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Reactive power comprehensive optimization in distribution network based on multiple active management schemes

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Abstract

A comprehensive reactive power optimization model considering multiple active management strategies and priorities is proposed, which includes reactive power compensation with capacitor; tap adjusting with on-load tap changing transformer, reactive power dispatching with distributed generation and distribution network reconfiguration. The priorities of reactive power optimization strategies are included in the model, with the analysis of the negative effects to the system; the model also takes the power loss of transformers into account in order to makeitmore practical. Numerical simulation results on the IEEE 33 test system have showed that the modelproposed which hastaken multiple active management strategies and the negative effects to the system into account is effective and can obtain a more reasonable reactive power optimization scheme. Furthermore, the active power loss and the voltage quality can be greatly ameliorated.
39 6 Vo l . 3 9 N o . 6
2015 6 Power System Technology Jun. 2015
文章编号:1000-3673201506-1504-07 中图分类号:TM 721 文献标志码:A 学科代码:470·4051
基于多种主动管理策略的配电网综合无功优化
邢海军 1,程浩忠 1,张逸 2
1.电力传输与功率变换控制教育部重点实验室(上海交通大学),上海市 闵行区 200240
2.福建省电力科学研究院,福建省 福州市 350007
Reactive Power Comprehensive Optimization in Distribution Network
Based on Multiple Active Management Schemes
XING Haijun1, CHENG Haozhong1, ZHANG Yi2
(1Key Laboratory of Control of Power Transmission and Conversion(Shanghai Jiao Tong University), Ministry of Education,
Minhang District, Shanghai 200240, China; 2. Fujian Electric Power Research Institute, Fuzhou 350007, Fujian Province, China)
ABSTRACT: A comprehensive reactive power optimization
model considering multiple active management strategies and
priorities is proposed, which includes reactive power
compensation with capacitor; tap adjusting with on-load tap
changing transformer, reactive power dispatching with
distributed generation and distribution network reconfiguration.
The priorities of reactive power optimization strategies are
included in the model, with the analysis of the negative effects
to the system; the model also takes the power loss of
transformers into account in order to make it more practical.
Numerical simulation results on the IEEE 33 test system have
showed that the model proposed which has taken multiple
active management strategies and the negative effects to the
system into account is effective and can obtain a more
reasonable reactive power optimization scheme. Furthermore,
the active power loss and the voltage quality can be greatly
ameliorated.
KEY WORDS: active distribution network; active
management; differential evolution algorithm; reactive power
optimization
摘要:建立了主动配电网综合无功优化模型,该模型基于主
动配电网中各种主动管理措施和优化策略,包括电容器无功
补偿、变压器有载调压、分布式电源无功调节、配电网络重
构。通过分析无功优化策略对配电网的负面效应,在模型中
加入了无功优化策略之间的优先次序,同时还加入了变压器
损耗,使优化模型更具实际意义。通过改进的 IEEE 33 节点
系统仿真对模型进行了验证,结果表明:应用考虑各种主动
管理策略及其对配电网负面效应的综合无功优化模型可以
得到更加合理的无功优化方案,并且网损和电压质量都较传
基金项目:国家高技术研究发展计划(863 计划) (2014AA051901)
国家自然科学基金 (51261130473)
Project Supported by National High Technology Research and
Development Program (863 Program) (2014AA051901) and National
Natural Science Foundation of China (51261130473).
统无功优化方案有大幅改善。
关键词:主动配电网;主动管理;差分进化算法;无功优化
DOI10.13335/j.1000-3673.pst.2015.06.006
0 引言
配电网无功优化是在满足网络约束的前提下,
通过调节各种无功补偿设备和其他可以改变系统
无功潮流的手段,确定未来某一时刻或者某一时段
内配电网设备的运行状态,从而保证整个系统运行
的安全性、经济性及稳定性。传统配电网的无功优
化方法包括电容器无功补偿、变压器有载调压。
电容器无功补偿包括变电站和环网柜等集中
补偿、配电线路分散补偿(即杆上电容器)、用户终
端分散随机补偿。理想的电容器不消耗电能。作为
能量传递的媒介,电容器无功补偿可以避免无功在
配电系统中的大容量传输,因此合理的电容器无功
补偿可以降低电源、变压器的功率损失,提高系统
功率因数,降低线路损耗,减少系统发电费用。
压器有载调压是通过改变变压器分接头位置来调
节变压器输出电压,其作用是调节无功在变压器一
次侧与二次侧之间的传输,并不能改变系统总的无
功容量。当系统无功功率缺额较大时,为保持受端
电压水平,有载调压变压器动作会使受端电压暂时
上升,将系统无功功率缺额全部转嫁到一次侧,使
其电压下降,甚至可能引发系统电压崩溃。所以变
压器有载调压一般应用在无功容量充足的系统中。
早期配电网无功优化研究主要集中在无功优
化算法研究方面,即研究速度快,收敛性、稳定性
高的算法。包括遗传算法[1-2]粒子群算法[3]、免
算法[4]Tab u 搜索算法[5]、差分进化算法[6-7]等。
39 6 1505
配电网中分布式电源的出现与发展对配电网
无功优化提出了新的挑战。分布式电源作为无功电
源的一种补充,需要在无功优化中综合考虑。
文献[8]基于聚类和竞争克隆机制的多智能体免疫
算法,研究含分布式电源的配电网无功优化,通过
分布式电源对电网进行无功补偿可较大程度降低
系统有功网损。文献[9]基于概率统计方法建立同时
考虑风能、太阳能分布式发电出力和负荷随机波动
的配电网无功优化模型,采用化学反应算法对所建
立的模型进行求解。文献[10]通过无功优化手段解
决分布式电源接入系统时引起的电压升高问题。
随着配电自动化的建设与发展,主动配电网
(active distribution networkAND)关键技术研究与
示范,配电网内的有源设备、可控器件越来越多,
同时配电网的自动化水平也不断提高。配电网无功
优化需要有新的拓展,主动配电网为配电网无功优
化提供了新的思路与手段,如:需要快速通信、
制技术的配电网络重构;需要智能终端、智能测量
仪表、智能控制技术的需求侧响应;根据网络实时
运行状态对分布式电源进行有功、无功实时调度
等。同时主动配电网也能更实时、准确的控制并联
电容器投切及有载调压变压器分接头。
本文将全面分析各种配电网无功优化策略,
括:电容器无功补偿、变压器有载调压、分布式电
源无功调节、配电网络重构,同时基于各种无功优
化策略对配电网的负面效应,在模型中加入各种优
化策略的优先次序。传统无功优化策略未计及变压
器侧的损耗,会导致网络损耗下降,但变压器损耗
升高,总的系统损耗无法降低。为了更贴近运行实
际,本文将变压器损耗也纳入到综合优化模型中。
1 主动配电网无功优化
ADN 的核心是主动管理(active management
AM)AM 措施包括:分布式能源有功/无功调度、
电容器分组无功补偿、有载调压变压器(on-load tap
changerOLTC)分接头调整、可控负荷(需求侧响
)电压调节器(voltage regulatorVR)、网络重构
等。在主动配电网配电管理系统和信息通信系统等
自动化软硬件的帮助下,AM 对于配电网无功优化
将起到积极的作用[11-14]
目前,针对主动配电网无功优化问题的研究较
少,文献[15-16]涉及到配电网的综合优化:文献[15]
的综合无功优化中以网损最小为目标,研究了配电
网重构及电容器投切对无功优化的影响;文献[16]
以控制电压为目标,研究了分布式电源(distributed
generationDG)和电容器投切等无功补偿策略。
动配电网无功优化由于有智能量测仪器、先进的信
息通信、控制技术作为基础,能够实现传统配电网
无功优化无法实现的效果。
以专线接入的大用户或冲击负荷为例:当负荷
突然投入或退出时,电压会大幅波动,电压波动可
以由公式(1)表示:
2
cj cj
ufh
dd
1
2
QP
UKf
SS

 

 (1)
式中:Qcj 为冲击负荷或专线接入的大用户无功负
荷;Pcj 为冲击负荷或专线接入的大用户有功负荷;
Sd为冲击负荷或专线接入的大用户母线短路容量;
Kufh 为负荷电压的频率效应系数;f为冲击负荷或
专线接入的大用户突然投入时引起的频率降低。
当冲击负荷或专线接入的大用户突然投入时,
为有效抑制电压波动,需使用能够快速响应的动态
无功补偿设备,如静止无功补偿器。若采用本文提
出的综合无功优化模型,不仅可以节省大用户侧的
无功设备投资费用,而且能够实现快速补偿。
一些负荷变动比较大的配电系统中,在传统无
功补偿情况下,系统轻载或空载时希望并联电容器
退出,满载或重载时希望并联电容器投入。这必将
导致并联电容器的频繁动作,影响并联电容器的寿
命,严重时将对并联电容器的绝缘造成损害。而主
动配电网无功优化可以权衡各种优化策略,从而避
免电容器的频繁投切。
负荷变动比较大的配电系统同样可能造成变
压器分接头的过度调节,引起一、二次系统之间无
功的不合理交换,在一次系统没有足够的无功容量
支撑的情况下,造成一次系统电压过低,严重时导
致系统电压崩溃。主动配电网无功优化由于实时性
高,能够检测系统无功缺额从而合理地使用有载调
压变压器进行无功优化,同时权衡各种优化策略,
防止变压器分接头的过度调节和一、二次系统之间
的不合理无功交换。
1.1 传统配电网无功优化模型
传统配电网无功优化是在满足网络约束的前
提下,通过无功补偿设备、变压器分接头调节来实
现系统有功网损最小、系统电压质量最优或系统总
的运行费用最省等目标。以网损最小和电压质量最
优为目标的优化函数如下[17]
1loss
min
f
P (2)
2
,0
2
,max
min ii
i
UU
fU




(3)
1506 邢海军等:基于多种主动管理策略的配电网综合无功优化 Vo l . 3 9 N o . 6
式中:Ploss 为网络损耗;Ui是节点 i的电压幅值;
Ui,0为节点 i的理想电压幅值;Ui,max 为节点 i的最
大允许电压偏差。约束条件除了常规的功率平衡约
束、节点电压约束和支路潮流约束外,还包括:
1)电容器分组投切约束:
min max
C, C, C,jjj
QQQ
j=1n1 (4)
2)有载调压变压器抽头调节约束:
min max
kkk
TTT
k=1n2 (5)
式中:n1n2分别是电容器安装节点数和有载调压
变压器安装数量; C, j
Q表示第 j个节点无功补偿设
备的投切量; max
C, j
Qmin
C, j
Q表示无功补偿设备投切量
的上限和下限; k
Tmax
k
Tmin
k
T分别是第 k台有载
调压变压器抽头位置;抽头调节范围上限和下限。
1.2 主动配电网综合无功优化模型
本文中主动配电网综合无功优化模型全面分
析各种配电网无功优化策略,包括电容器无功补
偿,变压器有载调压,分布式电源无功调节,配电
网络重构,对配电系统进行综合无功优化。同时计
及各种优化策略的优先次序及变压器损耗,目标函
数为总的运行损耗最小化,包括网络损耗、变压器
损耗、电容器投切等价损耗、变压器有载调压等价
损耗、分布式电源无功调节等价损耗、配电网络重
构等价损耗。
min F= Ploss_net + Ploss_tf + k1fc(x1) + k2ft(x2) +
k3fd(x3)+ k4fr(x4) (6)
式中:Ploss_net 是系统网络损耗;Ploss_tf 是变压器损
耗;fc(x1)是电容器投切等价损耗函数;ft(x2)是变压
器有载调压等价损耗函数;fd(x3)是分布式电源无功
调节等价损耗函数;fr(x4)是配电网络重构等价损耗
函数。系数 xi(i=1~4)分别是电容器无功补偿控制变
量、变压器有载调压控制变量、分布式电源无功调
节控制变量以及配电网络重构控制变量。
x1=[QC,1, QC,2, …, QC,n1]T (7)
x2=[T1, T2, …, Tn2]T (8)
x3=[QDG,1, QDG,2, …, QDG,n3]T (9)
x4=[ S1, S2, …, Sn4]T (10)
式中:n3n4分别是分布式电源安装节点数和配电
网络中可操作的分段开关和联络开关数量;
QDG,l(l=1n3)是第 lDG 的无功出力;Sm(m=1
n4)是第 m个可操作的分段开关或联络开关状态。
Ploss_net可通过系统潮流计算得到;Ploss_tf 包含
变压器可变损耗和固定损耗,在配电网中通过有载
调压变压器提高运行电压,可能带来变压器损耗的
增加。
Closs_tf=Pkb+Pgd (11)
式中:变压器可变损耗Pkb=[(P2+Q2)/U2]R固定损
Pkb=(U/Ue) Σ∆P0PQ是变压器传输有功及无
功;U为变压器实际运行电压,Ue变压器为额定电
压;P0是变压器空载损耗,R为变压器等值电阻。
fd(x3)DG 无功调节损耗费用,此处 DG 均为
可固定出力 DG 或可储能的间歇性 DG,均可受配
电管理系统(distribution management systemDMS)
调度,有功按日前调度出力不变,无功可单独调节。
由于无法得到 fc(x1)ft(x2)fd(x3)fr(x4)的具
体表达式,为了体现各种无功优化策略的损耗情
况,现将各种无功优化策略与网络损耗情况进行等
价,定义如下:

11
c1 loss c
11
()/ ()
nn
jj
f
xP Nj Nj



(12)

22
t2 loss t
11
()/ ()
nn
kk
f
xP Nk Nk



(13)

33
d3 loss d
11
()/ ()
nn
ll
f
xP Nl Nl



(14)

44
r4 loss r
11
()/ ()
nn
mm
f
xP Nm Nm



(15)
式中:Ploss 是包括网络损耗及变压器损耗的系统总
损耗;Nc(j)N(j)分别是第 j个电容器安装点的投切
组数,总的分组数;Nt(k)N(k)分别是第 k个变压
器有载调压档位绝对值,总的档位数;Nd(l)N(l)
分别是第 l个分布式电源安装点的无功输出和额定
无功容量;Nr(m)N(m)分别是第 m个可操作的分
段开关或联络开关状态相对于初始状态发生转换
的数量和总的开关数量。
系数 ki(i=14)分别是 4种无功调节手段的优
先系数或权重系数,0 ki 1其值主要取决于各种
无功调节手段的应用情况、技术成熟度、对系统的
影响等。电容器无功补偿技术成熟,沿用至今,
以将其取为最小值;变压器有载调压也是较成熟的
调节手段,但需要考虑系统无功容量,所以将其取
为次小值;分布式电源的发展,使得配电网越来越
像微缩版的输电网,无功优化有了新的无功源;
络重构一般在故障或线路重载时才使用,实际运行
中的无功优化会造成负荷短暂失电,所以将其取为
最大值;基于此,系数 ki的关系为 0<k1<k2<k3<k4<1
系数 ki的关系并非一尘不变,若上级网络足够坚强、
无功容量充足,而并联电容器分组不恰当,容易引
起系统谐振,此时变压器有载调压优先次序可以前
移;在自动化水平较高、网络结构调节灵活的区域,
网络重构可以适当前移;在未来配电网自动化水
平、测量监控技术、“三遥”技术全面应用的背景
下,各无功优化手段的优先次序将没有区别。
39 6 1507
1.3 主动配电网综合无功优化约束
主动配电网全局无功优化约束除了传统配电
网的功率平衡约束、节点电压约束、支路潮流约束、
电容器分组投切约束和有载调压变压器抽头调节
约束外,还包括如下约束:
1DG 无功出力约束:
min max
DG, DG , DG,mmm
QQQ
(16)
min max
PPPmmm
FFF (17)
2)网络结构约束:
k
g
G (18)
式中: DG,m
Qmax
DG, m
Qmin
DG, m
Q分别是第 mDG
无功出力和可调上下限; Pm
F
max
Pm
Fmin
Pm
F
别是第 mDG 的功率因数和可调上下限;gk为网
络重构后新形成的网络结构;G为所有能满足负荷
供电的辐射状且无孤立节点的网络拓扑结构集。
2 算例及结果分析
2.1 算例
IEEE 33 节点配电网是一个 12.66 kV 单电源的
配电系统,包括 33 个节点与 5条联络线,总负荷
3 715 kW2 300 kvar网络结构图见图 1,具体
网络参数见文献[18]。为了验证本文所提模型,本
文对算例做如下修改:
电容器组安装在节点 51129,安装组数均
10 组,每组 50 kvar;有载调压变压器为三相双
绕组变压器,其额定容量为 50 MVA,额定电压为
11081.25% kV,联接组标号为 YNd1117 档可
调,额定空载损耗为 47.8 kW,额定负载损耗为
194 kW空载电流百分比 0.58%短路阻抗百分比
10.5%[19];分布式电源安装在节点 17 32,额定
容量均为 800 kW,日前调度 500 kW,功率因数
0.95~0.95 可调[20];可操作的联络开关为 7-20
8-1411-2117-3224-28、所有支路均安装有分
段开关;节点电压允许范围标幺值为 0.95~1.05 pu
支路长期运行额定容量为 5 MVA
本文采用差分进化算法[6-7]对算例进行求解,
数设置为:比例因数 F和交叉因数 CR 均设为 0.8
种群规模 NP=30;最大迭代次数为 80 次。对于主
1 改进的 IEEE 33 节点网络
Fig. 1 Network structure of modified IEEE 33–bus system
动管理中网络重构部分的实现,采用双层规划模
型:上层规划利用文献[21]中方法生成不同网络拓扑
结构;下层规划采用差分进化算法求解不同网络结
构下的无功优化结果。
2.2 结果分析
通过 Matlab 8.1 编写程序对算例进行了分析,
设定 4类场景对综合无功优化结果进行分析。包括:
场景 1综合无功优化(不考虑网络重构、变压
器损耗、主动管理损耗)
场景 2综合无功优化(考虑变压器损耗,不考
虑网络重构、主动管理损耗)
场景 3综合无功优化(考虑变压器损耗,主动
管理损耗,不考虑网络重构)
场景 4综合无功优化(考虑变压器损耗,主动
管理损耗,网络重构)
主动管理的优先次序按照自动化水平的高低,
设定为下面 3类,k=[k1 k2 k3 k4]1不考虑主动管
理损耗:P0=[0 0 0 0]2自动化水平较低:P1=[0.1
0.3 0.5 0.7]3)自动化水平提升:P2=[0.1 0.2 0.3
0.4]4)智能配电网情况:P3=[0.1 0.1 0.1 0.1]
本文综合无功优化中,原始网络指未作修改的
IEEE 算例,网络中没有 DG 和电容器组,变压器分
接头位置为 0传统无功优化(DG)指仅通过电容
器组和变压器分接头位置调节进行无功优化;传统
无功优化(含固定 DG)指网络中含有 DG,但是 DG
固定出力,无功不可调节;主动配电网无功优化包
含所有主动管理措施。仿真结果如表 16所示。
1 场景 1无功优化结果
Tab. 1 Reactive power optimization result of scenario 1
结果 网损/
kW
电容器投切组数
(5/11/29)
OLTC
档位
DG 功率因
(17/32)
原始网络 202.677 — —
传统无功优化
(DG) 128.302 10/10/10 +8 —
传统无功优化
(固定 DG) 48.004 10/6/10 +8 0.950/0.950
主动配电网无功
优化 46.062 9/4/10 +8 0.948/0.766
2 场景 2无功优化结果
Tab. 2 Reactive power optimization result of scenario 2
DG/
kW
总损耗/
kW
网损/
kW
电容器投切组数
(5/11/29)
OLTC
档位
DG 功率因数
(17/32)
100 196.676 99.817 10/6/10 +8 0.625/0.215
250 163.342 74.458 10/6/10 +8 0.892/0.491
500 123.840 46.261 10/5/10 +8 0.945/0.758
750 103.634 35.127 10/3/8 +7 0.948/0.807
800 101.736 34.720 10/3/9 +6 0.948/0.879
由表 1可以看出主动配电网无功优化较含固定
DG 的传统无功优化网损下降了 4.05%。主动配电
1508 邢海军等:基于多种主动管理策略的配电网综合无功优化 Vo l . 3 9 N o . 6
3 场景 3无功优化结果(DG=500 kW)
Tab. 3 Reactive power optimization result of
scenario 3 with DG=500 kW
P 总等价损耗/
kW
网损/
kW
电容器投切组数
(5/11/29)
OLTC
档位
DG 功率因数
(17/32)
P
1 214.054 54.794 7/7/10 +0 0.950/0.949
P
2 186.542 54.428 8/8/10 +0 0.950/0.948
P
3 156.371 48.061 10/5/10 +8 0.950/0.949
4 场景 3无功优化结果(P2)
Tab. 4 Reactive power optimization result of
scenario 3 with P2
DG/
kW
总等价损耗/
kW
网损/
kW
电容器投切
组数(5/11/29)
OLTC
档位
DG 功率
因数(17/32)
100 312.355 108.053 9/8/10 +7 0.943/0.941
250 253.130 78.825 8/8/10 +8 0.949/0.948
500 186.542 54.428 8/8/10 0 0.950/0.948
750 150.786 38.856 10/610 +1 0.949/0.950
800 147.681 39.215 6/6/10 +0 0.947/0950
网无功优化中由于 DG 功率因数可调,DG 安装节
17/32 功率因数分别调节到 0.948/0.766,通过调
DG 功率因数提升网络末端节点的无功支撑,降
低了电容器的投切组数及无功传输,减少了网络损
耗。由线路损耗计算公式 RL (P2+Q2)/U2知电压越大
网络损耗越小,所以 OLTC 档位一直处于高位+8
若减少 DG 有功出力到 100 kW无功出现缺额,
了实现无功优化,将电容器投切组数变为 10/5/10
DG 功率因数变为 0.584/0.229OLTC 档位保持+8
若增加 DG 有功出力到 800 kWDG 接入点将出现
电压越限,为了实现无功优化,电容器投切组数变
10/3/10DG 功率因数变为 0.949/0.904,同时
OLTC 档位拉低到+6
2是场景 2在不同 DG 有功出力下的无功优化
5 场景 4无功优化结果(DG=500 kW)
Tab. 5 Reactive power optimization result of scenario 5 with DG=500 kW
P 总等价
损耗/kW
网损/
kW
变压器空载
损耗/kW
变压器负载
损耗/kW
主动管理等价
损耗/kW
电容器投切
组数(5/11/29)
OLTC
档位
DG 功率因数
(17/32)
网络重构
开关状态
P0 123.806 46.261 50.190 27.355 10/5/10 +8 0.945/0.758 9,33,34,36,37
P1 211.646 52.701 47.800 32.352 78.793 7/7/10 0 0.949/0.935 28,33,34,35,36
P2 182.649 51.303 47.800 31.193 52.353 8/7/10 0 0.950/0.949 28,33,34,35,36
P3 156.371 48.061 50.190 28.496 29.623 10/5/10 +8 0.950/0.949 33,34,35,36,37
6 场景 4无功优化结果(P2)
Tab. 6 Reactive power optimization result of scenario 5 with P2
DG/kW 总等价损耗/
kW
网损/
kW
变压器空载
损耗/kW
变压器负载
损耗/kW
主动管理
等价损耗/kW
电容器投切
组数(5/11/29)
OLTC
档位
DG 功率因数
(17/32)
网络重构
开关状态
100 309.940 105.827 49.891 49.212 105.010 9/8/10 +7 0.949/0.948 9,33,34,36,37
250 248.457 76.217 50.190 38.387 83.663 8/7/10 +8 0.950/0.942 28,33,34,35,36
500 182.649 51.303 47.800 31.193 52.353 8/7/10 0 0.950/0.949 28,33,34,35,36
750 150.786 38.856 48.099 20.616 43.214 10/6/10 +1 0.949/0.950 33,34,35,36,37
800 147.681 39.215 47.800 20.618 40.048 6/6/10 +0 0.947/0.950 33,34,35,36,37
结果。考虑变压器损耗后总的损耗 123.840 kW,网
损耗为 46.261 kW,变压器空载损耗为 50.190 kW
负载损耗为 27.389 kW,相对于不考虑变压器损耗
的结果网络损耗上升了 0.199 kW,总损耗下降了
0.2 kW。由于本文未考虑每一个负荷节点配电变压
器的损耗,总损耗下降较少。对于一个大型配电网
络,若考虑网络中所有的变压器损耗,可以预计考
虑变压器损耗的结果能为配电网络无功优化提供
新的思路,同时为配电网络降损提供不同的策略。
由表 2可以看出随着 DG 有功出力的增加,为
了防止网络电压越限,电容器投切组数、OLTC
位均在下降,DG 功率因数上升。同时可以看出:
随着 DG 有功出力的增加,总的损耗及网络损耗均
下降,但下降速度减慢, loss
dg
d
d
P
<0
2
loss
2
dg
d
d
P
P>0
是因为 DG 有功出力的增加导致反向潮流带来的损
耗增加大于导致正向潮流带来的损耗减少,所以对
DG 的有功调度不能过大。
2是不同无功优化策略下的网络节点电压分
布。可以看出原始网络存在电压越限,其他各种无
功优化策略均能保证电压不越限。不含 DG 的传统
无功优化,由于没有 DG 无功出力的支撑,电压偏
低。含固定出力 DG 的传统无功优化,由于 DG
功支撑不够,而 25~32 号节点总的无功负荷较大,
所以在该处电压曲线出现分叉。是否计及变压器损
耗的两条电压曲线基本重合,由于本文没有考虑每
一个负荷节点配电变压器的损耗,电压曲线变化较
小。图 3是变压器总损耗及网络损耗曲线。
3是考虑主动管理损耗的无功优化结果,
4是在主动管理优先次序 P2情况下改变 DG 出力
的无功优化结果。由表 3可以看出,优先次序 P1
P2情况下,由于 3种主动管理措施中 OLTC DG
调度所占比重较大,结果几乎不变。主要的调节手
段为电容器组投切。对于 P1,总变压器损耗为
80.467kW,主动管理等价损耗为 78.793 kW;对于
P2,总变压器损耗为 79.829 kW,主动管理等价损
39 6 1509
2 场景 1电压分布
Fig. 2 Voltage profile of scenario 1
3 场景 12损耗
Fig. 3 Power loss of scenario 1 and 2
耗为 52.285 kW。对于 P3,由于主动管理优先次序
相等,主动管理措施中采用电容器投切及 OLTC
节等价网损更小,可得到采用;总变压器损耗为
98.251 kW,主动管理等价损耗为 29.623 kW
4和表 2有相同的结论,即随着 DG 有功出
力的增加,为了防止网络电压越限,电容器投切组
数、OLTC 档位均在下降,DG 功率因数上升。同
时可以看出随着 DG 有功出力的增加,总的损耗及
网络损耗均下降,但在下降速度减慢,这是因为
DG 有功出力的增加导致反向潮流带来的损耗增加
大于导致正向潮流带来的损耗减少。所以对 DG
有功调度不能过大。
4是场景 3DG=500kW,主动管理不同优
先次序情况下,无功优化后网络节点电压情况。
图可知:P1P2由于主动管理调节量基本一致,
点电压曲线基本重合。P3由于优先次序相等,主动
管理措施中采用电容器投切及 OLTC 调节等价网损
4 场景 3电压(DG=500 kW)
Fig. 4 Voltage profile of scenario 3 with DG=500 kW
更小,可得到采用,电压曲线得到明显提升。
5是场景 4DG=500 kW 无功优化结果,
6是在主动管理优先次序 P2情况下改变 DG 出力
的无功优化结果。由表 5可以看出:P0P1P2
对于初始网络仅一处开关动作,P3无开关动作。
网络重构在此起的作用不大,这是因为:1)网络
重构在考虑主动管理优先次序时排在最后,等价损
耗最高;2)本文电容器组及 DG 安装位置合理,
DG 安装在长支路的末端 17/32电容器组安装在长
支路负荷集中处。
对比表 5与表 3可以看出:优先次序 P1P2
情况下,由于网络重构的引入,网络及变压器损耗
稍有下降,主动管理损耗 P1不变,P2上升。对比
6与表 4可以看出:随着 DG 出力的增加总的损
耗已较低,网络重构带来的损耗下降不足以抵消引
起的等价主动管理损耗。DG=750 kW DG=
800 kW 网络重构开关均未动作。
5是场景 4在优先次序 P1情况下,不同 DG
出力的电压变化曲线。由于 P1优先次序之间差异较
大,DG 出力较小时 OLTC 分接头调节带来的网损
下降大于等价主动管理损耗,所以在 DG 100 kW
250 kW 时,OLTC 档位为正。在 DG 出力较大时
OLTC 分接头调节带来的网损下降已小于等价主动
管理损耗,OLTC 均未调节。
电压/pu
5 场景 4电压(P1)
Fig. 5 Voltage profile of scenario 4 with P1
3 结论
1)计及变压器损耗后总的系统损耗为
123.840 kW,网络损耗为 46.261 kW,相对于不考
虑变压器损耗的结果网络损耗上升了 0.199 kW
的损耗下降了 0.2 kW由于本文没有考虑每一个负
荷节点配电变压器的损耗,总的损耗下降较小。
于一个大型配电网络,若考虑网络中所有的变压器
损耗,可以预计考虑变压器损耗的无功优化结果能
为配电网络无功优化提供新的思路,同时为配电网
络降损提供不同的策略。
2)随着 DG 有功出力的增加,总的损耗及网
络损耗均下降,但在下降速度减慢,所以对 DG
有功调度不能过大。
1510 邢海军等:基于多种主动管理策略的配电网综合无功优化 Vo l . 3 9 N o . 6
3)在应用不同主动管理优先次序的情况下,
网络损耗有较大差异。在实际无功优化中可以依据
网络情况来确定主动管理措施之间的优先次序,
而确定最优且最合理的无功优化方案。
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收稿日期:2014-10-09
作者简介:
邢海军(1979),男,博士研究生,主要研究方
向为配电网规划与运行,E-mailxinghj@sjtu.edu.cn
程浩忠(1962),男,博 士,教 授,博 士生 导师
主要研究方向为电力系统规划、电压稳定、电能质
量等,E-mailhzcheng@sjtu.edu.cn
邢海军
实习编辑 余俊
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