CAJ | 학술논문

换相失败是高压直流输电系统的常见故障之一.通过合理设计换相失败控制器,能够抑制换相失败故障发生的频率和减少相继换相失败的次数,从而降低换相失败对电力系统安全稳定运行的影响.本文基于小波分析方法,研究换相失败的控制方式,利用小波分析时频域分析的优点,对换相失败的进行实时控制.提取直流电压和交流电压并进行小波分析,计算信号小波系数d6的方差,能有效判断换相失败故障;通过移动窗口采样的方式,实现了故障的实时测量和控制;当判断发生换相失败故障时,及时提高熄弧角的给定值,能够有效防止严重故障引发的相继换相失败和控制方式不当引发的换相失败.仿真结果验证该控制策略的有效性和实时性.
환상실패시고압직류수전계통적상견고장지일.통과합리설계환상실패공제기,능구억제환상실패고장발생적빈솔화감소상계환상실패적차수,종이강저환상실패대전력계통안전은정운행적영향.본문기우소파분석방법,연구환상실패적공제방식,이용소파분석시빈역분석적우점,대환상실패적진행실시공제.제취직류전압화교류전압병진행소파분석,계산신호소파계수d6적방차,능유효판단환상실패고장;통과이동창구채양적방식,실현료고장적실시측량화공제;당판단발생환상실패고장시,급시제고식호각적급정치,능구유효방지엄중고장인발적상계환상실패화공제방식불당인발적환상실패.방진결과험증해공제책략적유효성화실시성.
@@@@Commutation failure is the common fault in HVDC systems. If the controller of commutation failure can be designed properly, commutation failure and successive commutation failure can be restrained. The impact of commutation failure on power system is lowered. Wavelet transform is a signal-processing method both in time and frequency. The application of wavelet transform can control commutation failure correctly in real-time. DC voltage and AC voltage in inverter side are the signals analyzed by wavelet. The variances of wavelet coefficient d6 are used to identify the fault. By moving sample windows,the measurement and classification of fault can be done online. When the controller identifies a fault,it can improve the desired value of distinguished angle and improve the margin of commutation. The control strategy prevents the successive commutation failure caused by AC three-phase short circuit fault and commutation failure caused by single-phase short circuit fault and improper control mode. The simulation results show that the controller is with well performance.