金属氧化物避雷器在500千伏线路操作过电压下的性能研究

根据在暂态网络分析仪(TNA)上对国内50多条500kV输电线路所做的电磁暂态研究结果,本文分析了断路器装设或不装设合闸并联电阻时,正常及故障操作过电压下,线路两端金属氧化物避雷器保护过电压的性能和避雷器的工况。文中还提出,用金属氧化物避雷器作为500kV线路操作过电压的主保护,本身裕度很大。     

220kV带串联间隙线路避雷器保护性能研究

鹰潭供电公司220 kV月铜线发生的两起雷击跳闸故障,故障相均安装了线路避雷器,因此,供电公司对线路避雷器的保护效果产生了疑虑。为深入验证线路避雷器的保护效果,避免类似事件的再次发生,国网江西省某电力科学研究院通过开展线路避雷器雷电冲击50%放电电压试验和工频湿耐受电压试验对避雷器间隙距离进行了深入研究,得到了不同间隙距离线路避雷器与不同绝缘子串的配合裕度,在此基础上给出220 kV线路避雷器间隙距离推荐值(840±10)mm,可以同时满足保护可靠性与运行安全性的要求。     

110 kV输电线路的线路避雷器防雷问题分析

对线路避雷器与杆塔绝缘子串的并联安装形式进行了分析,指出,在杆塔绝缘子串、线路避雷器先后承受雷电过电压的情况下,线路避雷器将有可能失去保护作用。文中还提出了改进意见,建议应从设计及运行上改进线路避雷器的安装,使雷击杆塔顶部时所产生的雷电过电压先作用于线路避雷器,后作用于杆塔绝缘子串,或至少同时作用于两者,以有效发挥线路避雷器的防雷保护作用。     

±800kV直流系统过电压保护和绝缘配合研究

依托向家坝至南汇直流输电工程,研究了±800kV换流站交流侧工频过电压、交直流侧操作过电压和雷电过电压、直流线路操作和雷电过电压。重点分析了±800kV与±500kV在直流过电压和绝缘配合方面不同之处。给出了避雷器配置方式、参数的选择原则和方法,确定了换流站各避雷器的保护水平和配合电流及避雷器的能耗及能耗与直流侧的快速保护定值、延迟时间的配合。提出换流站绝缘配合裕度系数和主要设备绝缘水平要求及直流线路操作冲击和雷电冲击要求的最小空气间隙计算方法。     

±800 kV直流系统过电压保护和绝缘配合研究

依托向家坝至南汇直流输电工程,研究了±800 kV换流站交流侧工频过电压、交直流侧操作过电压和雷电过电压、直流线路操作和雷电过电压.重点分析了±800 kV与±500 kV在直流过电压和绝缘配合方面不同之处.给出了避雷器配置方式、参数的选择原则和方法,确定了换流站各避雷器的保护水平和配合电流及避雷器的能耗以及能耗与直流侧的快速保护的定值、延迟时间的配合.提出换流站施缘配合裕度系数和主要设备绝缘水平要求以及直流线路操作冲击和雷电冲击要求的最小空气间隙计算方法.     

线路避雷器在输电线路防雷中的应用及建议

分析线路避雷器在天生桥地区220 kV及以上交流线路防雷工作中的应用情况。通过查询雷电定位系统,统计天生桥地区雷电参数,总结、分析2001年以来该地区输电线路雷击跳闸情况,结果表明安装线路避雷器能有效降低线路雷击跳闸率,具有较好的防雷效果。根据运行经验及线路避雷器只对安装塔安装相有保护作用的特点,提出了线路避雷器安装选点和运行维护方面的建议。     

ZnO避雷器在架空输电线路防雷保护中的应用

重点分析了线路在遭受雷电时,ZnO避雷器与绝缘子串之间的相互配合使用.同时分析了避雷器的基本参数并提出有关建议,从而得出应用ZnO避雷器在防雷保护中有显著效果,为设备提供最佳保护,提高了保护可靠性,为可靠性供电提供了保障.     

线路避雷器的安装方式对防雷效果的影响

文章按雷击杆塔顶部时所产生的雷电过电压的作用顺序,将线路避雷器与杆塔绝缘子串的并联安装方式分为雷电过电压先后作用于两者、同时作用于两者及先作用于后者,再作用于前者等3种安装方式,分析了3种安装方式对线路避雷器防雷效果的影响。文中还建议改进线路避雷器的安装方式,提出了新的安装方式,使雷电直击杆塔或绕击导线时所产生的雷电过电压先作用线路避雷器,或同时作用于线路避雷器与杆塔绝缘子串,以有效发挥线路避雷器的防雷保护作用。     

特高压GIS变电站雷电过电压防护研究

为综合研究避雷器配置方案对特高压GIS变电站雷电侵入波防护的经济性以及可靠性的影响,通过将某1 000 kV特高压GIS变电站进线段和变电站视为一体化模型,考虑雷击点、雷击方式、地面倾角等因素,采用国际通用暂态程序ATP-EMTP对不同避雷器配置方案、不同运行方式下变电站主要设备上雷电侵入波过电压进行计算研究。仿真结果表明:进线侧高抗和互感器共用一组避雷器、主变安装一组避雷器可以满足设备绝缘裕度要求,但保护裕度较低,可通过进线段优化进一步提高保护裕度;由于架空线路与GIS波阻抗的不对等而形成的过电压波的复杂折反射问题,雷击引起主变处过电压超过高压套管处过电压;相同条件下绕击出现概率以及在主变上产生的过电压幅值相对反击均较高;绕击上相导线产生过电压更加危险。因此,建议后续研究重视绕击防护。研究结果可为该站避雷器配置方案提供重要依据,对后续新建特高压交流变电站雷电过电压防护具有重要指导意义。     

500 kV线路避雷器保护失效分析及改进措施研究

线路避雷器是防止输电线路雷击跳闸的有效手段,随着高电压等级线路避雷器的使用,出现了因安装方式导致的线路避雷器保护失效问题。针对某500 kV输电线路发生的线路避雷器在大幅值雷电流反击下对绝缘子串保护失效的问题,采用电磁暂态分析软件ATP-EMTP建立了仿真分析模型,分别对雷电流绕击和反击情况下绝缘子串和线路避雷器两端承受的电压进行了量化,得出了导致反击情况下线路避雷器保护失效的原因;提出了对现有500 kV线路避雷器安装方式的改进方案,并对改进方案下反击雷电流导致的绝缘子串和线路避雷器两端电压波形进行了比较,验证了改进措施的有效性。所研究成果对于500 kV及以上电压等级线路避雷器的使用具有重要参考价值。     

配电线路避雷器雷电感应过电压防护研究

应用ATP-EMTP对配网架空线路雷电感应过电压下,线路避雷器的保护效果进行了仿真计算研究。仿真计算结果表明,安装线路避雷器可以对配网架空线路雷电感应过电压进行防护,其保护效果与避雷器的配置方式及线路杆塔接地电阻有关,降低杆塔接地电阻可以减小线路避雷器的安装密度。     

Suppression of lightning-induced overvoltages by distribution line surge arresters

The primary aim of surge arresters in power distribution lines is to protect lines and equipment from the voltage induced by nearby lightning strokes. To further improve power systems, methods to protect distribution lines against direct lightning strokes are still needed. An effective measure against direct lightning strokes is to increase the number of arresters. However, if the surge current is too large, some surge arresters absorb energy in excess of their capability and may break; this leads to a line fault. To evaluate the protective effect of the surge arresters against direct lightning strokes to overhead ground wire, the authors measured both the voltage across the surge arresters and the energy absorbed by them using a full-scale model line and a 12 MV impulse generator. The results were compared with simulation results by EMTP. There have been no previous studies making a comparison of this kind.     

Effect of overhead ground wires on reduction of failure rates of surge arresters on power distribution lines

Surge arresters are sometimes damaged by lightning strokes with high energy, in spite of installation of conventional protection methods. In order to reduce the number of failures of surge arresters, we should consider another protection method, such as an increase in the withstand capability of surge arresters and installation of additional overhead ground wires. However, quantitative comparison of these methods for preventing damage to surge arresters against lightning strokes with high energy has never been performed. This paper describes the effects of additional overhead ground wires for preventing damage to surge arresters. The main results are: (1) The failure rate of surge arresters on a distribution line with two overhead ground wires is about one third of that with an overhead ground wire. (2) Installation of a second overhead ground wire six to eight spans from the end of a line reduces the failure rate of a surge arrester at the end as effectively as increasing the withstand capability by a factor of two. © 1998 Scripta Technica. Electr Eng Jpn, 122(2): 12–20, 1998     

Transmission line arrester energy, cost, and risk of failureanalysis for partially shielded transmission lines

Application of metal oxide surge arresters in power systems has been traditionally linked to electrical equipment protection. The industry has noted a very significant increase in the application of metal oxide arresters on transmission lines in an effort to reduce lightning initiated flashovers. This paper describes a cost-effective installation of surge arresters on a partially shielded transmission line. It compares several options with respect to cost and gains in terms of lightning performance improvement. This paper also presents a new approach to calculate risk of failure of transmission line surge arresters (TLSAs) due to lightning strokes to towers, shield/phase conductors, and illustrates the method with an example for a partially shielded line. Results show that the risk of failure is very small. The installation of TLSAs completed in 1997 demonstrated that it is possible to afford adequate lightning protection levels by selectively applying surge arresters only to the towers most sensitive to backflashover and shielding failures     

Suppressing the effect of lightning-induced overvoltages by the combined use of surge arresters and overhead ground wires

Lightning voltage induced by nearby strokes is one of the causes of major overvoltages which threaten the insulation of power distribution lines. Surge arresters as well as an overhead ground wire usually are employed for the protection of equipment and line insulation on overhead power distribution lines. The fundamental mechanism of suppressing effects of overvoltages induced by nearby strokes has been demonstrated independently by one of the present authors for surge arresters and for an overhead ground wire. In this paper, the protective effect of the combination of surge arresters and overhead ground wire is analyzed. As a result, it is found that the effect of surge arresters used together with an overhead ground wire is almost the same as that of surge arresters alone.     

Temporary overvoltage capability of surge arresters for 1000 kV power systems

Insulation level (LIWV 2250 kV) of 1000 kV gas insulated switchgear will be adopted by installing high performance 1000 kV surge arresters. But when temporary overvoltage (TOV) is generated in power systems at line faults and load rejection including Ferranti effects, high performance surge arresters flow discharge current according to the value of TOV. Therefore, it is important to check TOV discharge capability of surge arresters. This paper describes the screening of zinc oxide elements using thermography (thermal uniformity factor) obtained by an infrared radiation camera, with discharge capability of surge arresters for 1000 kV power system.     

线路型避雷器的应用

输电线路跳闸原因约有60％是因为雷击输电线路引起的,所以,采用线路型避雷器降低线路的雷击跳闸率是很有必要的。为此,对线路型避雷器分类作了介绍,并对各类线路型避雷器原理及应用作了详尽的介绍分析。从已安装了线路型避雷器的输电线路运行情况来看,线路型避雷器在输电线路防雷及变电站防止雷电侵入波方面发挥了重要的作用。     

复合外套避雷器在昌房500kV紧凑型线路的防雷效果分析

５００ ｋＶ昌房紧凑型线路采用线路避雷器后,能较大地提高线路的耐雷水平。紧凑型线路避雷器本体的荷电率取０．９,完全能承受雷击杆塔时的放电电流和放电能量。     

750 kV输变电示范工程单相人工接地故障试验现场实测和计算分析

应用电磁暂态计算程序(electromagnetictransientprogram,EMTP)对安装金属氧化物避雷器的35kV配电线路的耐雷水平进行了分析计算。具体比较了雷击有、无避雷线的线路,采取不同避雷器安装方案时的耐雷水平;分析了杆塔冲击接地电阻、绕击导线位置对耐雷水平的影响。仿真计算结果表明,安装线路避雷器﹑减小杆塔的接地电阻可有效提高35kV配电线路的耐雷水平。对于35kV有避雷线配电线路,加装线路避雷器后可显著降低其发生绕击闪络的概率。     

向家坝—上海±800kV特高压直流工程直流滤波器过电压与绝缘配合研究

基于向家坝—上海±800 kV特高压直流输电工程,给出了两种直流滤波器暂态计算必须考虑的故障工况:直流极线接地和直流极线侵入操作波。介绍了这两种故障的模拟计算方法,给出了计算中采用的陡波模型。模型中需要考虑直流母线寄生电感、滤波器高压端电容器寄生电感和滤波器避雷器保护特性等因素。计算结果给出了电抗器和电阻器的最大暂态电流和冲击能量,根据计算得到的避雷器最大配合电流确定了避雷器的保护水平,进而依据绝缘裕度确定了该特高压直流工程直流滤波器各设备最终的绝缘水平。