潮流计算及电压降[版本].docVIP

第3章 简单电力系统的潮流计算 　3.1 线路的电压降落和功率损耗 　3.2 变压器的电压降落和功率损耗 　3.3 辐射网潮流计算 　3.4 环网潮流计算 　　电力系统潮流计算是指节点电压和支路功率分布的计算。详细地讲，电力系统潮流计算就是根据给定的某些运行条件（比如：有功、无功负荷，发电机的有功出力，发电机母线电压大小等）和电力系统接线方式，求解电网中各母线的电压、各条线路和各台变压器中的功率及功率损耗。 3.1 线路的电压降落和功率损耗 字体大小:小中大 3.1.1 标志电网电压运行水平的指标 电压降落—指线路始、末两端电压的相量差，即： 比如： 电压损耗—指线路始、末两端电压的数量差，即：U1–U2 或 比如： 电压损耗 电压偏移—指线路始端或末端电压与线路额定电压的数值差，即：U1–UN及 U2–UN或 比如，始端电压偏移： 末端电压偏移： 3.1.2 线路的电压降落 在短线路的等值电路中，如果参数和变量都用单相值，则 在上式两边同乘以√3∠30°，便可以将相电压相量改为线电压相量，单相功率也可以用三相功率表示： 取，则电压降落为： 相量图： 如果取，则 3.1.3 线路的功率损耗 单相功率损耗： 三相功率损耗： 3.1.4 考虑线路并联导纳时的电压降落和功率损耗 当采用Ⅱ型等值电路时，必须考虑并联导纳支路的功率： 电压降落： 三相功率损耗： 注意：公式中的功率为三相功率，电压为线电压。如果功率为容性，即，则有关公式中的无功功率符号要改变，为： 3.1.5 高压线路空载特性分析 可见，U1＜U2! 此外， [例3-1] 一条220kV线路，长150km，始端电压225kV，参数为：r1=0.131Ω/km，x1=0.394Ω/km，b1=2.89×10-6 S/km，试求线路空载时的末端电压。 解：全线路的集中参数为 R=0.131×150=19.65(Ω) X=0.394×150=59.1(Ω) B=2.89×10-6 ×150=433.5×10-6 (S) of the contract must be /; Seven or one copy of the contract, each contract form, contents and elements; VIII, master/slave contract and complete specification interface, contract number. 5.9 other provisions the Bank supports risk managers, accompanied by professional risk management, such as account managers handle the pre-loan investigation, contracts and other key sectors. Risk managers and other professional accompanied by risk managers, account managers are still subject to these measures (procedures) for the fulfilment of duties, qilu Bank risk managers, risk managers, in accordance with the administrative procedures (trial implementation) called for duties. Risk management risk managers and other professional personnel involved in handling, account manager with double handle. 6. the credit policy of the Bank to support capital uses reasonable and sufficient source of repayment, parties of good credit personal loans. As described in the Banks credit policy, marketing advice, business management and other documents. 7. process description and control business processes including personal loans loan application, acceptance and