浅析电网动态仿真培训系统的结构与应用

随着我国电网互联后带来系统稳定性的下降,需要开发先进、灵活、功能全面的电力系统动态仿真培训系统,并加强对调度员的早期培训,从而提高调度人员的事故应急处理能力,对现代电网的安全稳定的运行具有十分重要的意义。     

浅谈变电站“五防”闭锁系统

随着现代电力系统规模愈来愈大,电压等级愈来愈高,电气误操作事故也成为电力系统频发性事故之一。为了确保电力系统的安全稳定运行,避免各类误操作事故的发生,除强化运行管理手段,还必须重视“五防”工作。本文就变电站五防系统及存在问题和解决方案进行了分析与探讨。     

电力系统在线安全稳定分析的数据预处理方法

在日益庞大和复杂的现代电力系统中,远距离、高电压及大容量已成为现代电力系统的发展方向。在电力系统向着大规模电网互联发展的同时,其事故影响也随之扩大,一旦电力系统发生事故,将造成极其严重的后果。本文研究了电力系统在线安全稳定分析的安全稳定方法。阐述了在线安全稳定分析系统的整体结构及其数据仓库的建立方法。     

电力系统频率降低事故的危害及处理方法

本文主要阐述了电力系统低频率运行的危害、系统低频率运行事故的处理、电力系统频率的调节等问题。     

电力系统中继电保护事故原因分析及处理技术

电力系统继电保护是电力系统的重要组成部分,它在保证电力系统安全、稳定和经济运行等方面起着非常重要的作用。随着电力系统的迅速发展,电网的规模的日益扩大,网络的结构日益的复杂,系统短路电流的容量也在不断的变化,经常要进行短路电流的计算和继电保护的整定值的校验。为此,要对继电保护事故原因进行系统的归纳分析,有针对性的提出处理方法。本文主要对继电保护事故的种类进行了分析,提出了继电保护存在的问题及对策。     

浅述造成主变继电保护误动的原因及防范措施

继电保护在我国电力系统中占有重要的位置,差动保护是变压器的主保护,它的误动将造成变压器的非常停运,影响电力系统的发供电,甚至是造成系统振荡,对电力系统发供电的稳定运行是很不利的。对一起在系统无故障冲击的情况下,变压器一次差动保护误动作的事故,介绍了事故的经过及保护的理,分析了事故产生的技术原因,其主要是由变压器升高座CT的伏安特性不一致造成的,进行了理论证,并提出相应的防范措施。     

GPS在电厂的应用及存在问题分析

电力系统的运行状况瞬息万变,发生事故后更要及时处理、分析事故原因。自动控制系统要准确反映、判断、控制电力系统的运行,必须要有一个统一的时间基准。介绍GPS原理,GPS对时方式。论述我厂监控ECS系统中GPS系统的应用情况,分析目前GPS对时系统存在的问题,提出解决方案。     

电力系统继电保护问题探讨

现代电力系统是一个由电能产生、输送、分配和用电环节组成的大系统。电力系统的飞速发展对电力系统的继电保护不断提出新的要求,在电力系统中的任何一处发生事故,都有可能对电力系统的运行产生重大影响,为了确保城市电网配电系统的正常运行。必须正确地设置继电保护装置。     

浅谈输变电系统中的继电保护

在电力系统中的任何一处发生事故,都有可能对电力系统的运行产生重大影响,为了确保城市电网配电系统的正常运行,因此必须正确地设置继电保护装置。本文探讨了输变电系统继电保护常见的问题,并提出了解决措施。     

浅谈电力电压稳定及控制

近几年,随着各种科技日益的更新及发展,电力系统已经进入到了一个新时代。由于系统日益复杂化,使得电力系统中的电压稳定性问题越来越突出,成为了现代电力系统要解决的重要问题之一。而各地先后发生了多起由于电压失稳导致的大面积停电事故,造成了巨大的经济损失和严重的社会影响,因此,如何解决电压稳定及控制技术,避免电压崩溃事故的发生,具有重要的意义。     

Coordinated stability control

An adaptive coordination scheme is proposed to improve the transient stability, voltage security and frequency damping of a power system network by optimally scheduling the parameters of the available controllers. A set of real-time stability indicators, including a transient stability index, transient voltage stability index and damping factor are used to reflect the stabilities of power systems. Then, the relative significances of a group of controllers to the power system are used as references for the optimiser to schedule new controller parameters. This coordinated control scheme effectively allocates power system resources to handle different stability issues in different time frames. The results suggest that power system security can be further enhanced by means of coordinated control.     

Fast prediction of loadability margins using neural networks to approximate security boundaries of power systems

Determining loadability margins to various security limits is of great importance for the secure operation of a power system, especially in the current deregulated environment. Here, a novel approach is proposed for fast prediction of loadability margins of power systems based on neural networks. Static security boundaries, comprised of static voltage stability limits, oscillatory stability limits and other operating limits such as generator power output limits, are constructed by means of loading the power system until these security limits are reached from a base operating point along various loading directions. Back-propagation neural networks for different contingencies are trained to approximate the security boundaries. A search algorithm is then employed to predict the loadability margins from any stable operating points along arbitrary loading directions through an iterative technique based on the trained neural networks. The simulation results for the IEEE two-area benchmark system and the IEEE 50-machine test system demonstrate the effectiveness of the proposed method for on-line prediction of loadability margins     

三相异步电动机驱动振动系统的Sommerfeld效应分析

提供有限动力的原动机称为非理想原动机。在工程中,几乎所有提供动力的原动机均为非理想原动机。由非理想原动机带动的振动系统称为非理想振动系统。在非理想振动系统中,原动机与振动系统的运动状态是相互作用、相互影响的。Sommerfeld效应是由于非理想原动机在振动系统共振区附近无法提供足够动力而产出的一种非线性跳跃现象。该试验研究了由一种典型原动机——三相异步电动机驱动振动系统的Sommerfeld效应。将三相异步电动机的动力学模型引入到振动系统中,建立了非理想振动系统的动力学模型。采用解析方法,建立了电机供电频率与转速之间的解析表达式,并应用摄动法进行了稳定性分析。基于MATLAB/Simulink进行了仿真验证,说明了所采用解析方法的正确性。分析了偏心质量与电机功率对非理想振动系统的影响规律。通过研究发现,对于非理想振动系统的研究必须充分考虑原动机与振动系统的相互作用,忽略二者之间的相互作用是不合适的。     

Voltage stability analysis considering the uncertainties of dynamic load parameters

Many uncertainties exist in power systems and they will affect the stability analysis results. Voltage stability considering uncertainty in load parameters will be discussed. With the assumption that parameter variation is normal distribution, the probabilistic characteristics of eigenvalues under the uncertainties of dynamic load parameters can be obtained. Distribution of the critical eigenvalue will determine the stability probability of a power system. The stability margin can be inferred from the probabilistic critical load level, which is the maximal load level where system is `probabilistically` stable. Case studies on three test systems illustrate that the stability margin will be reduced with load uncertainty. The proposed probabilistic results are validated using deterministic method of Monte Carlo on multi 10`000 sample studies.     

松动裂纹转子轴承系统周期运动分岔及稳定性分析

根据松动裂纹耦合故障转子轴承系统的非线性动力学方程,利用求解非线性非自治系统周期解的延拓打靶方法,研究了系统周期运动的分岔特性及其稳定性。研究发现,在较大和较小的偏心量作用下,系统的周期运动都由倍周期分岔而失稳,在适当的偏心量下,系统的周期运动以Hopf分岔形式失稳且稳定性较强。转轴裂纹和基础松动故障都使系统周期运动稳定性降低、系统Hopf分岔存在的偏心量范围变大。结论为转子轴承系统的安全稳定运行和振动的抑制及控制提供了理论参考。     

Complex dynamics of Cournot game with bounded rationality in an oligopolistic electricity market

In order to accurately simulate the dynamic decision-making behaviors of market participants, a novel dynamic Cournot game model with bounded rationality of electricity market that considers the constraints of realistic power networks is proposed in this paper. This model is represented by discrete difference equations embedded within the optimization problem of consumption benefits. The Nash equilibrium of electricity market and its stability are quantitatively analyzed. It is found that there are different Nash equilibriums with different market parameters corresponding to different operating conditions of power network, i.e. congestion and non-congestion, and even in some cases there is no Nash equilibrium at all. Numerical simulations with the 2-node and IEEE 30-node systems are carried out to evaluate the dynamic behaviors of electricity market, especially the periodic and chaotic behaviors when the market parameters are beyond the stability region of Nash equilibrium.     

基于浸入与不变原理的电力系统混沌振荡分析与控制

针对电力系统中普遍存在的参数变化引起系统混沌振荡导致系统不稳定问题,提出了一种基于浸入与不变(immersion and invariance,Ⅰ&Ⅰ)原理的自适应反演滑模控制(adaptive backstepping sliding mode control,ABSMC)算法,以提高电力系统运行稳定性.首先,利用电...     

Application of core vector machines for on-line voltage security assessment using a decisiontree-based feature selection algorithm

This study presents a core vector machine (CVM)-based algorithm for on-line voltage security assessment of power systems. To classify the system security status, a CVM has been trained for each contingency. The proposed CVM-based security assessment algorithm has a very small training time and space in comparison with support vector machines (SVMs) and artificial neural networks (ANNs)-based algorithms. The proposed algorithm produces less support vectors (SVs). Therefore is faster than existing algorithms. One of the main points to apply a machine learning method is feature selection. In this study, a new decision tree (DT)-based feature selection algorithm has been presented. The proposed CVM algorithm has been applied to New England 39-bus power system. The simulation results show the effectiveness and the stability of the proposed method for on-line voltage security assessment. The effectiveness of the proposed feature selection algorithm has also been investigated. The proposed feature selection algorithm has been compared with different feature selection algorithms. The simulation results demonstrate the effectiveness of the proposed feature algorithm.     

Composite load models based on field measurements and their applications in dynamic analysis

The composite load model with an induction motor in parallel with a static load has been studied and applied in analysis of dynamics of power systems for a long time. However, the load parameters from field tests are still very limited. Based on the theoretical results of identifiability and estimation methodology of load parameters that have been achieved in the previous work, a project of load modelling based on field measurements is described. Eight sets of equipment for load modelling were installed in HeNan Electric Power Grid (HNEPG) Corporation, and the dynamics of the load were recorded and a dynamic index is proposed to evaluate the dynamic characteristics of the data measured. The load models derived from the field measurements are applied to stability analysis of HNEPG. The critical clearing time and power transfer capability analyses illustrate the enhancement of the stability analysis of the power grid using the load parameters derived from the field measurements and show the benefits of application of such model parameters in power system dynamic analysis.