Three-defense Line Coordination Strategy of the Guizhou Power Grid with the New Security Situation

In order to meet the requirements of Decree of the State Council of the People's Republic of China (No.599), this paper presents a three-defense line coordination strategy based on the Decree of the State Council (No.599). Taking the Guizhou power grid of 220 kV&500 kV as an example, the security and stability problem of the Guizhou power grid is analyzed. The strategy using three-defense line coordination for lowering the level of electricity safety accidents is researched. The analysis results show that the proposed coordination strategy is feasible, which can lower the level of electricity safety accidents under the same fault in same operation mode. Through studying the three-defense line of the Guizhou power grid, this paper presents a basic idea of the three-defense line coordination strategy based on the Decree of the State Council (No.599). The three-defense line coordination strategy provides reference for other provinces power grid.

Next Generation Narrowband(Under 500 kHz) Power Line Communications(PLC) Standards

In the past decade,several efforts around the world were started with the goal of introducing "smart metering" capabilities into the power grid.These efforts have spurred renewed interest in the design of next generation Narrowband Power Line Communications(NB-PLC) transceivers.In the past few years,ITU-T and IEEE have standardized a family of next generation OFDM-based NB-PLC transceivers some of which are today being considered for massive deployments in Europe and Asia.This paper addresses the important role that PLC has not only for smart metering but also for many other Smart Grid applications,and also gives an overview of the main differences between these next generation NB-PLC standards.

Regulating cost for renewable energy integration in power grids

To address the issue of climate change caused by the use of polluting, non-renewable energy sources, the use of renewable energy has gained momentum worldwide. Consequently, the increased integration of renewable energy sources into power grids has necessitated the inclusion of flexible capacities in the power systems to solve problems of intermittent and fluctuating characteristics associated with renewable generation outputs. In this work, we study the regulating cost of a power system with high renewable penetration using an improved time-series system production simulation analysis method. The operational cost of the system is considered as the objective function. Three different methods to increase regulating capacities, including using interconnection lines, building additional flexible power capacities, and retrofitting existing thermal power plants, are adopted and simulated to compare the costs of accommodating renewable energy in the system in these cases. Our results indicate that increasing the flexibility of thermal power plants and developing crossregional connection lines are cost-effective methods of increasing renewable energy consumption.

Implementation of Dynamic Line Rating in a Sub-Transmission System for Wind Power Integration

Based on conventional static line rating method, the actual current carrying capability of overhead conductors cannot be judged. Due to continuous increment in electricity demand and the difficulties associated with new line constructions, the overhead lines are therefore required to be rated based on a method that should establish their real-time capability in terms of electricity transmission. The method used to determine the real-time ampacity of overhead conductors not only can enhance their transmission capacity but can also help in allowing excessive renewable generation in the electricity network. In this research work, the issues related to analyzing an impact of wind power on periodical loading of overhead line as well as finding its static and dynamic ampacities with line current are investigated in detail. Moreover, the investigation related to finding a suitable location for the construction of a 60 MW wind farm is taken on board. Thereafter, the wind park is integrated with a regional grid, owned by Fortum Distribution AB. In addition to that, the electricity generated from the wind park is also calculated in this project. Later on, the work is devoted to finding the static and dynamic line ratings for “VL3” overhead conductor by using IEEE-738-2006 standard. Furthermore, the project also deals with finding the line current and making its comparison with maximum capacity of overhead conductor (VL3) for loading it in such a way that no any violation of safe ground clearance requirements is observed at all. Besides, the line current, knowing the conductor temperature when it transmits the required electricity in the presence of wind power generation is also an important factor to be taken into consideration. Therefore, based on real-time ambient conditions with actual line loading and with the help of IEEE-738-2006 standard, the conductor temperature is also calculated in this project. At the end, an economic analysis is performed to evaluate the financial advantages related to applying the dynamic line ratings approach in place of traditional static line ratings technique across an overhead conductor (VL3) and to know how much beneficial it is to temporarily postpone the rebuilding and/or construction of a new transmission line. Furthermore, an economic analysis related to wind power system is taken into consideration as well to get familiar with the costs related to building and connecting a 60 MW wind farm with the regional grid.

A Liability Division Method for Harmonic Pollution Based on Line-Transferred Power Components

The existing liability division methods for harmonic pollution are either inexplicit or incomplete in physical meaning. To compensate these defects, two new methods are proposed based on line-transferred power components in this paper. At first, all harmonic sources are represented by ideal equivalent current source, line current components and bus voltage components of a source are determined by stimulation of this source with all other sources disabled. Then, the line-trans- ferred power component owing to a source under all sources action together is determined by the theory of line-transferred power components, and called source’s line-transferred power component. At last, the liability of a source for line-end harmonic pollution is divided by two methods: the ration of the source’s line-transferred active power component to the total line-transferred power, and the ration of projection of the source’s line-transferred complex power component to absolute value of the total line-transferred complex power. These two methods are taken into account not only harmonic voltage but also harmonic current in the liability division. Simulation results show that the proposed liability division method based on active power component is the most effective and ideal one.

Broadband over Power Line (BPL): An Emerging Technology for Bangladesh

Broadband over Power Line (BPL) is an alternative means of providing high-speed Internet access, Voice over Internet Protocol (VoIP), and other broadband services to homes and businesses by using the existing medium voltage (MV) and low voltage (LV) power lines. This paper provides a comprehensive understanding about BPL with its implementation prospects. In this context, the existing power grid infrastructures are discussed elaborately. BPL system functionality with its components and its benefits over other access technologies is also pointed out. Implementation scenarios for various deployment options are illustrated here. The different implementation challenges for BPL system, such as the characteristics of power lines, attenuation problem, noise, potential interference with the other radio frequencies are also presented with their remedies. Comparative analysis between several broadband access technologies shows the feasibility of BPL deployments all over the world.

基于限流电抗器两侧特定频段暂态能量比的MTDC电网单端量保护方案

柔性直流输电技术有利于未来大量分布式能源接入电网,而配置快速、可靠的保护方案是柔性直流技术发展的关键。基于直流电网等效模型,提出一种基于限流电抗器两侧电压特定频段暂态能量比差异性的单端量故障区域识别方法。该方法依据贝瑞隆等效模型计算出限流电抗器两侧电压比,通过广义S变换提取限流电抗器两侧特定频段电压,根据故障时正负极限流电抗器的电压幅值差的差异性实现故障选极。最后在PSCAD/EMTDC平台搭建仿真模型,分析出发生区内外故障时差异性明显,具备较强的耐过渡电阻与抗噪声干扰能力。

多直流馈入受端电网的最大受电能力估计方法

为保证多直流馈入受端电网稳定运行,提出一种静态稳定约束下多直流馈入受端电网的最大受电能力估计方法。首先,基于奇异值理论推导出多直流馈入受端电网静态电压稳定约束;然后,在考虑静态电压稳定性约束的情况下,建立多直流馈入受端电网优化调度模型;接着,给出一种计及静态电压稳定约束的优化调度模型分段线性求解方法,并基于该方法给出最大受电能力估计方法;最后,通过修改的IEEE39节点系统验证本文所提方法的有效性。

一种基于RPA技术的电网线路故障检测方法

由于电网电力故障检测具有重复性、高精度、低价值特征,线路故障数据的人工检测效率极低。为此利用RPA思维设计电网线路故障数据检测方法。在故障判断流程中引入三阶段RPA重复判断方法,通过构建检测矩阵和时间矩阵,计算故障初始行波波头到达端点的时间确定故障区域。在故障区域内找出一条疑似故障线路,并结合所定义的一条虚拟母线,通过反复计算验证找出准确故障线路。实验结果表明,所提方法故障检测的绝对误差小,错误故障检测率和遗漏故障检测率较低,故障数据检测的查全率与查准率较高,实际应用效果好。

基于改进下垂的多逆变器并联控制策略

针对微电网孤岛运行时,传统解耦式下垂控制策略由于未能考虑线路阻抗的影响,多逆变器并联运行时存在无功功率分配不均、环流等问题,论文提出一种基于自适应电压补偿的改进下垂控制策略。文中首先针对因线路阻抗不同所带来的电压跌落问题,增加了线路压降补偿环节,在此基础上,考虑逆变器出口处电压与母线电压的一致性,改进了下垂控制式,并利用低带宽通信技术获取各逆变器输出功率信息,引入自适应电压补偿环节,提高了逆变器间无功功率的均分精度。最后,基于Matlab平台搭建文章所提控制策略的仿真模型,仿真结果验证了所提控制策略的正确性与有效性。

山区电网线路过载保护协调优化控制策略研究

山区电网小水电众多但负荷轻,若叠加新能源大量接入,将造成夏季丰水期输电断面过载,限制清洁能源外送和威胁电网设备安全。为此,提出将断面过载保护与可调节电源进行协调配合以获得最优控制效果的保护动作策略。首先,基于潮流追踪法确定电源至断面的功率传输路径,并基于功率灵敏度确定单个电源对过载线路的影响大小;然后,建立以系统电源损失出力最小和保护动作后系统安全裕度最大为目标的多目标优化模型,通过优化电源出力和保护动作量实现电源出力损失最小和系统安全裕度最大,减少因源荷波动造成保护频繁动作;最后,以某一山区电网为算例进行仿真验证,计算结果表明所建立的模型能够实现电源出力损失最小和系统安全裕度最大的目标。

市县级电网线损管理水平对标评价方法研究

为解决当前地区线损管理考评方式仅关注线损率指标的高低,而难以全面地评价电网企业线损管理能力优劣的问题,文章提出了一种市县级电网线损管理水平对标评价方法。首先,基于地区客观特征,应用聚类分析方法,对市县级对标群组进行科学划分;其次从电网结构、设备属性等5个维度,构建电网线损影响因素评价指标体系;最后,基于灰色关联分析计算地区线损综合评分,通过比较综合评分排名与电网实际线损率排名的差距,实现对同类地区电网线损管理水平的对标评价。

南公1水电站功率送出受限问题引发的对于老挝电网现状的思考

本文从南公1水电站投产中遇到的电力输送通道问题出发,辅以相关的改接线方案设计以及发电机进相试验与数据分析,佐证中资机构对老挝电站投资建设难题,提出中资投资重点方向,建议加快推进老挝骨干输电网互联互通建设,参与中国碳中和进程。

一种低压发电车带电并网装置设计

随着供电可靠性要求不断提高,重要会议和活动现场保电均需要提前接入低压发电车,但低压发电车接入时需市电短时停电,难以实现带电并网和“零停电”保电,越来越难以满足特殊保电场所全天候不停电的要求。文章对现有的低压发电车进行简单改造,解决了带电接入、带电并网、带电退网等技术难点,能实现大部分情况下的“零停电”保电需求。

基于轮廓线与特征融合的电网变电设备三维自动化运检方法

因工作环境的复杂性,变电设备成为智能电网中故障频率最高的装置之一,易发生设备接地故障、保险熔断故障、绝缘材料老化等问题,为提高电网变电设备三维自动化运检精度,提出基于轮廓线与特征融合的电网变电设备三维自动化运检方法研究。采集电网变电设备三维图像,获取电网变电设备三维图像初始轮廓点,筛选变电设备轮廓点,依照顺序连接提取出的关键轮廓点,得到变电设备三维图像轮廓线,结合形态学滤波算法,对图像进行开、闭运算,依据轮廓线的闭合情况,分割出目标图像与背景图像,提取包括HOG特征与LBP特征的变电设备目标图像特征,经过特征融合后,构造最优分类超平面,制定电网变电设备三维自动化运检规则,判定变电设备运维情况,最终实现变电设备的三维自动化运检。实验数据显示:该方法识别出变电设备的正常与异常状态,在不同实验工况背景下,应用提出方法获得的变电设备运检精度达到了96%。提高了变电设备的自动化运检的识别及运检精度,满足现今变电设备的运检需求。

10 kV分支线路改造分析

针对XX地区10 kV 586盘常营线察老口等分支线路存在的老旧设备和安全隐患问题,进行改造升级,改造范围包括12.1 km的10 kV线路,涉及多个分支线路及相应的杆塔、导线等配套设施。工程的主要目标是优化电网结构,提升供电可靠性,消除安全隐患,以满足当地日益增长的用电需求,通过采用新技术、新材料和新工艺,将有效提高线路的健康水平和运行效率,减少停电时间和停电范围,为当地居民和企业提供更加稳定、可靠的电力供应。

基于短路电流的10 kV电网线路继电保护误动作识别研究

常规的10 kV电网线路继电保护误动作识别方法多采用LVRT保护动作判据,存在局限性较大、识别查全率较低、不能有效降低继电保护过程中误动作发生率的问题。基于此,开展了基于短路电流的10 kV电网线路继电保护误动作识别研究。首先,计算10 kV电网线路短路电流,获取电网线路继电保护工况及特征,缩小线路误动作故障影响范围。然后,计算线路继电保护误动作时变概率,识别继电保护误动作行为。实验分析结果表明,应用提出的方法后,误动作识别查全率始终不低于98%,能更加全面地召回识别出线路继电保护误动作,降低误动作发生率。