分布式電能存儲技術應用前景與挑戰
分(fen)(fen)布式(shi)電能(neng)(neng)存儲(chu)設(she)備(bei)的功率從幾千瓦(wa)至幾兆瓦(wa)不等,儲(chu)能(neng)(neng)容量一般小于10MW·h,多接入中(zhong)低(di)壓配(pei)電網(wang)或用戶(hu)側(ce)。從能(neng)(neng)量儲(chu)存形式(shi)看,分(fen)(fen)布式(shi)電能(neng)(neng)存儲(chu)技(ji)術(shu)可分(fen)(fen)為機械(xie)儲(chu)能(neng)(neng)、電磁儲(chu)能(neng)(neng)、化學儲(chu)能(neng)(neng)等。
分布式電能(neng)存(cun)儲(chu)設備(bei)的(de)(de)功(gong)率從(cong)幾千瓦至幾兆(zhao)瓦不等,儲(chu)能(neng)容(rong)量(liang)(liang)一般(ban)小于10MW·h,多接入中低壓配電網或(huo)用戶側。從(cong)能(neng)量(liang)(liang)儲(chu)存(cun)形式看,分布式電能(neng)存(cun)儲(chu)技術可分為機械儲(chu)能(neng)、電磁儲(chu)能(neng)、化學儲(chu)能(neng)等。若(ruo)按照能(neng)量(liang)(liang)存(cun)儲(chu)和釋放的(de)(de)外(wai)部特(te)征劃(hua)分,又(you)可分為功(gong)率型(xing)和能(neng)量(liang)(liang)型(xing)2種(zhong)。
1、分布式電能存儲技術的特點及發展情況
分(fen)布式(shi)電(dian)(dian)能(neng)(neng)(neng)(neng)(neng)存(cun)(cun)儲設備的(de)(de)(de)功(gong)(gong)(gong)(gong)率(lv)(lv)(lv)(lv)(lv)從(cong)(cong)幾千瓦(wa)至幾兆瓦(wa)不(bu)等(deng)(deng)(deng),儲能(neng)(neng)(neng)(neng)(neng)容量(liang)一般小于(yu)10MW·h,多接入中低壓(ya)配電(dian)(dian)網或用戶側。從(cong)(cong)能(neng)(neng)(neng)(neng)(neng)量(liang)儲存(cun)(cun)形(xing)式(shi)看,分(fen)布式(shi)電(dian)(dian)能(neng)(neng)(neng)(neng)(neng)存(cun)(cun)儲技術(shu)可(ke)分(fen)為機械(xie)儲能(neng)(neng)(neng)(neng)(neng)、電(dian)(dian)磁(ci)儲能(neng)(neng)(neng)(neng)(neng)、化學儲能(neng)(neng)(neng)(neng)(neng)等(deng)(deng)(deng)。若按(an)照能(neng)(neng)(neng)(neng)(neng)量(liang)存(cun)(cun)儲和釋放的(de)(de)(de)外部(bu)特征劃分(fen),又可(ke)分(fen)為功(gong)(gong)(gong)(gong)率(lv)(lv)(lv)(lv)(lv)型(xing)(xing)和能(neng)(neng)(neng)(neng)(neng)量(liang)型(xing)(xing)2種(zhong)。前(qian)者適用于(yu)短(duan)時間(jian)內對(dui)(dui)功(gong)(gong)(gong)(gong)率(lv)(lv)(lv)(lv)(lv)需(xu)求較高(gao)的(de)(de)(de)場合(he),如改善電(dian)(dian)能(neng)(neng)(neng)(neng)(neng)質量(liang)、提(ti)供(gong)快速功(gong)(gong)(gong)(gong)率(lv)(lv)(lv)(lv)(lv)支(zhi)撐等(deng)(deng)(deng);后者適用于(yu)對(dui)(dui)能(neng)(neng)(neng)(neng)(neng)量(liang)需(xu)求較高(gao)的(de)(de)(de)場合(he),需(xu)要(yao)儲能(neng)(neng)(neng)(neng)(neng)設備提(ti)供(gong)較長時間(jian)的(de)(de)(de)電(dian)(dian)能(neng)(neng)(neng)(neng)(neng)支(zhi)撐。功(gong)(gong)(gong)(gong)率(lv)(lv)(lv)(lv)(lv)型(xing)(xing)儲能(neng)(neng)(neng)(neng)(neng)響應迅速、功(gong)(gong)(gong)(gong)率(lv)(lv)(lv)(lv)(lv)密度較大,包括超級(ji)電(dian)(dian)容、飛(fei)輪儲能(neng)(neng)(neng)(neng)(neng)、超導儲能(neng)(neng)(neng)(neng)(neng)等(deng)(deng)(deng)。能(neng)(neng)(neng)(neng)(neng)量(liang)型(xing)(xing)儲能(neng)(neng)(neng)(neng)(neng)具(ju)有(you)較高(gao)的(de)(de)(de)能(neng)(neng)(neng)(neng)(neng)量(liang)存(cun)(cun)儲密度,充(chong)放電(dian)(dian)時間(jian)較長,包括壓(ya)縮空氣儲能(neng)(neng)(neng)(neng)(neng)、鈉硫電(dian)(dian)池、液(ye)流電(dian)(dian)池、鉛酸電(dian)(dian)池、鋰離子電(dian)(dian)池等(deng)(deng)(deng)。各(ge)種(zhong)分(fen)布式(shi)電(dian)(dian)能(neng)(neng)(neng)(neng)(neng)存(cun)(cun)儲技術(shu)的(de)(de)(de)發展水平不(bu)同(tong),成(cheng)本也有(you)明顯差異,在(zai)效率(lv)(lv)(lv)(lv)(lv)、壽(shou)命、功(gong)(gong)(gong)(gong)率(lv)(lv)(lv)(lv)(lv)/能(neng)(neng)(neng)(neng)(neng)量(liang)密度等(deng)(deng)(deng)方面具(ju)有(you)不(bu)同(tong)特點。采(cai)用混合(he)儲能(neng)(neng)(neng)(neng)(neng)形(xing)式(shi),將不(bu)同(tong)性(xing)能(neng)(neng)(neng)(neng)(neng)的(de)(de)(de)儲能(neng)(neng)(neng)(neng)(neng)系(xi)統進行組合(he),可(ke)充(chong)分(fen)發揮不(bu)同(tong)儲能(neng)(neng)(neng)(neng)(neng)技術(shu)的(de)(de)(de)優勢,以(yi)滿(man)足功(gong)(gong)(gong)(gong)率(lv)(lv)(lv)(lv)(lv)和能(neng)(neng)(neng)(neng)(neng)量(liang)等(deng)(deng)(deng)多方面的(de)(de)(de)需(xu)求,這將是(shi)未來分(fen)布式(shi)電(dian)(dian)能(neng)(neng)(neng)(neng)(neng)存(cun)(cun)儲技術(shu)的(de)(de)(de)發展和應用的(de)(de)(de)趨勢之一。
2、分布式電能存儲系統的應用場景
分(fen)(fen)布式(shi)(shi)電(dian)(dian)能存(cun)儲(chu)系(xi)統(DESS)的(de)(de)應用涉(she)及配(pei)用電(dian)(dian)系(xi)統中的(de)(de)各個環節(jie),與大規模、集中式(shi)(shi)的(de)(de)儲(chu)能電(dian)(dian)站相比(bi),分(fen)(fen)布式(shi)(shi)電(dian)(dian)能存(cun)儲(chu)系(xi)統對接入(ru)位置的(de)(de)環境條件限制較(jiao)少,接入(ru)電(dian)(dian)網的(de)(de)方式(shi)(shi)更(geng)加靈活,在配(pei)電(dian)(dian)網、微電(dian)(dian)網、分(fen)(fen)布式(shi)(shi)電(dian)(dian)源側,以及用戶側都可(ke)以發揮(hui)獨特(te)的(de)(de)作(zuo)用。
2.1 在配(pei)電系統中(zhong)的應(ying)用
參與系統(tong)調峰(feng)。利用分(fen)布式電能存儲系統(tong)在高峰(feng)負荷時放電,在低谷負荷時充電,可(ke)(ke)有(you)效實現負荷的削峰(feng)填谷。其效果可(ke)(ke)體現在如下3個方面(mian):
① 緩解電(dian)網(wang)功率阻塞(sai);
② 延緩配電網升級改造;
③ 降低網絡能量(liang)損耗。
參(can)與系(xi)(xi)統(tong)頻率調(diao)節。分(fen)(fen)布(bu)式電(dian)能存(cun)儲系(xi)(xi)統(tong)具(ju)(ju)有(you)響(xiang)應速度(du)快(kuai)、輸出功率控制(zhi)精度(du)高等特點(dian),十分(fen)(fen)符合電(dian)網(wang)調(diao)頻的(de)需(xu)求。與傳統(tong)調(diao)頻電(dian)源相(xiang)比,分(fen)(fen)布(bu)式電(dian)能存(cun)儲系(xi)(xi)統(tong)具(ju)(ju)有(you)較(jiao)為明顯的(de)技術優勢。隨著分(fen)(fen)布(bu)式電(dian)能存(cun)儲系(xi)(xi)統(tong)成本的(de)下降,在(zai)調(diao)頻服(fu)務(wu)中(zhong)也將逐漸顯現(xian)出其經濟性(xing)。
參與系(xi)(xi)統或饋線級(ji)調壓。大量分(fen)(fen)布式電(dian)(dian)源(yuan)在配電(dian)(dian)系(xi)(xi)統中(zhong)接(jie)入,將直接(jie)改變配電(dian)(dian)網中(zhong)功率(lv)的流動規律,造(zao)成一些(xie)節點(dian)電(dian)(dian)壓的升(sheng)高。利用(yong)分(fen)(fen)布式電(dian)(dian)能存儲系(xi)(xi)統有(you)(you)功功率(lv)的調節能力,可以有(you)(you)效(xiao)緩解分(fen)(fen)布式電(dian)(dian)源(yuan)接(jie)入后的節點(dian)電(dian)(dian)壓升(sheng)高問題,提高配電(dian)(dian)網對分(fen)(fen)布式電(dian)(dian)源(yuan)接(jie)納(na)能力。
2.2 在改善(shan)分布式電源運行特性方面(mian)的應(ying)用
平(ping)滑分(fen)布式電(dian)(dian)(dian)源(yuan)(yuan)(yuan)的(de)功(gong)(gong)率(lv)(lv)波動(dong)。將分(fen)布式電(dian)(dian)(dian)能存儲(chu)系統(tong)與(yu)光伏發電(dian)(dian)(dian)、風電(dian)(dian)(dian)等(deng)波動(dong)性分(fen)布式電(dian)(dian)(dian)源(yuan)(yuan)(yuan)緊密配(pei)合,利用(yong)儲(chu)能的(de)快(kuai)速充放電(dian)(dian)(dian)特(te)性平(ping)抑這些(xie)電(dian)(dian)(dian)源(yuan)(yuan)(yuan)的(de)快(kuai)速波動(dong),可在一(yi)定時(shi)(shi)間尺度上(shang)(分(fen)鐘(zhong)至小時(shi)(shi)級)實現輸出(chu)功(gong)(gong)率(lv)(lv)的(de)平(ping)滑,顯著提高這些(xie)電(dian)(dian)(dian)源(yuan)(yuan)(yuan)的(de)功(gong)(gong)率(lv)(lv)輸出(chu)品質,降低其對系統(tong)的(de)影響。
實現(xian)分(fen)布(bu)式電(dian)源端(duan)節(jie)(jie)點電(dian)壓(ya)(ya)控制。將分(fen)布(bu)式電(dian)源直接與儲能系(xi)統相配合,對(dui)分(fen)布(bu)式電(dian)源的端(duan)電(dian)壓(ya)(ya)實現(xian)有效控制,在饋線(xian)中一定比例的分(fen)布(bu)式電(dian)源上(shang)采(cai)用這樣的手(shou)段,完全可以克服饋線(xian)節(jie)(jie)點電(dian)壓(ya)(ya)升高問(wen)題。該方案不會(hui)隨分(fen)布(bu)式電(dian)源的接入改變系(xi)統運行或(huo)控制策略,能夠實現(xian)“即插(cha)即用”。
增強(qiang)分(fen)布式電源的(de)功(gong)率可(ke)調度(du)性。將分(fen)布式電能存儲系統(tong)與(yu)風電和光伏發(fa)電等分(fen)布式電源有效加以集成(cheng),對電網而言形(xing)成(cheng)一(yi)(yi)個統(tong)一(yi)(yi)的(de)單元(yuan),實現在一(yi)(yi)定(ding)時間尺度(du)(分(fen)鐘至小時級)上輸出總功(gong)率的(de)調節(jie),進而使其具(ju)備一(yi)(yi)定(ding)程度(du)的(de)可(ke)調度(du)性。
2.3 在微(wei)電(dian)網中的應(ying)用
實(shi)現聯(lian)絡線(xian)功(gong)率控制(zhi)。微電(dian)網(wang)(wang)聯(lian)網(wang)(wang)運行時(shi),微電(dian)網(wang)(wang)與配(pei)電(dian)網(wang)(wang)間聯(lian)絡線(xian)功(gong)率的(de)(de)波(bo)動可(ke)能(neng)(neng)對(dui)配(pei)電(dian)網(wang)(wang)產生較大的(de)(de)影響(xiang)。通過對(dui)微電(dian)網(wang)(wang)中分布式電(dian)能(neng)(neng)存儲系統的(de)(de)控制(zhi),能(neng)(neng)將聯(lian)絡線(xian)功(gong)率的(de)(de)波(bo)動控制(zhi)在一定范圍之內。聯(lian)網(wang)(wang)運行時(shi),對(dui)配(pei)電(dian)網(wang)(wang)而言,微電(dian)網(wang)(wang)將成為一個(ge)可(ke)調(diao)度的(de)(de)電(dian)源(或(huo)負荷),可(ke)以(yi)利用微電(dian)網(wang)(wang)實(shi)現一些電(dian)網(wang)(wang)輔助服務功(gong)能(neng)(neng),進而更多地發揮出微電(dian)網(wang)(wang)的(de)(de)技術優勢。
支(zhi)撐(cheng)系(xi)統電(dian)(dian)壓(ya)(ya)(ya)與頻(pin)率。微(wei)電(dian)(dian)網孤島(dao)運行(xing)模(mo)式時(shi),分布式電(dian)(dian)能(neng)存儲(chu)系(xi)統可(ke)作為微(wei)電(dian)(dian)網的(de)(de)主電(dian)(dian)源提供(gong)電(dian)(dian)壓(ya)(ya)(ya)和頻(pin)率支(zhi)持(chi),發(fa)揮快速響(xiang)應的(de)(de)特點,實時(shi)平衡微(wei)電(dian)(dian)網中的(de)(de)功(gong)率波動,維持(chi)電(dian)(dian)壓(ya)(ya)(ya)和頻(pin)率穩定。此外,分布式電(dian)(dian)能(neng)存儲(chu)系(xi)統還可(ke)以在微(wei)電(dian)(dian)網運行(xing)模(mo)式切換時(shi)提供(gong)暫態功(gong)率支(zhi)撐(cheng),盡可(ke)能(neng)減小對用(yong)戶(hu)負(fu)荷(he)的(de)(de)沖(chong)擊(ji)。
2.4 在用(yong)戶側的應用(yong)
發揮不(bu)間(jian)斷電源作用。分布(bu)式電能存儲系統由于具有快速(su)響(xiang)應(ying)能力,可以作為不(bu)間(jian)斷電源(UPS),在停電時確保重要(yao)負荷供電,提高(gao)供電可靠(kao)性,這一模(mo)式已經獲得廣泛應(ying)用。
實(shi)現(xian)需(xu)求側響應(ying)。安(an)裝在用(yong)戶側的分布式電(dian)能存(cun)儲系統,可(ke)用(yong)于(yu)參與需(xu)求側響應(ying),幫助用(yong)戶在不改(gai)變用(yong)電(dian)習(xi)慣的情況下進行(xing)錯(cuo)峰用(yong)電(dian),降低購(gou)電(dian)費用(yong)。對于(yu)電(dian)網而言,錯(cuo)峰用(yong)電(dian)將(jiang)會顯著提高(gao)電(dian)網的資產利用(yong)率,延(yan)緩系統改(gai)擴(kuo)建,具有多方面的經濟性。
改善電能質量(liang)。間歇性的分布式(shi)電源(yuan)和大量(liang)電力(li)電子設(she)備的應用可(ke)能會造成高(gao)次諧波(bo)、電壓(ya)(ya)閃變、電壓(ya)(ya)跌(die)落等電能質量(liang)問題。在用戶側接入分布式(shi)電能存儲系(xi)統(tong),能快速響應系(xi)統(tong)中(zhong)各種擾動,有效控(kong)制(zhi)波(bo)形畸(ji)變率在較小的范圍內,提高(gao)用戶電能質量(liang)。