电力系统保护与控制
電力繫統保護與控製
전력계통보호여공제
POWER SYSTM PROTECTION AND CONTROL
2014年
10期
23-28
,共6页
张国军%任荣%韩静静%田永峰
張國軍%任榮%韓靜靜%田永峰
장국군%임영%한정정%전영봉
小电流接地系统%希尔伯特变换%频带能比因子%高频能量%直流分量
小電流接地繫統%希爾伯特變換%頻帶能比因子%高頻能量%直流分量
소전류접지계통%희이백특변환%빈대능비인자%고빈능량%직류분량
neutral ineffectively grounded system%Hilbert transform%frequency band energy factor%high-frequency wavelet energy%DC component
为克服目前小电流接地系统单相故障发生在相电压过零点附近选线方法灵敏度低的缺点,提出了一种基于希尔伯特变换的综合选线判据。将零序电流进行小波包分解的同时,运用希尔伯特变换对分解结果进行瞬时频率分析,计算频带能比因子。将频带能比因子作为启动选线方法的条件,当高频分量多时比较小波高频能量,当低频分量多时比较直流分量能量,将两种方法进行有机综合可以构成完善的故障选线方案。仿真结果表明该方法有效、准确、且适用性强,不受系统结构和运行方式等的影响。
為剋服目前小電流接地繫統單相故障髮生在相電壓過零點附近選線方法靈敏度低的缺點,提齣瞭一種基于希爾伯特變換的綜閤選線判據。將零序電流進行小波包分解的同時,運用希爾伯特變換對分解結果進行瞬時頻率分析,計算頻帶能比因子。將頻帶能比因子作為啟動選線方法的條件,噹高頻分量多時比較小波高頻能量,噹低頻分量多時比較直流分量能量,將兩種方法進行有機綜閤可以構成完善的故障選線方案。倣真結果錶明該方法有效、準確、且適用性彊,不受繫統結構和運行方式等的影響。
위극복목전소전류접지계통단상고장발생재상전압과영점부근선선방법령민도저적결점,제출료일충기우희이백특변환적종합선선판거。장령서전류진행소파포분해적동시,운용희이백특변환대분해결과진행순시빈솔분석,계산빈대능비인자。장빈대능비인자작위계동선선방법적조건,당고빈분량다시비교소파고빈능량,당저빈분량다시비교직류분량능량,장량충방법진행유궤종합가이구성완선적고장선선방안。방진결과표명해방법유효、준학、차괄용성강,불수계통결구화운행방식등적영향。
In order to overcome the disadvantage of low sensitivity of line selection method in neutral ineffectively grounded system when fault occurs near the zero-crossing point of phase voltage, a faulty line selection based on Hilbert transform is proposed, which carries out the wavelet packet decomposition of transient zero-sequence current for each line into low and high frequency subbands, whose instantaneous frequency are calculated by Hilbert transform at the same time, calculates the frequency band energy factors according to the wavelet coefficients. The frequency band energy factor is used as a condition of starting line selection method, when the high-frequency component is the main ingredient, we select the faulty line according to the maximum value of high-frequency wavelet energy;when the low-frequency component is the main ingredient, we select the faulty line according to the maximum value of DC component energy. A perfect scheme will be worked out combining with the two methods. Results of simulation show that, the proposed method, which is immune to the system structures and the mode of operations, has the characteristics of reliability, accurately and practicality.