电测与仪表
電測與儀錶
전측여의표
ELECTRICAL MEASUREMENT & INSTRUMENTATION
2014年
4期
8-13
,共6页
吴丽娜%邵龙%刘观起%胡婷
吳麗娜%邵龍%劉觀起%鬍婷
오려나%소룡%류관기%호정
电子式互感器%Rogowski线圈%小波分析%雷击
電子式互感器%Rogowski線圈%小波分析%雷擊
전자식호감기%Rogowski선권%소파분석%뢰격
electronic current transformer%Rogowski coil%wavelet transform%lightning strike
已有的Rogowski线圈式电流互感器在运行中存在长期稳定性和测量准确度不高等问题。针对实际运行过程中电力系统遭受雷击或者出现过电压时,Rogowski式电流互感器由于本身结构导致其二次侧电流发生较大变化,造成保护装置误动的现象进行了原理分析,给出相应的解决方法。针对常用的Fourier变换不能很好地区分故障电流与雷击产生电流的问题,利用小波分析对正常工作时的测量电流、雷击过电压导致测量电流增大和故障造成的测量电流增大进行分析,利用之间的不同,来判断电流互感器二次侧电流增大的原因。最终得出,通过小波分析的细节图能够很好地将故障造成的测量电流值过大与雷击过电压造成的测量电流值过大区分开来。
已有的Rogowski線圈式電流互感器在運行中存在長期穩定性和測量準確度不高等問題。針對實際運行過程中電力繫統遭受雷擊或者齣現過電壓時,Rogowski式電流互感器由于本身結構導緻其二次側電流髮生較大變化,造成保護裝置誤動的現象進行瞭原理分析,給齣相應的解決方法。針對常用的Fourier變換不能很好地區分故障電流與雷擊產生電流的問題,利用小波分析對正常工作時的測量電流、雷擊過電壓導緻測量電流增大和故障造成的測量電流增大進行分析,利用之間的不同,來判斷電流互感器二次側電流增大的原因。最終得齣,通過小波分析的細節圖能夠很好地將故障造成的測量電流值過大與雷擊過電壓造成的測量電流值過大區分開來。
이유적Rogowski선권식전류호감기재운행중존재장기은정성화측량준학도불고등문제。침대실제운행과정중전력계통조수뢰격혹자출현과전압시,Rogowski식전류호감기유우본신결구도치기이차측전류발생교대변화,조성보호장치오동적현상진행료원리분석,급출상응적해결방법。침대상용적Fourier변환불능흔호지구분고장전류여뢰격산생전류적문제,이용소파분석대정상공작시적측량전류、뢰격과전압도치측량전류증대화고장조성적측량전류증대진행분석,이용지간적불동,래판단전류호감기이차측전류증대적원인。최종득출,통과소파분석적세절도능구흔호지장고장조성적측량전류치과대여뢰격과전압조성적측량전류치과대구분개래。
Many problems such as long-term stability and inaccurate measurement exist in the actual running of Rogowski coil current transformer. When the power system is struck by lightning strike or over-voltage, the secondary side current of the Rogowski current transformer is significantly interfered because of its structure, which causes the mis-operation of the protection device. In this paper, the principle of the phenomenon is analyzed, and appropriate solution is put forward. To deal with the problem that the commonly used Fourier Transform cannot well distinguish the fault current and lightning current, wavelet transform method is used to analyze the measured current in normal conditions, measured current increase caused by lightning strike and grid faults. Their difference is used to decide whether the current increase is caused by lightning strike or grid faults. And according to the results, the differences will be found which can be used to judge whether the increased current is caused by lightning strike or the grid faults.