簡婷

安科瑞電氣股份有限公司 上海(hai)嘉定  201801

      防孤島保護是對分布式光(guang)伏(fu)電(dian)(dian)(dian)站有(you)著重要保護作用的(de)。即當電(dian)(dian)(dian)網出現電(dian)(dian)(dian)壓高、電(dian)(dian)(dian)壓低(di)、頻率(lv)高、頻率(lv)低(di)故障時(shi)(shi)，光(guang)伏(fu)并網開(kai)關(guan)及時(shi)(shi)跳閘(zha)。當電(dian)(dian)(dian)網恢復供電(dian)(dian)(dian)并且電(dian)(dian)(dian)壓和頻率(lv)達(da)到(dao)允許值時(shi)(shi)，并網開(kai)關(guan)要自(zi)動合閘(zha)。這樣(yang)的(de)目的(de)是在為了國家電(dian)(dian)(dian)網不受太大影(ying)響(xiang)的(de)情況下，盡(jin)可(ke)能保證光(guang)伏(fu)的(de)發電(dian)(dian)(dian)效率(lv)。

什么是“孤島效應"

      當(dang)光伏電(dian)站(zhan)出(chu)(chu)現(xian)(xian)孤(gu)島(dao)效(xiao)應(ying)時(shi)(shi)，即(ji)當(dang)電(dian)網(wang)由于某(mou)種(zhong)故障原因造成失壓時(shi)(shi)，應(ying)具備(bei)快速監測孤(gu)島(dao)并(bing)立即(ji)斷開(kai)(kai)與電(dian)網(wang)連接的能力，局部電(dian)網(wang)出(chu)(chu)現(xian)(xian)孤(gu)島(dao)會(hui)影響到供電(dian)質(zhi)量和維修人(ren)員的生命安全(quan)，所(suo)以在光伏電(dian)站(zhan)中必需(xu)要配備(bei)防孤(gu)島(dao)保護裝置。而光伏防孤(gu)島(dao)保護裝置就(jiu)是(shi)為了解決“孤(gu)島(dao)效(xiao)應(ying)"的。防孤(gu)島(dao)保護裝置能夠精確檢定(ding)并(bing)網(wang)點(dian)的電(dian)壓、頻率(lv)，然(ran)后當(dang)電(dian)壓、頻率(lv)出(chu)(chu)現(xian)(xian)波動且(qie)大(da)于定(ding)值時(shi)(shi)跳閘出(chu)(chu)口動作(zuo)，斷開(kai)(kai)并(bing)網(wang)開(kai)(kai)關。

1 防孤島保護存在的意義

      “十四五"規(gui)(gui)劃奠(dian)定(ding)國內光(guang)(guang)(guang)伏(fu)市場需(xu)求的(de)(de)(de)(de)(de)(de)(de)整體基調(diao)。據(ju)了解，在能源(yuan)轉型(xing)的(de)(de)(de)(de)(de)(de)(de)目(mu)標下，各(ge)省(sheng)可再生能源(yuan)占比目(mu)標都在相應提高，加(jia)上近(jin)光(guang)(guang)(guang)伏(fu)成本(ben)下降(jiang)潛力(li)可期(qi)，各(ge)省(sheng)的(de)(de)(de)(de)(de)(de)(de)初步規(gui)(gui)劃對(dui)于光(guang)(guang)(guang)伏(fu)的(de)(de)(de)(de)(de)(de)(de)發(fa)(fa)(fa)展有著非常積極的(de)(de)(de)(de)(de)(de)(de)推動，尤其是光(guang)(guang)(guang)照資源(yuan)優渥的(de)(de)(de)(de)(de)(de)(de)西部以及東(dong)北地區，各(ge)省(sheng)份年均新增規(gui)(gui)模高達1GW至5GW。回望剛(gang)過去的(de)(de)(de)(de)(de)(de)(de)五年，是中國光(guang)(guang)(guang)伏(fu)電(dian)(dian)站(zhan)(zhan)建(jian)設快(kuai)速(su)發(fa)(fa)(fa)展的(de)(de)(de)(de)(de)(de)(de)一段歷程，現(xian)在光(guang)(guang)(guang)伏(fu)行業正昂首闊步邁(mai)向新的(de)(de)(de)(de)(de)(de)(de)征程。根據(ju)光(guang)(guang)(guang)伏(fu)電(dian)(dian)站(zhan)(zhan)電(dian)(dian)壓等(deng)(deng)級不(bu)同，配置(zhi)防(fang)(fang)孤(gu)(gu)(gu)島(dao)保(bao)(bao)護(hu)(hu)的(de)(de)(de)(de)(de)(de)(de)要(yao)求也不(bu)一樣(yang)。0.4kV~10kV電(dian)(dian)壓等(deng)(deng)級分(fen)布式(shi)光(guang)(guang)(guang)伏(fu)電(dian)(dian)站(zhan)(zhan)，只需(xu)逆變器(qi)具備快(kuai)速(su)監測孤(gu)(gu)(gu)島(dao)并立(li)(li)即斷(duan)開與(yu)(yu)電(dian)(dian)網(wang)(wang)(wang)連(lian)接的(de)(de)(de)(de)(de)(de)(de)能力(li)。而對(dui)于35kV及以上電(dian)(dian)壓等(deng)(deng)級的(de)(de)(de)(de)(de)(de)(de)光(guang)(guang)(guang)伏(fu)電(dian)(dian)站(zhan)(zhan)，主(zhu)電(dian)(dian)網(wang)(wang)(wang)繼電(dian)(dian)保(bao)(bao)護(hu)(hu)裝(zhuang)置(zhi)必須(xu)保(bao)(bao)證主(zhu)電(dian)(dian)網(wang)(wang)(wang)故(gu)障時切除光(guang)(guang)(guang)伏(fu)電(dian)(dian)站(zhan)(zhan)，此時應配備孤(gu)(gu)(gu)島(dao)保(bao)(bao)護(hu)(hu)裝(zhuang)置(zhi)。防(fang)(fang)孤(gu)(gu)(gu)島(dao)保(bao)(bao)護(hu)(hu)：根據(ju)《光(guang)(guang)(guang)伏(fu)發(fa)(fa)(fa)電(dian)(dian)站(zhan)(zhan)接入電(dian)(dian)力(li)系統技術規(gui)(gui)定(ding)》GB/T19964-2012第12.3.3條的(de)(de)(de)(de)(de)(de)(de)規(gui)(gui)定(ding)：“光(guang)(guang)(guang)伏(fu)發(fa)(fa)(fa)電(dian)(dian)站(zhan)(zhan)應配置(zhi)獨(du)立(li)(li)的(de)(de)(de)(de)(de)(de)(de)防(fang)(fang)孤(gu)(gu)(gu)島(dao)保(bao)(bao)護(hu)(hu)裝(zhuang)置(zhi)，動作(zuo)時間(jian)(jian)應不(bu)大(da)于2s。"以及《光(guang)(guang)(guang)伏(fu)發(fa)(fa)(fa)電(dian)(dian)站(zhan)(zhan)接入電(dian)(dian)力(li)系統設計規(gui)(gui)范(fan)》GB/T50866-2013第6.3.2條的(de)(de)(de)(de)(de)(de)(de)規(gui)(gui)定(ding)：“光(guang)(guang)(guang)伏(fu)發(fa)(fa)(fa)電(dian)(dian)站(zhan)(zhan)需(xu)要(yao)配置(zhi)獨(du)立(li)(li)的(de)(de)(de)(de)(de)(de)(de)防(fang)(fang)孤(gu)(gu)(gu)島(dao)保(bao)(bao)護(hu)(hu)裝(zhuang)置(zhi)，保(bao)(bao)證電(dian)(dian)網(wang)(wang)(wang)故(gu)障及檢(jian)修時的(de)(de)(de)(de)(de)(de)(de)安全"。總結(jie)規(gui)(gui)范(fan)所(suo)述，分(fen)布式(shi)電(dian)(dian)源(yuan)檢(jian)測到孤(gu)(gu)(gu)島(dao)現(xian)場時，應迅(xun)速(su)斷(duan)開與(yu)(yu)主(zhu)電(dian)(dian)網(wang)(wang)(wang)連(lian)接的(de)(de)(de)(de)(de)(de)(de)斷(duan)路器(qi)，斷(duan)開連(lian)接時間(jian)(jian)需(xu)在2s內。以防(fang)(fang)止(zhi)光(guang)(guang)(guang)伏(fu)電(dian)(dian)站(zhan)(zhan)所(suo)發(fa)(fa)(fa)電(dian)(dian)量與(yu)(yu)用(yong)戶(hu)站(zhan)(zhan)負荷量匹(pi)配，形成自發(fa)(fa)(fa)自用(yong)的(de)(de)(de)(de)(de)(de)(de)小系統，與(yu)(yu)主(zhu)電(dian)(dian)網(wang)(wang)(wang)脫軌。

2 防孤島保護的作用

      防孤(gu)島：包(bao)含負荷和電源的部分(fen)電網，從主網脫離后繼(ji)續孤(gu)立運行的狀態。

 ;     非計劃性(xing)孤(gu)島現象(xiang)發生(sheng)時，由(you)于系統供電狀態未知，將(jiang)造成以(yi)下不利(li)影響：①可(ke)能危(wei)及電網設(she)施維護人(ren)員和用戶的人(ren)事安全；

      ②干擾(rao)電網的正常(chang)合閘；

      ③電網不能控制(zhi)孤島中(zhong)的電壓和(he)頻率，從(cong)而損壞配(pei)電設(she)備和(he)用戶設(she)備。

      當發(fa)生(sheng)非計劃性孤(gu)島(dao)時，由光伏(fu)電(dian)站側(ce)防孤(gu)島(dao)保護裝置動作實現故障切除(chu)。同時由于發(fa)生(sheng)孤(gu)島(dao)概率較小，建議光伏(fu)電(dian)站側(ce)運行方式能配合(he)電(dian)網檢(jian)修計劃進行安排。

      防孤(gu)島(dao)保護(hu)是(shi)(shi)對(dui)(dui)分布式光伏電(dian)(dian)站有著重要(yao)保護(hu)作(zuo)用(yong)(yong)的(de)(de)。即(ji)當(dang)電(dian)(dian)網出現電(dian)(dian)壓(ya)(ya)高、電(dian)(dian)壓(ya)(ya)低(di)、頻率(lv)(lv)高、頻率(lv)(lv)低(di)故(gu)障時，光伏并(bing)網斷路器及時跳閘(zha)。當(dang)電(dian)(dian)網恢復供電(dian)(dian)并(bing)且電(dian)(dian)壓(ya)(ya)和頻率(lv)(lv)達到允許值時，并(bing)網斷路器要(yao)自動合(he)閘(zha)。這樣(yang)的(de)(de)目的(de)(de)是(shi)(shi)在(zai)為了國家電(dian)(dian)網不(bu)(bu)受太大影(ying)響的(de)(de)情況下，盡可(ke)能(neng)保證光伏的(de)(de)發(fa)電(dian)(dian)效率(lv)(lv)。部分地(di)區會根據(ju)當(dang)地(di)供電(dian)(dian)部門的(de)(de)要(yao)求對(dui)(dui)防孤(gu)島(dao)保護(hu)裝(zhuang)(zhuang)置功能(neng)進一步完(wan)善，比如添(tian)加過(guo)電(dian)(dian)流保護(hu)、不(bu)(bu)平衡電(dian)(dian)壓(ya)(ya)保護(hu)等，這些(xie)都是(shi)(shi)無可(ke)厚非的(de)(de)。然而目前(qian)市(shi)場上(shang)有的(de)(de)用(yong)(yong)戶認為逆(ni)變器本身就具備防孤(gu)島(dao)功能(neng)，怎么(me)還需(xu)要(yao)單獨加裝(zhuang)(zhuang)防孤(gu)島(dao)保護(hu)。其實防孤(gu)島(dao)保護(hu)裝(zhuang)(zhuang)置剛開始在(zai)高壓(ya)(ya)電(dian)(dian)壓(ya)(ya)等級上(shang)使(shi)用(yong)(yong)的(de)(de)，不(bu)(bu)過(guo)后來也慢慢使(shi)用(yong)(yong)于低(di)壓(ya)(ya)中(zhong)。對(dui)(dui)于目前(qian)的(de)(de)逆(ni)變器來講(jiang)，當(dang)電(dian)(dian)網電(dian)(dian)壓(ya)(ya)被拉高的(de)(de)時候(hou)，逆(ni)變器還是(shi)(shi)會正常工作(zuo)的(de)(de)。

3 防孤島保護案例分析

      陜西省(sheng)白水縣扶(fu)貧電站，容(rong)量(liang)(liang)為(wei)400KWP，變(bian)壓器為(wei)50KWP，在夏季(ji)中午發(fa)電量(liang)(liang)比較高的情況下(xia)，并網電壓可(ke)達到(dao)500V左右，此時如(ru)果并網開關不跳閘，逆(ni)變(bian)器還是(shi)會正常運(yun)(yun)行，但是(shi)這樣長期運(yun)(yun)行勢必(bi)會對電網有所沖(chong)擊。

      江蘇南通一(yi)生產光(guang)(guang)伏(fu)組價的廠房自(zi)己安裝屋頂(ding)光(guang)(guang)伏(fu)來(lai)實(shi)現自(zi)發自(zi)用(yong)余電(dian)(dian)(dian)上(shang)網。然而自(zi)從安裝光(guang)(guang)伏(fu)發電(dian)(dian)(dian)后，廠房內的一(yi)些測試儀器電(dian)(dian)(dian)源模(mo)塊會有燒毀的情況發生，造成這(zhe)個原(yuan)因是(shi)電(dian)(dian)(dian)源端(duan)不穩定(ding)，后采取(qu)UPS供電(dian)(dian)(dian)，問(wen)題就解決(jue)了。

      山東德州某一光伏電(dian)(dian)(dian)站(zhan)(zhan)(zhan)(zhan)突然與電(dian)(dian)(dian)網解列，后由運(yun)維人員發現是系統站(zhan)(zhan)(zhan)(zhan)內(nei)(nei)主變(bian)低(di)壓(ya)側備自投(tou)聯合防孤島(dao)保護動作將(jiang)對(dui)側站(zhan)(zhan)(zhan)(zhan)內(nei)(nei)帶有光伏電(dian)(dian)(dian)站(zhan)(zhan)(zhan)(zhan)的支(zhi)路聯切，目的就(jiu)是防止電(dian)(dian)(dian)源(yuan)端(duan)電(dian)(dian)(dian)壓(ya)頻率不穩定對(dui)用戶站(zhan)(zhan)(zhan)(zhan)和光伏電(dian)(dian)(dian)站(zhan)(zhan)(zhan)(zhan)造(zao)成(cheng)影(ying)響。當對(dui)側站(zhan)(zhan)(zhan)(zhan)供電(dian)(dian)(dian)電(dian)(dian)(dian)源(yuan)完成(cheng)切換(huan)后，再將(jiang)光伏電(dian)(dian)(dian)站(zhan)(zhan)(zhan)(zhan)支(zhi)路投(tou)運(yun)，本側光伏電(dian)(dian)(dian)站(zhan)(zhan)(zhan)(zhan)繼續為電(dian)(dian)(dian)網送(song)電(dian)(dian)(dian)。

      以上三個案例說(shuo)明，分布式光伏發電輸出電壓(ya)一(yi)直不太穩定，當并(bing)網電壓(ya)或頻(pin)率出現異常(chang)現象(xiang)，及時準確跳閘也是非常(chang)有必要的。

      防孤島保(bao)護裝(zhuang)(zhuang)置檢(jian)測到系統側或本側光伏(fu)電站母線電壓(ya)(ya)出(chu)現(xian)幅(fu)值、頻(pin)率異(yi)常時，保(bao)護裝(zhuang)(zhuang)置會迅(xun)速向并(bing)網斷路器發出(chu)跳閘命令，從而很好的保(bao)證了(le)電網電壓(ya)(ya)異(yi)常時不會對兩側主要設備造成沖擊，避免事(shi)故進一步擴大。

      當光(guang)伏(fu)(fu)(fu)電(dian)(dian)(dian)站(zhan)本(ben)側(ce)(ce)(ce)出(chu)現停電(dian)(dian)(dian)故障時(shi)(shi)，需(xu)要運維(wei)人(ren)員(yuan)查找問題點的(de)時(shi)(shi)候(hou)，而與對(dui)側(ce)(ce)(ce)站(zhan)相連的(de)線路上還帶電(dian)(dian)(dian)，這時(shi)(shi)會出(chu)現對(dui)側(ce)(ce)(ce)站(zhan)會向光(guang)伏(fu)(fu)(fu)電(dian)(dian)(dian)站(zhan)反送電(dian)(dian)(dian)的(de)情況，給本(ben)側(ce)(ce)(ce)站(zhan)內(nei)(nei)的(de)運維(wei)人(ren)員(yuan)帶來(lai)安全隱患。另當對(dui)側(ce)(ce)(ce)站(zhan)失電(dian)(dian)(dian)的(de)時(shi)(shi)候(hou)，需(xu)要對(dui)側(ce)(ce)(ce)站(zhan)內(nei)(nei)運維(wei)人(ren)員(yuan)去查找事故點，若此(ci)時(shi)(shi)光(guang)伏(fu)(fu)(fu)電(dian)(dian)(dian)站(zhan)還在(zai)正(zheng)常送電(dian)(dian)(dian)，容易形成非計(ji)劃性孤(gu)(gu)島效應，給對(dui)側(ce)(ce)(ce)站(zhan)內(nei)(nei)的(de)運維(wei)人(ren)員(yuan)造成安全威脅。配置(zhi)的(de)防孤(gu)(gu)島保(bao)護(hu)(hu)裝置(zhi)在(zai)此(ci)時(shi)(shi)發揮作用，當電(dian)(dian)(dian)網側(ce)(ce)(ce)或者光(guang)伏(fu)(fu)(fu)本(ben)側(ce)(ce)(ce)任一側(ce)(ce)(ce)失電(dian)(dian)(dian)的(de)時(shi)(shi)候(hou)，防孤(gu)(gu)島保(bao)護(hu)(hu)裝置(zhi)都會迅(xun)速向并網斷路器發出(chu)跳閘信號，讓斷路器分閘，從而很好的(de)保(bao)證了光(guang)伏(fu)(fu)(fu)兩(liang)側(ce)(ce)(ce)檢修人(ren)員(yuan)的(de)生命安全。

      防孤島(dao)保護(hu)(hu)帶有檢(jian)(jian)測線路(lu)(lu)(lu)側(ce)PT 失壓(ya)自(zi)(zi)(zi)動(dong)(dong)跳閘、檢(jian)(jian)測線路(lu)(lu)(lu)PT有壓(ya)自(zi)(zi)(zi)動(dong)(dong)可以合(he)閘的(de)功能，當線路(lu)(lu)(lu)故障(zhang)解除后，光(guang)伏和(he)系統(tong)側(ce)都處于正(zheng)常(chang)狀態。這時防孤島(dao)保護(hu)(hu)裝置會自(zi)(zi)(zi)動(dong)(dong)檢(jian)(jian)測線路(lu)(lu)(lu)PT和(he)母線PT電壓(ya)是否一致，并(bing)發出合(he)閘命令，將并(bing)網斷(duan)路(lu)(lu)(lu)器合(he)上，讓線路(lu)(lu)(lu)正(zheng)常(chang)工(gong)作(zuo)，節省人工(gong)開操(cao)作(zuo)票等一系列(lie)繁雜的(de)手續。

4 防孤島保護的實際應用

防孤島保護裝置保護功能如圖1所示：

      ①電(dian)(dian)壓頻(pin)率過(guo)低解(jie)(jie)列(lie)；②電(dian)(dian)壓頻(pin)率過(guo)高(gao)解(jie)(jie)列(lie)；③零(ling)序電(dian)(dian)壓過(guo)高(gao)解(jie)(jie)列(lie)；④零(ling)序電(dian)(dian)壓過(guo)低解(jie)(jie)列(lie)；⑤母線電(dian)(dian)壓過(guo)高(gao)解(jie)(jie)列(lie)；告警(jing)功能如(ru)下：①常(chang)規電(dian)(dian)壓回路(lu)PT 斷線報警(jing)；②快(kuai)速電(dian)(dian)壓回路(lu)PT斷線報警(jing)；③母線電(dian)(dian)壓頻(pin)率異常(chang)報警(jing)。

      主要(yao)適用于10kV 電(dian)壓(ya)等(deng)級的(de)(de)分(fen)布(bu)式發(fa)電(dian)項目，其(qi)功(gong)(gong)能(neng)設(she)定依據(ju)國家發(fa)布(bu)的(de)(de)分(fen)布(bu)式電(dian)源并(bing)網相(xiang)關標準規(gui)范，集成(cheng)分(fen)布(bu)式電(dian)源并(bing)網所需的(de)(de)開(kai)關設(she)備、保護裝置、測(ce)控、通信(xin)等(deng)功(gong)(gong)能(neng)，滿足(zu)分(fen)布(bu)式電(dian)源接入的(de)(de)孤島檢測(ce)、自動安全(quan)并(bing)網、保護及安全(quan)隔離等(deng)要(yao)求。

5 結束語

      綜上所述，防孤島保護(hu)對(dui)光(guang)伏(fu)電(dian)(dian)(dian)站(zhan)(zhan)(zhan)接入電(dian)(dian)(dian)網(wang)(wang)是否穩定起著很大的(de)(de)作用(yong)。電(dian)(dian)(dian)力配(pei)(pei)電(dian)(dian)(dian)網(wang)(wang)設(she)計(ji)人(ren)員想要(yao)設(she)計(ji)出(chu)完(wan)整的(de)(de)、可(ke)行的(de)(de)方(fang)案，在設(she)計(ji)光(guang)伏(fu)電(dian)(dian)(dian)站(zhan)(zhan)(zhan)接入方(fang)案時，必須要(yao)考慮到防孤島保護(hu)的(de)(de)配(pei)(pei)置型式。為(wei)了保證電(dian)(dian)(dian)網(wang)(wang)系統(tong)正常運行，需要(yao)謹(jin)慎設(she)置防孤島保護(hu)的(de)(de)功能參數(shu)，以便于(yu)提升光(guang)伏(fu)電(dian)(dian)(dian)站(zhan)(zhan)(zhan)的(de)(de)供(gong)電(dian)(dian)(dian)可(ke)靠性，繼續為(wei)當地居民提供(gong)源源不斷的(de)(de)、高質量的(de)(de)電(dian)(dian)(dian)能。

作者簡(jian)介：簡(jian)婷(ting)，女，本科，現就(jiu)職于安科瑞電氣股份有限(xian)公司(si)，主要研究方向為防孤(gu)島(dao)保(bao)護裝(zhuang)置。