500kV变电设备运行故障及处理措施分析

目前,超高压输电已经成为我国远距离输送电力的主要方法,在超高压远距离输电中,500kV变电站是其中非常重要的环节,500kV电网是区域电网的主干网架,保证500kV电网安全可靠性运行对于电网公司具有重要意义。分析了500kV~电设备运行故障及处理措施,总结了500kV电力变压器的常见故障及处理方法,提出了500kV变压器运行中的巡视检查及反事故措施,研究了500kV并联电抗器故障判别方法。     

关于东莞电网限制短路电流的研究分析

通过对500kV变电站220kV母线单相短路电流普遍超标主要原因、限制短路电流措施、小电抗阻值的选择、小电抗对继电保护的影响、小电抗电气主接线方案等进行了分析。为提高500kV主变供电可靠率和主变的利用率,适应东莞电网220kV电网的发展要求,提出相应的解决方案。     

500kV输电线路风偏的探讨

随着我国500kV电网建设的快速发展,电网规模的不断扩大,各地区的输电线路日益增多,本文根据风偏闪落的原因,对500kV线路风偏跳闸进行技术分析并提出了相应的举措。     

山西电网特殊天气下降压运行的必要性研究

本文对山西省污区分布、山西电网主网线路和变电站绝缘子使用情况等进行了初步调研,在易出现污闪气象条件的南部盆地地区选取了500RV和220kV两条典型线路,依据国内外多年来积累的大量污闪试验数据、污闪理论研究的进展和实际运行经验,通过简化模型对所选取的典型线路的污闪概率进行了计算和分析,进而对山西电网主网在特殊天气下降压运行的必要性进行了讨论。     

直流融冰装置在电力系统的应用

2008年初,韶关北部地区遭遇了有气象记录以来最为严重的冰雪凝冻灾害天气,恶劣的天气使输电线路上凝结了坚硬而厚重的冰,导致输电线路不堪重负,发生断线、倒塔,整个韶关北部电网处于崩溃状态,此次灾害天气给韶关电网带来了很大的损失,220kV通济站在此次灾害中也有220kV坪通线、110kV通洛甲线、通洛乙线等多条线路因冰灾停运,针对韶关地区的特点,韶关供电局在220kV通济站装设了直流融冰装置,该装置可进行站内220kV及110kV出线的融冰工作,为重要负荷的安全供电提供了保证。     

浅谈500kV变电运行的精益化管理

随着电网建设不断加强,各地500kV变电站数目的迅速增加使运行部门面临新的挑战和机遇。分析超高压局500kV变电运行管理现状,发现存在的问题,并根据500kV集控中心建成后对变电运行管理带来的影响,阐述了适合超高压局500kV变电运行精益化管理的具体做法。     

500KV变电站保护配置及相关回路浅析

随着电网的高度发展,500kV系统在电网系统中的重要性发明显,数量也逐年增加。500kV变电站通常采用3／2接线方式,这种主接线方式具有供电可靠性高,运行调度灵活等优点。但也造成保护屏间的配合回路复杂化,给运行人员对保护装置停投和动作情况分析带来困难,同样也为检修人员布置安全措施带来一定的难度。因此对500kV检修工作人员提出了更高的要求。本文结合现场实际对500kV线路保护及开关保护,母线保护屏间配合方法做简要分析,对优化运行操作、提高系统运行稳定性和可靠性提供帮助。     

500kV输变电设备运行维护探讨

近年来,我国变电技术快速发展,电网运行对于输变电设备提出了更高的要求,500kV输变电设备作为电力系统的重要组成部分,其运行状态对于整个电力系统的安全、稳定运行有着直接的影响。因此针对500kV输变电设备运行故障,积极采取有效措施,做好500kV输变电设备的运行维护,提高500kV输变电设备的运行状态和使用寿命。本文分析了500kV输变电设备的运行现状,阐述了500kV输变电设备的运行现状。     

500kV输电线路引流板故障发热问题探析

2014年11月~12月省公司对江门供电局管辖的500kV输电线路开展直升飞机巡视测温工作,其中在32条500kV输电线路19416个引流板测温中发现一般热缺陷15处,重大热缺陷3处。输电线路引流板发热严重影响了电网供电的质量,并且在大负荷单回路供电情况下还特别容易出现烧跳弓断线的电网事故,造成重大的经济损失。因此,对500kV输电线路的引流板故障发热问题进行研究势在必行。基于此,本文将对500kV输电线路引流板故障发热问题进行深入的分析和研究,并通过实验来分析引流板故障发热问题产生的原因,针对这些问题提出几点科学的解决措施,希望可以为有关单位解决引流板故障发热问题提供一些参考和建议。     

500KV变电站无人值班运行管理探析

随着电网建设的不断加强,各地500kV变电站数量的迅速增加给运行管理部门带来了新的挑战和机遇,传统的运行管理模式在一定程度上已不能满足超高压电网的发展要求,在500kV变电站实行无人值班已是大势所趋。本文分析了我国500KV变电站的工作运行特征,然后详细阐述了500KV变电站无人值班运行管理的要点。     

Evaluation and measurement of magnetic field exposure at a typical high-voltage substation and its power lines

This study presents a survey of magnetic field measurements including those resulting from 380/154 kV power substations, which play a vital role in human body biological studies. The survey was carried out in the main power substation of Antalya, Turkey, located at the suburban region of the city, under actual loads. The paper also presents the actual magnetic field strength measured near the 380/154 kV substation and power transmission lines (380 and 154 kV) connecting to the substation. Since most part of these lines pass through a residential area, they have been included in the study, and the actual magnetic field variation around them has been investigated by comparative analysis of measured data. For the occupants working at substations, occupational exposure has been analysed with actual magnetic fields at operating locations. Induced internal electric fields and current densities in the occupants' body due to exposure to external magnetic fields produced by a conventional 380/154 kV power substation have been investigated.     

复合材料的Ⅰ型层间断裂韧性

本文采用铰链式双悬臂梁试件对碳/双马来酰亚胺复合材料的Ⅰ型层间断裂韧性进行了研究,分析比较了层间断裂韧性G_IC的表达方法,用三次多项式和幂函数拟合实验柔度的方法得到的结果比较满意,实验结果表明纤维桥连对单向层合板的G_IC的影响是显着的,用刀片切割桥连纤维后G_IC值下降百分之二十,分散性也有显着下降。另外发现G_IC值随试件厚度增加而增大。     

Glass-ionomer dental restorative: Part I: a structural study

A structural study of glass-ionomer cement (GIC) dental restoratives has been completed. Transmission electron microscopy, selected area electron diffraction, and X-ray diffraction studies indicate domain-like microstructure in a new experimental material, whereas a featureless amorphous gel-like microstructure exists in the conventional GIC. Nuclear magnetic resonance studies were also conducted. The new experimental GIC contains domains of (i) bonelike material (apatite), (ii) mesoporous material and (iii) other framework structures (aluminium phosphate in the high cristobalite structure), with its setting chemistry a restructuring of the aluminosilicate glass around the template of poly(acrylic acid). Conventional glass-ionomer cement may set by a similar but slower process. Leaching properties of glass-ionomer cements are also explained.     

Special report on relationship between wind farms and power grids

The installed capacity of a large scale wind power plant will be up to a number of hundreds MW, and the wind power is transmitted to load centers through long distance transmission lines with 220 kV, 500 kV, or 750 kV. Therefore, it is necessary not only considering the power transmission line between a wind power plant and the first connection node of the power network, but also the power network among the group of those wind power plants in a wind power base, the integration network from the base to the existed grids, as well as the distribution and consumption of the wind power generation by loads. Meanwhile, the impact of wind power stochastic fluctuation on power systems must be studied. In recent years, wind power prediction technology has been studied by the utilities and wind power plants. As a matter of fact, some European countries have used this prediction technology as a tool in national power dispatch centers and wind power companies.     

The present state of R & D for superconducting transmission in Japan

The advantages of superconducting cables for large-scale, long-distance power transmission have been widely recognised. However, there is a need for much costly research into the scientific and engineering problems before superconducting cables can be incorporated in the power network. This paper outlines the current state of R & D in Japan on superconducting transmission. The immediate aim is a 10 GW cable that can handle 500 kV ac or ± 200 kV dc.     

Dynamic equivalencing of distribution networks with dispersed generation using Hankel norm approximation

Nowadays the number of dispersed generators (DGs) is growing rapidly. This change will greatly influence power system dynamics. A distribution network, where DGs are connected to the grid, cannot be considered as passive anymore. Therefore, in the future it will not be possible to use simple equivalents of distribution networks for power system dynamic modelling, as it was done before. At the same time, the whole power system cannot generally be represented in a detailed manner for dynamic studies because of huge system dimension. Therefore special techniques have to be applied for aggregation and order-reduction of distribution networks with DG. A brief review of existing techniques is provided here, and the dynamic reduction using Hankel norm approximation is performed for a 10 kV distribution network, which includes DG of different types.     

Design of Power Supplies for the Pulsed High Magnetic Field Facility at HUST

Two types of pulsed power supply, a modular 12 MJ/25 kV capacitor bank and a 100 MVA flywheel pulsed generator, are under construction for the pulsed high magnetic field facility at the Huazhong University of Science and Technology (HUST) in Wuhan, China. The capacitor bank consists of 11 independent 1 MJ modules with a short circuit current of 40 kA each and 2 independent 0.5 MJ modules for 50 kA each. The bank is used to energize coils for magnetic fields in the 50–80 T range with pulse duration from 15 to 200 ms. The pulsed flywheel-alternator is used to energize a 50 T/100 ms long-pulse magnet via two 12-pulse power converter modules. Each converter module is designed to operate in the 95 to 66 Hz frequency operation range of the generator and can provide a no-load voltage of 4.6 kV and a full-load voltage of 3.4 kV at the rated current of 20 kA. In this paper the design of these two types of power supply is presented.     

The New Developed Components Tests for 1 MJ Capacitor Power Supply System in Wuhan High Magnetic Field Facility

A new 1 MJ, 25 kV, 40 kA pulsed capacitor power supply system for the Wuhan High Magnetic Field Facility (WHMFF) has been achieved. The desire for 70 or higher tesla magnetic field to support a lot of scientific researches based on it is just now beginning to be realized. The system consists of charger, capacitor bank, polarity changing switches, protective inductor, thyristor switch, crowbar, dump circuit and so on. In this paper, a series of tests for the new developed components such as high energy pulsed capacitor with 160 μF/25 kV/10 kA/10 ms/30% voltage reversal, thyristor switch (25 kV, 40 kA, 10 ms), polarity changing switch and ZnO linearly resistor disc for crowbar are introduced. The results show that all of new components are good or better than the old 1 MJ power supply system.     

Development of 500 m HTS power cable in super-ACE project

A high temperature superconducting power cable (HTS power cable) is highly promises as a low cost and large capacity power line. An HTS cable is also effective in increasing power capacity of underground cable in a city part. A demonstration of a 500 m HTS cable that contributes to research for commercial applications was planned in a part of “Super-ACE project” of METI (Ministry of Economy, Trade and Industry). Furukawa Electric has been taking charge of designing, manufacturing and installation of the 500 m cable. The cable is a 77 kV 1 kA single-core cable with liquid nitrogen (LN₂) impregnated paper insulation. The manufacturing and the installation of the cable have been completed in November 2003, and now preparations of peripheral equipments are proceeding for a test starting in March 2004. This paper describes the design, manufacturing and installation of the 500 m HTS cable.     

A 1000 A/20 kV/25 kHz-500 kHz Volt-Ampere-Wattmeter for loads withpower factors from 0.001 to 1.00

Many industrial processes and scientific experiments utilize large amounts of ac power at frequencies from 3 kHz to 500 kHz. The phase angle and the impedances of these loads often vary over a wide range. This paper describes an instrument to provide an accurate measurement of currents (1 A to 1000 A), voltages (100 V to 20 kV), and powers (100 W to 20 MW) over the frequency range from 25 kHz to 500 kHz. It deals with loads having power factors down to nearly zero and with load impedances from 10 Ω to 20 kΩ. The paper contains practical details of both the design and the calibration of the front-end voltage and current transducers. The characteristics of a nearly ideal broadband current transducer are presented. Overall instrument calibration, verification and traceability problems are considered in detail