光伏电源对IEEE 34节点测试馈线过电流保护的影响

以IEEE 34节点测试馈线为研究对象,加入重合器和熔断器等过电流保护设备,在特定位置接入不同容量的光伏电源,利用PSCAD软件进行仿真,就短路电流和保护之间的协调性,研究光伏电源对过电流保护设备的影响。为此进行了多种故障仿真,以验证接入光伏电源后,电网的保护设备之间的协调性是否改变。仿真结果表明：并不是电网中的所有位置接入光伏电源,都会对保护产生影响,只有在特定位置接入光伏电源时,才会使某些保护失去选择性,导致其误动或拒动。     

覆冰不平衡张力计算分析

以IEEE 34节点测试馈线为研究对象,加入重合器和熔断器等过电流保护设备,在特定位置接入不同容量的光伏电源,利用PSCAD软件进行仿真,就短路电流和保护之间的协调性,研究光伏电源对过电流保护设备的影响。为此进行了多种故障仿真,以验证接入光伏电源后,电网的保护设备之间的协调性是否改变。仿真结果表明：并不是电网中的所有位置接入光伏电源,都会对保护产生影响,只有在特定位置接入光伏电源时,才会使某些保护失去选择性,导致其误动或拒动。     

分布式发电对配电网继电保护的影响

在介绍分布式电源概念及传统配电网结构和继电保护配置的基础上,以包含分布式电源(DG)的配电系统为模型,详细讨论了DG并入配电网不同馈线不同区段时,对原有配电网继电保护及安全自动装置的影响,重点分析DG上下游及相邻馈线不同地点发生短路故障,短路电流的大小和分布对三段式过流保护和反时限过电流保护配合特性及动作行为的影响,并论述了DG对自动重合闸的影响,为并入DG后的配电网继电保护算法研究提供了一定的理论依据.     

基于继电保护配合的分布式电源准入容量研究

分布式电源(Distributed Generation,DG)接入配电网会引起保护检测到的电流发生变化,从而影响保护范围。本文以DG接入35kV配网为例,描绘了在线路不同位置发生三相短路故障时DG接入前后电流对比曲线。利用三段式电流保护约束条件,在不修改原有保护配置的前提下得出了最佳容量比,提出了DG对馈线电流保护的影响与DG的故障位置和接入容量有关。     

分布式发电对配电网线路保护影响的分析

为了分析分布式电源(distributed generation,DG)接入线路对重合闸和配电网线路保护的影响,以DG通过10kV线路并入配电网为例,考虑到DG接入容量较小、在配电网中接入位置不确定以及一次重合闸与DG的配合等问题,结合DG并网时电网拓扑,利用短路电流计算公式计算了电流的流向和大小,分析了DG在线路不同位置接入对配电网线路保护和重合闸的影响,指出在线路或系统出现任何形式的故障均快速无选择地切除DG的前提下,DG不会对原线路保护产生负面影响,无需更改原有线路保护的整定值。     

基于单片机控制的跌落式自动分段器

引言自动分段器是配电网中用来隔离故障线路区段的自动开关设备,在无电压或无电流情况下自动分闸。分段器按识别故障的原理不同,可分为“电流-时间”型和“电压-时间”型两大类。“电流-时间”型分段器通常与前级开关设备(重合器或断路器)配合使用,它不能开断短路电流,但具有“     

馈线自动化系统的两种模式及对馈线自动化建设的建议

介绍了基于重合器和分段器配合的馈线自动化系统和基于FTU的馈线自动化系统,及国外馈线自动化系统的发展和现状,对比了这两种馈线自动化方式的优缺点.建议我国馈线自动化应当逐步发展,基于重合器和分段器配合的馈线自动化系统和基于FTU的馈线自动化系统应相互结合,由基于重合器和分段器配合的馈线自动化逐步向基于FTU的馈线自动化发展.     

分布式电源对配电网电流保护的影响

分布式电源(DG)接入配电网后,改变了原有网络的短路电流流向,会导致原有馈线保护出现灵敏度降低、拒动、误动等问题.本文分析了配电网常用的三段式电流保护工作原理和整定原则,在此基础上分析了分布式电源对配电网电流保护运行影响。通过MATLAB仿真分布式电源并入配电网后在线路后,DG容量发生变化时发生三相短路故障对短路电流保护的影响,仿真结果验证了理论分析的可行性。     

分布式电源对配网继电保护的影响

介绍了分布式电源的发展概况、现有配电网络的结构及保护的配置方案、不同类型分布式电源提供短路电流的能力,以10 kV馈线保护为例,通过在配网不同位置加入DG,分析加入分布式电源之后对原有配电网电流保护的影响,包括对原保护灵敏性、选择性都会造成严重干扰,造成本线路保护拒动,非故障线路保护误动.并论述了DG对自动重合闸的影响,及对熔断器之间配合的影响,为并入DG后的配电网继电保护算法提供了一定的理论依据.     

分布式发电对配电网继电保护的影响

在介绍分布式电源概念及传统配电网结构和继电保护配置的基础上,以包含分布式电源（DG）的配电系统为模型,详细讨论了DG并入配电网不同馈线不同区段时,对原有配电网继电保护及安全自动装置的影响,重点分析DG上下游及相邻馈线不同地点发生短路故障,短路电流的大小和分布对三段式过流保护和反时限过电流保护配合特性及动作行为的影响,并论述了DG对自动重合闸的影响,为并入DG后的配电网继电保护算法研究提供了一定的理论依据。     

计及逆变型分布式电源控制特性的配电网故障分析方法

随着分布式电源(DG)的大量接入,DG的故障穿越行为对配电网的故障特性影响很大。而传统的等值模型均未计及DG的控制策略,从而造成含DG的配电网故障分析存在不可忽略的局限性。为此,文中在系统分析DG控制策略和动作行为的基础上,建立了计及控制策略的逆变器并网方式下DG压控电流源等值模型,更加真实地体现出DG故障电流的输出特性。在此基础上,通过建立故障前后电网支路电流和节点电压关系方程,推导出故障穿越时DG输出电流与公共连接点电压的求解方程组,从而建立故障精确分析方法。最后,基于DIgSILENT建立含DG的10kV配电网仿真模型,验证了所述方法的正确性和有效性。     

适用于含DG配电网故障处理性能测试的主站注入测试技术

论述了适用于含分布式电源(DG)配电网故障性能测试的改进主站注入测试法的平台组成和工作原理,论述了含DG配电网潮流计算和短路电流计算方法,提出了故障场景自然设置法,根据所设置的故障场景下短路电流的计算结果和继电保护定值、配电终端定值、自动装置的设置情况等自动判断是否应该保护动作跳闸、自动装置动作、上报相应的故障信息等,可以对健全区域恢复供电过程中的不当操作引发的开关动作或DG和电压敏感负荷脱网进行模拟,从而更加有效地对配电自动化系统的恢复策略和操作步骤的正确性进行测试检验。最后,给出测试实例详细说明了所论述的测试技术的可行性和有效性。     

Protection relay system using information network for distribution system with DGs

We propose a new protection scheme for selective and quick disconnection of a fault area in a distribution system, which can be flexibly adopted for a large‐scale introduction of distributed generators (DGs). When a fault occurs, relays provide a binary state signal which is activated if, for instance, the current at the corresponding relay location exceeds a certain value. Although each relay cannot locate the fault point with only its own signal, it can locate the fault by utilizing signals from other relays together with its own signal. Because only a binary state signal is transmitted instead of the actual physical variable such as the magnitude of the fault current, the network traffic is much less than when a conventional protection scheme for a transmission system using an information system is applied to a distribution system. The following are the main results of a simulation on our proposed protection scheme: (1) the proposed protection scheme can successfully disconnect only a fault feeder when the relays use signals provided from the sending end of the fault feeder and all other DGs on the same feeder, (2) in the case of a fault on a DG connected feeder, the DG can be disconnected within 0.06 s. © 2006 Wiley Periodicals, Inc. Electr Eng Jpn, 155(4): 30–35, 2006; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20232     

分布式电源接入配网对其静态电压稳定性影响多角度研究

分布式电源(Distributed Generation, DG)接入配网后,将对配网静态电压稳定性造成影响。基于IEEE33节点配电网络和Matlab仿真测试软件平台,考虑分布式电源的接入数量、接入位置、接入容量和功率因数4个影响因素。应用电压稳定性判定指标L,对比单个DG接入单分支线路和多个DG接入多条分支线路两种情况,得出各自对配网电压分布和电压稳定性造成的影响。对比测试所得L指标,结果表明多DG接入的方式更有利于配网电压稳定。该研究对配网中多DG的布局和规划具有积极的指导意义。     

Overcurrent protection for distribution feeders with renewable generation

Distribution systems in Taiwan are typically radial type or normally open loop type. Distribution feeders have a simple protection system that usually employs overcurrent relays. When renewable generation (RG) is connected to the distribution feeder, the feeder changes from a single-source system to a complex multi-source system, which causes loss of the original coordination among feeder protection devices. The operation of RG units can cause protection failure. Fault current produced by RG units may reduce the current measured by the feeder relay. Therefore, this paper proposes connecting RGs to the feeder via four-way circuit switches with overcurrent relays, and dividing the feeder into several protection zones. Each protection zone is capable of isolating fault itself.The algorithm process and design procedure of overcurrent protection are also proposed for distribution feeders with RG. Results of this research provide a valuable reference for overcurrent protection that improved protection coordination and system reliability.     

含低电压穿越型分布式电源配电网的短路电流计算方法

换流器型分布式电源(DG)在配电网中的应用使传统配电网的短路电流计算方法不再适用。根据DG在配电网故障点前后位置的不同,将DG处理为不同类型的故障等效模型,故障点上游DG采用低电压穿越故障等效模型,故障点下游DG采用恒定电流源故障等效模型。提出了一种基于叠加定理的短路电流迭代计算方法,在每一次迭代过程中,根据当前节点电压和DG的故障等效模型分别修正故障点上游DG和下游DG的输出短路电流,并利用节点电压方程求解配电网的短路电流和节点电压分布,直到满足收敛条件。通过对算例系统的分析计算,验证了所提方法的正确性。该方法可应用于含DG的大规模配电网的短路电流求解。     

A novel fault location method for distribution networks with distributed generations based on the time matrix of traveling-waves

To improve location speed, accuracy and reliability, this paper proposes a fault location method for distribution networks based on the time matrix of fault traveling waves. First, an inherent time matrix is established according to the normalized topology of the target distribution network, and a post-fault time matrix is obtained by extracting the head data of initial waves from traveling wave detection devices. A time determination matrix is then obtained using the difference operation between the two matrices. The features of the time determination matrix are used for fault section identification and fault distance calculation, to accurately locate faults. The method is modified by considering economic benefits, through the optimal configuration of detection devices of traveling waves when calculating fault distances. Simulation results show that the proposed method has good adaptation with higher fault location accuracy than two other typical ones. It can deal with faults on invalid branches, and the error rate is under 0.5% even with connected DGs.     

分布式电源接入对配网过电流保护的影响

分布式发电接入中低压配电网使传统配网成为有源配网,对继电保护提出了新的挑战。本文围绕有源配网继电保护问题展开研究,分析了有源配电网故障电流的特征以及DG接入对传统保护和安全自动装置运行的影响,并结合国内外主要的标准和技术规程,综述了当前主要的解决方案。最后以典型的辐射状配电网为算例,利用ETAP软件建立仿真模型,研究双馈风机接入配电网后潮流和短路电流的变化以及反时限保护的动作情况。结果表明,高渗透DG接入后,潮流双向流动,短路电流变化复杂,反时限保护较难满足要求,有必要利用微网技术,构建更为完善和智能的有源配网保护体系。     

A theory of maximum capacity of distributed generators connected to a distribution system using electric power density model

Recently, the number of distributed generators (DGs) connected to distribution systems has been increasing. System operators should know the maximum capacity of DGs that can be connected without problems to one feeder of the system in order to control the system appropriately. Many studies of the maximum capacity of the DG have been presented, but they have produced limited results calculated by a typical or average‐value model. However, many DGs will access one feeder if deregulation of the electric power industry is accelerated in the near future. In order to deal with this situation, the authors have derived a general formula to calculate the range of the maximum DG capacity per feeder. Copyright © 2004 Wiley Periodicals, Inc. In order to deal with sets of DGs that are dispersed completely on the distribution line, the authors have derived a differential equation for the complex power and one for the voltage drop, which are expressed as functions of distance from the substation. The general formula to calculate the range of the maximum DG capacity connected to the system is determined by solving these equations under the constraints of the line voltage, the line current, and the power factor of the DGs. By a numerical analysis, the authors have calculated the maximum capacity of DGs depending on many parameters, such as the length of the feeder, the DG power factor, and the like. In a short‐length system, the maximum DG capacity is governed by the current constraint, but in a long length system, it is governed by the upper voltage constraint. © 2006 Wiley Periodicals, Inc. Electr Eng Jpn, 155(3): 18–28, 2006; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20330     

Restoration of Directional Overcurrent Relay Coordination in Distributed Generation Systems Utilizing Fault Current Limiter

A new approach is proposed to solve the directional overcurrent relay coordination problem, which arises from installing distributed generation (DG) in looped power delivery systems (PDS). This approach involves the implementation of a fault current limiter (FCL) to locally limit the DG fault current, and thus restore the original relay coordination. The proposed restoration approach is carried out without altering the original relay settings or disconnecting DGs from PDSs during fault. Therefore, it is applicable to both the current practice of disconnecting DGs from PDSs, and the emergent trend of keeping DGs in PDSs during fault. The process of selecting FCL impedance type (inductive or resistive) and its minimum value is illustrated. Three scenarios are discussed: no DG, the implementation of DG with FCL and without FCL. Various simulations are carried out for both single- and multi-DG existence, and different DG and fault locations. The obtained results are reported and discussed.