三相交流电路仿真

关于三相交流电路的仿真实验庄烨912113100238摘要：在Multisim中建立三相交流电路，设计实验电路参数，通过软件所提供的仪表进行仿真实验，处理实验数据，进行实验分析，研究三相交流电路的特性。关键词：三相交流电路、星形连接、中线、三角形连接。引言：在Multisim仿真软件中进行模拟实验，很好的避开了实验室中场地、设备、数量的限制，如同实验操作台的界面很好的展示实验数据，更方便对三相交流电路的分析，使实验的结果更加清晰的展现出来。实验目的学习三相交流电路负载的星形与三角形连接方法。进一步了解三相交流电路星形与三角形连接时，对称、不对称的线、相电压及线、相电流的关系。加深理解中线在三相电路星形连接中的重要性。实验原理在三相电源对称的情况下，三相负载可以接成星形（Ｙ接)或三角形(△接)。三相四线制电源的电压值一般是指线电压的有效值。如“三相380V电源”是指线电压380V，其相电压为220V；而“三相220V电源”则是指线电压220V，其相电压为127V。1.负载作Y形联接当负载采用三相四线制(Yo)联接时，即在有中线的情况下，不论负载是否对称，线电压Ul是相电压UP的3倍，线电流Il等于相电流Ip，即U1=Up3，I1=Ip当负载对称时，各相电流相等，流过中线的电流Io＝0，所以可以省去中线。若三相负载不对称而又无中线(即三相三线制Y接)时，UP≠1/3Ul，负载的三个相电压不再平衡，各相电流也不相等，致使负载轻的那一相因相电压过高而遭受损坏，负载重的一相也会因相电压过低不能正常工作。所以，不对称三相负载作Y联接时，必须采用三相四线制接法，即Yo接法，而且中线必须牢固联接，以保证三相不对称负载的每相电压维持对称不变。2.负载作△形联接当三相负载作△形联接时，不论负载是否对称，其相电压均等于线电压，即Ul＝Up；若负载对称时，其相电流也对称，相电流与线电流之间的关系为：Il＝3Ip；若负载不对称时，相电流与线电流之间不再是3关系即：Il≠3Ip当三相负载作△形联接时，不论负载是否对称，只要电源的线电压Ul对称，加在三相负载上的电压Up仍是对称的，对各相负载工作没有影响。如图连接实验电路，示波器显示如下图，判断相序。Y型连接有中线负载对称如图连接电路，测出线、相电流及中线电流。连上电压表，分别测出线、相电压及中线电压。V2130V60Hz3PHS1Key=1S2Key=2S3Key=3S5Key=5S6Key=6U1AC1e-009W0.269A+-U2AC1e-009W0.269A+-U3AC1e-009W0.269A+-S4Key=SpaceU11AC1e-009W9.581uA+-1315132X1220VX2220VX3220VX4220VX5220VX6220V456789101112Y型连接无中线负载对称如图连接电路，测出线、相电流及中线电流。V2130V60Hz3PHS1Key=1S2Key=2S3Key=3S5Key=5S6Key=6U1AC1e-009W0.269A+-U2AC1e-009W0.269A+-U3AC1e-009W0.269A+-U4AC10MW225.134V+-U5AC10MW225.136V+-U7AC10MW225.135V+-U8AC10MW129.981V+-U9AC10MW129.984V+-U10AC10MW129.982V+-S4Key=SpaceU11AC1e-009W6.370uA+-13X1220VX2220VX3220VX4220VX5220VX6220V456789101112151162V2130V60Hz3PHS1Key=1S2Key=2S3Key=3S5Key=5S6Key=6U1AC1e-009W0.269A+-U2AC1e-009W0.269A+-U3AC1e-009W0.269A+-S4Key=SpaceX1220VX2220VX3220VX4220VX5220VX6220V4567891011120121615连上电压表，分别测出线、相电压及中线电压。Y型连接有中线负载不对称如图连接电路，测出线、相电流及中线电流。连上电压表，分别测出线、相电压及中线电压。V2130V60Hz3PHS1Key=1S2Key=2S3Key=3S5Key=5S6Key=6U1AC1e-009W0.269A+-U2AC1e-009W0.269A+-U3AC1e-009W0.269A+-U4AC10MW225.134V+-U5AC10MW225.136V+-U6AC10MW0.053pV+-U7AC10MW225.135V+-U8AC10MW129.981V+-U9AC10MW129.985V+-U10AC10MW129.982V+-S4Key=SpaceX1220VX2220VX3220VX4220VX5220VX6220V4567891011121162015V2130V60Hz3PHS1Key=1S2Key=2S3Key=3S5Key=5S6Key=6U1AC1e-009W0.134A+-U2AC1e-009W0.269A+-U3AC1e-009W0.269A+-S4Key=SpaceU11AC1e-009W0.134A+-1315132X1220VX2220VX3220VX4220VX5220VX6220V456789101112Y型连接无中线负载不对称如图连接电路，测出线、相电流及中线电流。V2130V60Hz3PHS1Key=1S2Key=2S3Key=3S5Key=5S6Key=6U1AC1e-009W0.134A+-U2AC1e-009W0.269A+-U3AC1e-009W0.269A+-U4AC10MW225.124V+-U5AC10MW225.129V+-U7AC10MW225.123V+-U8AC10MW129.978V+-U9AC10MW129.978V+-U10AC10MW129.978V+-S4Key=SpaceU11AC1e-009W0.134A+-13X1220VX2220VX3220VX4220VX5220VX6220V456789101112151162V2130V60Hz3PHS1Key=1S2Key=2S3Key=3S5Key=5S6Key=6U1AC1e-009W0.161A+-U2AC1e-009W0.246A+-U3AC1e-009W0.246A+-S4Key=SpaceX1220VX2220VX3220VX4220VX5220VX6220V4567891011120121615连上电压表，分别测出线、相电压及中线电压。Y型连接测量值项目线电压（V）相电压（V）线（相）电流（A）中线电压（V）中线电流（A）ABACBCAOBOCOABC负载对称有中线225.134225.136225.135129.982129.984129.9810.2690.2690.26900.581u无中线225.134225.136225.135129.982129.985129.9810.2690.2690.2690.053p0负载不对称有中线225.124225.129225.123129.978129.978129.9780.2690.1340.26900.134无中线225.134225.128225.128119.126155.980119.1270.2690.1610.26425.9950V2130V60Hz3PHS1Key=1S2Key=2S3Key=3S5Key=5S6Key=6U1AC1e-009W0.161A+-U2AC1e-009W0.246A+-U3AC1e-009W0.246A+-U4AC10MW225.134V+-U5AC10MW225.128V+-U6AC10MW25.995V+-U7AC10MW225.128V+-U8AC10MW119.127V+-U9AC10MW155.980V+-U10AC10MW119.126V+-S4Key=SpaceX1220VX2220VX3220VX4220VX5220VX6220V4567891011121162015三角形连接负载对称如图连接电路，测出线、相电流。连上电压表，分别测出线、相电压。三角型连接负载不对称V1130V60Hz3PHS1Key=1S2Key=2S4Key=4S5Key=5S6Key=6S3Key=3U1AC1e-009W0.806A+-U2AC1e-009W0.465A+-U3AC1e-009W0.806A+-U5AC1e-009W0.465A+-U6AC1e-009W0.465A+-U7AC1e-009W0.806A+-789121015X7220VX8220VX9220VX10220VX11220VX12220V123411145613V1130V60Hz3PHS1Key=1S2Key=2S4Key=4S5Key=5S6Key=6S3Key=3U1AC1e-009W0.806A+-U2AC1e-009W0.465A+-U3AC1e-009W0.806A+-U5AC1e-009W0.465A+-U6AC1e-009W0.465A+-U7AC1e-009W0.806A+-121015X7220VX8220VX9220VX10220VX11220VX12220V123411145613U4AC10MW225.121V+-U8AC10MW225.124V+-U9AC10MW225.124V+-879如图连接电路，测出线、相电流。连上电压表，分别测出线、相电压及中线电压。V1130V60Hz3PHS1Key=1S2Key=2S4Key=4S5Key=5S6Key=6S3Key=3U1AC1e-009W0.806A+-U2AC1e-009W0.465A+-U3AC1e-009W0.615A+-U5AC1e-009W0.233A+-U6AC1e-009W0.465A+-U7AC1e-009W0.615A+-789121015X7220VX8220VX9220VX10220VX11220VX12220V123411145613V1130V60Hz3PHS1Key=1S2Key=2S4Key=4S5Key=5S6Key=6S3Key=3U1AC1e-009W0.806A+-U2AC1e-009W0.465A+-U3AC1e-009W0.615A+-U5AC1e-009W0.233A+-U6AC1e-009W0.465A+-U7AC1e-009W0.615A+-121015X7220VX8220VX9220VX10220VX11220VX12220V123411145613U4AC10MW225.139V+-U8AC10MW225.131V+-U9AC10MW225.128V+-879测量值项目线相电压(V)线电流(A)相电流(A)ABCABACBCAOBOCO负载对称225.121225.124225.1240.4650.4650.4650.8060.8060.806负载不对称225.139225.128225.1310.4650.2330.4650.8060.6150.615实验结果及分析三相星形负载的三相电路中，不论三相负载对称与否，三相负载电压都是相等的，线电压约是相电压的√倍。当三相负载对称时，中线电流位零，且各相的线电流相等；当三线负载不对称是，中线电流不再为零，线电流也不再相等。三相星形负载的三相电路中，线电压约是相电压的√倍。当三相负载对称时，三相负载电压是对称相等的，且各相的线电流相等；当三相负载不对称时，三相负载电压不再对称且线电流也不再相等。在三角形负载三相电路中，当三相负载对称时，线电流是相电流的√倍；当三相负载不对称时，三相负载电流不再对称。