【作者】 马朝华；

【导师】 杨育霞；

【作者基本信息】 郑州大学 ， 电工理论与新技术， 2007， 硕士

【摘要】 电容式电压互感器(Capacitor Voltage Transformer，简称CVT)用于110kV及以上电压等级的电力系统的电压测量、电能计量、继电保护，其电容分压器可代替耦合电容器用于电力线载波通讯，并为高频保护提供讯号传递通道。在正常状态下，一次系统处于正弦稳态，CVT部件的可靠设计和调谐可以确保二次输出电压的真实性和准确性。由于电容式电压互感器电路固有的特性，其暂态特性较差。本论文围绕着CVT暂态特性所带来的问题及解决方法，进行了以下几个方面的研究：(1)建立了计及电容电压初值的CVT暂态等值电路模型。从理论上说明了电容分压器的电容电压初值对CVT暂态电路模型的影响。(2)应用MATLAB软件中的Power System Block-Set(PSB)和SIMULINK仿真工具，建立了CVT暂态模型。实现了对CVT暂态特性仿真和研究。最后通过与实验结果的对比，进一步验证了基于MATLAB／SIMULINK所建立的CVT暂态模型的可信性。(3)给出了一种利用MATLAB神经网络工具箱来修正CVT的二次电压失真问题的方法。通过检验不同参数情况下人工神经网络(Artificial Neural Network，ANN)的结果，表明提出的方法是正确的。并指出这一方法可以和微机保护算法结合起来。(4)在建立的暂态模型中，利用电力系统分析元件(POWERLIB)通过改变CVT的各种参数，研究了电容电压初值和阻尼器参数对CVT的影响。找出CVT出现最严重铁磁谐振的情况。为今后的CVT设计和分析提供一个相对可靠、准确的系统仿真模型，以提高预测的准确性。更多还原

【Abstract】 The capacitor voltage transformer (CVT) is widely applied in power systems of 110kV or more. It can be used for the measurement of voltage relay protection. Its capacitor divider can replace the coupling capacitor for carrier communication of the power transmission line, and it can be used for the transmission thoroughfare of the signal for high frequency of relay protection as well. Proper design and tuning of CVT components guarantee that its output is the required replica of the input (system voltage) under steady-state conditions. Due to the circuit inherent characteristics of CVT, its transients response is poor. The problem of CVT transient characteristic and solution are studied. This thesis researches and achievements are stated in following paragraph.(1) This paper established the transient equivalent circuit of CVT. Illustrate that the initial capacitor voltage values influence the model of CVT in theory.(2) Through the application of Power System Block-Set and Simulink based on MATLAB software, to achieve digital calculation and simulation of the CVT transient process. Lastly the experiments were performed with a sample CVT, and validate the model furthermore.(3) Presents the use of MATLAB neural network toolboxes to correct capacitor voltage transformer secondary waveform distortions. Performance studies results that the propose method is accurate. Presents the method can be incorporated within the digital protective relaying algorithm.(4) Using the CVT transient models, Through the application of Powerlib we can conveniently change different parameters and study the initial capacitor voltage values, damper resistence influence the ferroresonances process, by which we are able to determine the conditions for the occurrence of the most serious ferroresonances. Supply a relative credibility and accuracy system simulation model for the futurity design and study of CVT.更多还原