井下变电所处短路容量及三相短路电流

井下变电所处短路容量及三相短路电流 建设煤矿二采区井下变电所母线短路容量及短路电流 一、 已知技术参数 至建设矿开关所至 出口最小二采开关井下变电长度变电所名至二采开架空线型号 线号 短路容量 所长度所电缆型(Km) 称 关所线号 (Km) 号 3135 LGJ-240 1.8 33521 MYJV22-0.9 35 LGJ-120 1.11 龙湖变 81MVA 3216 LGJ-240 3.55 31604 MYJV22-0.9 35 二、电缆其主要参数为: 名称 型号 每公里电阻 每公里电抗 2 架空线 LGJ-2400.13 0.3 2 LGJ-1200.255 0.347 2交联聚氯乙烯 MYJV-35 0.612 0.064 22 三、龙湖变母线最小短路容量:81(MVA) (1) 3135电源短路容量:Sd = 81(MVA) 电源系统电抗:Xs = Up?/Ss = 6.3?/81 = 0.49(Ω) 高压线路总电阻:Xg = ?(XiLi) = (0.13×1.8+0.255×1.11+0.612×0.9) = 1.067(Ω) 高压线路总电抗:Rg = ?( RiLi ) = (0.3×1.8+0.347×1.11+0.064×0.9) = 0.982 (Ω) 总阻抗:Z = ?(Rg? + (Xs + Xg)?) = ?(1.067?+(0.49+0. 982)?) = 1.818 (Ω) (3)三相短路电流:I = U/(?3×Z)= 6300/(?3×1.818) = 1983.68(A)二相短dp(2)(3)路电流:I = (?3)/2×I = (?3)/2×2185.9 = 1717.86(A) dd 33521线至高防开关处短路容量: (3)-6?3)×ISd = (×U×10 dp-6 = ?3×1983.68×6300×10 = 21.64(MVA ) (2) 3216电源短路容量:Sd = 81(MVA) 电源系统电抗:Xs = Up?/Ss = 6.3?/81 = 0.49(Ω) 高压线路总电阻:Xg = ?(XiLi) = (0.13×3.55+0.612×0.9)= 0.9848 (Ω) 高压线路总电抗:Rg = ?( RiLi ) = (0.3×3.55+0.064×0.9)= 1.122 (Ω) 总阻抗:Z = ?(Rg? + (Xs + Xg)?) = ?(0. 9848?+(0.49+1.122)?) = 1.889 (Ω) (3)三相短路电流:I = U/(?3×Z)= 6300/(?3×1.889) = 1926.01(A)二相短dp(2)(3)路电流:I = (?3)/2×I = (?3)/2×1926.01 = 1667.9(A) dd 31604线至高防开关处短路容量: -6(3)Sd = (?3)×I×U×10 dp-6 = ?3×1926.01×6300×10 = 20.02(MVA ) 三、龙湖变母线最大短路容量:93(MVA) (1) 3135电源短路容量:Sd = 93(MVA) 电源系统电抗:Xs = Up?/Ss = 6.3?/93 = 0.43(Ω) 高压线路总电阻:Xg = ?(XiLi) = (0.13×1.8+0.255×1.11)= 0.517(Ω) 高压线路总电抗:Rg = ?( RiLi ) = (0.3×1.8+0.347×1.11) = 0.925 (Ω) 总阻抗:Z = ?(Rg? + (Xs + Xg)?) = ?(0.925?+(0.43+0. 517)?) = 1.324(Ω) (3)三相短路电流:I = U/(?3×Z)= 6300/(?3×1.324) = 2739(A)二相短路dp(2)(3)电流:I = (?3)/2×I = (?3)/2×2739 = 2372(A) dd 33521线至高防开关处短路容量: -6(3)I×U×10 Sd = (?3)×dp-6 = ?3×2739×6300×10 = 29.89(MVA ) (2) 3216电源短路容量:Sd = 93(MVA) 电源系统电抗:Xs = Up?/Ss = 6.3?/93 = 0.43(Ω) 高压线路总电阻:Xg = ?(XiLi) = (0.13×3.55)= 0.4615 (Ω) 高压线路总电抗:Rg = ?( RiLi ) = (0.3×3.55 )=1.065 (Ω) 总阻抗:Z = ?(Rg? + (Xs + Xg)?) = ?(1.065?+(0.43+0.4615)?) = 1.389 (Ω) (3)三相短路电流:I = U/(?3×Z)= 6300/(?3×1.389) = 2618(A)二相短路电dp(2)(3)流:I = (?3)/2×I = (?3)/2×2618 = 2267(A) dd 31604线至高防开关处短路容量: -6(3)Sd = (?3)×I×U×10 dp-6 = ?3×2618×6300×10 = 28.57(MVA )