現代電力系統的安全評價問題

電(dian)力系(xi)(xi)統(tong)(tong)(tong)的(de)安全(quan)性是(shi)指系(xi)(xi)統(tong)(tong)(tong)在(zai)發生故(gu)障情況(kuang)下(xia), 系(xi)(xi)統(tong)(tong)(tong)能保持穩(wen)(wen)定(ding)(ding)運(yun)行和正(zheng)常(chang)供(gong)電(dian)的(de)風險程度(du)[1]。傳(chuan)統(tong)(tong)(tong)的(de)電(dian)力系(xi)(xi)統(tong)(tong)(tong)安全(quan)性主要(yao)是(shi)在(zai)發生故(gu)障情況(kuang)下(xia)，研究(jiu)電(dian)力系(xi)(xi)統(tong)(tong)(tong)本身的(de)動態特性，包括系(xi)(xi)統(tong)(tong)(tong)的(de)功角穩(wen)(wen)定(ding)(ding)性、電(dian)壓穩(wen)(wen)定(ding)(ding)性、頻率穩(wen)(wen)定(ding)(ding)性、系(xi)(xi)統(tong)(tong)(tong)解列、熱過(guo)載(zai)等。 這類研究(jiu)一般是(shi)針對單一故(gu)障的(de)，而大面積停(ting)電(dian)事故(gu)則通常(chang)是(shi)連(lian)鎖事件的(de)復(fu)雜序(xu)列。

隨著現代(dai)通(tong)訊技(ji)(ji)(ji)術(shu)和(he)信(xin)息(xi)(xi)技(ji)(ji)(ji)術(shu)的(de)發展(zhan)，為(wei)了保(bao)障(zhang)大電(dian)(dian)(dian)網的(de)安(an)全和(he)經濟運行，各種(zhong)信(xin)息(xi)(xi)系(xi)(xi)(xi)(xi)(xi)統(tong)(tong)(tong)(tong)(tong)，如調度自(zi)(zi)動化(hua)（SCADA/EMS）、配電(dian)(dian)(dian)網自(zi)(zi)動化(hua)系(xi)(xi)(xi)(xi)(xi)統(tong)(tong)(tong)(tong)(tong)（DA）和(he)變電(dian)(dian)(dian)站綜(zong)合(he)自(zi)(zi)動化(hua)系(xi)(xi)(xi)(xi)(xi)統(tong)(tong)(tong)(tong)(tong)（SA），電(dian)(dian)(dian)力市場(chang)技(ji)(ji)(ji)術(shu)支(zhi)持系(xi)(xi)(xi)(xi)(xi)統(tong)(tong)(tong)(tong)(tong)等在電(dian)(dian)(dian)力系(xi)(xi)(xi)(xi)(xi)統(tong)(tong)(tong)(tong)(tong)領域里得到了廣泛應用(yong)。給出了現代(dai)電(dian)(dian)(dian)力系(xi)(xi)(xi)(xi)(xi)統(tong)(tong)(tong)(tong)(tong)的(de)整體構架，電(dian)(dian)(dian)力系(xi)(xi)(xi)(xi)(xi)統(tong)(tong)(tong)(tong)(tong)與信(xin)息(xi)(xi)系(xi)(xi)(xi)(xi)(xi)統(tong)(tong)(tong)(tong)(tong)、通(tong)信(xin)系(xi)(xi)(xi)(xi)(xi)統(tong)(tong)(tong)(tong)(tong)已經融合(he)成為(wei)高(gao)度集成的(de)混雜(za)系(xi)(xi)(xi)(xi)(xi)統(tong)(tong)(tong)(tong)(tong)，電(dian)(dian)(dian)力系(xi)(xi)(xi)(xi)(xi)統(tong)(tong)(tong)(tong)(tong)的(de)監(jian)測和(he)控(kong)制越(yue)來(lai)越(yue)依賴于信(xin)息(xi)(xi)系(xi)(xi)(xi)(xi)(xi)統(tong)(tong)(tong)(tong)(tong)和(he)通(tong)信(xin)系(xi)(xi)(xi)(xi)(xi)統(tong)(tong)(tong)(tong)(tong)的(de)可靠運行。信(xin)息(xi)(xi)系(xi)(xi)(xi)(xi)(xi)統(tong)(tong)(tong)(tong)(tong)中(zhong)的(de)計算(suan)機系(xi)(xi)(xi)(xi)(xi)統(tong)(tong)(tong)(tong)(tong)是核心，計算(suan)機系(xi)(xi)(xi)(xi)(xi)統(tong)(tong)(tong)(tong)(tong)的(de)維護(hu)不當是8.14美加(jia)大停電(dian)(dian)(dian)的(de)基本(ben)原因之一。一個(ge)關鍵通(tong)信(xin)系(xi)(xi)(xi)(xi)(xi)統(tong)(tong)(tong)(tong)(tong)發生故障(zhang)會使整個(ge)系(xi)(xi)(xi)(xi)(xi)統(tong)(tong)(tong)(tong)(tong)陷于癱瘓，進而失去可控(kong)性(xing)和(he)可觀測性(xing)。因此，必須把(ba)電(dian)(dian)(dian)力系(xi)(xi)(xi)(xi)(xi)統(tong)(tong)(tong)(tong)(tong)安(an)全性(xing)的(de)概念加(jia)以拓展(zhan)。

最近一些研究人員提出了電力系統脆弱性（Vulnerability）的概念，作為電力系統動態安全評估的一種新的框架。脆弱性一詞經常出現在環境、生態、計算機網絡等領域的有關文獻中, 用來描述相關系統及其組成要素易于受到影響和破壞, 并缺乏抗拒干擾、恢復初始狀態（自身結構和功能）的能力。它們在不同的學科中有不同的含義。對于電力系統脆弱性，可定義為：電力系統因人為干預、信息、計算機（軟、硬件）、通信、電力系統元件和保護控制系統等因素，而潛伏著大面積停電的災難性事故的危險狀態。系統脆弱性與系統安全評價的水平和在系統參數變化時系統安全性水平的變化趨勢這兩類信息密切相關]。

在這(zhe)個概(gai)念中, 人(ren)們(men)對它(ta)們(men)設定(ding)一個可被接受的基準(zhun)值, 當系(xi)統(tong)安(an)全現狀被評估后(hou)，系(xi)統(tong)安(an)全性水平和它(ta)的變化趨(qu)勢也就(jiu)被確定(ding)下來。系(xi)統(tong)是(shi)否脆弱取決于它(ta)們(men)是(shi)否高于或(huo)低于設定(ding)的基準(zhun)值。