同样，也可由首端电压和功率求得末端电压V, = V(V -△V)? +(SV)2SVVS=tgANV-AVV-VSVSPR+O,XAVi =ViAV2F(3-13)PX-Q,RoVi =ViSCU-SEEI-Tqliu2025/8/77
7 SCU-SEEI-Tqliu 2025/8/7 同样,也可由首端电压和功率求得末端电压 2 1 2 2 1 1 V = (V − V ) + (V ) 1 1 1 1 V V V tg − = − − = + = 1 1 1 1 1 1 1 1 V P X Q R V V PR Q X V (3-13)
电压降落公式的简化：高压输电线路的特性X>>R，可令R~0QXPR+OX-则: △V = AVViVPX-ORPX8V. =SVViVSCL-Taliu2025/8/7
8 SCU-SEEI-Tqliu 2025/8/7 电压降落公式的简化： 高压输电线路的特性 X>>R , 可令R0 则： = = V PX V V QX V − = + = 1 1 1 1 1 1 1 1 V P X Q R V V PR Q X V
2.网络元件的功率损耗12V.S,iR+jXS,i,POjAQB2jAQBIBB2s,iVRT+iXT?jBSCU-SEEI-Tqliu2025
9 SCU-SEEI-Tqliu 2025/8/7 2. 网络元件的功率损耗 V1 QB1 j 2 B j 1, 1 S I R + jX 2, 2 S I V2 2 B j QB2 j V T − jB GT RT+jXT
（1）电流流过串联阻抗产生的功率损耗() (R+ jX)AS =I(R+ jX)=RP2P?+Q?+02(R+iX(R+ jX)V2VD2福P2Q20PXR+VEV2= △P + jAQ10SCU-SEEI-Tqliu2025/8/7
10 SCU-SEEI-Tqliu 2025/8/7 (1)电流流过串联阻抗产生的功率损耗 ( ) 2 2 S = I R + jX( ) 2 2 2 2 2 2 R jX V P Q + + = ( ) 2 1 2 1 2 1 R jX V P Q + + = X V P Q R j V P Q 2 2 2 2 2 2 2 2 2 2 2 2 + + + = = P + jQ ( ) ( ) 2 2 2 R jX V S = +
（2）电压加在并联导纳产生的功率损耗BLNQBRIAOB-22△S。 =(Gr + jB,)V210%△S。 = P + jAQ。 = △P。S4入100B×100%(3）输电效率PSCU-SEEI-Tqliu2023店
11 SCU-SEEI-Tqliu 2025/8/7 (2) 电压加在并联导纳产生的功率损耗 (3) 输电效率 2 1 2 1 1 QB = − BV 2 2 2 1 2 QB = − BV 2 0 S = (GT + jBT )V SN I S P j Q P j 100 0 % 0 = 0 + 0 = 0 +