220KV电网继电保护本科生毕业论文

〔UdⅠ—Ⅲ(%)+UdⅡ—Ⅲ(%)-UdⅠ—Ⅱ(%)〕(2-13)Р式中:UdⅠ—Ⅱ(%)、UdⅠ—Ⅲ(%)、 UdⅡ—Ⅲ(%)分别为高压与中压,高压与低压,中压与低压之间的短路电压百分值。Р2)各绕组的电抗有名值:РXT1 = (2-14)РXT2 = (2-15)РXT3 = (2-16)Р各绕组的电抗标幺值: Р XT1* = (2-17)Р XT2* = (2-18)Р XT3* = (2-19)Р式中: SB ——基准容量1000MVA;Р SN ——变压器额定容量;Р ——发电机的额定电压;Р ——基准电压230kv.Р(3) 大同厂变压器参数计算:Р已知: SN = 240MW =14.12 Р 则: Р(4) 西万庄变压器参数计算:Р已知: SN = 240MW =11.50 =7.60 =23.70 则: 各绕组的阻抗百分值为:РUK1% = (+-)Р = ( 11.50 + 23.7 - 7.60 )Р = 13.8РUK2% = (+-)Р = ( 7.60 + 11.50 – 23.70 )Р = –2.3РUK1% = (+-)Р = ( 23.70 + 7.60 – 11.50 )Р = 9.9РXT1* = = = 0.575РXT2* = = =0.096РXT3* = = = 0.412Р对于高碑店变压器参数计算原则与2.4(4)相同,计算结果如表2-2所示:Р表2-2 各变压器参数计算结果Р变压器Р编号Р容量Р(MVA)Р绕组型式Р短路电压百分值РUk(%)Р等值电抗Р标幺值РT1Р240Р双相双绕组Р14.12%Р0.588РT2Р240Р双相双绕组Р14.12%Р0.588РT3Р240Р三相三绕组РUdⅠ—Ⅱ(%)= 11.50 %РUdⅡ—Ⅲ(%)= 7.60 %РUdⅠ—Ⅲ(%)= 23.70 %Р0.575Р0Р0.412