云南电网暂态稳定裕度仿真研究

以扩展等面积原则(EEAC)为理论依据的暂态稳定分析,与李亚普诺夫方法完全不同,具有突出的优势,能够对系统的暂态稳定给出定量的指标.应用EEAC理论方法对2005年和2006年丰大运行方式下的暂态稳定裕度进行了定量分析.云南电网中由七甸-罗平和曲靖-罗平500 kV线路组成的输电断面上发生扰动时,南方电网的暂态稳定裕度进行了仿真研究.2006年七甸、罗平间架设500 kV第二回线后,系统的暂态稳定裕度得到了较大程度的提高.     

电力系统在线暂态稳定分析方法评述

电力系统最具在线应用前景的暂态稳定分析方法是直接法,又可分为暂态能量函数法(又称李雅普诺夫直接法)和扩展等面积法.对这两类方法进行了评述,指出这些方法存在的关键问题是可靠性问题,并分析了主要的原因.认为需要开拓新的研究思路去实现可靠的在线暂稳定量分析方法.     

暂态能量函数用于寻找最优控制时刻的研究

电力系统中的控制手段大致可以分为两种类型：主要控制和断续辅助控制。本文基于电力系统的暂态能量,研究了断续控制最优控制时刻的问题,从理论上证明了单机无穷大系统中,不同时刻进行的断续辅助控制,控制结束后系统的暂态能量不同。对于复杂的系统,根据给定的故障经过EEAC等值,可以简化为两机系统,上述结论依然成立。本文利用该结论,给出了计算电力系统中最优控制时刻的方法。     

基于励磁调压特性的交流同步电机强励控制

为了探索励磁调压特性对交流同步电机强励的控制关系,通过励磁EEAC理论从励磁调压角度对交流同步电机的强励控制进行分析,应用Matlab系统建立自并励单机仿真模型,并仿真分析了暂态过程中机端电压对交流同步电机强励的调控关系.结果表明,机端电压决定着电功功率,电磁功率决定着系统暂态稳定的裕度.在忽略损耗的条件下,电功功率等价于电磁功率,因而机端电压决定着励磁系统暂态稳定的裕度.     

通过网络参数调控提高FACTS的稳定性

研究了灵活交流输电系统（ＦＡＣＴＳ）的稳定控制问题。通过电力网络结构控制及临界能量分析，提出网络结构参数控制对策及评价方法，借以提高系统的暂态稳定性。并实际应用于１０机３９母线系统，考察和验证电力网络结构控制对提高电力系统暂态稳定性的有效性     

A transient energy function for power systems including the induction motor model

A construction method for power system transient energy function is studied in the paper, which is simple and universal, and can unify the forms of some current energy functions. A transient energy function including the induction motor model is derived using the method. The unintegrable term is dealt with to get an approximate energy function. Simulations in a 3-bus system and in the WSCC 4-generator system verify the validity of the proposed energy function. The function can be applied to direct transient stability analysis of multi-machine large power systems and provides a tool for analysis of the interaction between the generator angle stability and the load voltage stability. Recommended by Prof. LU Qiang, Member of Editorial Committee of Science in China, Series E: Technological Sciences Supported by the Special Fund of the National Priority Basic Research of China (Grant No. 2004CB217904) and the National Natural Science Foundation of China (Grant No. 50323002)     

Study on undercooling of metal droplet in rapid solidification

In 1950, Turnbull et al.[1] dispersed 18 kinds of metals including Cu, Ni, etc. into droplets with diameters of 10-100 μm and obtained a large undercooling of 0.18 TL. Volkmann et al.[2] have successfully obtained the undercooling of 0.3 TL in the Co-Pd alloy by means of the molten glass purified technique. As yet, the maximum undercool-ing in liquid metals is acquired by Perepezko et al.[3], who makes the Ga with a diameter of 20 μm reach an undercooling of about 0.58 TL by use of the …     

Optimum line reclosing time for the enhancement of interconnected power system stability

0　INTRODUCTIONWiththegrowthoflargeinterconnectedpowersystemowingtothebenefitsofpowermarketderegulation ,thereisanurgentneedtoimplementtransientstabilitycontrolforaninterconnectedpowersysteminemergencyforavoidingthecatastrophicresult .Automaticlinereclosingschemesasappliedintheextra high voltagepowersystemisoneofeconomicalandeffectivemeanstomaintaintran sientstabilityandsynchronism[1] .Becausethemajority(6 0 %～ 80 % )oftransmissionlinefaultsareofatransitorynature[2 ] ,automaticlinere clos…     

Transient stability and emergency control

Comparability of emergency control strategies with different instability modes is the key issue to decide which control strategy to be implemented. This paper considers that the essential factor causing instability should be used to form a unified standard to assess the effectiveness of control strategies with different instability modes. Thus a switching control stabilization principle was proposed based on elimination of the unbalanced energy between mechanical and electrical energies of generator sets. Along this way, the difficulty of seeking a Lyapunov function was circumvented. According to the principle, an emergency control algorithm framework was established to handle transient stability assessment, control location selection and control amount evaluation. Within the framework, this paper studied instability mode transition, then proposed an algorithm based on prediction function and a new approach to normalized stability margin stemmed from static EEAC method, which can increase comparability of various control locations. The simulations on the New-England System verified the proposed emergency control method for stabilizing transient stability.     

一种基于暂态稳定风险的储能位置与容量优化方法

在电力系统中合理地接入具有快速功率响应能力的储能装置,能够改善电力系统的暂态稳定性,而储能装置安装位置和容量的选择严重影响作用效果.提出一种基于暂态稳定风险的储能位置与容量优化方法,基于暂态稳定风险指标衡量储能装置的作用效果,并考虑电力系统运行中的各种随机因素,为在电力系统中安装储能装置时选择最优的位置和容量提供一种新方法.通过在Matlab环境下,对新英格兰10机39节点系统进行仿真验证,证明该方法的可行性和有效性.     

暂态稳定性事故筛选与排序方法研究

暂态稳定性事故的筛选与排序的目的是针对一组预想的事故集合挑选出严重事故或过滤掉无害的事故。本文对目前的暂态稳定性分析的事故筛选与排序方法,如能量函数法中的PEBS法、基于扩展等面积法则的EEAC法及集中反应事故性能指标的方法进行了总结,并对各类方法进行了对比。指出了各种方法优点和不足。     

最佳跳闸-重合闸操作时机的选取及其整定计算

合理确定输电线路跳闸—重合闸操作时机对提高电力系统稳定性具有重要的意义。本文以跳闸-重合闸电气操作全过程为研究对象,建立了跳闸-重合闸操作时机对电力系统稳定性影响的数学模型,并使用能量函数导出了最佳操作时机的条件及其整定策略。仿真表明,按最佳操作时机进行操作大幅提高了网络的传输能力和系统的暂态稳定极限。     

直接法在电力系统暂态稳定分析中的应用

最近十几年来，直接法在电力系统暂态稳定分析中取得了丰硕的成果，本文简要地回顾了直接法在暂态稳定分析中的历史和现状，并从暂态能量对机组失稳的影响出发，对暂态能量函数法的几个分支作了简单讨论，给出了一个关于孤立稳定域现象的物理解释，最后，对直接法的发展作了展望。     

暂态稳定临界切除时间的计算及其在继电保护中的应用

电力系统在受到大干扰后,其暂态能量的计算与沿运行轨迹积分的能耗有关．运用能量函数PBES直接法对电力系统暂态稳定性进行分析,可快速、准确地确定系统的临界受扰轨迹,求取电力系统暂态稳定临界故障的切除时间,以更合理、准确地进行继电保护配置、时间整定及系统之间的配合校验．     

Decomposed input-output stability analysis and enhancement of integrated power systems

The integrated power system (IPS) is a foundation of all-electrical ships and vessels. The stability of IPS becomes a prerequisite of complicated cruise tasks. Thus, advanced stability analysis and regulation methods for IPS are of great importance. In this paper, a novel method is proposed for analyzing and enhancing transient stability of IPS, which is regarded as a cyber-physical system comprising of subsystems and connections. Criterions for determining input-output stability of such a system are firstly derived. Then, the stability analysis of IPS can be performed in the following two steps: 1) evaluating local input-output stability features of each subsystem independently through simulations. 2) Checking stability criterions with system topology and subsystem stability features. Moreover, synthetic approaches are proposed for stabilization and stability enhancement of IPS. To avoid system in-stability after major failures or topology changes, the optimal emergency control is performed to reconfigure subsystems. The other optimal regulation is used to strengthen system stability by adjusting subsystems’ control parameters during normal operation conditions. Case studies on a typical IPS validate the proposed stability analysis and enhancement approach.     

采用Taylor级数展开技术的直接法暂态稳定分析

本文采用高阶Taylor级数展开技术进行直接法暂态稳定性分析。在PEBS法临界切除能量的求取过程中,用高阶Taylor级数展开模拟持续故障轨迹和进行加速功率的求取。采用相对初始点势能的概态计算势能,避免了故障后稳定平衡点的潮流计算。通过对试验系统临界切除时间的估算,表明本文方法具有较好的精度和较快的计算速度。     

移相器在电力系统暂态过程中的行为和作用

运用暂态仿真法研究移相器在电力系统暂态过程中的行为和作用，分析了移相器在电力系统暂态过程中作用的机理，研究了移相器在暂态过程中的动作规律。实例分析表明，移相器对于提高电力系统的暂态稳定性有积极的作用。     

暂态能量在输电网络中的分布规律的研究

在网络暂态能量函数的基础上,结合系统的暂态能量在网络中分布的计算方法,通过对多机系统的仿真,研究了暂态能量在网络中的变化规律,指出了暂态能量在系统的临界割集所属支路上具有同调性以及暂态能量在网络中具有传播性的变化特点。     

基于脉动通风原理的局部通风机控制的实现

本文介绍了KJK1- 60/660型矿用局部通风机节能型瓦斯自动排放装置,着重阐述了脉动通风原理以及风机控制所采用的ON- OFF模式及其实现方法,并论述了该装置的软硬件结构及在瓦斯排放和节能方面的效果.     

一种基于广域角速度信号的暂态励磁控制方法

针对电网发生故障后的暂态稳定问题,文中提出了一种基于广域角速度信号的暂态励磁控制方法,电网中的角速度信号更易获取,因此该控制方法简单易行.首先,通过临界机群的识别判据识别出故障电网中的临界机群;然后,通过李雅普诺夫理论推导出一种将广域角速度信号作为控制信号的励磁控制器,并通过该控制器对临界机群内所有发电机组进行励磁控制;最后通过在Matlab/simulink仿真平台搭建的10机39节点系统验证该励磁控制方法能有效改善故障电网的暂态稳定性.