Engineering, 2013, 5, 32-36
doi:10.4236/eng.2013.51b006 Published Online January 2013 (
Copyright © 2013 SciRes. ENG
Overall Framework and Module of Distribution Network
Coordinated Planning Considering Distributed
Qianjin Liu, Huanghuang Liu
School of Electric power,South China University of Technology, Guangzhou, China
Received 2013
Combining with the characteristics of Chinas energy and the strategy of sustainable development, analyzing the pros
and cons which caused by the appearance of DG and their operation connecting to grid, this paper points out that the
two side s can ac hieve win -win under a reasonable combination between DG and distribution system, so as to optimize
the allocation of resources, improve the utilization ratio of resource, and obtain maximum social benefit, harmoniously
promote the development of power industry, economy and environment. As a word, this paper puts forward a new
model o f distr ibutio n net work p lanning inc ludi ng DG and bring s in pena lty fac torto guide the invest ment and constr uc-
tion of DG. Last of all, this paper presents the adoption of the coordination development coefficients which is to eva-
luate the power planning.
Keywords: Distributed Generation; Dis tr ibution Network; Plannin g; vPenalty Factor; Coordinated Development
1. Introduction
Most ofdistributed generations (DG)arethe clean and
renewable energy, they can enjoy priority scheduling
right s under the domest ic ener gy-saving sc hedul ing rule s
[1]. Distributed generatio ns also have a lot o f advantages
including low investment, low loss, high system reliability,
easy siting, short construction cycle, reducing transmis-
sion congestion, delay the lifetime of distribution equip-
ment and environmental protection,etc. [2-3].There is no
doubt that DG is the key to solve the energy crisis, large
enviro n mental pre ssur e a nd many ot her critical i ssues [4].
In recent years, in order to cope with the problem of en-
ergy shortages and environmental pollution, most coun-
tries around the world have enacted laws, regulation or
action plan in succession, and present clear objectives
and d eve lopment paths of renewable energy development.
China clearly plans to build 3T W hydropower and 30GW
wind power, 30GW raw biomass power generation,
1.8GW solar energy, and makes the consumption of re-
newable energy achieve to 15% in energy consumption
of the total by 2020.All of these give distributed power
generation vast business opportunities, in particular,
which are based on the distributed generatio ns of renew-
able energy.
According to some survey, data indicate that the trend
of DG connecting to grid is becoming more and more
obvious under the policy of encouraging and supporting
the generation of renewable energy connecting to grid,
and often run directly in the distribution network[5], so
DG brings many other impact on the economy of power
s y st em, planning and designing, operation, control, pro-
tection, security and stability. Therefore, the power sup-
ply companies is necessary to prospectively and scien-
tifically predict the possible construction situation of
future DG in the regulation planning stage, deeply re-
sear ch and anal ysi s the in flue nce whic h DG may bri ng to
the distribution network systems, ensure the high flexi-
bility of planning scheme for the development of DG.
This paper was inspired b y the papers [6,7], combined
with the relationship between DG and distribution net-
work system, fully considered the optimized allocation
and utilization of global resources, presents a mathe-
matical model to promote the coordination between DG
and distribution network planning, brings the concept of
penalty factor into the distribution network planning to
affect and guide the rational distribution of DG. To en-
sure the safe operation of grid, this design from this pa-
per fully excavates the potential of generation power for
renewable energy,reduces the adverse effects from DG to
system, and make resources and environmental benefits
maximize by scientific planning. The concept of coordi-
nated development coefficient from literature [7] is used
Copyright © 2013 SciRes. ENG
in this model to assess distribution planning c ompr ehend-
sively and systematically and gives the estimate results
back to a new round of planning, so that to build com-
plete overall framework which taking into account the
coordination of DG distribution plannin g.
2. Harmonious Development Analysis
Between DG and Distribution System
According to different investment subjects, there are two
kinds of DG configuration modes: a. Power suppliers
invest DG configuration in distribution network to meet
new load growing demand, While saving the investment
costs of the expansion of the distribution network and
substation equipment; b. DG investors (including Power
Generation Group, power users, etc.) configure the DG
near the distribution network users’ load, this configure-
tion mode makes the installation limit condition reduce
greatly, and expand the DG investment sources [8].
Power Generation Group has more enthusiasm to build-
ing DG than Grid Corporation, thus the second kind of
configuration mode is mainly used at this stage in our
country. But DG investors and the power company are
the different beneficiaries in this model, unreasonable
DG building may affect the power company’s economic
interest, and hinder the smooth promotion of DG.
As previously mentioned, the emergence of DG which
largely connecting to the grid c an give the grid compa ny
some interests on the one hand, for example: reasonable
DG arrangement is able to reduce the energy loss, trans-
mission and d istrib ution costs, etc. [ 9]; DG also can pro-
vide emergency back-up energy or ancillary services to
system, improve the reliability and stability of power
supply. In addition, reasonable DG appearing will post-
pone or reduce the investment of power grid expansion.
On the other hand, due to DG investors and power supply
companies are the different market entity, there are some
conflict interest between them, such as, they may cause
the grid to produce stranded costs, increase standby costs,
and that unreasonable DG connecting to network opera-
tion may lead to the increase of energy loss, and even
make power system’s reliability, stability and power
quality serious de te rioratio n [10].
Power supply companies are necessary and have the
means to take positive and effective measures to guide
the rational distribution of DG, promote the resources
rational develo pment a nd optimal alloca tion in their areas
of jurisdiction, reduce the uncertainty to the distribution
netwo rk pla nnin g by the appe arance of DG, lower ing the
investment risk, improving efficiency, and achieving
3. The Overall Framework for Distribution
Network Coordinated Planning
Considering DG
Before you begin to format your paper, first write and
save the content as a separate text file. Keep your text
and graphic files separate until after the text has been
formatted and styled. Do not use hard tabs, and li mit use
of hard returns to only one return at the end of a para-
graph. Do not add any kind of pagination anywhere in
the paper. Do not number text headsthe template will
do that for you.
Finally, complete content and organizational editing
before formatting. Ple a se ta ke note of t he follo wing items
when proofreading spelling and grammar:
The main task of traditional distribution system plan-
ning is based on load forecasting results in the network
and the basic conditions of the existing network during
the planning period to determine the optimal system-
building programs under the premise of meeting the load
growth and supplying power safely and reliably, making
the cost of distribution construction and operation to the
mini mum [1 1]. Ho wever, with the emergence of DG, the
traditional distribution network planning can’t adapt to
the needs of power industry development in the new pe-
riod. The distribution network planning is no longer just
the simple and traditional power system planning, but
becomes the reso urce allocatio n opti mization which closely
links to national energy policy, sustainable development
strategic initia tives.
The overall framework for distribution network coor-
dinated planning considering DG presented in this paper
includes two parts in detail: the distribution network
planning and DG investment construction. Both of them
interrelate and influence each other by penalty factor.
The power companies affect and guide the investment
planning of DG by penalty factorwhile the planning and
construction of DG investors also have an impact on the
penalty factor. The planning and coordinating process is
sho wn in Figure 1.
3.1. Power Supply Company’s Distribution
Network Planning Section
In this new model, apart from the annual load levels and
Part of the
distributio n networ k
Planning and
Part of DG
investment and
Figure 1. Theoverall framework for distribution network
coor dinated planning considering DG.
Copyright © 2013 SciRes. ENG
distribution of scientific forecast in futureneed to be
referred, but also the various national energy policy
should be activelyresponded and fully implemented in
time, considering the energy characteristics and investors
information of DG in the jurisdiction of the area, fully
exploiting the potential for using the renewable energy
under the premise what ensures a reasonable profit for
the power companies, encouraging and supporting the
development of DG.
First of all, in order to prevent the conflict of interest
between DG investors and the power supply companies,
and to avoid producing stranded costs and increased
standby costs and so on, the most powerful way for the
power companies is to grasp the determinate information
of the DG investment and construction during the next
planning period as much as possible. For example, to
encourage the DG investors to actively participate in the
grid planning, and to spontaneously submit development
strategies of a self-research optimized electricity genera-
tion plan, as well as the information and data of DG in-
vestment construction during the to-be planning period,
meanwhile encourage the DG investors which sign
agreement and contract with power companies to share
risk with the power companies after determining the
to-be investing plan.
Secondly, the gradual promotion of DG technologies
will have an impact on the node voltage, circuital flow,
short circuit current, network reliability etc. in the di stri -
bution net work, a nd its incidence is clo sely related to the
location and capacity of distributed power. Therefore, in
order to reduce or avoid the disorderly construction of
DG do damage to the sec urity and stability of distribution
system, it is necessary for the power companies to take
effective measures to guide the investors to choose the
reasonable location and capacity of distributed power. In
this framework, the power companies, which will effect
and guide the DG’s layout and capacitive construction b y
adopting the economic index, namely penalty factor,
bri ng into the con s t ructio n of t he DG investment secti on
3.2. DG Investment and Construction Section
Before making the final decision, the DG investors must
embark an individual study of the power generation
planning project, which mainly includes the expected
cost of the investment, the cost of operation,the existed
risks, network combined problem and the possible im-
pact on the power generation and so on. In addition, pen-
alty factor must be taken into account which has an im-
portant affection on the DG investment profit under new
planning mode. Finally, decisions are made by compare-
ing with the several comprehensive information of the
feasible DG layout points.
4. Model of Distribution Network Planning
and Coordination of DG
4.1. Penalty Factor
Coordination factor, the key to operate this mode, is the
conve rgence factor i n the who le planni ng proc ess, whic h
is organically combined with DG investment planning
and distribution network planning. The concept of coor-
dinated factor is to reflect the comprehensiveeconomic
indicator, bringing out by the impact of the feasible con-
struction of the layout point to the comprehensive plan-
ning program, which refers two sectors including global
coordination factor and local coordination factor. The
essence is to direct the DG site selection and constant
volume by using price leverage to restrict DG invested
construction when the DG installation adversely affects
the position of the power distribution system restricts,
and to encourage the reasonable DG investment con-
struction where the position has a favorable impact on
the distri but ion net work.
4.2. Coordination Optim iz ation Model
In order to promote the harmonious development of the
economy and environment, and to encourage and support
the DG development, under the object of optimized
resources of regional allocation which belongs to the
power companies, this paper establishes DG construction
and distribution network planning coordinated planning
model as the mi nimum target cost investment.
1) Objective funct ion ofd i s tributi on network p lannin g
The cost of distribution network planning investment
includes comprehensive costs of the investment of
building the substation, fixedly circuital investment, de-
preciation and overhaul, as well as the network loss. Grid
planning model of the power supply companies men-
tioned in this paper is transformed from the investment
model proposed in paper [12]:
11 11
1 111
i ui uijij
iui j
le jj
l ijj
Vpfc D
= == =
== ==
= +
∑∑ ∑∑
∑ ∑∑∑
In this formula, T, M, TN, SS, TU respectively
represent the planned time, load point, all nodes of the
distribution system, all substations of the distribution
system, all transformers of the distribution system (in-
cluding the to be built);
refers to the purchasing
power price;
respectively indicate
the binary decision variables and comprehensive costs of
the transformer u inside the substation i, circuit of the
node i and load point j;
represents the reference
value of the whole network number j penalty factor ;
in general, is the coordination coefficient of number j
Copyright © 2013 SciRes. ENG
feasible layout point.
2)The objective function of construction planning for
DG investme nt
DG investors typically proceed investments planning
by the maximize profittarget, while the minimum total
investment cost (including overall equipment cost and
installation cost) means more competitive. As a result,
this paper aims to decide whether to invest in the DG
construction by the assessment indicators of the total
investment cost. The mathematical model is transformed
from the model proposed in paper [13]:
[( )]
nn DGij
In this formula, DG
n is the amount of the feasible
layout point of the installed DG; DGi
is the compre-
hensive cost and installation cost of each equipment of
the numberi node.
3) The simplified mathematical model of distribution
network planning including DG
In order to reflect the characteristics of the coordina-
tion model and reflect the risk of the planning, the for-
mula (1) and (2) are simplify to (3). The objective func-
tion of the ne w model is a mathematica l model o f typical
dual output.
min{ *}*
= +
= +−
In the formula, { *}
and { *}
respectively indi-
cate the DG without considering penalty factor and in-
vestment costs ofindependent planning inthe distribution
is the reference value of the penalty fac-
tor in the wholedistribution network(namely, the equiva-
lent reference value of the power planning risk in this
round);K is the equivalent weight factor of the whole
distribution networkwhich ranges [0, 1], the purpose of
which is to coordinate the DG and distribution network
4) Calculation o f the penalty fac tor
The global coordination factor reflects pros and cons
under the situation that the volume and capacity of the
DG is on the largest scale in the current planning scheme.
In accordance with related national and local energy pol-
icy, planning and DG investors’ information, from the
macro perspective, the grid planning personnel will try
their best to estimate the DG investment construction
with the area during the planning period as much as
possible.Therefore, the calculation of the index can be
easily obtained for its equivalent to the deter ministic one.
Local coordination factor reflects the pros and cons
caused b y the construction of the investme nt to syste m in
every feasible layout point. From the microscopic point
of view, the possibility of the DG’s appearance in every
feasible layout po int is r andom and d iffic ult to pr edict, so
the ca lcula tio n of ind e x, whic h is more c o mplex, must be
obtained by other means.In this paper, calculations of
local coordinated factor are determined by two steps. For
one thi ng is the reliable index caused by the influence of
every feasible layout point to the distribution network;
then by another impact, that is transfer function trans-
form the index from benefit to t he economy.
Some researchersestablished a comprehensive evalua-
tion coefficient (IMO) of the position and c a pacity, which
is an effective evaluation of multiple indexes involving
network loss, vo ltage, short cir cuit current. Details o f the
computational method can be found in paper [14] and
[15].Inspired by that paper, suppose DG installation do
more harm to t he distr ibutio n networ k (na mel y, t he IMO
is lower), the greater efficiency losses will cause. There-
fore, the local coordination factor can be determined
based on global coordination factor and comprehensive
reliable inde x. That is:
In the for mula,
respectively refer to the
global coordination factor and the local coordination
refers to the index which is the impact of
distribution system caused by the number j feasible
layout point; DG
n is the total of the feasible layout
points with DG installation.
5. Coordinated Development Factor
With the further development of power market and per-
formance of all the aspects of energy polic y, the increas-
ing number of DG and connecting to the grid, all of
which enhance the uncertainty of this distribution net-
work planning, reducing inve stment ri sk, so as to have a
clear guidance on the whole distribution system and DG
coordinated planning system.The paper [7] introduces the
concept of coordinated development coefficient, which
uses the ratio of pla nning risk cost and actual risk co st as
λ, that is, the coefficient of DG and the coordinated de-
velopment of the distribution network. λ, bounded to 1, is
divided into three states representing the poor, qualified
and good. The power planning will be made a full range
of system assessment in this round after λ determined,
and make the appropriate guidance and adjustment to the
next round of planning.
6. Conclusion
DG and power distribution system are an organic whole
which are interrelated, interdependent and contradictory
with each other on the whole. In spite of some certain
micro con flict of interest e xist be tween DG inve stor s and
the power supply companies, with a reasonably coordi-
Copyright © 2013 SciRes. ENG
natio n and pla nning, the safet y be nefi ts of ea ch ot her, the
economic benefits as well as environmental effective will
improve, at last, to maximize the social benefit. The
model of distribution network planning considering DG
presented above will optimize the allocation of resources
to be a higher level, at the same time, transform the un-
certainty into the certainty in the new grid planning pe-
riod, and make planning approachas the way of certainty.
Besides the presented penalty factor and coordinated
development coefficient which effectively guide con-
struction of invest ment and d istribution net work plan ning,
are easy to achieve a rational distribution and constant
volume of geographical and time-domain as well as to
reduce the investment risk of the DG investors and the
power supply companies, in line with the sustainable
development needs of environmental protection and
energy in the new era, to realize the social benefits to
maximize accompany with the healthy and harmonious
development of the DG construction, distribution net-
work planning, the economy and the environment, so as
to provide a foundation of further study on distribution
netwo rk plan ning considering DGfor the new era.For the
reason that the distribution network planning including
DGrelates to the stationing and constant volume of DG,
the planning and design of distribution network, as well
as the calculation and introduction of penalty factor,
which will be a challenging and innovative work in the
[1] Wang Shouxiang, Wang Hui, CaiShengxia,“Review of
Distributed Generation Optimal Allocation,”Automation
of electricity power system, Vol. 33, No. 18, 2009, pp.
[2] Nad er i, E., Seifi,H., Sepasian,M.S., “A Dynamic Ap-
proach for Distribution System Planning Considering
Distributed Generation,” Power Delivery, IEEE Transac-
tions on , Vol. 27, No. 3, 2 01 2, pp . 1313-1322.
[3] Srivastava, A.K, Zamora,R.,Bowman,D.,“Impact of Dis-
tributed Generation with Storage on Electric Grid Stabili-
ty,”Power and Energy Society General Meeting IEEE,
San Diego, CA, 2011, pp. 1437-1442.
[4] Wang Menglin, Zhang Yongjun, Lin Jianxin, “The De-
velopment of Distributed Generation Technology Re-
view,” Electrotechnical Application, Vol. 9, 2011, pp.
[5] CaiLixia, Sun Ying,”A Study on Distribution Network
Planning with Distributed Generation,”Jinan: Shandong
University 2009, pp. 1-58.
[6] ZhangYongjun,LiuHanlin,JiangJinliang,LiangJinzhao,
“Research on Evaluation Index and Method of Coordi-
nated Planning Between Main System and Distribution
Network,” Automation of Electric Power Systems, Vol.
34, No. 15, 2010, pp. 34-41.
[7] Zhang Wuyang, YaoJiangang, “A New GlobalFramework
and Model to Promote the Coordination Planning of In-
dustrial Power Network,” The Electric Network Tech-
nology,Vol. 30, No. 1, 2006,pp: 50-54.
[8] HuShu. WuYaowu, Lou Suhua, etc. “A Game Between
the Users Who Generate Their Own Distributed Power
and Supplier,”Automation of Electric Power Systems,
Vol. 30, No. 20, 2006, pp. 21-25.
[9] Driesen, J., Katiraei, F., “Design for Distributed Energy
Resources,”IEEEPower and Energy Magazine,Vol. 6,
2007, pp . 30-40.
[10] Ayuyev, B.I.,Yerokhin, P.M.,Shubin, N.G.,etc.“The
Software Complex of Optimal Power Flow Solution for
United Power System of Russia in a Terms of Competi-
tive Electricity Market,”Power Tech, 2005 IEEE Rus-
sia,2005,pp. 1324-1329.
[11] Zeng Li, Jin Zhaoxia, “Distribution Network Planning
Based on Strategy,”Guangzhou: South China University
of Technology, 2011, pp. 1-57.
[12] WalidEI-Khattam,Hegazy YG,Salama MMA, “AnInte-
gratedDistributed Generation Optimization Model for
Distribution System Planning,”IEEETransactions on
Powe r Sys t ems,Vol. 20,2005, pp . 115 8-1165.
[13] ChenHaiyan, Chen Jinfu, YangXiongping, etc. “Distri-
buted Power Generation Planning of the Distribution
Networks Including the Short-circuit Current Con-
straints,”Automation of Electric Power Systems, Vol. 30,
No. 21, 20 06 , pp. 16-21.
P.,“Evaluating Distributed Generation Impacts with a
Muhiobjeetive Ind ex, ”I EEE Trans on Power Delivery,Vol.
21, No. 3, 20 06,pp. 14 52-1458.
[15] Pholborisut, N., Saksornchai, T., Eua-arporn, B., “Eva-
luating the impact of distributed generation on protection
system coordination using protection miscoordinationin-
dex,” Electrical Engineering / Electronics, Computer,
Telecommunications and Information Technology (ECTI-
CON), 2011 8th International Conference, 2011, pp.