Failure analysis on China power grid based on power law

This paper is concerned with the mechanism of blackouts in China power system from the viewpoint of self-organized criticality. By using two estimation algorithms of scaled window variance (SWV) and rescaled range-statistics R/S), this paper studies the blackout data in China power system during 1988-1997. The result of analysis shows that the blackout data of 1994-1997 coincides well with the autocorrelation. Furthermore, it is found that the function of blackout probability vs. blackout size exhibits power law distribution.     

电力系统暂态稳定性的数值仿真研究

由于系统暂态失稳引发的大停电等事故频繁,所以加强对电力系统暂态稳定分析的研究具有重要意义。数值计算是系统仿真的重要手段,计算结果可以为系统的规划、设计、运行、分析、控制等提供依据。首先介绍了电力系统暂态稳定分析的主要方法,并利用时域法讨论了单机无穷大系统的暂态稳定性。其次,采用龙格库塔方法求解离散发电机转子的运动方程,得到了系统δ-t曲线。最后,运用上述方法计算实际问题,结果表明暂态稳定分析与初始运行方式、故障点位置、故障切除时间、故障后状态有关。因此,在实际生产中应注意结合上述特点减少事故发生。     

Genetic algorithms to solve the power system restoration planning problem

This study reports the use of a Genetic Algorithm (GA) to solve the Power System Restoration Planning Problem (PSRP). The solution to the PSRP is described by a series of operations or a plan to be used by the Power System operator immediately on the occurrence of a blackout in the electrical power supply. Our GA uses new initialization and crossover operators based on the electrical power network, which are able to generate and maintain the plans feasible along GA runs. This releases the Power Flow program, which represents the most computer demanding component, from computing the fitness function of unfeasible individuals. The method was designed for large transmission systems and results for three different electrical power networks are shown: IEEE 14-Bus, IEEE 30-Bus, and a large realistic system.     

一种软启停正负双直流电源的设计

变形镜驱动器正负电源加电或者断电不同步,导致其在加电瞬间或者断电瞬间,输出端会输出一个-38.0V和86.0V的冲击电压,这个冲击电压使得变形镜在未开始工作时就产生了较为严重的面形畸变,为此研制了基于微处理器的软启停直流电源,它输出两路按一定时序变化的输出电压作为后续两个继电器的控制端,再通过这两个继电器分别控制变形镜驱动器正、负电源的导断,从而使得变形镜驱动器的正负电源同时加载或者卸载。在硬件平台了进行了实验验证,结果表明,使用软启停直流电源后,变形镜驱动器加电瞬间或断电瞬间,其产生的脉冲电压的峰-峰不超过0.45V,远远小于未使用软启停直流电源前的冲击电压,满足了系统的设计要求。     

Middle-long power load forecasting based on particle swarm optimization

Middle-long forecasting of electric power load is crucial to electric investment, which is the guarantee of the healthy development of electric industry. In this paper, the particle swarm optimization (PSO) is used as a training algorithm to obtain the weights of the single forecasting method to form the combined forecasting method. Firstly, several forecasting methods are used to do middle-long power load forecasting. Then the upper forecasting methods are measured by several indices and the entropy method is used to form a comprehensive forecasting method evaluation index, following which the PSO is used to attain a combined forecasting method (PSOCF) with the best objective function value. We then obtain the final result by adding all the results of every single forecasting method. Taking actual load data of a power grid company in North China as a sample, the results show that PSOCF model improves the forecasting precision compared to the traditional models.     

基于无线传感网的核电安全监控系统设计

低碳经济和能源可持续发展的要求下,新能源的开发和使用越来越受到世界各国的青睐。核电在新能源领域发电效率最高,电能质量最稳定,近年来取得长足的进步和丰硕的成果,然而,福岛核辐射事故的发生导致核电发展阻力重重,核电安全问题被提升到前所未有的高度。基于传感网技术的核电安全监控系统采用“检测层-接入层-汇聚层-数据中心”四层传感网结构,实时采集核电厂关键设备的运行状态和参数,并通过传感网传输到远程服务器,在数据中心对采集的数据进行数据挖掘和数据融合处理,对核电厂运行状态进行实时监测和预测,确保核电厂安全运营。核电安全监测网络的生命周期是保证整个网络使用可靠性和稳定性的前提和基础,从节点布局优化的角度出发,研究该监测网络的能量管理方法。     

基于改进遗传算法的电力系统无功优化的研究

电力系统无功优化问题是一个多变量、多约束的混合非线性规划问题,其操作变量既有连续变量又有离散变量,其优化过程比较复杂。遗传算法是模拟生物在自然环境中的遗传和进化过程而形成的一种自适应的全局优化搜索算法,可用于解决含有离散变量的复杂优化问题。本文选用遗传算法求解电力系统无功优化问题,并对基本遗传算法的编码、初始种群、适应度函数和交叉、变异策略等进行改进,使用本文提出的改进算法对IEEE1 4节点进行无功优化计算,结果证明本文模型和算法的实用性、可靠性和优越性。     

Frequency domain subspace-based identification of discrete-time power spectra from uniformly spaced measurements

In this paper, we revisit the problem of identifying multi-input/multi-output linear-time-invariant discrete-time systems from measured power spectrum data on uniform grids of frequencies studied by Van Overschee, De Moor, Dehandschutter, and Swevers (1997). We show that the algorithm proposed by these authors is not consistent. Then, we propose an interpolatory identification algorithm which is strongly consistent when the corruptions in the spectrum measurements have a bounded covariance function. The performance of the proposed algorithm is demonstrated in a simulation example.     

基于HLA/RTI的供配电仿真系统设计

针对传统供配电仿真系统的不足,本文提出基于HLA／RTI设计仿真系统框架,同时使用VegaPrime软件和Creator完成实时视景的开发,综合Visual C＋＋编程最终实现了一个具有一定先进性的供配电综合仿真系统。实践表明该仿真系统不仅可以用作电力运营的辅助工具,还可以为决策人员提供数据支持和决策建议,同时,还可用于对电力人员进行培训。     

An enhanced premium power park configuration using active power and voltage conditioning devices

In this paper, an enhanced premium power park (PPP) configuration is proposed to effectively mitigate power quality disturbances using a combination of active power and voltage conditioning devices in a spot-configuration-based distribution system. Furthermore, a new coordination algorithm is proposed to achieve full-range coordination between the controllers, thus ensuring the maximum reliability of the proposed configuration. To prove the enhancement of the proposed PPP configuration in terms of improved power quality and investigate the performance of the system under different types of power quality disturbances, several scenarios are simulated using the Matlab/Simulink software.     

Implementation of an on-line dynamic security assessment program for the central China power system

The central China power system is currently implementing an on-line stability program. This is the second largest power system in China to implement such an on-line stability program, and probably one of the earliest practical implementations of a dynamic security assessment program (DSA) reported in the world. This paper presents the features of this program, its computational methods, the design considerations used, and some numerical results.     

Infinite power series

The creation, manipulation and evaluation of univariate infinite power series is discussed. Unlike truncated power series, which store the first n terms of an expansion, infinite power series create a procedure for calculating a general term, and are thus a formal representation of the entire expansion. No term is calculated until it is actually needed. All results may be saved along with the environment in which they were evaluated in order to prevent repeated calculation. Laurent expansion is used, and expansion in rational powers is allowed to expand expressions containing poles and branch points. The formulas applicable to the manipulation of these extended series forms are presented. The system is implemented in MODE-REDUCE with infinite power series a new data type, or mode, which allows interfacing with the usual algebraic operators including substitution, differentiation, and integration. A series may also be inverted. Examples of the capabilities and use of the system are presented.     

基于电力载波及LabVIEW技术的远程自动抄表系统研究

为满足电力行业改革与发展的需要,本文开发了一种以电力载波传输技术为核心的远程自动抄表系统。重点对远程抄表系统中的电能表通信部分进行了设计,并使用MI200E芯片实现了电力载波通信,同时利用LabVIEW软件的TCP网络通信技术将用户用电数据从小区物业管理中心传输到供电公司,为电网调度、负荷预测、电网安全稳定运行提供数据依据。     

基于MATLAB的感应耦合电能传输系统的功率因数测定

介绍了感应耦合电能传输系统的基本组成和控制原理,并基于功率因数的定义,在MATLAB/SIMULINK通用平台下建立了功率因数测量方法的仿真模型,最后给出了系统的功率因数测量结果及分析。     

Data loss recovery for power failure in flash memory storage systems

Due to the rapid development of flash memory technology, NAND flash has been widely used as a storage device in portable embedded systems, personal computers, and enterprise systems. However, flash memory is prone to performance degradation due to the long latency in flash program operations and flash erasure operations. One common technique for hiding long program latency is to use a temporal buffer to hold write data. Although DRAM is often used to implement the buffer because of its high performance and low bit cost, it is volatile; thus, that the data may be lost on power failure in the storage system. As a solution to this issue, recent operating systems frequently issue flush commands to force storage devices to permanently move data from the buffer into the non-volatile area. However, the excessive use of flush commands may worsen the write performance of the storage systems. In this paper, we propose two data loss recovery techniques that require fewer write operations to flash memory. These techniques remove unnecessary flash writes by storing storage metadata along with user data simultaneously by utilizing the spare area associated with each data page.     

基于机载LiDAR点云的电力线自动提取

基于机载激光雷达数据提出了一种在林区中电力线自动提取方法,该方法是基于统计分析和二值化图像处理技术设计。首先采用高度阈值,分离出电力线候选数据集,并采用一组标准(例如,高度标准,密度标准和直方图阈值)来对候选集进行统计分析,选择电力线的候选点。然后将候选点转化为二值化图像,并进行形态学优化,采用基于图像的处理技术,利用渐进概率霍夫线性变换对图像进行直线分割。最后将分割出来的电力线二值化图像转换成三维点云,并利用区域增长精细化提取电力线点云。使用不同林区环境下的4组机载激光雷达数据进行实验,实验结果表明,算法在林区环境下能够完整地提取出电力线,且电力线分类精度较高,对于电力巡线具有较高的利用价值。     

Two-way中继系统中基于最小化中断概率的功率分配策略*

为了降低Two-Way中继系统中断概率,本文提出了一种Two-Way 中继系统中基于最小化中断概率的功率分配策略。首先推导了Two-way中继系统中断概率的闭合表达式,然后在总功率受限的条件下,提出了一种最小化中断概率的最优功率分配策略（OPA）。通过拉格朗日乘数法对该优化模型进行了求解。仿真结果证明了该策略能够有效的降低系统的中断概率,提高系统性能。     

浅析电力行业信息安全管理

该文总结了目前我国电力企业信息化的优势特征,列举了电力企业网络信息管理存在的主要问题,对问题的成因进行深入分析,并提出了一系列可行性较强的加强电力企业网络信息安全的建议和方法,对建立长效机制,使电力企业网络信息安全管理成为企业安全文化的重要组成部分,提出了比较切实有效的思路。     

基于MCU的智能功率因数调节仪

功率因数的提高,有利于节约能源,防止谐波污染,对于我国能源利用率不高的现状,有着很重要的现实意义。文章提出了一种基于MCU的功率因数调节仪的设计,包括硬件结构,计算方法以及相应的软件设计。     

基于电力载波及LabVIEW技术的远程自动抄表系统研究

为满足电力行业改革与发展的需要,本文开发了一种以电力载波传输技术为核心的远程自动抄表系统.重点对远程抄表系统中的电能表通信部分进行了设计,并使用MI200E芯片实现了电力载波通信,同时利用LabVIEW软件的TCP网络通信技术将用户用电数据从小区物业管理中心传输到供电公司,为电网调度、负荷预测、电网安全稳定运行提供数据依据.