眾所周知，目前國內電力調度網都是通過SDH設備與PCM設備配合承載著電力生產所需的話音、遠動、計算機信息等數據。但PCM設備這款產(chan)品的專(zhuan)用(yong)性，需要成對使用(yong)，所以它在(zai)使用(yong)的過程中也存在(zai)著一些端(duan)弊(bi)。

調(diao)度中(zhong)心(xin)、變(bian)(bian)(bian)電(dian)(dian)(dian)(dian)(dian)站(zhan)(zhan)(zhan)(zhan)、發電(dian)(dian)(dian)(dian)(dian)站(zhan)(zhan)(zhan)(zhan)等通(tong)(tong)信(xin)站(zhan)(zhan)(zhan)(zhan)點(dian)多而(er)(er)分散，每個(ge)變(bian)(bian)(bian)電(dian)(dian)(dian)(dian)(dian)站(zhan)(zhan)(zhan)(zhan)或發電(dian)(dian)(dian)(dian)(dian)站(zhan)(zhan)(zhan)(zhan)的業務通(tong)(tong)信(xin)種類較少，一(yi)般情(qing)況下只需(xu)傳送的電(dian)(dian)(dian)(dian)(dian)力調(diao)度數據主(zhu)要有(you)(you)調(diao)度專線電(dian)(dian)(dian)(dian)(dian)話(hua)信(xin)息、行政電(dian)(dian)(dian)(dian)(dian)話(hua)信(xin)息和自動化遠動信(xin)息。而(er)(er)且目前變(bian)(bian)(bian)電(dian)(dian)(dian)(dian)(dian)站(zhan)(zhan)(zhan)(zhan)或發電(dian)(dian)(dian)(dian)(dian)站(zhan)(zhan)(zhan)(zhan)都采用傳統的點(dian)對(dui)點(dian)通(tong)(tong)信(xin)方式，即調(diao)度中(zhong)心(xin)站(zhan)(zhan)(zhan)(zhan)與每一(yi)個(ge)變(bian)(bian)(bian)電(dian)(dian)(dian)(dian)(dian)站(zhan)(zhan)(zhan)(zhan)或發電(dian)(dian)(dian)(dian)(dian)站(zhan)(zhan)(zhan)(zhan)各配置一(yi)套PCM設備(bei)，如(ru)果(guo)有(you)(you)5個(ge)變(bian)(bian)(bian)電(dian)(dian)(dian)(dian)(dian)站(zhan)(zhan)(zhan)(zhan)的話(hua)，就等于調(diao)度中(zhong)心(xin)有(you)(you)5臺PCM設備(bei)分別(bie)與5個(ge)變(bian)(bian)(bian)電(dian)(dian)(dian)(dian)(dian)站(zhan)(zhan)(zhan)(zhan)的5臺PCM設備(bei)點(dian)對(dui)點(dian)傳輸（如(ru)圖1）。針對(dui)于一(yi)般變(bian)(bian)(bian)電(dian)(dian)(dian)(dian)(dian)站(zhan)(zhan)(zhan)(zhan)的通(tong)(tong)信(xin)量也(ye)不(bu)大，每個(ge)站(zhan)(zhan)(zhan)(zhan)點(dian)也(ye)就是10~20路(lu)話(hua)路(lu)數左(zuo)右就可以(yi)滿(man)足需(xu)求(qiu)，而(er)(er)一(yi)路(lu)2M通(tong)(tong)道可以(yi)傳輸30路(lu)話(hua)路(lu)，只占用了1/2左(zuo)右的2M電(dian)(dian)(dian)(dian)(dian)路(lu)，所以(yi)這種組(zu)網方式并沒有(you)(you)充分利用2M電(dian)(dian)(dian)(dian)(dian)路(lu)。

圖(tu)1（PCM設備(bei)點對點傳(chuan)輸）

針對上述情況，數字交叉連接設備（DXC）可(ke)以很好的(de)解決這(zhe)一(yi)(yi)問題。它是一(yi)(yi)款(kuan)能(neng)夠(gou)將任意一(yi)(yi)個64k時(shi)隙交叉連(lian)(lian)(lian)接(jie)(jie)，設備內(nei)部配有多路2M連(lian)(lian)(lian)接(jie)(jie)口(kou)(kou)，通過內(nei)置的(de)交叉矩陣(zhen)和軟件控制，某個E1端口(kou)(kou)的(de)某個用(yong)戶(hu)時(shi)隙都可(ke)以連(lian)(lian)(lian)接(jie)(jie)到(dao)任意一(yi)(yi)個E1端口(kou)(kou)的(de)任意一(yi)(yi)個用(yong)戶(hu)時(shi)隙，從而實現不同E1端口(kou)(kou)的(de)時(shi)隙交叉連(lian)(lian)(lian)接(jie)(jie)功能(neng)。

數字交叉連接設備工作原理很簡單，它可以將第1路2M電路里的第1時隙數據交叉連接到第2路2M電路里的第1時隙數據，如果沒有數字交叉連接設備的話，第1路2M電路里的第1時隙只能與第1路2M電路里的第1時隙數據相連接。如圖2所示，來自調度中心的的2M電路PCM信號都分(fen)別帶有調(diao)(diao)度(du)電話(hua)業務、遠動業務和會議電話(hua)業務等(deng)信息，被送至(zhi)調(diao)(diao)度(du)中(zhong)心的64 Kbps數字(zi)交叉設(she)(she)備(bei)(bei)；64 Kbps數字(zi)交叉設(she)(she)備(bei)(bei)利用其時隙交叉功能(neng)，把來(lai)自(zi)5個(ge)遠端站不同PCM設(she)(she)這(zhe)種(zhong)情況充(chong)分(fen)利用了PCM板卡(ka)各個(ge)模(mo)塊(kuai)(kuai)插(cha)槽(cao)(cao)位(wei)，減(jian)少調(diao)(diao)度(du)中(zhong)心PCM板卡(ka)數量，節省資金。備(bei)(bei)的同一種(zhong)業務挑選(xuan)出來(lai)，匯聚成一個(ge)或多個(ge)2 Mbps信號。這(zhe)一功能(neng)與郵局通過(guo)分(fen)揀(jian)郵件(jian)可大(da)大(da)提高郵遞(di)員工(gong)作效(xiao)率相似(si)。這(zhe)種(zhong)情況大(da)大(da)提高了PCM板卡(ka)各個(ge)模(mo)塊(kuai)(kuai)插(cha)槽(cao)(cao)位(wei)利用率，減(jian)少調(diao)(diao)度(du)中(zhong)心PCM板卡(ka)數量，節省資金。

圖2（1臺PCM設(she)備對應多臺PCM設(she)備）

目前國內(nei)一(yi)些(xie)電(dian)力系統招(zhao)標都(dou)配有數(shu)字(zi)交(jiao)叉連接設(she)備(bei)，當設(she)備(bei)正(zheng)常開通后(hou)卻忽略了這一(yi)點(dian)，使(shi)(shi)數(shu)字(zi)交(jiao)叉功能(neng)并沒有真正(zheng)的使(shi)(shi)用(yong)上(shang)。如果每(mei)一(yi)個變電(dian)站(zhan)都(dou)使(shi)(shi)用(yong)點(dian)對(dui)點(dian)方式組(zu)網，日(ri)子長了，將浪費很(hen)多資源(yuan)，而且不(bu)方便管理。通過(guo)本方案的分(fen)析后(hou)，相信大家都(dou)對(dui)數(shu)字(zi)交(jiao)叉連接設(she)備(bei)有了一(yi)定的了解，能(neng)夠很(hen)好的利用(yong)數(shu)字(zi)交(jiao)叉連接設(she)備(bei)組(zu)建一(yi)個的高效、穩定、安全(quan)、可靠的調度(du)網運。