Load identification and voltage stability monitoring

The paper describes an algorithm for recursive identification of the power system composite load by using recursive least squares. The variation of the composite load components during slow voltage transients has been shown to deteriorate voltage stability margins. By combining the load identification and voltage stability monitoring, it is possible to make a better assessment of the risks associated with power system operation under heavy loading conditions     

500 kV电容式电压互感器的在线监测装置

为监视 5 0 0kV电容式电压互感器运行情况 ,研制了在线监测的专用装置。介绍了监测装置的原理、功能和实际使用情况     

智能化中压开关柜的在线监测和传感器技术(一)

综述了用于中压开关柜监视、测量的两大类传感器：电流和电压测量保护用传感器；非电量数值传感器。新型的电流和电压传感器优越性明显，在解决了细节及接口问题后，将逐渐安装使用。非电量数值传感器技术是将开关柜“定期”维护转变为“按状态”维护的关键技术，有很好的应用前景。     

智能化中压开关柜的在线监测和传感器技术(二)

综述了用于中压开关柜监视、测量的两大类传感器：电流和电压测量保护用传感器；非电量数值传感器。新型的电流和电压传感器优越性明显，在解决了细节及接口问题后，将逐渐安装使用。非电量数值传感器技术是将开关柜“定期”维护转变为“按状态”维护的关键技术，有很好的应用前景。     

高压电缆线路护层接地超限电流在线监测系统

通过在线监测系统实时监测护层电流的瞬变、突变监测。捕捉护层电流的突变信号,分析故障原因,定位故障段,为线路抢修和前期预警提供技术条件。     

A new intelligent algorithm for online voltage stability assessment and monitoring

This paper presents a new approach for assessing power system voltage stability based on artificial feed forward neural network (FFNN). The approach uses real and reactive power, as well as voltage vectors for generators and load buses to train the neural net (NN). The input properties of the NN are generated from offline training data with various simulated loading conditions using a conventional voltage stability algorithm based on the L-index. The performance of the trained NN is investigated on two systems under various voltage stability assessment conditions. Main advantage is that the proposed approach is fast, robust, accurate and can be used online for predicting the L-indices of all the power system buses simultaneously. The method can also be effectively used to determining local and global stability margin for further improvement measures.     

基于广域测量系统的电压稳定动态监测

基于同步相量技术的广域动态测量系统,可以在时空坐标下监测电力系统动态运行特性,弥补了现有 SCADA 系统和故障滤波系统的不足,为大电网动态电压稳定监测奠定了基础.介绍了WAMS的基本原理,接着比较详细地阐述了电压稳定在线监测系统的内容及其在线应用的具体实现方法.在EPRI-36节点系统上的仿真结果验证了该监测系统的有效性.     

On-line voltage stability assessment using radial basis function network model with reduced input features

In recent years, voltage instability has become a major threat for the operation of many power systems. This paper presents an artificial neural network (ANN)-based approach for on-line voltage security assessment. The proposed approach uses radial basis function (RBF) networks to estimate the voltage stability level of the system under contingency state. Maximum L-index of the load buses in the system is taken as the indicator of voltage stability. Pre-contingency state power flows are taken as the input to the neural network. The key feature of the proposed method is the use of dimensionality reduction techniques to improve the performance of the developed network. Mutual information based technique for feature selection is proposed to enhance overall design of neural network. The effectiveness of the proposed approach is demonstrated through voltage security assessment in IEEE 30-bus system and Indian practical 76 bus system under various operating conditions considering single and double line contingencies and is found to predict voltage stability index more accurate than feedforward neural networks trained by back propagation algorithm and AC load flow. Experimental results show that the proposed method reduces the training time and improves the generalization capability of the network than the multilayer perceptron networks.     

An enhanced Radial Basis Function Network for voltage stability monitoring considering multiple contingencies

This paper proposes a scheme for online voltage stability monitoring using an enhanced Radial Basis Function Network (RBFN). A single RBFN is used to predict MW margins for different contingencies. A sequential learning strategy is used along with a regularization technique to design the RBFN and the weights in the output layer are determined by using linear optimization. The proposed network can be adapted with changing operating scenario of the power system. A network pruning strategy is used to limit the growth of the network size due to adaptive training. The proposed scheme is applied on the New England 39-bus power system model.     

Bibliography on voltage stability

This paper provides a comprehensive list of books, reports, workshops and technical papers related to voltage stability and security     

变压器有载调压对电压稳定性影响的仿真研究

利用中长期电压稳定时域仿真程序,计算分析变压器有载调压分接头调整(OLTC)对电力系统电压稳定性的影响。研究了有载调压变压器分接头的调节作用对变压器一、二次侧电压的影响与恒阻抗负荷、恒电流负荷、恒功率负荷以及电动机负荷等不同的负荷类型的关系和负荷快速增长可能引起电压崩溃的情况,提出了分接头闭锁与不闭锁的策略。     

低压配电箱故障电弧信号在线检测与报警系统

为可靠地检测出低压配电箱中的故障电弧,分别对电弧电压信号和弧光信号进行了检测.提取配电箱的进线电压和出线电压,分别转换成频率信号进行比较,获得电弧电压信号.并将其和弧光信号一起送入性能先进的 PIC16F877 单片机,做综合分析判断.最终设计出智能型故障电弧在线检测与声光报警系统,不仅可以实现低压配电箱电气故障的检测、预报,对供电电压进行实时显示,还可以实现对配电箱的电气火灾隐患的预警作用.     

Newly developed voltage security monitoring system

A voltage security monitoring system has been developed and installed in the energy management system of TEPCO's (Tokyo Electric Power Co.'s) central energy control center. The authors present the background and concept of the developed system, the newly developed algorithm, the configuration of the system and results of actual operation. A PV (total demand, voltage) curve is used for estimating voltage stability. To determine the curve, an algorithm for obtaining multiple load flow solutions is developed. The system has been in operation since February 1990, running at intervals of one minute     

电压稳定性分析探讨

简要讨论了电压稳定的意义,通过对影响电压稳定性的各种因素的分析、计算,得出各种因素对某电网电压稳定的影响程度,以及防止地区电网发生电压崩溃的措施,保证地区电网安全、可靠运行.     

电压稳定性分析与探讨

电力系统无法满足无功需求时会导致电压失去稳定性。利用PU曲线来分析功率裕度,运用功率裕度算法,结合暂态分析开展电压稳定性预测和分析,采取切负荷等一些措施,可防止电压失稳引起的系统崩溃。     

变电站电能质量在线监测系统

本文阐述了ZigBee监测变电站电能质量数据的基本原理和监测过程,设计完成了各相关部分的软硬件,并针对煤矿变电站做了电能质量测试工作.测试结果及传输实验表明,监测系统安装调试简便,工作稳定性高,电磁兼容性好,具有较高的推广应用价值.     

基于振动分析法的变压器在线监测

研究了变压器的振动原理,提出了变压器振动简化模型,用最小二乘法对现场试验数据进行参数拟合,得到振动模型参数,可作为指纹参数,由任意时刻电压、电流幅值计算求得变压器振动幅值,根据与实际振动的比较,判断变压器是否故障,实践证明,该方法预估的变压器振动信号具有很高精确度,在变压器在线监测绕组与铁心状态中有良好的应用前景.     

含二级电压控制的风电场电压稳定性研究

为研究自动电压控制（Automatic Voltage Control,AVC）对电网电压质量和运行经济性的作用效果,采用了将双馈风电机组作为无功源的风电场自动电压控制设计方法,分析二级电压控制对风电场电压稳定性的影响.以IEEE14节点为例,采用基于遗传算法的协调二级电压控制模型,并通过基于MATLAB的电力系统软件包PSAT进行动态仿真验证.结果表明,二级电压控制可以大幅度改善风电场的电压-无功水平.     

A new node voltage stability index based on local voltage phasors

The paper proposes an equivalent system model (ESM), which includes effects of both local network and system outside the local network. A new node voltage stability index called the equivalent node voltage collapse index (ENVCI), which is based on ESM and uses only local voltage phasors, is presented. The main advantages of ENVCI are accuracy in modeling and calculations, and ease in real time or on-line applications. The simulation results show that the ENVCI can identify not only the weakest node (bus) causing system instability but also the system voltage collapse point when it is near zero. This feature enables us to set an index threshold to monitor and predict system stability on-line so that a proper action can be taken to prevent the system from collapse.     

On-line monitoring of pressure in vacuum interrupters

Methods for on-line monitoring of the pressure in vacuum interrupters were investigated. Some experiments were carried out to investigate the characteristics of an inverted magnetron vacuum gauge in pulsed operation mode. According to the experimental results, a kind of vacuum chamber with intellectualized vacuum sensor was developed to implement the on-line monitoring of pressure in vacuum interrupters. The vacuum sensor can measure pressures ranging from 3times10^-4 Pa to 0.5 Pa