750 kV主變加裝中性點(diǎn)小抗的研究及應(yīng)用分析
蔡晶1,沈星2,石海珍1,楊利民1,張楠1
(1 國(guó)網(wǎng)新疆電力公司檢修公司,新疆 烏魯木齊 830000;
2 國(guó)網(wǎng)電力科學(xué)研究院武漢南瑞有限責(zé)任公司,湖北 武漢 430074)
摘 要: 為降低烏北750 kV 變電站220 kV 側(cè)的單相及兩相接地( 非對(duì)稱(chēng)) 短路電流,使其小于三相短路電流,采用變壓器中性點(diǎn)加裝小抗的方法來(lái)實(shí)現(xiàn)該目標(biāo)。研究了變壓器中性點(diǎn)小抗的選擇,以及變壓器中性點(diǎn)加裝小抗之后,對(duì)繼電保護(hù)、絕緣配合及倒閘操作的影響。結(jié)果表明,當(dāng)主變壓器中性點(diǎn)經(jīng)小抗接地時(shí),接地短路電流幅值變小,保護(hù)裝置的靈敏度變差,變電站的絕緣配合不受影響。
關(guān)鍵詞: 短路電流;中性點(diǎn)小抗;繼電保護(hù);絕緣配合;倒閘操作
中圖分類(lèi)號(hào):TM403.5 文獻(xiàn)標(biāo)識(shí)碼:A 文章編號(hào):1007-3175(2015)05-0015-05
Research and Application Analysis of 750 kV Main Transformer Adding Neutral Small Reactance
CAI Jing1, SHEN Xing2, SHI Hai-zhen1, YANG Li-min1, ZHANG Nan1
(1 State Grid Xinjiang Maintenance Company, Urumqi 830000, China;
2 Wuhan NARI Co., Ltd, State Grid Electric Power Research Institute, Wuhan 430074, China)
Abstract: To reduce the short-circuit current(asymmetric) of 220 kV side in Wubei 750 kV substation, making it reach the goal of less than three-phase short circuit current, the method of transformer adding neutral small reactance was adopted to reach the goal.This paper studied the choice of transformer neutral small reactance, and the influence of relay protection, insulation coordination and brake operation. The result shows that the grounding short-circuit current amplitude decreases, the sensitivity of protection device tails away, and the insulation coordination of the substation is not affected when the neutral point of main transformer via small reactance grounding.
Key words: short circuit current; neutral small reactance; relay protection; insulation coordination; switching operation
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