华北电力大学电力系统分析4-02

§4-2简单故障的再分析特殊相问题简单故障时：习惯上总是取a相作特殊相。若实际的特殊相不是a相，仍可套用。复杂故障时：多重故障；特殊相不都是a相；采用通用边界条件和通用复合序网。一、短路故障通用复合序网通用短路故障示意图：abcaUbUcUcIbIaI0IgZcZbZaZ单相接地短路：a相：Za=0、Zb=∞、Zc=∞b相：Za=∞、Zb=0、Zc=∞c相：Za=∞、Zb=∞、Zc=0Zg=0或较小两相(接地)短路：b,c相：Za=∞、Zb=0、Zc=0c,a相：Za=0、Zb=∞、Zc=0a,b相：Za=0、Zb=0、Zc=∞接地短路：Zg=0或较小不接地短路：Zg=∞一、短路故障通用复合序网短路故障的求解：1aU)1(K)1(N1aI正序网络)2(K)2(Na2Ua2I负序网络a0Ua0I零序网络)0(K)0(Na1a1(1)|0|UIZUa2a2(2)0UIZa0a0(0)0UIZ三个方程，六个未知量。一、短路故障通用复合序网1．单相接地短路1aU)1(K)1(N1aI正序网络)2(K)2(Na2Ua2I负序网络a0Ua0I零序网络)0(K)0(Na0a2a1IIIa0ga0a2a13IZUUUa相短路：0bI0cIagaIZUg3Z03a0ga0a2a1IZUUU一、短路故障通用复合序网1．单相接地短路a0a2a1III03a0ga0a2a1IZUUUa相短路：1aU)1(K)1(N1aI正序网络)2(K)2(Na2Ua2I负序网络a0Ua0I零序网络)0(K)0(Ng3Za0a2a12IIaIaa0ga0a2a123IZUUaUab相短路：0aI0cIbgbIZUb0b2b1IIIb0gb0b2b13IZUUU1:a21:a1:103a0ga0a2a12IZUUaUa一、短路故障通用复合序网1．单相接地短路1:a21aU)1(K)1(N1aI正序网络1:a)2(K)2(Na2Ua2I负序网络1:1a0Ua0I零序网络)0(K)0(Ng3Za0a2a1IIIa0a2a12IIaIa03a0ga0a2a12IZUUaUaa相短路：b相短路：a0a22a1IIaIa03a0ga0a22a1IZUUaUac相短路：03a0ga0a2a1IZUUU一、短路故障通用复合序网1．单相接地短路a0a2a1IIIa0a2a12IIaIaa0a22a1IIaIaa相短路：b相短路：c相短路：1:a1aU)1(K)1(N1aI正序网络1:a2)2(K)2(Na2Ua2I负序网络1:1a0Ua0I零序网络)0(K)0(Ng3Z03a0ga0a2a12IZUUaUa03a0ga0a22a1IZUUaUa03a0ga0a2a1IZUUU一、短路故障通用复合序网1．单相接地短路1:n11aU)1(K)1(N1aI正序网络1:n2)2(K)2(Na2Ua2I负序网络1:n0a0Ua0I零序网络)0(K)0(Ng3Za0a2a1IIIa0a2a12IIaIaa0a22a1IIaIa0)3(a0ga00a22a11a00a22a11IZUnUnUnInInIna相短路：b相短路：c相短路：通用边界条件：故障相n1n2n0a111ba2a1caa2103a0ga0a2a12IZUUaUa03a0ga0a22a1IZUUaUa03a0ga0a2a1IZUUU一、短路故障通用复合序网2．两相接地短路1aU)1(K)1(N1aI正序网络)2(K)2(Na2Ua2I负序网络b,c相接地短路：0aI0gcbIZUU0a0a2a1IIIa0ga0a2a13IZUUUa0Ua0I零序网络)0(K)0(Ng3Z一、短路故障通用复合序网2．两相接地短路通用边界条件：)3(0a0ga00a22a11a00a22a11IZUnUnUnInInIn1:n11aU)1(K)1(N1aI正序网络1:n2)2(K)2(Na2Ua2I负序网络1:n0a0Ua0I零序网络)0(K)0(Ng3Z故障相n1n2n0b,c111c,aa2a1a,baa21b,c相接地短路：0a0a2a1III0a0a2a12IIaIa0a0a22a1IIaIac,a相接地短路：a,b相接地短路：a0ga0a2a123IZUUaUaa0ga0a22a13IZUUaUaa0ga0a2a13IZUUU一、短路故障通用复合序网3．两相短路通用边界条件：a22a11a22a110UnUnInIn1:n11aU)1(K)1(N1aI正序网络1:n2)2(K)2(Na2Ua2I负序网络故障相n1n2b,c11c,aa2aa,baa2二、断线故障通用复合序网通用断线故障示意图：abcbUcUcIbIaIcZbZaZaU单相断线故障：a相：Za=∞、Zb=0、Zc=0b相：Zb=∞、Za=0、Zc=0c相：Zc=∞、Za=0、Zb=0两相断线故障：a,b相：Za=∞、Zb=∞、Zc=0b,c相：Zb=∞、Zc=∞、Za=0c,a相：Zc=∞、Za=∞、Zb=0二、断线故障通用复合序网1．两相断线b,c相断线：1aU)1(L)1(L1aI正序网络)2(L)2(La2Ua2I负序网络)1(L零序网络)1(L)0(L)0(La0a2a1III0a0a2a1UUU0bI0cIagaIZU二、断线故障通用复合序网1．两相断线a0a2a1IIIa0a2a12IIaIaa0a22a1IIaIab,c相断线：c,a相断线：a,b相断线：通用边界条件：0a0a2a1UUU0a0a2a12UUaUa0a0a22a1UUaUa0a00a22a11a00a22a11UnUnUnInInIn1:n11:n21:n01aU)1(L)1(L1aI正序网络)2(L)2(La2Ua2I负序网络)1(L零序网络)1(L)0(L)0(L故障相n1n2n0b,c111c,aa2a1a,baa21二、断线故障通用复合序网2．单相断线1aU)1(L)1(L1aI正序网络)2(L)2(La2Ua2I负序网络)1(L零序网络)1(L)0(L)0(La相断线：0aI0cbUU0a0a2a1IIIa0a2a1UUU二、断线故障通用复合序网2．单相断线0a0a2a1III0a0a2a12IIaIa0a0a22a1IIaIaa相断线：b相断线：c相断线：a0a2a1UUUa0a2a12UUaUaa0a22a1UUaUa通用边界条件：a00a22a11a00a22a110UnUnUnInInIn1aU)1(L)1(L1aI正序网络)2(L)2(La2Ua2I负序网络)1(L零序网络)1(L)0(L)0(L1:n11:n21:n0故障相n1n2n0a111ba2a1caa21三、小结①若实际故障的特殊相不同于参考相a相，则在边界条件中出现复数运算子a，复合序网中出现理想变压器。②单相接地短路和两相断线具有类似边界条件：0a00a22a11a00a22a11UnUnUnInInIn复合序网的理想变压器二次侧串联，串联型故障。③单相断线和两相接地短路具有类似边界条件：a00a22a11a00a22a110UnUnUnInInIn复合序网的理想变压器二次侧并联，并联型故障。三、小结④复合序网中理想变压器的变比取决于特殊相别：特殊相n1n2n0A111Ba2a1caa21