique(SMO)are used to address the CEED dilemma.By following the generator’s scheduling process,the SMO meth-od is used to regulate the output from the power generation system in terms of pollution and fuel cost.The Fission-Fusion social(FFS)structure of spider mon-keys promotes them to utilize a global optimization method known as SMO dur-ing foraging behaviour.The emphasis is mostly on lowering the cost of generation and pollution in order to improve the efficiency of the power system and han-dle dispatch problems with constraints.The economic dispatch has been reme-died,and the improved result demonstrates that the system’s performance is stable andflexible in real time.Finally,the system’s output demonstrates that the system has improved in resolving CEED difficulties.When compared to ear-lier investigations,the proposed model’sfindings have improved.As the gener-ating units,wind and solar are used to explore the CEED crisis in the IEEE 30 bus system.

Renewable Energy:Wind Turbines,Solar Cells,Small Hydroelectric Plants,Biomass,and Geothermal Sources of Energy

In this paper,we present five basic types of renewable energy sources,namely:wind turbines,solar cells,small hydroelectric plants,biomass,and geothermal sources of energy.Wind turbines transform energy of wind into electrical energy,solar cells transform energy of sun into electric energy,hydroelectric plants transform energy of water into electric energy,devices or machines can be constructed to transform energy of biomass into heat energy,and geothermal energy into some form of energy.In this paper we present basic information and reasons why there is need today to use these forms of energy—called green energies,we present how these devices or machines function,and we propose for future work design of typical devices or machines that will satisfy basic functional needs.

Hybrid PV/Wind/Diesel Based Distributed Generation for an Off-Grid Rural Village in Afghanistan

Afghanistan has a tremendous resource potential of renewable energy especially solar and the wind. Therefore, utilization of these resources has a special rule for the remote areas where access to the electrical grid or secure power supply is a dream for most of the people. This paper presents a feasibility and usefulness of hybrid power generation based on PV/wind/diesel generator for an off-grid rural village that feeds the load at a rate of average 7.9 kWh/day with 1.32 kW peak load. GsT （geospatial toolkit） is used to obtain the solar and wind data of the site. Windographer software is used to analyze the wind resource data of the site. HOMER Pro software package is used to select the suitable and reliable hybrid generation system and calculate the optimal capacities and costs of the components. Through the study, it is found that this state of the art adaptation could provide vast opportunities for off-grid rural communities such as in Afghanistan where enough high penetration of renewable energy is available.

Development modes analysis of renewable energy power generation in North Africa

North African countries generally have strategic demands for energy transformation and sustainable development.Renewable energy development is important to achieve this goal.Considering three typical types of renewable energies—wind,photovoltaic(PV),and concentrating solar power(CSP)—an optimal planning model is established to minimize construction costs and power curtailment losses.The levelized cost of electricity is used as an index for assessing economic feasibility.In this study,wind and PV,wind/PV/CSP,and transnational interconnection modes are designed for Morocco,Egypt,and Tunisia.The installed capacities of renewable energy power generation are planned through the time sequence production simulation method for each country.The results show that renewable energy combined with power generation,including the CSP mode,can improve reliability of the power supply and reduce the power curtailment rate.The transnational interconnection mode can help realize mutual benefits of renewable energy power,while the apportionment of electricity prices and trading mechanisms are very important and are related to economic feasibility;thus,this mode is important for the future development of renewable energy in North Africa.

Optimization of Minimum Power Output for Combined Heat and Power Units Considering Peak Load Regulation Ability

Northern China has rich wind power and photovoltaic renewable resources. Combined Heat and Power (CHP) Units to meet the load demand and limit its peaking capacity in winter, to a certain extent, it results in structural problems of wind-solar power and thermoelectric. To solve these problems, this paper proposes a plurality of units together to ensure supply of heat load on the premise, by building a thermoelectric power peaking considering thermal load unit group dynamic scheduling model, to achieve the potential of different thermoelectric properties peaking units of the excavation. Simulation examples show, if the unit group exists obvious relationship thermoelectric individual differences, the thermal load dynamic scheduling can be more significantly improved overall performance peaking unit group, effectively increase clean energy consumptive.

Impact of Reactive Power in Power Evacuation from Wind Turbines

Application of Distributed Generation (DG) to supply the demands of a diverse customer base plays a vital role in the renewable energy environment. Various DG technologies are being integrated into power systems to provide alterna-tives to energy sources and to improve reliability of the system. Power Evacuation from these remotely located DG’s remains a major concern for the power utilities these days. The main cause of concern regarding evacuation is con-sumption of reactive power for excitation by Induction Generators (IG) used in wind power production which affects the power system in variety of ways. This paper deals with the issues related to reactive power consumption by Induc-tion generators during power evacuation. Induction generator based wind turbine model using MATLAB/SIMULINK is simulated and its impact on the grid is observed. The simulated results are analyzed and validated with the real time results for the system considered. A wind farm is also modeled and simulations are carried out to study the various im-pacts it has on the grid &nearby wind turbines during Islanding and system event especially on 3-Phase to ground fault.

Simulation Analysis for Massive Deployment of Variable Renewables Employing an Optimal Power Generation Mix Model

This paper develops a high time-resolution optimal power generation mix model in its time resolution of 10 minutes on 365 days by linear programming technique. The model allows us to analyse the massive deployment of photovoltaic system and wind power generation in power system explicitly considering those short-term output variation. PV （photovoltaic） and wind output are estimated, employing meteorological database. Simulation results reveal that variable fluctuation derived from a high penetration level of those renewables is controlled by quick load following operation of natural gas combined cycle power plant, pumped-storage hydro power, stationary NAS （sodium and sulfur） battery and the output suppression control of PV and wind. It additionally turns out that the operational configuration of those technologies for the renewable variability differs significantly depending on those renewable output variations in each season and solving the seasonal electricity imbalance as well as the daily imbalance is important if variable renewables are massively deployed.

Collaborative Planning of Distributed Wind Power Generation and Distribution Network with Large-scale Heat Pumps

With the advancement of clean heating projects and the integration of large-scale distributed heat pumps into rural distribution networks in northern China,power grid companies face tremendous pressure to invest in power grid upgrades,which bring opportunities for renewable power generation integration.The combination of heating by distributed renewable energy with the flexible operation of heat pumps is a feasible alternative for dealing with grid reinforcement challenges resulting from heating electrification.In this paper,a mathematical model of the collaborative planning of distributed wind power generation(DWPG)and distribution network with large-scale heat pumps is developed.In this model,the operational flexibility of the heat pump load is fully considered and the requirements of a comfortable indoor temperature are met.By applying this model,the goals of not only increasing the profit of DWPG but also reducing the cost of the power grid upgrade can be achieved.

含分布式电源和电动汽车的配电网可靠性评估

针对目前大规模分布式电源和电动汽车接入配电网后,给配电网可靠性带来一定影响的问题,提出了一种含有分布式电源和电动汽车的新型配电网的可靠性评估方法。首先,考虑到风光出力的不确定性和相关性,选择拟合性最优的Frank-Copula函数,建立了风光联合出力概率模型。其次,分析了电动汽车用户行为特征,提出了基于动态分时电价的电动汽车有序充放电控制策略。最后,基于改进IEEE-RBTS Bus6测试系统的主馈线F4,对系统的可靠性指标进行计算分析,结果表明所提的风光联合出力模型和有序充放电控制策略可以有效降低对配电网可靠性的影响。

风光储联合就近供电多时间尺度优化调度

针对新能源消纳困难的问题,提出一种风光储联合就近供电模式,并建立了多时间尺度的多目标优化调度模型。文中关注不同时间尺度下的调度问题,包括日前、超短期和实时。在日前调度计划中,以风光发电和本地负荷需求日前预测数据为基础,考虑风光储发电系统运行成本问题和负荷供电可靠性问题,建立了双目标优化模型,并使用基于PSO改进的黄金搜索优化算法(GSO)进行求解。在日内超短期计划中,结合日内功率预测更新数据和双储能实际利用情况对储能系统与电网并/离网情况进行调整。在实时调度中,基于本地供需设备监测情况和双储能荷电状态持续可用性,以电网峰谷电价为依据,建立了双电池储能实时调度模型,以实现源/网/荷/储能量的综合管理。最后,利用Matlab搭建了仿真模型,验证了所提出的多时间尺度双储能风光发电功率调度方法的经济性和实用性。

基于时序运行模拟的贵州省新能源消纳能力分析

新能源发电受到了越来越多的关注,然而新能源出力的不确定性、电网负荷的不可控性以及电网跨区传输等因素的限制,新能源难以完全消纳。传统分析方法不利于提高新能源消纳能力。该文以贵州省为例,基于时序运行模拟法对电力系统新能源消纳能力进行分析。首先分析了贵州省新能源资源分布情况、出力特性以及在时间和空间上的分布特点,并研究了风电、光伏的波动特性;其次,在研究系统短期运行的过程中,建立了考虑新能源不确定性的电力系统时序运行模拟模型。由于存在预测误差,考虑了新能源出力的不确定性,并根据系统的运行模式量化了新能源消纳能力;最后,基于贵州省新能源出力、负荷情况等规划数据进行了算例分析,并对所提模型进行了验证。

可再生能源分布式发电系统建模综述

基于可再生能源的分布式发电是国民经济可持续发展战略和环境保护的重要组成部分,总结了包括PWM(Pulse Width Modulation,脉宽调制)变换器、风力发电单元(含恒速恒频异步风力发电机组、双馈风力发电机组和直驱式永磁同步风力发电机组)、太阳能光伏发电单元、各种储能单元(含蓄电池储能、超级电容器储能、飞轮储能及超导磁储能)、负荷及输电线路的分布式发电系统详细的稳态和暂态数学模型,模型的研究为进一步研究分布式发电系统及其并网运行特性提供理论基础。

考虑电网调峰的热电联产热负荷动态调度模型

我国北方地区有丰富的风光可再生资源,冬季热电联产机组为满足热负荷需求而限制了其调峰能力,在一定程度上造成了风光与热电的结构性矛盾。针对上述问题,提出以多个机组共同满足热负荷为前提,通过构建考虑电网调峰的热电机组群热负荷动态调度模型,实现对不同热电性能机组的调峰潜力挖掘。仿真算例表明,如果机组群内存在较为明显的热电关系个体差异,热负荷动态调度可以较为明显地提升机组群的整体调峰性能,有效增加风光清洁能源消纳。

低碳智慧岛能源体系设计及经济可靠性评价模型

根据我国岛屿用能特点,构建小型岛屿、中型岛屿和大型岛屿这3类低碳智慧岛分布式能源体系。建立包含缺负荷期望(LOLE)、电力缺口(EENS)、能源可靠性指数(EIR)等可靠性评价指标的以风光互补发电系统为主的低碳智慧岛可靠性评估模型,并通过发电成本和碳减排成本来评估低碳智慧岛的经济性。对平潭岛的仿真结果表明,与接入风光互补发电系统前相比,接入后系统可靠性提高了18.38%,每年可节省成本2 325万元,验证了所建能源体系的合理性和可靠性。

济南地区太阳能风能发电潜力分析与实施方案

指出了在济南地区发展可再生能源的重要性,依据济南地区标准年气象资料,进行了太阳总辐射强度和风速频率分析,探讨了济南地区太阳能和风能资源的潜力,通过风光互补发电实验系统的应用研究,分析了系统的经济效益和环境效益,为济南地区太阳能发电和风力发电的推广应用提供了理论依据。

基于联合概率分布的风光互补发电系统优化配置

为提高风光互补发电系统效率、降低建设成本和增强供电可靠性,提出一种系统优化配置的设计方法。综合考虑风力发电和光伏发电出力的相关性及储能蓄电池寿命等因素,建立以系统发电成本最低为目标和以负载失电率为约束条件的优化函数,用改进和声搜索算法对目标函数进行优化。整个求解过程通过二次优化完成,在初次优化结果的基础上,对得到的风电机组功率根据市场实际情况进行修正,然后对目标函数重新优化,最终得到光伏发电和储能装置容量的优化结果。通过实例对提出的优化配置方法进行模拟验证,结果表明经过优化配置后的风光互补发电系统能够满足负载供电需求并降低建设成本。

风光互补发电系统对配电网可靠性的影响

风能和太阳能的瞬时性和不可控性使风力发电和太阳能发电并网后会对配电网的可靠性指标造成影响。为此,介绍了一种风光互补发电系统,以最小路法对配电网的可靠性进行计算,分析风光互补发电系统对配电网的影响,并分别与单独的风力发电、光伏发电系统进行比较。得出风光互补优化后对配电网的扰动远小于单独的风力、光伏发电系统对配电网扰动的结论。

锦—苏特高压直流对江苏电网变压器直流偏磁的影响

±800 kV锦-苏特高压直流工程大功率双极不平衡调试期间,江苏电网建设了直流偏磁在线监测系统,开展了直流偏磁带电检测工作。对距苏州换流站接地极100 km内主要500 kV和220 kV主变开展直流偏磁测试,包括中性点直流电流、振动、噪声等,并研究其对江苏电网的影响。研究发现,该工程直流偏磁会造成附近主变振动加剧、噪声增加,但未见造成局部过热现象,对主变的安全运行影响较小。提出了对新投运主变出厂试验增加直流偏磁试验和加强直流偏磁在线监测跟踪的建议。

基于实测功率数据的风光输出特性分析

中国已进入能源发展的调整阶段,利用新能源发电是调整能源发展的重要趋势,其中风光互补发电是新能源发电的新兴方向,而分析风光输出功率的特性是评估风光互补发电系统对电网影响的重要内容。因此,笔者通过计算风光输出功率概率密度分布、输出功率波动量概率密度分布,以及分布函数的特性,分析了风光输出特性,并基于实测功率数据的算例,验证了风光互补发电能够提高新能源入网的利用率,削弱风电对电网的影响,风光互补发电可行。