基于虛擬制動(dòng)電流的改進(jìn)互感器飽和識(shí)別方法研究
周斌,卜京,湯雪松,游步新
南京理工大學(xué) 自動(dòng)化學(xué)院,江蘇 南京 210094
摘 要:為解決利用時(shí)差法識(shí)別區(qū)外故障后閉鎖差動(dòng)保護(hù)期間發(fā)生區(qū)內(nèi)故障,導(dǎo)致保護(hù)延時(shí)動(dòng)作的問(wèn)題,結(jié)合虛擬制動(dòng)電流采樣點(diǎn)檢測(cè)CT飽和方法,提出了引入相對(duì)磁鏈積累變化情況及交流量幅值特征作為開放保護(hù)的輔助判據(jù),并利用相對(duì)磁鏈累積一周波內(nèi)的方差來(lái)代表變化情況以及最小二乘法擬合得到二次電流的交流幅值,以達(dá)到正確識(shí)別轉(zhuǎn)換性故障的目的。通過(guò)四種工況仿真表明,該法提高了抗區(qū)外故障的飽和能力,保證了保護(hù)的可靠性和靈敏性。
關(guān)鍵詞:電流互感器;虛擬制動(dòng);相對(duì)磁鏈積累;差動(dòng)保護(hù)
中圖分類號(hào):TM452 文獻(xiàn)標(biāo)識(shí)碼:A 文章編號(hào):1007-3175(2015)10-0016-05
Research on an Improved Method to Identify Current Transformer Saturation Based on Virtual Brake Current
ZHOU Bin, BU Jing, TANG Xue-song, YOU Bu-xin
School of Automation, Nanjing University of Science and Technology, Nanjing 210094, China
Abstract: To solve the delay action of protection when the external faults change to be the internal faults during the block of differential current protection, based on the method of testing current transformer saturation at virtual brake current sampling point, this paper proposed to introduce the characteristic of relative flux linkage accumulation and the amplitude of the current as a new criterion to open the protection, using the relative flux linkage accumulation variance at one cycle and the real-time least square (RLS) algorithm to obtain the amplitude of secondary current, so as to distinguish the transferring faults accurately. Four kinds of working conditions simulation shows that this method resists external faults saturation more strongly to ensure the reliability and sensibility of protection.
Key words: current transformer; virtual brake; relative flux linkage accumulation; differential protection
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