电力系统暂态识别与人工智能技术

本文介绍了电力系统暂态研究的近期进展,包括人工智能技术的应用以及新开发撕于暂态的继电保护技术。其中重点介绍了电力系统暂态研究成果和基于人工的暂态识别技术。当前的常规技术是电力系统中的电磁暂态看作是干扰噪声而将其滤掉;而基于人工智能的暂态识别与其相反,它对由故障拉生的高频暂态分量进行在线检测,进而应用人工智能技术识别这一暂态的源头和性质。     

电力系统暂态识别与人工智能技术

介绍了近期内对电力系统暂态研究的进展情况,包括人工智能(AI)技术的应用及新开发的基于暂态的继电保护技术。其中重点介绍了电力系统暂态研究的新成果:基于人工智能的暂态识别(AITI)技术。同基于人工智能的暂态识别技术相反,当前的常规技术将电磁暂态量当作干扰予以滤除。AITI技术对由故障产生的高频暂态分量先进行在线检测,然后利用 AI 技术进一步判别出暂态的源头和性质。本文通过几个正开发的新方案概述了这一新技术的优点及其所能提供的潜在经济效益。     

Agent技术在超高压输电线路暂态保护中的应用

Agent技术是计算机技术、网络技术和分布式人工智能相结合的产物,是近年来新兴的计算机软件工程技术之一。阐述了Agent技术的概念、特点。根据超高压输电线路故障暂态电流的特点和暂态保护的基本原理,建立了基于Agent技术的暂态电流保护的结构。并且提出了基于Agent技术的暂态电流保护方案。     

利用小波分析实现EHV输电线路单端量暂态保护的研究

介绍了连续小波变换定义,基于多分辨分析的Mallat快速小波分解算法,基于超高压（EHV）输电线路故障暂态电流的特点和暂态保护的基本原理,充分利用小波分析的时频局部化特点,建立了基于小波分析的暂态保护启动判据和跳闸判据,借助EMTDC仿真分析软件,研究了一实际电网EHV输电线路故障电弧特点和在不同故障条件下保护判据的有效性,结果表明,基于小波分析的暂态保护方案是可行的。     

同杆双回线路保护研究进展

分析了目前同杆双回输电线路的主要保护,分别对基于工频量和暂态量的双回线路保护研究内容进行了综述。介绍了双回线路保护基于工频量的故障分析、故障识别和故障选相,基于暂态量的故障电气行波分析和故障识别,在此基础上分析了现阶段同杆双回线路保护的特点和实际运行中出现的问题,讨论了今后的研究思路,并对其发展方向进行了展望。     

利用小波分析实现EHV输电线路暂态保护初探

介绍了连续小波变换定义、基于多分辨分析的Mallat快速小波分解算法,研究了小波在电力系统应用中的几个关键问题.基于输电线路故障暂态电流的特点和暂态保护基本原理,建立了基于小波变换的暂态保护启动判据和跳闸判据.仿真分析了一实际电网EHV输电线路在不同故障点及不同故障时刻该暂态保护方案的可行性.     

利用小波分析实现EHV输电线路暂态保护初探

介绍了连续小波变换定义、基于多分辨分析的Mallat快速小波分解算法 ,研究了小波在电力系统应用中的几个关键问题。基于输电线路故障暂态电流的特点和暂态保护基本原理 ,建立了基于小波变换的暂态保护启动判据和跳闸判据。仿真分析了一实际电网EHV输电线路在不同故障点及不同故障时刻该暂态保护方案的可行性。     

矿井3．3kV电网电压故障特征研究

分析了矿井3．3kV电网电压暂态过电压与稳态电压故障特征的特点,计算了矿用3．3kV电动机的绝缘承受能力,确定了阻容吸收和压敏电阻的额定参数,设计了由暂态过电压保护和稳态电压保护组成的电压故障保护系统。试验结果表明系统运行稳定、可靠,实现了电压故障保护功能。     

基于波形相关性分析的输电线路暂态保护方法

针对现有暂态保护方法可靠性不高的现状,提出了一种基于波形相关性分析的暂态保护新方法。该方法根据故障产生的宽频带暂态信号的波形特征实现输电线路故障暂态保护。当输电线路发生故障后,采集故障暂态波形并提取幅值、相位等波形特征;利用波形相关性方法,将暂态信号波形与样本数据库中的波形进行相关性分析,计算波形相关系数;根据波形相关系数来判别区内外故障,实现线路故障快速保护。仿真分析结果表明,该保护方法综合利用宽广频带暂态信号的时域特征与频域特征,可消除单一使用暂态信号时域或频域的局部故障特征信息导致的缺陷,有望显著提高暂态保护的可靠性。     

基于OVT的EHV输电线路暂态电压保护的研究

主要介绍基于光学电压互感器（OVT）的EHV输电线路暂态电压保护的研究方法。介绍了光学电压互感器OVT的结构和原理，分析了EHV输电线路故障高频暂态分量产生的原因，并根据OVT能够正确传变高频暂态分量的特点，分析了基于故障电压分量的单端暂态电压保护的原理，最后分析了光学电压互感器与继电保护的接口问题。     

基于暂态功率的高压直流线路单端量保护

针对传统高压直流单端量保护存在可靠性较低的问题,通过计及直流边界、线路频变等因素影响,研究了高压直流线路暂态功率故障特性,提出了基于暂态功率的单端量保护方案。根据暂态功率在正方向区内外故障的频率段差异性,利用高低频段暂态能量比值,构成边界保护元件;针对利用暂态功率频率衰减特征无法区分正反方向故障的局限性,利用暂态功率极性构造方向辅助判据。结合保护启动元件和故障选极元件构成基于暂态功率的单端量保护方案。仿真结果表明,该保护方案能够快速有效地区分直流线路区内外故障,具有一定的抗过渡电阻性能及抗干扰能力,可靠性较高。     

Positional protection of transmission line using fault generatedhigh frequency transient signals

This paper presents a new technique for high-speed protection of transmission lines, the positional protection technique. The technique uses a fault transient detector unit at the relaying point to capture fault generated high frequency transient signals contained in the primary currents. The decision to trip is based on the relative arrival times of these high frequency components as they propagate through the system. Extensive simulation studies of technique were carried out to examine the response to different power system and fault conditions. Results show that the scheme is insensitive to fault type, fault resistance, fault inception angle and system source configuration, and that it is able to offer both very high accuracy and speed in fault detection     

Integrated protection based on multifrequencydomain information for UHVhalf-wavelength AC transmission line

Half-wavelength AC Transmission (HWACT) can improve capability of AC transmission significantly. According to the basic principle of HWACT, the electromagnetic transient model of HWACT is built to analyze the fault transient process of transmission line. Based on fault characteristics of HWACT, the adaptability of traditional protections for transmission lines is analyzed briefly, such as current differential protection, distance protection and over current protection. In order to solve the problems of conventional protection caused by HWACT, a novel integrated protection based on multi-frequency domain information is proposed in this paper, which uses both the power frequency information and transient information. The integrated protection based on multi-frequency domain information takes advantages of power frequency and transient protections, which can not only improve the performance of traditional protection of AC transmission line but also realize fast fault judgment by transient travelling wave protection.     

Integrated protection based on multifrequency domain information for UHV half-wavelength AC transmission line

Half-wavelength AC Transmission (HWACT) can improve capability of AC transmission significantly. According to the basic principle of HWACT, the electromagnetic transient model of HWACT is built to analyze the fault transient process of transmission line. Based on fault characteristics of HWACT, the adaptability of traditional protections for transmission lines is analyzed briefly, such as current differential protection, distance protection and over current protection. In order to solve the problems of conventional protection caused by HWACT, a novel integrated protection based on multi- requency domain information is proposed in this paper, which uses both the power frequency information and transient information. The integrated protection based on multi-frequency domain information takes advantages of power frequency and transient protections, which can not only improve the performance of traditional protection of AC transmission line but also realize fast fault judgment by transient travelling wave protection.     

新一代人工智能技术在电力系统调度运行中的应用评述

以深度学习、强化学习为代表的新一代人工智能技术及其应用是当前电力系统领域的研究热点。人工智能技术具有不依赖物理机理,计算速度快,辨别效率高等优点。但人工智能固有的可解释性差、稳定性弱等缺点也制约了其在电力系统一些场景的应用。文中梳理了新一代人工智能技术在电力系统负荷和新能源预测、故障诊断、在线稳定性评估、频率及电压优化控制和电网运行方式制定等调度运行场景中的应用,并进行了分析和评述。总结了现有研究中存在的问题,指出人工智能技术的应用应当以问题为导向,以场景为基础,以应用为目的。最后,对未来人工智能技术在电力系统调度运行中的应用作出了展望。     

基于高频暂态分量进行相关分析及模糊推理的选相新方法

提出一种利用故障分量中高频分量实现故障选相的新原理。该原理直接利用电流互感器饱和前传变的暂态高频电流,使用小波提取相应频段暂态信号特征,对提取的信号特征进行相关分析,使用模糊集合对相关系数的隶属度综合评判进行选相。用该原理实现的选相装置可以配合基于暂态量的单端保护使用,具有超高速的特点,且不受过渡电阻、故障初始角及系统振荡的影响。对于三相换位不完全造成模量不平衡的情况也能进行正确选相。对某典型500 kV线路进行各种故障类型仿真,取得了满意的效果。     

基于小波变换的电力系统故障暂态信号分析

介绍了连续小波变换定义.小波变换具有良好的时频局部化特性,并可根据信号频率的变化自动调节时频窗口,因此小波变换十分适合电力系统故障产生的暂态信号的分析.电力系统故障暂态信号的小波变换模极大值标志着电力系统最重要的故障特征,可以作为继电保护和故障测距的依据     

Impacts of DFIG‐based wind farm integration on its tie line distance protection and countermeasures

Modern power grids, especially high‐voltage grids, are increasingly integrated with wind farms. The correct action of distance protection for the wind farm tie line plays an important role in the safe and stable operation of the power system. However, based on the fault characteristics of wind farms based on the doubly fed induction generator, considering crowbar action and weak infeed properties, this paper reveals some serious defects of conventional distance protection. The result shows that, due to the influences of mixed data window and damped current component with near‐rotor‐speed frequency, the fault distance calculation result obtained by the fundamental‐component‐based distance protection is inaccurate. To tackle this problem, a transient‐based distance protection countermeasure along with a faulted phase selection technique is proposed. Specifically, the transient phase voltage characteristic for different fault types is analyzed to select the faulted phase. Considering the effect of high‐frequency components, pre‐fault voltage compensation, and transducer characteristics, a distance calculation procedure including a low‐pass filter, the reconstruction of voltage at the fault point, and an iterative fault distance calculation is proposed. The comprehensive performance of the proposed method is validated by the simulation case studies using the PSCAD /EMTDC software. © 2017 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

基于测后模拟原理的半波长输电线路暂态量纵联保护

针对特高压半波长超长的输电距离带来的继电保护难题,提出基于测后模拟原理的半波长输电线路暂态量纵联保护方法。特高压半波长交流输电具有传输距离远、输送容量大、全线无功自平衡等优点,可以作为未来清洁能源电力输送的一种可选方案。通过分析现有输电线路保护方法对于半波长交流输电线路的不适用性,对特高压半波长输电线路在区内外故障情况下,推导至中点的暂态量电流和的绝对值在短时窗内积分方向的不同进行理论分析;以贝杰龙模型为基础,利用测后模拟原理构成输电线路暂态量纵联保护方法,进行仿真实验;进而判别输电线路单相接地故障时故障初始角、故障位置和过渡电阻对故障判据的影响。仿真实验证明,此方法构成的保护计算精度高,相较于工频量构成的保护其动作速度更快且几乎不受过渡电阻、故障距离及故障初始角变化的影响,理论分析与实际的仿真结果相一致。