變壓器內局(ju)部放(fang)電(dian)源(yuan)與(yu)超聲(sheng)傳(chuan)感器之(zhi)間(jian)的位置關系(xi)壹般(ban)有三種(zhong)情況:*種(zhong)是(shi)局(ju)部放(fang)電(dian)源(yuan)位於超聲(sheng)傳(chuan)感器和(he)繞(rao)組之(zhi)間(jian);第二種(zhong)情況是(shi)局(ju)部放(fang)電(dian)源(yuan)與(yu)超聲(sheng)傳(chuan)感器之(zhi)間(jian)隔(ge)著(zhe)繞(rao)組;第三(san)種(zhong)情況是(shi)局(ju)部放(fang)電(dian)源(yuan)在(zai)繞(rao)組的側面。
三種(zhong)情況下超聲(sheng)波(bo)在(zai)局(ju)部放(fang)電(dian)源(yuan)與(yu)超聲(sheng)陣列傳(chuan)感器之(zhi)間(jian)傳播(bo)有多種(zhong)路(lu)徑(jing)。根據(ju)局(ju)部放(fang)電(dian)的發聲原理,我(wo)們(men)可(ke)以將(jiang)局(ju)部放(fang)電(dian)源(yuan)發出的超聲(sheng)波(bo)看成是(shi)球(qiu)面波,球(qiu)面波輻(fu)射的聲波(bo)波(bo)陣面是(shi)均(jun)勻(yun)球(qiu)面,所以(yi)聲波(bo)向各(ge)個(ge)方向傳(chuan)播(bo)是(shi)*相同(tong)的。由於(yu)實(shi)際變壓器內結構復(fu)雜(za),無(wu)法(fa)理(li)論(lun)分(fen)析(xi)超聲(sheng)波(bo)的傳播(bo)途徑(jing),所以(yi)簡化(hua)了變壓器結構以分(fen)析(xi)局(ju)部放(fang)電(dian)發聲時超聲(sheng)波(bo)的傳播(bo)路(lu)徑。以下分(fen)析(xi)歸(gui)納(na)了幾種(zhong)變壓器內超聲(sheng)波(bo)在(zai)局(ju)部放(fang)電(dian)發聲時從(cong)局(ju)部放(fang)電(dian)放(fang)電(dian)源(yuan)傳(chuan)播(bo)到(dao)超聲(sheng)陣列傳(chuan)感器的路徑(jing)。*條(tiao)路徑,超聲(sheng)波(bo)以直(zhi)達(da)波的形式(shi)從(cong)局(ju)部放(fang)電(dian)源(yuan)位置到(dao)達(da)陣列傳(chuan)感器。第二條(tiao)路徑,超聲(sheng)波(bo)從(cong)局(ju)部放(fang)電(dian)源(yuan)位置先(xian)到(dao)達變壓器壁,再在(zai)變壓器壁內傳播(bo)到(dao)達超聲(sheng)陣列傳(chuan)感器。第三(san)條(tiao)路徑,超聲(sheng)波(bo)從(cong)局(ju)部放(fang)電(dian)源(yuan)位置先(xian)到(dao)達變壓器壁,再通過變壓器壁的反射zui終到(dao)達(da)超聲(sheng)陣列傳(chuan)感器。第四條(tiao)路徑,超聲(sheng)波(bo)從(cong)局(ju)部放(fang)電(dian)源(yuan)位置在(zai)繞(rao)組處發生繞(rao)射或者(zhe)透射,再到(dao)達超聲(sheng)陣列傳(chuan)感器。第五(wu)條(tiao)路徑,超聲(sheng)波(bo)從(cong)局(ju)部放(fang)電(dian)源(yuan)位置到(dao)達(da)繞(rao)組,通過繞(rao)組、變壓器壁內傳播(bo)到(dao)達超聲(sheng)陣列傳(chuan)感器。局(ju)部放(fang)電(dian)源(yuan)的三種(zhong)位置發生局(ju)部放(fang)電(dian)時(shi)超聲(sheng)波(bo)傳播(bo)都(dou)存(cun)在(zai)這(zhe)五(wu)種(zhong)路(lu)徑(jing),但(dan)是(shi)由(you)於(yu)局(ju)部放(fang)電(dian)源(yuan)位置的不同(tong)導致(zhi)的不同(tong)路(lu)徑的傳播(bo)距(ju)離不(bu)同以(yi)及超聲(sheng)波(bo)在(zai)不(bu)同(tong)介(jie)質(zhi)內傳播(bo)速(su)度(du)不同,每(mei)種(zhong)路(lu)徑(jing)的超聲(sheng)波(bo)到達(da)超聲(sheng)陣列傳(chuan)感器的時間(jian)不(bu)同。