A study of adaptive zero - sequence current protection 自適應零序電流保護的研究
In this thesis , we study the exponents of convergence of the zero - sequence and the hyper - order of solutions of linear differential equations 本文研究了線性微分方程解的零點收斂指數和超級。
Under some conditions , we obtain the precise estimates of the orders of growth and of the exponents of convergence of the zero - sequence of the solutions of the above equations 在一定的條件下,得到了上述方程解的增長級與零點收斂指數的精確估計。
In chapter 2 , we investigate the problem on the orders of growth and the convergences of the zero - sequence of the solutions of second linear differential equations with entire coefficients to the functions with smaller order of growth 其中第二章研究了二階整函數系數線性微分方程的解取慢增長函數時的增長級與零點收斂的問題;第三章研究了一類高階亞純系數線性微分方程解的超級。
Main functions : 3 - stage complex - voltage blocked overcurrent protection , 3 - stage zero - sequence overcurrent protection , clearance discharging zero - sequence overcurrent protection , zero - sequence overvoltage protection , overvoltage alarming , overload alarming , fan start stop , tap changer blocking , pt wire broken blocking and alarming , etc 其保護配置:復合電壓閉鎖過流段保護,零序過流段保護,間隙放電零序過流保護,零序過壓保護。
This article has studied the deficiency and shortcoming of various kinds of methods of the parameter measurement of transmission line at present , proposed the measurement under operation on the basis of gps , researched gps application way and error that may appear in the power system synchronal sampling , put forward the parameter computing technology based on the information of both sides of transmission line , which solved some problems that exist in the parameter measurement , especially the problem that exist in the zero - sequence parameter measurement of transmission line with mutual inductance 本文研究了目前輸電線路參數測量的各種方法,分析了其中存在的不足和缺點,提出了基于gps的輸電線路參數在線測量方法,研究分析了gps在電力系統同步采樣中的應用方式以及可能出現的誤差,在同步采樣的基礎上提出了基于雙端信息的線路參數計算方法,較好地解決了輸電線路參數測量中存在的一些問題,尤其是多回互感線路零序參數測量困難的問題。
In order to optimize the modulation performance , the relationships between the modulation signals ( include fundamental signals and zero - sequence signal ) and space vectors , between the modulation signals and space - vector sectors were discussed , then three kinds of optimal switching pattern of space - vector modulation are established 文章首先從研究svpwm調制中零序信號與零電壓矢量和非零電壓矢量之間的關系這一獨特角度出發,探討了svpwm的優化調制方法,找出了三種開關損耗小、適用于高頻化逆變器的優化開關模式。
In chapter 2 , we discuss the problem of the relationship between the solution of non - homogeneous linear differential and small function . in chapter 3 , we investigated the relationship between exponent of convergence to zero - sequence of the solution of certain homogeneous linear differential equation f ( k ) + a ( z ) f = 0 and the order of growth of a ( z ) 其中第二部分討論了非齊次線性微分方程解取小函數的收斂指數,第三部分研究了齊次線性微分方程f ~ ( k ) + a ( z ) f = 0的解的零點收斂指數與a ( z )的級的關系
To resolve the situation that the sensitivity of present ground fault protection schemes is low for the large - sized hydro - generators , a kind of protection scheme based on the fault component of third - harmonic voltage and two kinds of protection scheme based on the fault component of zero - sequence voltage at the terminals and neutral are developed , and they can obtain higher sensitivity and reliability and provide 100 % protection for the stator windings . the influence of noise on the stator ground fault protection based on the local modulus maximum of wavelet transform is analyzed 針對目前大型水輪發電機定子繞組單相接地保護靈敏度偏低的問題,通過分析單相接地故障后機端和中性點零序電壓的變化特點,提出了一種基于機端和中性點三次諧波電壓故障分量和兩種基于機端和中性點零序電壓故障分量的高靈敏度、高可靠性保護方案,并實現定子繞組的100 %保護。
The device can protect start - up status and running status of asynchronous motors by differential protection , over current protection , negative - sequence current protection , zero - sequence current protection , inverse time current protection , under - voltage protection and so on , can measure every kind of electricity , and can process the function of telecontrol , telemetering and telecommunication 其依靠電流差動、速斷、負序過流、反時限、零序過流和低電壓等保護方法實現了片電動機的運行、啟動和自啟動過程進行保護,并實現各種電量的計量,同時具有遙控、遙測、遙信的功能。