第11章 电力系统潮流计算-手算.ppt

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1、第11章电力系统潮流计算手算 电力系统潮流计算：在给定的稳态运行条件下确定电力系统的运行状态（包括母线电压相量，网络中的功率分布和功率损耗）第11章 电力系统潮流计手算如何计算电力系统的潮流?传统方法手算(11-1,11-2)计算机计算(11-3,11-4,11-5)11.1 开式网的潮流计算第1步:做简化的等值电路及其相应的运算负荷或运算功率第11章 电力系统潮流计手算Abcd用额定电压计算运算负荷或运算功率11.1 开式网的潮流计算第11章 电力系统潮流计手算第1步:做简化的等值电路及其相应的运算负荷或运算功率11.1 开式网的潮流计算第11章 电力系统潮流计手算第2步:在简化的等值电路上

2、选用两类过程两类过程之一进行潮流计算两类过程两类过程简单辐射形网络的潮流计算有两类基本过程。过程过程1:已知同一端的功率和电压，求另一端功率和电压；过程过程2:已知始端电压、末端功率，求始端功率、末端电压（以此居多）；或已知末端电压、始端功率，求末端功率、始端电压。两类过程两类过程简单辐射形网络的潮流计算有两类基本过程。过程过程1:已知同一端的功率和电压，求另一端功率和电压；过程过程2:已知始端电压、末端功率，求始端功率、末端电压（以此居多）；或已知末端电压、始端功率，求末端功率、始端电压。11.1 开式网的潮流计算第11章 电力系统潮流计手算第2步:在简化的等值电路上选用两类过程两类过程之一

3、进行潮流计算过过程程1：总结为从已知功率、电压端，用第十章中适当的公式齐头并进逐段求解功率和电压。求功率求电压求功率求电压求功率求电压计算起点计算终点V4(已知)S4(已知)12341图：已知同一点电压和功率求辐射形网络潮流求功率求电压求功率求电压求功率求电压计算起点计算终点S4(已知)V1(已知)3214图：已知一点电压、另一点功率求辐射形网络潮流过程过程2：总结为“一来、二去”共两步，一来即：设所有未知电压节点的电压为线路额定电压，用第十章中适当的公式从已知功率端开始逐段求功率，直到推得已知电压点的功率；二去即：从已知电压点开始，用推得的功率和已知电压点的电压，选用第十章中适当的公式，往回

4、逐段向未知电压点求电压。两类过程两类过程简单辐射形网络的潮流计算有两类基本过程。过程过程1:已知同一端的功率和电压，求另一端功率和电压；过程过程2:已知始端电压、末端功率，求始端功率、末端电压（以此居多）；或已知末端电压、始端功率，求末端功率、始端电压。11.1 开式网的潮流计算第11章 电力系统潮流计手算第2步:在简化的等值电路上选用两类过程两类过程之一进行潮流计算11.1 开式网的潮流计算第11章 电力系统潮流计手算11.2 闭式网的潮流计算环网两端供电网第11章 电力系统潮流计手算11.2 闭式网的潮流计算AbcdjQB3第11章 电力系统潮流计手算11.2 闭式网的潮流计算第1步:做简

5、化的等值电路及其相应的运算负荷或运算功率Acd第2步:忽略功率损耗，计算初步功率分布a2b21Za1Zb2Z12S2S1Sa1S12Sb2第11章 电力系统潮流计手算11.2 闭式网的潮流计算Acda2b21Za1Zb2Z12S2S1Sa1S12第11章 电力系统潮流计手算11.2 闭式网的潮流计算第2步:忽略功率损耗，计算初步功率分布Acda2b21Za1Zb2Z12S2S1Sa1S12Sb2第11章 电力系统潮流计手算11.2 闭式网的潮流计算第2步:忽略功率损耗，计算初步功率分布Acda2b21Za1Zb2Z12S2S1Sa1S12Sb2即即 初步功率分布初步功率分布=基本功率分布基本功

6、率分布 循环功率循环功率第11章 电力系统潮流计手算11.2 闭式网的潮流计算第2步:忽略功率损耗，计算初步功率分布AcdFundamental power relates to load power and grid configuration and is irrelevant to the power source voltage.a2b21Za1Zb2Z12S2S1Sa1S12Sb2第11章 电力系统潮流计手算11.2 闭式网的潮流计算即即 初步功率分布初步功率分布=基本功率分布基本功率分布 循环功率循环功率AcdWhereas circulate power relates to t

7、he difference of power source voltage and is irrelevant to the load power and grid configuration.a2b21Za1Zb2Z12S2S1Sa1S12Sb2第11章 电力系统潮流计手算11.2 闭式网的潮流计算即即 初步功率分布初步功率分布=基本功率分布基本功率分布 循环功率循环功率AcdStep 2:Neglect the power loss,calculate the preliminary powera2b21Za1Zb2Z12S2S1Sa1S12Sb2In the case of unifor

8、m grid(均一网均一网)第11章 电力系统潮流计手算11.2 闭式网的潮流计算AcdStep 3:Find the power convergence point according to the preliminary power.Mark the point by“”or“”.a2b21Za1Zb2Z12S2=6+j6S1=3+j3Sa1=5+j5S12=2+j2Sb2=4+j4“”or“”第11章 电力系统潮流计手算11.2 闭式网的潮流计算AcdStep 3:Find the power convergence point according to the preliminary

9、power.Mark the point by“”or“”.Then separate the two-end supplied grid into two open-ended grids.a2b21Za1Zb2Z12S2=6+j6S1=3+j3Sa1=5+j5S12=2+j2Sb2=4+j4“”or“”第11章 电力系统潮流计手算11.2 闭式网的潮流计算AcdStep 4:Calculate the power flow of open-ended grids.a2b21Za1Zb2Z12S2=6+j6S1=3+j3Sa1=5+j5S12=2+j2Sb2=4+j4“”or“”第11章 电

10、力系统潮流计手算11.2 闭式网的潮流计算例例(习题习题集例集例2-5)110KV简单环网示于题，导线型号均为LGJ-95，已知：线路AB段为40KM，AC段30KM，BC段30KM；变电所负荷为SB20j15MVA，SC10+j10MVA。电源点A点电压为115KV。求电压最低点和此网络的最大电压损耗和有功总损耗；(导线参数：LGJ-95 r0.33/km,x=0.429/km,b=2.65X10-6s/km)15+j11.0420+j13.88-5-j2.8415+j11.88“”and“”15+j11.0410+j9.045+j2.8415+j11.8815+j11.045+j2.84C

11、hapter 11 The Power Systems Power Flow Calculation 11.2 The Power Flow Calculation of close-ended Grid*The power flow calculation of multi-voltage level gridChapter 11 The Power Systems Power Flow Calculation 11.2 The Power Flow Calculation of close-ended Grid*The power flow calculation of multi-vol

12、tage level gridChapter 11 The Power Systems Power Flow Calculation 11.2 The Power Flow Calculation of close-ended Grid*The power flow calculation of multi-voltage level gridChapter 11 The Power Systems Power Flow Calculation 11.2 The Power Flow Calculation of close-ended Grid*The power flow calculat

13、ion of multi-voltage level gridChapter 11 The Power Systems Power Flow Calculation 11.2 The Power Flow Calculation of close-ended Grid*The power flow calculation of multi-voltage level gridwhere11.2 The Power Flow Calculation of close-ended Grid*The power flow calculation of multi-voltage level grid

14、Chapter 11 The Power Systems Power Flow Calculation whereChapter 11 The Power Systems Power Flow Calculation 11.2 The Power Flow Calculation of close-ended Grid*The power flow calculation of multi-voltage level grid?例例（习题集例2-7）两台型号相同的降压变压器并联运行，已知每台容量为5.6MVA，额定变比为35/10.5，归算到35KV侧的阻抗为2.22j16.4，10KV侧的总

15、负荷为8.5j5.27MVA，高压侧电压为35KV。不计变压器内部损耗，试计算：两台变压器变比相同时，各变压器输出的有功功率和低压侧电压；变压器1工作在2.5抽头，变压器二工作在0%抽头时，各变压器输出的有功功率；此时变压器运行有什么问题？Chapter 11 The Power Systems Power Flow Calculation 11.2 The Power Flow Calculation of close-ended Grid*The power flow control of close-ended gridThe fundamental power,also called

16、as natural power,is uncontrollable and in inverse proportion to the conjugate impedance.?Chapter 11 The Power Systems Power Flow Calculation 11.2 The Power Flow Calculation of close-ended Grid*The power flow control of close-ended grid?How to control the power flow so that the grid power loss is the

17、 minimum.And the power flow with the minimum power loss is referred to as optimum power flow.Chapter 11 The Power Systems Power Flow Calculation 11.2 The Power Flow Calculation of close-ended Grid*The power flow control of close-ended grid?How to control the power flow so that the grid power loss is

18、 the minimum.And the power flow with the minimum power loss is referred to as optimum power flow.orChapter 11 The Power Systems Power Flow Calculation 11.2 The Power Flow Calculation of close-ended Grid*The power flow control of close-ended gridThe grid power loss reaches the minimum when the power

19、flow is in reverse proportion to the resistance,or in other words,the optimum power flow is in reverse proportion to the resistance.Chapter 11 The Power Systems Power Flow Calculation 11.2 The Power Flow Calculation of close-ended Grid*The power flow control of close-ended grid?Chapter 11 The Power

20、Systems Power Flow Calculation 11.2 The Power Flow Calculation of close-ended Grid*The power flow control of close-ended gridChapter 11 The Power Systems Power Flow Calculation 11.2 The Power Flow Calculation of close-ended Grid*The power flow control of close-ended grid11.2 The Power Flow Calculati

21、on of close-ended GridChapter 11 The Power Systems Power Flow Calculation series transformer exciting transformer Regulating transformer series transformer exciting transformer Regulating transformer*The power flow control of close-ended grid11.2 The Power Flow Calculation of close-ended GridChapter

22、 11 The Power Systems Power Flow Calculation series transformer Direct regulating transformer*The power flow control of close-ended gridexciting transformer Direct regulating transformer is mainly used to control reactive power11.2 The Power Flow Calculation of close-ended GridChapter 11 The Power S

23、ystems Power Flow Calculation series transformer exciting transformer Quadrature regulating transformer*The power flow control of close-ended gridQuadrature regulating transformer is mainly used to control active power11.2 The Power Flow Calculation of close-ended GridChapter 11 The Power Systems Po

24、wer Flow Calculation series transformer Hybrid regulating transformer*The power flow control of close-ended gridexciting transformer 11.2 The Power Flow Calculation of close-ended GridChapter 11 The Power Systems Power Flow Calculation Another way of controlling the power flow is using FACTS(Flexible AC Transmission System).See Page 5052*The power flow control of close-ended grid