含分布式电源的配电网继电保护技术

随着分布式电源(distributed generation,DG)并入配电网,使配电网的拓扑结构、潮流分布发生变化,传统的配电网继电保护配置不再适用于含分布式电源的配电网络.为了保证电力系统供电可靠性,充分发挥分布式能源的优势,需要对含有分布式电源的配电网保护方案进行研究.在阐述配电网三段式电流保护原理的基础上,详细讨论了分布式电源的准入容量和接入位置不同时,对其配电网不同故障点的电流保护产生的具体影响.并结合国内外的前沿研究成果,论述当前主要的解决方案,对其进行分类讨论不同保护方案的原理和特点,说明其利弊.该文所做工作对含有分布式电源的配电网保护有一定的参考价值.     

分布式电源对配电网继电保护的影响分析及对策

分布式电源的短路电流特征可分三类,与传统的同步发电机不尽相同。通过分析同步发电机型、异步发电机型、逆变型分布式电源型的短路电流特征,发现同步发电机型的短路电流最具代表性,为此利用PSCAD仿真软件,构建等效的分布式电源接入配电网模型,分析对继电保护的影响。结合实际算例,分析分布式电源接入配电网后,对传统三段式电流保护造成保护灵敏度下降、保护出现误动、重合闸不成功等原因,提出将距离保护应用于分布式电源接入的配电网。计算结果表明,接入距离保护装置必要可行,可以有效地解决三段式保护灵敏度下降和误动等问题。     

分布式发电对配电网继电保护的影响

分布式发电是一种新兴的高效、环保的发电技术,近年来获得飞速发展。然而,大量分布式发电系统的接入改变了配电网的故障电流大小和分布以及原有继电保护装置的基础条件,对配电网的继电保护造成影响。分析了分布式发电接入对馈线的两段式保护和自动重合闸以及分支线的熔断器保护产生的各种可能影响,对分布式发电的广泛推广具有一定的意义。     

分布式电源戴维南等效及并网对系统电压影响

针对分布式电源DG接入配电网将影响系统电压的问题,提出了DG的戴维南等效模型接入配电网方法。通过对风力发电机及光伏电源工作原理的研究,利用戴维南定理求取分布式电源在潮流计算中的模型,并接入配电网,采用PQ分解法计算含DG的配电网潮流,分析其对系统电压稳定性的影响。计算结果表明:当配电网系统接入分布式电源时,系统的电压会增加,增加的大小与接入节点的位置、DG的容量和类型有关。     

考虑分布式电源与随机负荷的主动配电网继电保护新方法

配电网由被动控制向主动控制是转变未来电力系统发展的必然趋势,主动配电网为实现清洁电源的分布式并网与随机负荷的接入提供了有效的解决方案.分析了主动配电网环境下,分布式电源与随机负荷的动态特性及其对传统继电保护四性的影响,提出了一种适用于主动配电网的继电保护新方法.首先,对传统三段式电流保护进行自适应整定,优先保证继电保护...     

工频变化量距离保护在含DG配电网中的应用分析

针对分布式电源的接入使配电网中各个支路的电流流向及大小复杂化,对传统电流保护造成很大影响,分析了工频变化量距离保护在含DG典型配电网故障时的动作情况.结果表明,工频变化量距离保护方向性明确、动作快速,其可靠性、灵敏度等性能均优于配电网传统的距离保护和电流保护,适于35 kV及以下电压等级电网.分析了电动机馈送短路电流对工频变化量距离保护的影响,大型电动机与DG在配电网故障时表现相似,工频变化量距离保护同样可正确动作.     

基于电流保护约束的逆变型分布式电源最大接入容量与接入位置选择

摘要： 逆变型分布式电源接入配电网后,传统配电网采用的三段式电流保护可能会发生不正确动作。为了解决这一问题,提出了基于电流保护约束的逆变型分布式电源最大接入容量和接入位置选择的确定方法。当配电网发生故障时,根据零电压穿越控制的逆变型分布式电源的故障输出特性,分析逆变型分布式电源并网点电压及输出的故障电流随逆变型分布式电源输出功率和接入位置变化而变化的规律。发现逆变型分布式电源的并网点电压及电流随逆变型分布式电源输出功率的增大呈非线性变化、随接入位置远离系统电源而逐渐减小的特征。根据该变化特征,以传统配电网电流保护在不改变原有整定值的情况下能正确动作为条件,确定了逆变型分布式电源的接入容量及接入位置。仿真验证了该方法的有效性。     

分布式发电条件下配电网故障定位的矩阵算法

分布式发电(DG)接入配电网后,配电网变成了多电源复杂网络,传统的故障定位算法不再适用.本文提出了一种能解决多电源复杂配电网多重故障定位(可含有馈线末端故障)的矩阵算法.该算法对于故障信息不完备和故障信息畸变的情况同样适用.算例测试结果验证了该方法的正确性和可行性,在配电网实时故障定位的应用中具有很大的潜力.     

基于自适应算法的含分布式电源继电保护研究

针对分布式电源的接入将影响配电网短路电流和继电保护整定等问题,提出基于自适应算法的含分布式电源配电网继电保护方法,该方法将分布式电源戴维南模型接入配电网的不同位置,对含分布式电源的配电网进行等效建模。根据仿真模型的故障分析表明:当接入点在保护装置上游或相邻母线时,整定值随着接入位置越近、容量的增加而增加;接入点在保护装置下游时,该段线路按双侧电源方式整定保护装置;故障类型会影响整定值的大小。     

考虑电流保护可靠性的分布式电源准入容量研究

为了研究配电网对分布式电源的最大准入容量,利用DIg SILETT建立同步发电机型的分布式电源,分析配电网各个母线对分布式电源的准入容量以及限制因素。仿真分析结果表明,在不改变现有三段式电流保护的前提下,从分布式电源接入对配电网电流保护可靠性影响角度进行分析,不同母线对分布式电源准入容量的限制差异较大,最后提出可以通过重新整定保护装置的动作值和采用电压电流连锁速断保护来提高分布式电源的准入容量。     

Current phase comparison pilot scheme for distributed generation networks protection

The trends of the actual distribution networks are moving toward a high penetration of distributed generation and power electronics converters. These technologies modify contribution-to-fault current magnitudes and raise concern about new protection parameters settings to accurately detect faults on distribution networks. This paper proposes a differential phase jump pilot scheme to detect faulted branches in distribution networks. The aim of the proposed scheme is to provide an efficient algorithm with functions of fault detection and isolation, which are part of the self-healing functions used for smart grids. The proposed scheme is based on the current phase jump measured in each node with fault inception. Then, by comparing the phase jump obtained with the prefault conditions and rate changes, it determines the fault direction enabling a trip signal to the corresponding nodes to isolate the branch under fault. A distribution network has been modeled in PSCAD/EMTDC program to verify the proposed algorithm, taking into account distributed generation provided by both wind turbines (doubly fed induction generator and permanent magnet generator with full converter) and solar photovoltaic installations. The behavior of the current phase jump has been studied for both generation and load nodes. This algorithm is not affected by the magnitude of current and voltage and has been tested varying fault location and resistance along the modeled distribution network.     

Probabilistic load flow using Monte Carlo techniques for distribution networks with photovoltaic generators

Connections of distributed generation (DG) systems to distribution networks are increasing in number, though they may often be associated with the need of costly grid reinforcements or new control issues to maintain optimal operation. Appropriate analysis tools are required to check distribution networks operating conditions in the evolving scenario. Load flow (LF) calculations are typically needed to assess the allowed DG penetration level for a given network in order to ensure, for example, that voltage and current limits are not exceeded.

The present paper deals with the solution of the LF problem in distribution networks with photovoltaic (PV) DG. Suitable models for prediction of the active power produced by PV DG units and the power absorbed by the loads are to be used to represent the uncertainty of solar energy availability and loads variation. The proposed models have been incorporated in a radial distribution probabilistic load flow (PLF) program that has been developed by using Monte Carlo techniques. The developed program allows probabilistic predictions of power flows at the various sections of distribution feeders and voltage profiles at all nodes of a network.

After presenting theoretical concepts and software implementation, a practical case is also discussed to show the application of the study in order to assess the maximum PV peak power that can be installed into a distribution network without violating voltage and current constraints. A comparison between Deterministic Load Flow (DLF) and PLF analyses is also performed.     

计及谐波指标影响的含分布式电源配电网多目标规划

以分布式电源给配电网带来的电能质量管理问题为研究对象,通过一种考虑谐波指标影响的配电网多目标规划方法,对分布式电源接入配电网的网损和节点谐波阻抗矩阵进行分析;然后以最小网络损耗指标和最大谐波管理指标为目标,通过构造隶属度函数,将多目标优化问题转化为对优化结果的满意度;最后采用乌鸦搜索算法进行求解,并通过对IEEE 33节点配电系统的仿真分析验证所提方法的有效性。     

Future development of the electricity systems with distributed generation

Electrical power systems have been traditionally designed taking energy from high-voltage levels, and distributing it to lower voltage level networks. There are large generation units connected to transmission networks. But in the future there will be a large number of small generators connected to the distribution networks. Efficient integration of this distributed generation requires network innovations. A development of active distribution network management, from centralised to more distributed system management, is needed. Information, communication, and control infrastructures will be needed with increasing complexity of system management. Some innovative concepts such as microgrids and virtual utilities will be presented.     

含分布式电源的配电网快速前推回代算法

为解决分布式电源接入配电网带来的配电网潮流计算问题,在已有配电网潮流算法基础上,提出了一种能有效处理分布式电源并网问题的配电网快速前推回代改进算法。该算法首先基于配电网拓扑分析求得配电网快速前推回代算法所需的支路电流-节点电流关系矩阵和支路电流-节点电压降关系矩阵。其次,根据各种分布式电源的潮流计算模型计算其输出有功、无功功率,并引入节点等效注入电流模型作为前推变量,从而实现配电网快速前推回代算法求解含分布式电源的配电网潮流计算问题。最后通过对IEEE33节点系统进行仿真计算,验证了该算法的可行性,为含分布式电源的配电网潮流计算提供了新方法。     

Constructal design of distributed cooling on the landscape

Here we constructal design to determine the area size (or number of users N) to be allocated to a central refrigeration plant, and to configure the distribution network for the distributed cooling system. The main objective is to maximize the net cooling capacity delivered to every user, and to minimize the pumping power required for transporting the chilled water. Two types of distribution networks are investigated: radial and tree‐shaped networks. First, when ducts with a single diameter are used, the net cooling capacity delivered to every user is almost the same, while the pumping power requirement for the tree network is greater than that for the radial network. Multi‐diameter tree networks are investigated next. The pumping power requirement for multi‐diameter tree‐shaped network is less than for radial network when N is greater than 19 if the flow is laminar, and when N is greater than 80 if the flow is turbulent. The global performance of the area‐based cooling system can be improved by increasing the freedom to morph the configuration. Copyright © 2010 John Wiley & Sons, Ltd.     

分布式电源对杭州配网保护的影响及准入容量的计算

分布式电源具有投资少、见效快、节约土地、清洁更环保等优点,作为未来能源结构的一个重要组成部分,已得到人们的普遍认可。分布式电源的接入对整个电力系统的影响巨大而深远,同时给系统的运行带来一系列技术问题。文章详细分析了分布式发电对配网保护的影响及准入容量的计算。     

分布式发电及其在电力系统中的应用研究综述

随着能源危机和环保意识的增强,分布式发电越来越受到重视。对分布式发电（DG）的概念和分类进行了归纳总结,分析了分布式发电对配电网规划、网损、线路上潮流和系统保护的影响．并对未来分布式发电需要进一步研究的问题作了展望。