高压直流输电系统可靠性影响因素分析

为保证直流输电系统安全可靠运行,根据中国电力企业联合会发布的全国直流输电系统运行可靠性指标的统计数据,通过研究直流系统可靠性指标,发现停运次数和停运小时数为影响系统能量可用率的重要因素。并将影响直流输电系统可靠性指标因素按停运部件原因进一步分类分析。在此基础上,初步确定"其他"、交流及其辅助设备和直流线路为可靠性指标三大影响因素。最后提出提高直流输电系统可靠性的措施,为直流输电系统进一步提高运行管理水平提供了信息和依据。     

汽轮发电机组两班制或周末停机调峰运行可靠性特征量分析

针对目前电网调峰任务的日益突出,应用可靠性理论,对汽轮发电机组调峰的两班制和周末停机运行方式进行了研究。指出在机组进行调峰时应注意的若干问题,并提供了提高可靠性的手段及其理论依据。     

大型火力发电厂主系统继电保护可靠性分析

大型火力发电厂的继电保护配置复杂,可靠性问题日益突出,针对大型火力发电厂常见的一些问题进行了探讨,提出了一些提高继电保护可靠性的办法。     

电力市场环境下电力系统可靠性分析的框架探讨

随着电力系统规模的扩大和市场化步伐的加快,电力系统运行过程中的安全风险和市场风险相互交织、相互影响。电力市场环境下的电力系统可靠性问题表现出许多新特点,利用市场机制保证电力系统可靠性成为一个新的研究方向。从市场角度重新审视传统可靠性分析的特点,尝试将电力市场与电力系统可靠性分析两个课题融合在一起进行探索性研究,形成了市场环境下可靠性分析的总体框架,对做好市场环境下可靠性分析与评估工作具有重要的参考价值。     

电力市场环境下电力系统可靠性分析的框架探讨

随着电力系统规模的扩大和市场化步伐的加快，电力系统运行过程中的安全风险和市场风险相互交织、相互影响。电力市场环境下的电力系统可靠性问题表现出许多新特点，利用市场机制保证电力系统可靠性成为一个新的研究方向。从市场角度重新审视传统可靠性分析的特点，尝试将电力市场与电力系统可靠性分析两个课题融合在一起进行探索性研究，形成了市场环境下可靠性分析的总体框架，对做好市场环境下可靠性分析与评估工作具有重要的参考价值。     

Reliability challenge for impedance network‐based DC‐DC boost converters

In this paper, reliability evaluation is proposed for some of the most famous impedance network‐based DC‐DC boost converters. Markov reliability approach is used to evaluate the reliability of the converters. Also, some other factors such as components' failure rates, reliability functions, and mean time to failures are introduced and evaluated. Detailed explanations for the evaluation methods of the mentioned factors are also provided in the context of the paper. In addition to the mathematical analysis, numerical calculations are also done through the simulation results of the converters. Simulations are done in PSCAD/EMTDC. Finally, a numerical and graphical reliability comparison is provided for the mentioned converters. The purpose of this paper is to give a comprehensive reliability evaluation and comparison for some of the most popular impedance network‐based DC‐DC converters. In addition, this paper gives a detailed reliability analysis that can be used in reliability assessment of all types of power electronic converters, so it can help the researchers to consider reliability calculations into their designing.     

基于扩展顺序图的多风格软件可靠性分析方法

传统UML顺序图模型在描述软件结构风格多样性方面存在不足,并且与基于离散时间Markov链的软件可靠性分析模型DTMC之间也存在差异。提出了一种基于扩展顺序图的多风格软件可靠性分析方法。首先通过分析不同软件结构风格的组成原理给出了对应的可靠性计算方法,然后通过对顺序图模型进行形式化扩展,使之具备了可靠性分析所必需的软件结构信息,最后将扩展的顺序图模型转换为能够处理多风格软件可靠性问题的DTMC模型。实例分析表明,这种模型和方法可以使得软件开发早期的可靠性分析工作变得更加方便、高效、合理。     

提高特高压直流输电系统可靠性的措施

随着我国经济的持续、高速发展,电力需求越来越大,长距离大容量直流输电项目越来越多,超高压、特高压直流输电系统的可靠性问题愈显重要。本文分析总结了已建±500kV换流站运行情况,分析各种典型故障原因及改善薄弱环节的措施。在对特高压直流输电工程特点和可靠性系统分析的基础上,提出了提高特高压直流输电系统可靠性的系列手段和方法,从而为新建特高压直流输电系统设计、运行和管理提供借鉴。     

Reliability evaluation of ring and triple-bus distribution systems – General solution for n-feeder configurations

Reliability of power distribution schemes can always be improved at the expense of cost and size. The addition of extra paths proves to increase the continuity of supply but it adds more complexity to the system and the system structure may become very complex. In complex distribution system, there are several difficulties in reliability evaluation: reliability, availability and MTBF. Subsystems may follow various failure distributions; subsystems may conform to arbitrary failure and repair distributions for maintained systems; the failure data of subsystems are sometimes not sufficient and reliability test sample sizes tend to be small. Hence, simplification for the reliability inputs, electrical parameters and load data are needed.In this paper, a simple reliability-oriented method to calculate some complex distribution system reliability such as ring and triple-bus systems is presented. The major purpose is to simplify the reliability inputs, electrical parameters and load data. The simplification assumes that the repair time here is a random variable, and certain values of repair times are usually so small that can be neglected at each load point. Therefore complete reliability analysis with repair time omission and modified availability (reliability) and unavailability (h/year) can be obtained at each load feeder point using the simple methods of probability and the theory of sets. This approach is dealt with in this paper and a general formula for calculation of n-feeder ring-bus reliability is developed and applied to some practical distribution schemes.In an n-feeder ring-bus system, it is found that the reliability of each feeder is decreased by increasing the number of the outgoing feeders, so it is recommended that the total number of the outgoing feeders in this scheme should be carefully decided.A meshed network (triple-bus scheme), which makes it possible to serve the consumers from three sources is also considered. With this scheme, the reliability of the outgoing feeders is largely improved as compared with the ring-bus system.     

基于网络等值法的配电网可靠性研究

配电网可靠性评价是电力系统可靠性研究的重要环节,电力部门必需保证配电网的可靠性。为此,介绍了对带有复杂分支馈线的配电网进行可靠性评估的网络等值法的基本原理。该方法用等效元件代替一部分网络分支馈线,从而将复杂网络逐步等值为简单的辐射形配电网,然后通过等效的简单辐射网计算系统的可靠性指标,从而运用可靠性指标对配电网的可靠性进行评价。最后通过实例来验证该等值法的有效性、可行性。     

基于网络等值法的配电网可靠性研究

配电网可靠性评价是电力系统可靠性研究的重要环节,电力部门必需尽力保证配电网的可靠性。介绍了对于带有复杂分支馈线的配电网进行可靠性评估的网络等值法的基本原理。该方法首先用等效元件代替一部分网络分支馈线,从而将复杂网络逐步等值为简单的辐射形配电网,然后通过等效的简单辐射网计算系统的可靠性指标,从而运用可靠性指标对配电网的可靠性进行评价,通过实例验证了等值法的有效性。     

水轮机顶盖的可靠性设计计算

顶盖是水轮机中起支撑与过流双重作用的重要部件,其刚、强度及其可靠性在一定程度上影响、甚至确定整台机组运行的安全、稳定性.但在其刚、强度设计中,目前因为大多数水力机组制造厂家仍沿用传统的安全系数法,而该方法没有把机械可靠性的理念引入到设计中,忽略了顶盖工作过程中许多不确定的因素,不能准确反映该部件工作中的可靠程度和寿命,因而,已不能满足科技发展的要求.针对水轮机顶盖的机械可靠性问题,分别运用传统机械设计方法和机械可靠性设计方法进行了计算,给出了两种计算结果的比较分析.实例计算结果表明,采用机械可靠性设计方法所得的结果更准确,更接近于水轮机的实际工作状况,保证其可靠度和寿命.     

一起JCC-11D型装置二次回路故障分析

分析了南京某厂生产的JCC 1 1D型保护、控制装置的一起合闸回路的故障 ,提出了改进方法 ,实践表明 :该方法提高了分合闸回路的可靠性。同时 ,针对查找故障过程中的相关问题 ,提出了排除二次故障时值得注意的问题     

浅析低压配网供电可靠性及其增强措施

就乡镇用户供电质量差的问题,分析了影响低压配网供电可靠性的主要因素,如外力破坏,闪络,过电压等,介绍了提高低压配网可靠性的技术措施,如使用联络开关,多举措防闪,防雷等.     

圆柱齿轮减速器可靠性优化设计

本文将圆柱齿轮减速器看作一个由不可修复零件组成，具有多种故障的可修复系统。按照减速器的一般设计步骤，把设计参数处理成随机变量，并将可靠性设计与优化设计相结合，提出了圆柱齿轮减速器可靠性优化设计的方法和原则。同时采用非线性混合离散变量组合形的优化方法，对单级直齿圆柱齿轮减速器进行了可靠性优化计算，取得了满足可靠度要求的优化结果。本文还就如何建立工程设计上适用的可靠性优化设计数学模型，提出了见解。     

电力电子系统可靠性模型综述

近年来,电力电子装置广泛应用于生产生活各个领域中,其可靠性日益为人们所重视,尤其随着科学技术的飞速发展,可靠性研究也亟需与时俱进。可靠性关乎产品质量,其作为产品和设备安全性的评估指标不仅涉及企业、国家的经济效益,还涉及使用者的人身安全。首先主要介绍了电力电子系统级可靠性建模的主要开展方法、步骤及常见的可靠性建模方式,其可靠性建模主要有故障分析、失效判据选取、可靠性模型选取、建模和定量计算评估等主要步骤,故障分析是可靠性分析的基础,通过故障分析可以得到系统的主要故障类型,并基于所选取的失效判据判断系统在各故障类型下的运行状态;然后根据系统的规模、精度要求以及应用场合选取合适的可靠性模型有利于准确评估系统的可靠性,建模后进行定量计算,得到相应的可靠性指标,由此分析总结系统的可靠性;再介绍了4种常见的系统级可靠性模型,并依次对各模型进行了分析比较,总结了4种模型的特点与适用范围;最后对研究内容进行了总结与展望。     

CONCEPT OF BUILT-IN RELIABILITY IN THE DESIGN OF LARGE INDUCTION MOTORS

ABSTRACT

In recent years, the reliability study of the equipment has been given vital importance alongwith the other studies. In this paper, an attempt is made to construct the reliability model of a large induction motor in order to predict the reliability, with the knowledge of realistic failure data. Since the author is not aware of any failure data, the prediction is based on some realistic failure data. However, in this paper the basic concepts are laid down, to ensure reliability goal of each component in the design stage. It is also emphasised here, the effect of supply conditions, ambient and malfunctioning of accessories in induction motor on its reliability goal. The method of attack is based on Markov model, by judiciously choosing ‘Available’ states and ‘Failed’ states. This method affords better realisation of failure modes and possible decisions to improve the same. The theory of reliability is presented in short, in order to make the ideas presented in this paper, more clear. A numerical example is presented at the end, to elucidate the theory presented here.     

可靠性技术与智能化高压电器

阐述了高压电器产品智能化的概念以及实现高压电器产品智能化的主要研究方向和技术问题,探讨了智能高压电器可靠性的特点并提出了提高智能高压电器可靠性的一些途径和方法。     

基于可靠性的配电网规划的思考

对传统配电网规划方法和基于可靠性的配电网规划方法进行了比较,指出传统规划方法存在的问题,分析了两者的差异,提出开展基于可靠性的配电网规划工作需要解决的一些问题并给出建议。     

变电站自动化系统的可靠性分析

变电站自动化系统的可靠性是电网安全经济调度极为重要的因素。文中阐述了可靠性的基本概念，对变电站自动化系统（SAS）的可靠性进行了分析，并对提高SAS可靠性的措施提出了建议。