簡述發電機勵磁系統

東莞發電機出租發電機的勵磁系統維持電壓水平是其主要任務，主要有三個原因：確保電(dian)(dian)(dian)(dian)(dian)力(li)(li)系統(tong)運行設備的(de)(de)(de)(de)安全。電(dian)(dian)(dian)(dian)(dian)力(li)(li)系統(tong)操作設備有其額定工(gong)作電(dian)(dian)(dian)(dian)(dian)壓(ya)。發電(dian)(dian)(dian)(dian)(dian)機(ji)及其電(dian)(dian)(dian)(dian)(dian)力(li)(li)系統(tong)設備的(de)(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)壓(ya)保持在允(yun)許的(de)(de)(de)(de)水平(ping)是(shi)基本條件之一。因此，發電(dian)(dian)(dian)(dian)(dian)機(ji)的(de)(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)壓(ya)應(ying)保持在給(gei)定的(de)(de)(de)(de)允(yun)許水平(ping)，無論是(shi)靜(jing)態(tai)的(de)(de)(de)(de)還是(shi)動(dong)態(tai)的(de)(de)(de)(de)，大型發電(dian)(dian)(dian)(dian)(dian)機(ji)的(de)(de)(de)(de)工(gong)作電(dian)(dian)(dian)(dian)(dian)壓(ya)不(bu)(bu)應(ying)高于(yu)額定值的(de)(de)(de)(de)１１０％。保持發電(dian)(dian)(dian)(dian)(dian)機(ji)運行的(de)(de)(de)(de)經濟性。如果電(dian)(dian)(dian)(dian)(dian)壓(ya)下(xia)降，輸出相同功率所需的(de)(de)(de)(de)定子電(dian)(dian)(dian)(dian)(dian)流將增加，從而增加損耗。大型發電(dian)(dian)(dian)(dian)(dian)機(ji)的(de)(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)壓(ya)不(bu)(bu)應(ying)低于(yu)額定值的(de)(de)(de)(de)９０％，低于(yu)９５％時應(ying)限制發電(dian)(dian)(dian)(dian)(dian)機(ji)帶負(fu)荷(he)運行。

東莞發電機出租時勵磁系統對改善系統的靜態、動態和瞬態性能有重要作用，是簡單而有效的措施。勵(li)磁控制(zhi)系統對暫態(tai)穩(wen)定的影響。暫態(tai)穩(wen)定性(xing)取決于(yu)加速(su)區(qu)是否小于(yu)或等于(yu)減(jian)速(su)區(qu)。因(yin)此，提(ti)高暫態(tai)穩(wen)定性(xing)的方法有兩種：一(yi)種是減(jian)小加速(su)面積，快速(su)排除(chu)故(gu)障；二(er)是增大(da)減(jian)速(su)面積，增大(da)勵(li)磁系統勵(li)磁電壓響應比，增大(da)強(qiang)勵(li)電壓倍數，使(shi)故(gu)障切除(chu)后(hou)發電機內部電位(wei)ＥＱ迅速(su)增大(da)，從而增大(da)減(jian)速(su)面積。強(qiang)勵(li)一(yi)般為(wei)高電壓一(yi)般為(wei)７～９倍。

東莞發(fa)電(dian)(dian)(dian)(dian)(dian)機(ji)出租(zu)時勵(li)磁控制系(xi)統(tong)(tong)(tong)(tong)對動(dong)態穩(wen)定(ding)(ding)性(xing)的(de)(de)(de)(de)(de)影響。電(dian)(dian)(dian)(dian)(dian)力系(xi)統(tong)(tong)(tong)(tong)的(de)(de)(de)(de)(de)動(dong)態穩(wen)定(ding)(ding)性(xing)可以說(shuo)是(shi)電(dian)(dian)(dian)(dian)(dian)力系(xi)統(tong)(tong)(tong)(tong)機(ji)電(dian)(dian)(dian)(dian)(dian)振蕩的(de)(de)(de)(de)(de)阻(zu)(zu)尼(ni)問題(ti)。自動(dong)電(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)調節在勵(li)磁控制系(xi)統(tong)(tong)(tong)(tong)中的(de)(de)(de)(de)(de)作用是(shi)電(dian)(dian)(dian)(dian)(dian)力系(xi)統(tong)(tong)(tong)(tong)機(ji)電(dian)(dian)(dian)(dian)(dian)振蕩阻(zu)(zu)尼(ni)減弱（甚至為負）的(de)(de)(de)(de)(de)重(zhong)要(yao)原因(yin)。在一定(ding)(ding)的(de)(de)(de)(de)(de)運行(xing)方式(shi)和(he)勵(li)磁系(xi)統(tong)(tong)(tong)(tong)參數下，電(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)調節能(neng)保持(chi)(chi)發(fa)電(dian)(dian)(dian)(dian)(dian)機(ji)電(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)恒(heng)定(ding)(ding)，產(chan)生(sheng)負阻(zu)(zu)尼(ni)效應。在正(zheng)常(chang)的(de)(de)(de)(de)(de)實際范(fan)圍內(nei)，勵(li)磁電(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)的(de)(de)(de)(de)(de)負阻(zu)(zu)尼(ni)效應隨著開(kai)環增(zeng)(zeng)益的(de)(de)(de)(de)(de)增(zeng)(zeng)大而增(zeng)(zeng)大。因(yin)此，提高(gao)電(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)調節精度和(he)動(dong)態穩(wen)定(ding)(ding)性(xing)的(de)(de)(de)(de)(de)要(yao)求(qiu)是(shi)不相容(rong)的(de)(de)(de)(de)(de)。解決調壓(ya)(ya)精度與動(dong)態穩(wen)定(ding)(ding)性(xing)之間的(de)(de)(de)(de)(de)矛(mao)盾，就是(shi)在不影響調壓(ya)(ya)功能(neng)和(he)維(wei)持(chi)(chi)發(fa)電(dian)(dian)(dian)(dian)(dian)機(ji)電(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)能(neng)力的(de)(de)(de)(de)(de)前提下，增(zeng)(zeng)加控制信號，使動(dong)態穩(wen)定(ding)(ding)性(xing)達到或超(chao)過靜態穩(wen)定(ding)(ding)水平。