南方电网在线稳定分析中的动态等值方案

针对南方电网离线和在线稳定计算数据之间存在较大差异的情况,分析了同时忽略一定规模的发电机和负荷、忽略220 kV电网数据、负荷从110 kV侧移置220 kV侧以及忽略香港电网等因素对南方电网在线稳定分析结果的影响,对合理扩大监视控制与数据采集/能量管理系统的在线数据采集规模提出建议。利用动态等值技术提出了对应南方电网目前在线数据规模和建议发展规模的等值方案,从潮流分布、短路电流、典型故障分析等方面对2个方案进行了比较分析,表明推荐方案在保留系统稳定特性方面具备更好的适应性。     

大薛家湾地区电网规划问题探讨

根据内蒙古电力集团公司提出的"大薛家湾供电区"发展战略,结合薛家湾地区电源和电网规划的特点,提出了电源和电网规划的2种方案,并对其进行了稳态潮流计算、N-1开断潮流计算、短路电流计算以及系统薄弱点分析计算,建议增设前房子—清水河220 kV双回输电线、长胜—宁格尔220 kV输电线,将城关110 kV变电站改接到清水河220 kV变电站供电,用以提高电网的可靠性。     

宁夏电网电力系统稳定器PSS参数整定及其对系统稳定性的影响

基于宁夏电网大机组励磁系统实测模型,分析宁夏电网大扰动动态稳定问题特性,提出加强其动态阻尼的PSS整定原则.对网内主要机组进行了PSS参数整定试验,并以特定机组为例进行说明.仿真分析计算表明PSS参数整定后对宁夏电网系统大扰动动态稳定和小干扰动态稳定特性均有改善作用;并通过网内大机组甩负荷的大扰动试验证明了PSS整定的有效性.     

实时动态监测系统在东北电网负荷建模中的作用

东北–华北联网后的计算分析表明,选择不同的发电机和负荷模型对稳定计算结果的影响较大,东北电网负荷模型的建模或校核需要以大扰动试验数据为依据,分析了实时动态监测系统(wide area measurement system,WAMS)在东北电网基于大扰动事件的负荷建模过程中的作用,WAMS是大扰动试验风险可观测、试验出现异常情况可控制的基本保障,为基于大扰动事件负荷建模研究提供了电网动态测试数据,其实测的相量数据同时也是建立仿真计算运行方式的重要数据源。运行经验表明,开展东北电网负荷建模的可持续研究需要基于WAMS的扰动数据收集、处理和分析制度的保障。     

电网短路电流计算外网等值模型的构造

为满足电力应用软件短路电流计算模块的实用化要求,构造短路电流计算外网等值模型,实现统一进行全网短路电流计算成为了关键.以昆明电网为例,介绍了构造其外网等值模型的方法.     

计及配电网负荷模型的短路电流计算方法

为了探寻由于数据问题给计算结果带来的误差,本文以襄阳电网为例,将110kV线路、变电站以及10kV配电网络布在襄阳电网数据包中,并且采用将整个10kV站配电网络阻抗等效的方法来进行建模,通过襄阳电网算例计算对比分析,表明考虑110kV以及10kV网络数据对于220kV站短路电流计算有影响,但是影响程度基本维持在5%以内,因此目前PSASP中220kV层面的网络数据可以用于计算短路电流。     

一种工程实用的电力系统等值方法

硬件在环试验中,为了兼顾仿真规模和交直流相互影响,需要对交流系统进行等值。基于等值前后系统短路容量一致原理,提出一种新型交流大电网等值方法。根据等值节点的短路电流构建等值发电机的额定容量及并网阻抗参数;根据短路电流大小与系统动态特性强弱关系,提出一种基于短路电流贡献率的新判据;采用该判据选择等效发电机的主导控制器类型,并计算控制器的参数;对静态Ward等值进行修正,消除负电阻及发电机有功输出为负的情况。通过算例对比等值前后系统电压、功率流动、短路容量以及故障后动态响应特性,验证了所提方法的有效性。     

河南电网重要负荷特性研究

电动机群负荷和电解铝整流负荷是电力负荷的重要组成部分。根据大扰动过程中电动机群负荷对系统稳定性影响较大的特点,在河南电网濮阳供电区的中原油田进行了110 kV线路三相短路故障试验。针对电解铝整流负荷的电压特性,在河南电网焦作供电区沁阳铝厂进行了调节电压的小干扰试验。介绍了河南电网人工扰动试验的方案和实施情况。由于试验过程中严格按照试验方案和预定步骤操作,上述实验没有对河南主网的安全稳定运行造成影响,获得了完整清晰的试验数据,达到了预期的试验目的。     

基于WAMS的电网扰动识别方法

电网规模的不断扩大带来了潜在的安全问题。为保证电网安全可靠运行,运行人员需要及时掌握电网扰动情况,并采取适当的控制措施。近年来,基于全球定位系统（GPS）技术构建的广域测量系统（WAMS）能够实时地将全网同步测量信息传送至调度中心,使全网动态监测成为可能。文中提出了基于WAMS的电网扰动检测和识别方法,以便根据不同的扰动类型快速确定相应的控制措施,抑制其对系统的影响。首先,从理论上对电网中常见扰动（短路、切机和切负荷）的特征进行了分析;在此基础上,应用模式识别的思想,初步探讨了借助于电力系统中同步相量测量单元（PMU）实时量测量所反映的特征进行扰动识别的方法与实现步骤;最后,通过华北电网扰动仿真进一步明确扰动的特征,验证了理论分析的正确性和利用所提出的方法区分电网扰动的有效性。     

华东电网短路电流计算标准研究

介绍了目前国内短路电流计算工程应用主要根据IEC 60909形成的5种常用的计算方法,从理论分析的角度,结合小系统算例、华东实际电网以及现场人工短路试验实测数据,分析了5种短路计算方法的合理性以及影响短路电流计算的因素,并提出了适合华东220 kV及以上电网短路电流计算的标准。     

Laboratory verification of an excitation control system for increasing power transfer capability

An excitation control system is described that is based on five identifiable stages of the transient behaviour following a disturbance. It combines discrete control with power system stabilizers and automatic voltage regulators. Also investigated is the effectiveness of increasing power transfer capability, of both large and small disturbances, and the performances in various operation conditions by extensive physical model tests.     

Damping of subsynchronous oscillations in EHV series-compensated ACDC transmission system

Subsynchronous oscillations in a power system with series-compensated lines can be amplified and sustained because of interaction between the electrical power system and the turbine generator system. Recently, it has been found that an HVDC link may have a similar effect. A subsynchronous resonance study is described for an EHV series-sompensated ACDC transmission system performed on a digital computer which includes mathematical modelling of a synchronous machine with torsional dynamic representation. Owing to the fast controllability of HVDC transmission, a simple DC current regulator can be incorporated into the rectifier current control system to modulate the DC power whereby the rather fast (10–20 Hz) torsional oscillations can be damped out. This power mudulation can be used for the damping of oscillations caused by the series-compensated AC line as well as by an HVDC link.     

Electromechanical distance measure for decomposition of power systems

A concept of electromechanical distance measure which reflects the interaction among the machines during a transient is presented. This measure is then used as a criterion for decomposing the power system into regions, each requiring different levels of model complexity. The complexity of models for regions decreases progressively away from the point of fault. Grouping of coherent generators within each region can also be done using the results of this analysis. The analysis takes into account the fault location, magnitude of disturbance, and changes in boundary between the study area and the external system.     

基于反应堆堆芯非线性模型的核电机组动态行为分析

针对核电机组接入电力系统后的动态行为进行了研究。在反应堆非线性数学模型的基础上,结合电力系统的数学模型,对系统受扰动后的动态行为进行了分析,所涉及的扰动形式包括反映核电机组对电网影响的反应堆功率调节和机端电压调节以及反映电网对核电机组内部物理过程影响的三相短路及无故障断线。仿真结果表明,该模型和经典理论的结果一致,所提方法能够较准确地描述系统的动态行为,同时还能为系统励磁参数和反应堆控制参数的整定提供参考。     

Operational transform technique for generating Lyapunov functions

An operational transform technique is established to generate Lyapunov functions for the transient stability study of a power system modelled to full complexity. This method requires the system equations in state-space form without any additional assumption. A modifiable skew symmetric transformation matrix is shown to exist, via which the Lyapunov functions for a power system are generated. The power and the simplicity of the presented method is demonstrated by applying it to a single-machine, infinite-bus system, taking into account the effects of transfer conductances and all control equipment. The applicability of the method to a typical multimachine power system is examined and presented.     

Theoretical and practical dynamic equivalents in multimachine power systems: Part 2: Construction of practical equivalent

A practical dynamic equivalent of a machine group is constructed, based on the single-machine theoretical equivalent formulated in the first part.     

Theoretical and practical dynamic equivalents in multimachine power systems : Part 1: Construction of coherency-based theoretical equivalent

Taking account of the structural conditions for theoretical coherency, a single machine equivalent circuit is determined. This is an extension of the Thévenin theorem to electromechanic circuits and will be used as the basis for constructing a practical dynamic equivalent in the second part of the paper.     

同步电机稳定性能仿真分析

运用EasiMotorFlow软件平台,利用场路结合方法分析某1200kW电励磁同步电机的静态稳定性能,并利用电磁场有限元法结合实际性能指标分析了该电机的动态稳定性能,有效地解决了电励磁同步电机中的电机稳定性能分析精度不高、计算复杂的问题。     

浅谈10kV中置式开关成套设备中母排动稳定校验的方法

本文综合应用了电气、机械和计算机方面的知识，探讨了10kV中乒式开关成套设备中母排动稳定校验的一种方法。     

Multimachine stability analysis using vector Lyapunov functions with inertial-centre decomposition

Multimachine power system stability is investigated by means of a new decomposition technique. The power system is decomposed into subsystems using the inertial-centre concept. Individual Lyapunov functions are then obtained for each subsystem. Stability conditions for the overall system are established, taking into account the interconnection characteristics. The least restrictive overall system Lyapunov function is obtained by weighting each subsystem instability is then used to determine the critical clearing time.