光伏電站系統中光伏逆變器可能出現的問題：

1.直流拉弧

在(zai)整個光(guang)伏(fu)系統中直流側(ce)電壓通常高達600-1000V，由于光(guang)伏(fu)組(zu)件(jian)接(jie)頭接(jie)點松脫，接(jie)觸不良、電線受潮、絕(jue)緣破裂(lie)等原因而極易(yi)引起直流拉弧現(xian)象(xiang)。直流拉弧會導(dao)致(zhi)接(jie)觸部(bu)分溫度急劇升(sheng)高，持續的(de)電弧會產生3000-7000℃的(de)高溫，并伴隨著(zhu)高溫碳化周圍器件(jian)，輕者熔斷(duan)保險(xian)、線纜，重者燒毀組(zu)件(jian)和設備引起火災。

2.交流輸出側過/欠壓保護

所謂過(guo)(guo)(guo)/欠壓保(bao)(bao)護(hu)主(zhu)要(yao)是(shi)指電(dian)網(wang)電(dian)壓大幅波(bo)動，其范(fan)圍超過(guo)(guo)(guo)CQC并(bing)(bing)網(wang)標(biao)準規定(ding)的(de)(de)(de)(de)過(guo)(guo)(guo)欠壓閥(fa)值時，逆變器需要(yao)停(ting)機(ji)，并(bing)(bing)指示出(chu)相應(ying)停(ting)機(ji)原因。過(guo)(guo)(guo)/欠壓保(bao)(bao)護(hu)是(shi)判定(ding)逆變器是(shi)否合格的(de)(de)(de)(de)主(zhu)要(yao)考(kao)量(liang)因素，逆變器CQC認證的(de)(de)(de)(de)主(zhu)要(yao)內容包括EMC、安(an)全和并(bing)(bing)網(wang)三部分(fen);過(guo)(guo)(guo)/欠頻、過(guo)(guo)(guo)/欠壓保(bao)(bao)護(hu)是(shi)并(bing)(bing)網(wang)要(yao)求中的(de)(de)(de)(de)重(zhong)(zhong)要(yao)部分(fen)之一，保(bao)(bao)護(hu)功能不合格，嚴重(zhong)(zhong)情況下會(hui)影響光伏系統的(de)(de)(de)(de)穩(wen)定(ding)和配電(dian)網(wang)絡的(de)(de)(de)(de)穩(wen)定(ding)。

3.諧波和波形畸變

逆變(bian)器能造(zao)成包括(kuo)諧(xie)波在(zai)內的電網干擾。電網干擾是能夠在(zai)幅度、頻(pin)率上改變(bian)電壓與(yu)電路的理想正弦曲線的所有現象。

諧(xie)波(bo)在電(dian)(dian)(dian)(dian)能的產生、傳輸與消(xiao)費環(huan)節都(dou)有可能產生，主要來源(yuan)于電(dian)(dian)(dian)(dian)網(wang)中非線性的設備與日益增(zeng)多的電(dian)(dian)(dian)(dian)力(li)電(dian)(dian)(dian)(dian)子裝(zhuang)置。諧(xie)波(bo)電(dian)(dian)(dian)(dian)流的危害(hai)在于會在電(dian)(dian)(dian)(dian)網(wang)短路阻抗(kang)上產生諧(xie)波(bo)電(dian)(dian)(dian)(dian)壓(ya)降(jiang)，從而影響電(dian)(dian)(dian)(dian)壓(ya)波(bo)形(用戶端電(dian)(dian)(dian)(dian)壓(ya)=無(wu)窮大電(dian)(dian)(dian)(dian)網(wang)穩(wen)定電(dian)(dian)(dian)(dian)壓(ya)-諧(xie)波(bo)電(dian)(dian)(dian)(dian)壓(ya)降(jiang))。

4.孤島效應

所(suo)謂孤島(dao)效(xiao)應，指并入公共(gong)電(dian)(dian)網(wang)中的(de)(de)(de)(de)發電(dian)(dian)裝置，在(zai)電(dian)(dian)網(wang)斷電(dian)(dian)的(de)(de)(de)(de)情況(kuang)下，這個發電(dian)(dian)裝置卻不能檢(jian)(jian)測到(dao)或根本沒有(you)相應檢(jian)(jian)測手(shou)段，仍然向公共(gong)電(dian)(dian)網(wang)饋送電(dian)(dian)量(liang)。為了檢(jian)(jian)修(xiu)(xiu)人員的(de)(de)(de)(de)安全，電(dian)(dian)網(wang)上(shang)(shang)必(bi)須有(you)一個防孤島(dao)功能的(de)(de)(de)(de)逆變器，但(dan)是這個逆變器也(ye)存在(zai)百分之零點幾的(de)(de)(de)(de)盲(mang)區(qu)。所(suo)以一旦盲(mang)區(qu)發生(sheng)，光伏發電(dian)(dian)站所(suo)發的(de)(de)(de)(de)電(dian)(dian)傳到(dao)待檢(jian)(jian)修(xiu)(xiu)的(de)(de)(de)(de)線路(lu)母(mu)線上(shang)(shang)，對檢(jian)(jian)修(xiu)(xiu)人員的(de)(de)(de)(de)生(sheng)命就會造(zao)成(cheng)嚴重威脅。

5.監測數據不準確

逆(ni)變(bian)器監測數據(ju)不(bu)(bu)準(zhun)確、采樣精度(du)不(bu)(bu)夠(gou)，造成故(gu)障信息判斷(duan)不(bu)(bu)準(zhun)確、不(bu)(bu)及時。

據(ju)媒(mei)體報道(dao)，內蒙某電站(zhan)集中式逆(ni)變器監(jian)控數據(ju)與實際發電量(liang)嚴重不符，監(jian)控上報值比實際值虛高了3%。