一、通信電源為什么是-48V

1、-48V的(de)電源電壓(ya)(ya)會比較安(an)全一點：例如人身體(ti)是50K歐(ou)姆(mu)電阻，電壓(ya)(ya)-48V，48/50000=0.00096A=0.96mA，人體(ti)流過9mA就有(you)生命危險(xian)了。

2、歷史(shi)的沿襲：多年(nian)前(qian)，使用(yong)電子管和PNP型鍺管的時候(hou)，電路正極接(jie)地(di)來得直觀簡單方便。負電源(yuan)(yuan)的抗(kang)干(gan)擾性(xing)要好一(yi)些，不過這是很久(jiu)以前(qian)的原(yuan)因，現在的數(shu)字化技(ji)術對(dui)這要求已(yi)不高，所(suo)以現在設(she)備也(ye)有用(yong)正電源(yuan)(yuan)，但考慮習慣通用(yong)性(xing)大多也(ye)還是-48V。

3、電源系統正極接地可以(yi)減少蓄電池正極的腐蝕(shi)現象。

4、降(jiang)低系統雜(za)音，減(jian)少干擾。

5、早(zao)期通信可用大地作回路，節約線(xian)材(cai)。

6、為保(bao)護線(xian)(xian)纜，使其不會由于(yu)電池(chi)反應而被腐蝕(shi)，線(xian)(xian)纜必須為負極(ji)。

7、電壓比(bi)-24V高，有利于電量傳(chuan)輸，減少(shao)損耗。

二、通信電源系統有哪幾部分組成？

1、交流(liu)配電(dian)(dian)(dian)(dian)(dian)單元：交流(liu)配電(dian)(dian)(dian)(dian)(dian)單元將市(shi)(shi)(shi)電(dian)(dian)(dian)(dian)(dian)接入，經過切換送入系(xi)統，交流(liu)電(dian)(dian)(dian)(dian)(dian)經分配單元分配后，一部分提供(gong)給(gei)開關整(zheng)流(liu)器，一部分作為(wei)備用輸出(chu)，供(gong)用戶使用。 系(xi)統可以由(you)兩路(lu)市(shi)(shi)(shi)電(dian)(dian)(dian)(dian)(dian)(或一路(lu)市(shi)(shi)(shi)電(dian)(dian)(dian)(dian)(dian)一路(lu)油機)供(gong)電(dian)(dian)(dian)(dian)(dian)，兩路(lu)市(shi)(shi)(shi)電(dian)(dian)(dian)(dian)(dian)主備工(gong)作方式，平時由(you)市(shi)(shi)(shi)電(dian)(dian)(dian)(dian)(dian)1供(gong)電(dian)(dian)(dian)(dian)(dian)，當市(shi)(shi)(shi)電(dian)(dian)(dian)(dian)(dian)1發生故障時，切換到市(shi)(shi)(shi)電(dian)(dian)(dian)(dian)(dian)2（或者油機），在切換過程(cheng)中，通信設備的(de)供(gong)電(dian)(dian)(dian)(dian)(dian)由(you)蓄電(dian)(dian)(dian)(dian)(dian)池來供(gong)給(gei)。

2、整(zheng)流部(bu)分：整(zheng)流部(bu)分的功能是將由交流配電單(dan)元(yuan)提供(gong)的交流電變換(huan)成(cheng)48V或者24V直(zhi)流電輸(shu)出到直(zhi)流配電單(dan)元(yuan)。整(zheng)流部(bu)分包(bao)括整(zheng)流模塊和(he)結構(gou)部(bu)分（機架(jia)）。

該圖片由注冊用戶"生活有品"提供，版權聲明反饋

3、直(zhi)(zhi)流(liu)(liu)(liu)配(pei)(pei)(pei)電(dian)(dian)單(dan)(dan)元(yuan)：直(zhi)(zhi)流(liu)(liu)(liu)配(pei)(pei)(pei)電(dian)(dian)單(dan)(dan)元(yuan)完成直(zhi)(zhi)流(liu)(liu)(liu)的(de)(de)(de)分(fen)配(pei)(pei)(pei)和(he)備用電(dian)(dian)池(chi)(chi)組的(de)(de)(de)接(jie)入。開關(guan)整(zheng)流(liu)(liu)(liu)器(qi)的(de)(de)(de)輸(shu)出(chu)經(jing)匯流(liu)(liu)(liu)母(mu)排接(jie)入直(zhi)(zhi)流(liu)(liu)(liu)配(pei)(pei)(pei)電(dian)(dian)單(dan)(dan)元(yuan)，配(pei)(pei)(pei)電(dian)(dian)單(dan)(dan)元(yuan)為負(fu)載(zai)分(fen)配(pei)(pei)(pei)不(bu)同(tong)容量(liang)的(de)(de)(de)輸(shu)出(chu)，可滿足不(bu)同(tong)的(de)(de)(de)需要，后備電(dian)(dian)池(chi)(chi)組的(de)(de)(de)輸(shu)入與開關(guan)整(zheng)流(liu)(liu)(liu)器(qi)輸(shu)出(chu)匯流(liu)(liu)(liu)母(mu)排并聯，以(yi)保(bao)證(zheng)開關(guan)整(zheng)流(liu)(liu)(liu)器(qi)無輸(shu)出(chu)時，后備電(dian)(dian)池(chi)(chi)組能(neng)向負(fu)載(zai)供電(dian)(dian)。

4、蓄電池組：通信電(dian)(dian)源系(xi)統中(zhong)采用(yong)(yong)整(zheng)流器和蓄(xu)電(dian)(dian)池組并聯冗余供電(dian)(dian)方(fang)式(shi)。蓄(xu)電(dian)(dian)池組既為備用(yong)(yong)電(dian)(dian)源，又(you)可以吸收高頻紋波電(dian)(dian)流。目前常用(yong)(yong)的蓄(xu)電(dian)(dian)池為閥控(kong)式(shi)密封鉛酸蓄(xu)電(dian)(dian)池，即VRLA，因為較之傳統的開口型電(dian)(dian)池密封性好、自(zi)放(fang)電(dian)(dian)小、壽命長，又(you)被稱(cheng)為“免維護蓄(xu)電(dian)(dian)池”。

5、監控(kong)(kong)系(xi)統：監控(kong)(kong)系(xi)統以多級自(zi)下而上逐級匯接(jie)(jie)(jie)的(de)方式(shi)構成(cheng)。每個監控(kong)(kong)級一般按輻射方式(shi)與若干(gan)下級監控(kong)(kong)級連(lian)接(jie)(jie)(jie)成(cheng)一點對多點的(de)監控(kong)(kong)系(xi)統，最低一級為設備監控(kong)(kong)單元(yuan)（監控(kong)(kong)模塊(kuai)）與其監控(kong)(kong)的(de)若干(gan)設備的(de)連(lian)接(jie)(jie)(jie)。