Created by Simpo PDF Creator Pro(unregistered version) taA4 AIAILSIMAA年O 条察大普 Xinjiang University 第三章简单电力网络的计算和分析 ·网络元件的电压降落和功率损耗 。开式网络的电压和功率分布 ·闭式网络的电压和功率分布 ·多级电压环网的功率分布 。电力网的电能损耗 电气工程学院 电气工程及其有动化专业
Created by Simpo PDF Creator Pro (unregistered version) http://www.simpopdf.com 第三章 简单电力网络的计算和分析 • 网络元件的电压降落和功率损耗 • 开式网络的电压和功率分布 • 闭式网络的电压和功率分布 • 多级电压环网的功率分布 • 电力网的电能损耗 Xinjiang University 电气工程学院 电气工程及其自动化专业
Created by Simpo PDF Creator Pro(unregistered version) 3-1网络元件的电压降落和功率损耗 1.网络元件的电压降落 元件首末端两点电压的向量差。 V1-V2=(R+X)12=(R+X)1
Created by Simpo PDF Creator Pro (unregistered version) http://www.simpopdf.com 1. 网络元件的电压降落 元件首末端两点电压的向量差。 3-1 网络元件的电压降落和功率损耗 1 V& 1 S 1 I & R jX 2 S 2 I & 2 V& LD S 1 2 2 1 V V (R jX )I (R jX )I & - & = + & = + &
Created by Simpo PDF Creator Pro(unregistered version) n.Ihin西n:inAA问fAAy S,=V,1=P2+j0, ,=:+r+) =,+2+)） 以V2为参考轴 =W,+,R+0)+j,X-08 V 。 0S
Created by Simpo PDF Creator Pro (unregistered version) http://www.simpopdf.com ( ) ( ) 2 2 1 2 R jX V S V = V + + * & & & 2 2 2 2 2 2 2 2 2 2 1 2 ( ) ( )( ) V P X Q R j V P R Q X V R jX V P jQ V V - + + = + + - & = + 2 2 * 2 2 2 S = V& I & = P + jQ 1 V& 1 S 1 I & R jX 2 S 2 I & 2 V& LD S 以V2为参考轴
Created by Simpo PDF Creator Pro(unregistered version) V-V,+PR+2xtjPx-0.R V V1=V2+△V2+6V2=V2∠8 V1=VW2+AV2)2+(62)2 0=9 6V2 V2+AV2 B 4 P2R+02X 8V? V2 o 6V:= 2X-Q2R 02 A RIz (a) V,-72=(R+X)12=(R+X)I1
Created by Simpo PDF Creator Pro (unregistered version) http://www.simpopdf.com ï ï þ ï ï ý ü - = + D = 2 2 2 2 2 2 2 2 V P X Q R V V P R Q X V d = + D + d = Ðd V 1 V 2 V 2 V 2 V 2 & & & & 2 2 2 1 2 2 V = (V + DV ) + (d V ) 2 2 1 2 V V V tg + D = - d d V 2 D & V 2 & d 2 2 2 2 2 2 1 2 V P X Q R j V P R Q X V V - + + & = + 1 2 2 1 V V (R jX )I (R jX )I & - & = + & = + &
Created by Simpo PDF Creator Pro(unregistered version) n.Ihins西n:inmA网fAA 因此，由末端电压和功率可求得首端电压 V,=V,+△V,+6V =y,+P,R+0,X+jP,X-0,8 V, V =V∠0a V1=VW2+△V2)》2+(6z)2 B 162 8=8"V2+AV: (P2 D R Ri2 (a) LD
Created by Simpo PDF Creator Pro (unregistered version) http://www.simpopdf.com 因此, 由末端电压和功率可求得首端电压 1 12 2 2 2 2 2 2 2 1 2 2 2 d d = Ð - + + = + = + D + V V P X Q R j V P R Q X V V& V& V& V& 2 2 2 1 2 2 V = (V + DV ) + (d V ) 2 2 -1 2 V V V tg + D = d d 1 V& 1 S 1 I & R jX 2 S 2 I & 2 V& LD S
Created by Simpo PDF Creator Pro(unregistered version) 卡网中hintaunimnn网AfAA 同样，也可由首端电压和功率求得末端电压 V2=VW1-AV1)2+(6Y1)2 -1 8V 8=V-AV 4V,= PR+0X △ V - ov= PX-OR V (b)
Created by Simpo PDF Creator Pro (unregistered version) http://www.simpopdf.com 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 - DV ) + (d V ) 1 1 1 1 V V V tg - D = - d d ï ï þ ï ï ý ü - = + D = 1 1 1 1 1 1 1 1 V P X Q R V V P R Q X V d
Created by Simpo PDF Creator Pro(unregistered version) hn,hisimnon小fnA V 两种分解 P2R+02X V2 V2 △, := 2X-02R V2 AV PR+QX V 4y,= PR+0X Vr ov= PX -OR 6V,=P:X-2R V 特别注意： 计算电压降落时，必须用同一端的电压与功率
Created by Simpo PDF Creator Pro (unregistered version) http://www.simpopdf.com 两种分解 2 V& 2 V D & V& d 1 V& 1 V D & 1 V& d V V & & - 1 特别注意: 计算电压降落时,必须用同一端的电压与功率. ï ï þ ï ï ý ü - = + D = 2 2 2 2 2 2 2 2 V P X Q R V V P R Q X V d ï ï þ ï ï ý ü - = + D = 1 1 1 1 1 1 1 1 V P X Q R V V P R Q X V d ï ï þ ï ï ý ü - = + D = V PX QR V V PR QX V d
Created by Simpo PDF Creator Pro(unregistered version) 汽Ahan4西4。in汽A年 电压降落公式的简化 高压输电线路的特性X)>R,可令R≈0，则： △= PR +0X V △V= QX V PX -OR 6y= PX
Created by Simpo PDF Creator Pro (unregistered version) http://www.simpopdf.com 电压降落公式的简化 高压输电线路的特性 X>>R,可令R»0,则： ï ï þ ï ï ý ü = D = V PX V V QX V d ï ï þ ï ï ý ü - = + D = V PX QR V V PR QX V d
Created by Simpo PDF Creator Pro(unregistered version) n.Ihin西n:inAA问fAAy 电压损耗和电压偏移 ·电压损耗：两点间电压模值之差 △V=V1-V2=AG≈△V2 ·或表示为百分值： Ay%=V1-'2X100% V2 △2 电压偏移：线路始末端电压与线路额定电 压之差 电压偏移(%='-'×10%
Created by Simpo PDF Creator Pro (unregistered version) http://www.simpopdf.com 电压损耗和电压偏移 • 电压损耗:两点间电压模值之差 • 或表示为百分值: • 电压偏移:线路始末端电压与线路额定电 压之差 O A D B G 1 V& 2 V& 2 V D & d DV = V 1 -V 2 = AG » DV 2 (%) 1 ´100% - = N N V V V 电压偏移 % 1 2 ´100% - D = V N V V V
Created by Simpo PDF Creator Pro(unregistered version) 卡网中hintaunimnn网AfAA 2.网络元件的功率损耗 B jAOB2 B 线路 2 2 Rr+iXr 变压器 2
Created by Simpo PDF Creator Pro (unregistered version) http://www.simpopdf.com 2. 网络元件的功率损耗 1 V& Q B 1 j D 2 B j 1, 1 S I & R + jX 2, 2 S I & 2 V& 2 B j Q B 2 j D 线路 V& T - jB G T S I & , R T+jXT 变压器 11 12