隨(sui)著新能源行業的日漸興起，光伏發電能源(yuan)儼然已(yi)成為新能源(yuan)行業的巨頭，光伏電站的(de)安全運行也成為維持電網穩定的(de)一個重要因(yin)素，電站的(de)站內保護像是光伏逆變器的防孤島(dao)保護、低電(dian)壓穿越，以(yi)及站內的靜止無功發生裝(zhuang)置都(dou)成為光伏電(dian)站必不可少的配(pei)置。

　　低(di)電壓穿越功能是指當(dang)電網(wang)電壓跌落(luo)時并(bing)網(wang)逆變器(qi)能夠(gou)正常(chang)并(bing)網(wang)一段時間(jian)，“穿(chuan)越”這個低電壓(ya)時間(jian)(區域)直到電網(wang)恢復正常(chang)；孤島效應保護是指當電網(wang)斷電時并網(wang)逆變器(qi)應立即停止并網發(fa)電(dian)，保護時間不(bu)超過0.2秒(miao)。可以看出，孤島效應保護與低電(dian)壓穿越(yue)是相互矛盾的，兩(liang)種功能(neng)不(bu)能(neng)同時并存(cun)，需要根據(ju)電(dian)站規模(mo)和要求進(jin)行選擇，一般原(yuan)則如下：

　　對(dui)于小型光伏電站(zhan)，并網(wang)(wang)(wang)逆變(bian)器在(zai)電網(wang)(wang)(wang)中所(suo)占(zhan)的(de)容量較小，對(dui)電網(wang)(wang)(wang)的(de)影響(xiang)較小，在(zai)電網(wang)(wang)(wang)故障(zhang)時(shi)不會對(dui)電網(wang)(wang)(wang)的(de)穩定性(xing)(xing)產(chan)生實質性(xing)(xing)的(de)影響(xiang)，所(suo)以應(ying)具備(bei)快速監測孤(gu)(gu)島且立即斷開與電網(wang)(wang)(wang)連接的(de)能(neng)力，即此時(shi)并網(wang)(wang)(wang)逆變(bian)器應(ying)選(xuan)擇孤(gu)(gu)島效應(ying)保護功能(neng)。

　　對(dui)于大中型光伏(fu)電(dian)站，并網(wang)(wang)逆變器在電(dian)網(wang)(wang)中所占的容(rong)量較(jiao)大，對(dui)電(dian)網(wang)(wang)的影(ying)響較(jiao)大，在電(dian)網(wang)(wang)故障時不會(hui)對(dui)電(dian)網(wang)(wang)的穩定(ding)性產生實質性的影(ying)響，所以應具備一定(ding)的低(di)電(dian)壓穿越(yue)能力，即(ji)此時并網(wang)(wang)逆變器應選擇低(di)電(dian)壓穿越(yue)功能。

　　對于目前(qian)大多數光伏并(bing)網發(fa)電(dian)(dian)(dian)(dian)系統來說，逆(ni)(ni)(ni)變(bian)(bian)(bian)器(qi)(qi)所配置的都是(shi)低電(dian)(dian)(dian)(dian)壓(ya)(ya)穿(chuan)越。大型(xing)和中(zhong)型(xing)光伏(fu)電(dian)(dian)(dian)(dian)站的低電(dian)(dian)(dian)(dian)壓(ya)(ya)耐(nai)受能力要(yao)求為(wei)了實(shi)(shi)現(xian)并網(wang)逆(ni)(ni)(ni)變(bian)(bian)(bian)器(qi)(qi)的低電(dian)(dian)(dian)(dian)壓(ya)(ya)穿(chuan)越功(gong)能，并網(wang)逆(ni)(ni)(ni)變(bian)(bian)(bian)器(qi)(qi)需要(yao)采用新的軟(ruan)件控(kong)制算(suan)法(fa)，軟(ruan)件控(kong)制算(suan)法(fa)需實(shi)(shi)時監(jian)測網(wang)，并判(pan)斷電(dian)(dian)(dian)(dian)網(wang)是(shi)否發(fa)生電(dian)(dian)(dian)(dian)壓(ya)(ya)跌落(luo)(luo)(luo)（平(ping)衡或者不(bu)平(ping)衡跌落(luo)(luo)(luo)）。當(dang)CPU發(fa)現(xian)電(dian)(dian)(dian)(dian)網(wang)發(fa)生電(dian)(dian)(dian)(dian)壓(ya)(ya)跌落(luo)(luo)(luo)故障(zhang)時，立(li)即(ji)啟動低電(dian)(dian)(dian)(dian)壓(ya)(ya)穿(chuan)越功(gong)能，控(kong)制輸(shu)出(chu)電(dian)(dian)(dian)(dian)流(liu)(liu)以(yi)及輸(shu)出(chu)的功(gong)率，當(dang)電(dian)(dian)(dian)(dian)網(wang)電(dian)(dian)(dian)(dian)壓(ya)(ya)在(zai)一(yi)定(ding)范(fan)圍以(yi)內時，逆(ni)(ni)(ni)變(bian)(bian)(bian)器(qi)(qi)進(jin)入(ru)(ru)低電(dian)(dian)(dian)(dian)壓(ya)(ya)穿(chuan)越階(jie)段(duan)；當(dang)電(dian)(dian)(dian)(dian)網(wang)進(jin)入(ru)(ru)電(dian)(dian)(dian)(dian)壓(ya)(ya)恢復(fu)階(jie)段(duan)，此(ci)時并網(wang)逆(ni)(ni)(ni)變(bian)(bian)(bian)器(qi)(qi)輸(shu)出(chu)無功(gong)功(gong)率起到迅速支撐(cheng)起電(dian)(dian)(dian)(dian)網(wang)電(dian)(dian)(dian)(dian)壓(ya)(ya)的功(gong)能。如果(guo)電(dian)(dian)(dian)(dian)網(wang)跌落(luo)(luo)(luo)是(shi)不(bu)平(ping)衡跌落(luo)(luo)(luo)，逆(ni)(ni)(ni)變(bian)(bian)(bian)器(qi)(qi)會以(yi)輸(shu)出(chu)三相平(ping)衡電(dian)(dian)(dian)(dian)流(liu)(liu)為(wei)目標(biao)函數，通過軟(ruan)件控(kong)制算(suan)法(fa)實(shi)(shi)現(xian)在(zai)電(dian)(dian)(dian)(dian)網(wang)電(dian)(dian)(dian)(dian)壓(ya)(ya)不(bu)平(ping)衡階(jie)段(duan)，逆(ni)(ni)(ni)變(bian)(bian)(bian)器(qi)(qi)的電(dian)(dian)(dian)(dian)流(liu)(liu)是(shi)平(ping)衡的；當(dang)電(dian)(dian)(dian)(dian)網(wang)恢復(fu)正(zheng)常(chang)(chang)，逆(ni)(ni)(ni)變(bian)(bian)(bian)器(qi)(qi)迅速轉入(ru)(ru)正(zheng)常(chang)(chang)并網(wang)狀(zhuang)態。

深圳恒通源公司作為華為公(gong)司(si)智(zhi)能(neng)光(guang)伏電站解(jie)決方案授權經銷商，依托華為公(gong)司(si)強大(da)的技術支(zhi)持，恒通源可為廣大(da)光(guang)伏發電用戶提供華(hua)為逆變器產品以及(ji)智能光伏電站全面解決方案等一站式(shi)服務。