基于支持向量机的网损分摊新算法

针对电力市场联营模式,提出了一种在Z-bus法网损分摊基础上基于支持向量机的网损分摊新算法。该算法将Z-bus法对网络不同运行情况下的分摊结果作为样本,然后利用支持向量机进行训练,得到网损分摊模型,进而可以直接利用该模型计算在不同负荷水平下各节点需要分摊的网损。通过对5节点系统进行的仿真分析,验证了该方法的正确性和合理性。     

基于支持向量机的网损分摊新算法

针对电力市场联营模式，提出了一种在Z-hus法网损分摊基础上基于支持向量机的网损分摊新算法。该算法将Z-hus法对网络不同运行情况下的分摊结果作为样本，然后利用支持向量机进行训练，得到网损分摊模型，进而可以直接利用该模型计算在不同负荷水平下各节点需要分摊的网损。通过对5节点系统进行的仿真分析，验证了该方法的正确性和合理性。     

一种简捷的网损分摊方法

基于当前国内网损分摊的某种理论[1],作者提出了一种直观、简捷、实用的网损分摊计算方法,在潮流计算的基础上,该方法可以把任意复杂电网的网络损耗分摊到任何一个负荷和电源节点,同时能直观地看出电网中某一负荷(或电源)的潮流相关路径及其对输电设备的利用份额,为合理安排系统运行方式,防止电网发生网络阻塞,优化电网经济调度提供依据.用所提出的方法以甘肃电网330kV、220kV主网网损分摊为实例进行网损分摊计算,计算结果用西安交通大学王锡凡教授编制的网损分摊程序[2]进行验证,证明该方法是完全切实可行的.     

一种新的网损分摊方法研究

电力市场环境下,不同的网损分摊方法对交易电价有一定影响。提出了一种新的网损分摊方法,即基于交流电气剖分方法。针对普通交流节点分析和推导了分摊到输出流和输入流的网损公式,然后利用电气剖分方法的拓扑关系,将针对交流节点的网损分摊关系推广到网络,无需将有功无功解耦即可求取电力网络中各电源(或负荷)应分摊的网络损耗。算例计算结果表明,该方法合理有效。     

考虑网损与负荷偏差的节点边际电价模型与求解

文中分析了中国在市场出清和节点边际电价计算时,存在发用电负荷偏差和系统网损难以精确计算的问题。首先,提出2种节点边际电价计算模型,利用网损分布因子分摊系统网损与负荷偏差分配因子分配负荷偏差相结合的方法,实现系统网损与负荷偏差的精确计算。然后,基于迭代的节点边际电价模型,以母线负荷为初始点编制发电计划,每次求解后将总发电量与系统负荷的偏差分摊至节点,修正其负荷,通过多次迭代求解节点边际电价。两步法节点边际电价模型,以系统负荷为依据,建立考虑系统网损与负荷偏差的耦合模型。第1步计算负荷偏差,第2步固定偏差计算节点边际电价。最后,通过比较所提方法与网损直接分摊方法的节点边际电价,以及分析不同负荷偏差水平、不同负荷偏差分配因子对节点边际电价的影响,验证了所提模型的有效性。     

最佳路径法应用于网损分摊的探讨

针对电力市场初步形成条件下按比例分摊计算网损存在的问题。提出了基于图论思想的最佳路径法。该方法的主要优点是充分考虑了各个节点在网络中的位置。特别是电源节点与负荷节点之间的电气距离。通过仿真计算．说明该方法在电力市场成员之间进行网损分摊计算的可行性。     

基于改进潮流追踪法的网损分摊方案研究

现有的各种潮流追踪方法按照追踪的方向或对象不同,可以分为顺流追踪法和逆流追踪法,但进行网损分摊都是单向进行的,只能对负荷和发电机分别进行单独的网损分摊,忽视了网损由两者共同作用产生的事实.为了克服此方法的缺点和不足,提出一种面向输电元件的网损分摊模式,引入电网运营机构规定系数作为一种改进的潮流追踪方法.首先将线损当做负荷点处理,把有损网络转化为无损网络,然后以少节点有损系统为例进行仿真计算,计算结果证明基于双向网损分摊模式的改进方法,实现过程简单,物理意义明确,适用于各种可进行潮流追踪的复杂电力系统.     

一种基于潮流追踪的电力系统无功补偿方法

提出了一种旨在改善电力系统无功传输和降低有功网损的无功补偿点选择和补偿容量确定方法。该方法通过无功潮流追踪,获得负荷无功功率的传输路径,结合无功流动与支路有功网损的关系,定义了节点的网损分摊系数,进而根据系数的大小选择无功补偿点;推导了网损分摊系数对负荷无功功率的近似表达式,结合网损优化的近似模型,推导出了各补偿点最优补偿容量的计算公式;通过39节点测试系统,验证了该方法的有效性。所提出的网损分摊系数的物理概念清晰,计算便捷,据此进行的无功补偿对改善无功分布和降低网损均有较好的效果。     

改进的Z-BUS网损分摊方法

提出了一种改进的网损分摊方法RD-ZBS,并研究了其在不同电力市场模式下的应用。在联营模式下,该方法在Z—BUS法的基础上．根据系统总的收支平衡的原则将分配到发电机节点上的损耗份额进行二次分配．重新分配到负荷节点上,克服了Z-BUS法无法选择损耗分摊节点和发电机节点上损耗分摊量过大的缺点。在双边合同模式下．RD-ZBS法通过对Z-BUS法与增量法的结合．将Z-BUS法分配到发电机上的损耗份额重新分配给与之签订合同的双边交易上．并且考虑了双边合同模式下的联营交易．该方法很好地反映了网络的电气结构以及合同双方之间的网络联系对网损的影响。最后．通过几个具体算例对RD-ZBS法与其他几种网损分摊法进行了详细的比较与分析。计算结果表明,所提出的RD-ZBS法是一种公平、合理的网损分摊方法。     

基于电流跟踪的网损分摊新方法

针对电力市场中不同的运营模式需要采用不同的网损分摊方法 ,提出了一种新的网损分摊方法。即在电力库模式下 ,基于电流比例分配原则 ,利用潮流跟踪原理进行电流追踪 ,进一步把各支路网损精确地分摊到发电侧或负荷侧 ,通过分摊成本降低整个系统网损。通过对 5节点系统进行算例分析 ,验证了该方法的正确性和合理性     

Cross-term Decomposition Method for Loss Allocation in Distribution Systems Considering Load Power Factor

The customers of distribution system are generally encouraged to maintain better power factor through suitable tariff structures. The feeder power loss allocation is a part of tariff. The feeder power losses also depend upon power factor of loads. Therefore, loss allocation method should incorporate suitable rewarding and penalizing strategy for better and poor factors loads. This paper proposes a new distribution loss allocation method that considers load power factor to allocate losses in a more practical way. The proposed method employs bifurcation of cross terms of branch power loss among contributing nodes. The method provides loss allocation to system nodes in such a way that it provides rebates/penalties against variation in load power factor only to the concerned nodes. The proposed method is applied to 30-bus and 33-bus test distribution system and compared with other established methods. The analysis of the application results highlights the importance of the proposed method.     

Loss allocation of radial distribution system using Shapley value: A sequential approach

This paper presents a new method to allocate the power loss in a radial distribution system to loads and distributed generations (DGs). Integration of DGs has increased the importance of loss allocation because it alters the total power losses. The proposed method calculates the loss allocation in sequential manner using Shapley value method specifically for radial distribution system. The losses allocated by using proposed method are same as obtained from the conventional Shapley value method which satisfy the axioms of fairness. An important virtue of proposed method is that it reduces the memory and computational burden as well as ensures the fair allocation and recovery of total complex losses. The results are discussed and illustrated on different test systems.     

Transmission loss allocation in a deregulated electrical energy market

This paper presents a new method for transmission loss allocation in a deregulated electrical power market. The proposed method is based on physical flow through transmission lines. The contributions of individual loads to the line flows are used as basis for allocating transmission losses to different loads. With minimum assumptions, that sound to be reasonable and cannot be rejected, a novel loss allocation formula is derived. The assumptions made are: a number of currents sharing a transmission line distribute themselves over the cross section in the same manner; that distribution causes the minimum possible power loss.Application of the proposed method is straightforward. It requires only a solved power flow and any simple algorithm for power flow tracing. Both active and reactive powers are considered in the loss allocation procedure. Results of application show the accuracy of the proposed method compared with the commonly used procedures.     

点对点损耗灵敏度一致的等值辐射网输电损耗分摊

用等值辐射网络分摊输电损耗是一个全新的思路。文中分析发现已有方法没有充分利用实际输电网络的结构与潮流状态,且存在以辐射网络的支路导纳为待求量去求辐射网络不能解决发电机与负荷同节点的问题。文中方法通过引入实际输电网络发电机与负荷之间的点对点损耗灵敏度,可比较充分地利用实际网络的结构与潮流状态;以辐射网络中支路上的潮流作为待求量,可解决发电机与负荷同节点问题。一个包含4台发电机6个负荷节点系统的计算结果验证了文中方法的合理性。     

Z-bus loss allocation

This paper presents a new procedure for allocating transmission losses to generators and loads in the context of pools operated under a single marginal price derived from a merit-order approach. The procedure is based on the network Z-bus matrix, although all required computations exploit the sparse Y-bus matrix. One innovative feature and advantage of this method is that, unlike other proposed approaches, it exploits the full set of network equations and does not require any simplifying assumptions. The method is based on a solved load flow and is easily understood and implemented. The loss allocation process emphasizes current rather than power injections, an approach that is intuitively reasonable and leads to a natural separation of system losses among the network buses. Results illustrate the consistency of the new allocation process with expected results and with the performance of other methods     

基于叠加定理和Aumann-Shapley法的发电权交易网损分摊

发电权交易使得电网的潮流以及损耗发生变化,对电网的运行成本产生影响,因此如何有效计及这种影响并对电网进行相应的补偿是亟待解决的问题。为解决此问题,首先针对断面网损进行研究,在断面下将输电网等效为线性电路,发电机和负荷等效为电流源,通过叠加原理确定各支路潮流及功率损耗与各电流源的关系式,进而确定发电权交易量与网损变化量的关系式。其次,将网损分摊看作一个合作博弈问题,即网损是由所有参与者共同合作的结果。应用Aumann-Shapley法对支路的互耦合功率损耗进行分摊,可保证结果公平合理,且具有经济一致性。最后,通过IEEE9节点标准算例进行仿真,验证了所提方法的正确性和有效性。     

基于Shapley值的网损分摊新方法

介绍了目前网损分摊方法的研究现状，提出了一种基于Shapley值的网损分摊新方法，这种方法根据每个交易加入交易联盟后给交易联盟带来的边际网损大小来分摊网损，该网损分摊方法平等地对待所有可能的交易加入次序，并且考虑了所有可能存在的包含该交易在内的交易联盟，因此能够被各市场成员视为公平，另外，这种网损分摊方法能保证收支完全平衡，并且能够向各交易提供适当的经济激励信号，促进电力负荷的合理分布，从而降低系统的总网损，数值算例结果表明，基于Shapley值的网损分摊方法是公平，有效的。     

基于电流叠加法的网损分摊算法

提出基于线性电路叠加原理的功率贡献计算方法，用各电源共同作用时的负载电压与单独作用时的负载电流的乘积表示电源对负载的功率贡献，并用这种方法解决电力市场中的网损分摊问题。用电源共同作用时的线路压降和单独作用时的线路电流的乘积计算各个电源在各条支路上引起的网损，计算系统网损在各个电源中的分摊。根据电源对负荷的功率贡献因子计算电源和负荷分别承担网损及它们按比例承担时的系统网损分摊。该方法原理简明、计算量小、方便灵活、合理性强。以IEEE-14节点系统为例进行仿真计算，验证了该方法的合理性。     

Incremental transmission loss allocation under pool dispatch

Incremental transmission loss analysis has been used for decades, but recent interest in its application to loss allocation calls for new in-depth results. This paper demonstrates that, for incremental methods to be applied correctly in loss allocation, it is first necessary to specify the load distribution and loss supply strategies. Incremental loss allocation among bus power injections is shown to be arbitrary and, therefore, open to challenge as discriminatory. Loss allocation is possible among incremental loads and/or generators, but the proportion of the total losses assigned to either one is arbitrary. Unique, nonarbitrary incremental loss allocations are however possible among the "equivalent" incremental bilateral exchanges between generators and loads. From these basic components it is possible then to calculate the allocation among generators or loads in any specified proportion. The main results, although developed initially for small increments, are extended to large variations. Finally, a general incremental loss allocation algorithm is developed and tested     

Allocation of the cost of transmission losses using a radial equivalent network

This paper provides a procedure for the allocation of the cost of transmission losses that is based on deriving a radial network that is fully equivalent to the original one. This equivalence materializes in that voltage magnitudes and angles, and active and reactive power injections are identical for both networks. Once this radial equivalent network is available, the allocation of the cost of transmission losses to generators and demands can be performed in a straightforward manner. This equivalent network is derived solving a simple quadratic optimization problem whose solution can be obtained efficiently. A realistic case study including two load scenarios is analyzed. Results using the proposed technique are compared with those obtained using alternative allocation procedures.