International Conference on Electrical, Electronics, and Optimization Techniques (ICEEOT) - 2016
978-1-4673-9939-5/16/$31.00 ©2016 IEEE
The Concept of Distributed Generation & the effects
of its Placement in Distribution Network
Devang K. Mer
Department of Electrical Engineering
G. H. Patel college of Engineering & Technology
Vallabh Vidyanagar - 388120 , India
E-mail : dev.vmer@gmail.com
Ritesh R. Patel
Department of Electrical Engineering
G. H. Patel college of Engineering & Technology
Vallabh Vidyanagar - 388120 , India
E-mail : riteshpatel@gcet.ac.in
Abstract—The electrical industry is growing tremendously.
Various types of load which are to be supplied constantly for
economic growth, but the demand cannot be fulfill with limited
central generation hence the distributed generators can be very
beneficial option for that. Distributed generation is also an
interesting topic for researchers as it gives other benefits like loss
reduction, voltage profile improvement, adoption of new
technologies, improved reliability, security and some
environmental effects. In this paper the effects of distributed
generator at various locations of the system on power losses and
voltage regulation is examined. The work is carried out in
MATLAB environment on standard 15-bus distribution system.
Keywords—Distributed generation; Power loss reduction;
Voltage profile improvement; LPF- load power factor; UPF- unity
power factor
I. INTRODUCTION
We know that the beginning of electricity supply industry
was distributed, i.e. The electrical energy was produced near
the loads. With the increasing demand, we adopted centralized
electricity supply industry by installing huge generating
station and very complex transmission line network to satisfy
the need of electricity. Due to continuous change in the
regulatory system and operational climate, the problem of
excess demand is still there, but we cannot construct more
generating station of transmission lines in a small range of
time and hence the distributed generation with centralized
supply industry can form a new type of electricity supply
industry that can fulfill the demand of electricity in the
future[1].
The term distributed generation is not properly defined
term still now as different societies and countries treat it as per
their own rules and regulation and they all have its different
definitions. In different countries or region, it is known as
different names as dispersed generation, embedded generation
or decentralized generation. The term distributed generation is
not relevant to many parameters such as rating, power delivery
area, ownership, etc. Which are the reason why it couldn’t be
standardly defined. One can commonly define the distributed
generation as “Electrical power generation within the
distribution network or on the customer side of the
network”[2].
The distributed generator can be of any technology,
renewable or nonrenewable and we can classify DG in three
categories as Synchronized type, Asynchronized type and
Inverter based distributed generator. Micro-turbines, stirling
engines, CHP (combined heat and power) turbines, etc. are
some new technologies of DG which works on non-renewable
supply. Photovoltaic arrays, wind farms, fuel-cells, gas
turbines etc. are technologies of DG which give the electrical
energy using renewable energy resources[3].
II. PROBLEM FORMULATION
In any study on either electrical transmission system or
electrical distribution system, its load flow analysis is needed.
With the help of load flow analysis, we can know the voltage
magnitude and power angle at each bus or node, active and
reactive power flow through each branch, total active and
reactive power losses of the system which all become an
essential data for security analysis, state estimation, economic
dispatch, etc.
The newton-raphson method, gauss-sheidal method and
FDLF method are very popular in load flow analysis of the
transmission system, but the characteristics of the transmission
system and distribution system are different hence the use of
above mentioned method can give the problem of
convergence. The reasons why these methods can not be
helpful is R/X ration which is larger for the distribution
system, then transmission system and hence distribution
system is always remains in ill condition[4].
In distribution load flow, there are numbers of methods
and techniques which can be used, but the most efficient and
popular method is backward forward sweeping method.
In this method, the system is assumed flat voltage start and
then active and reactive power flow is calculated from end
node to source node i.e. in backward direction. Once power
flow is known, voltage and angle are calculated using those
values from source node to end node, i.e. in the forward
direction, hence it is named as backward forward sweep
method. This modified voltage and angle values are further
used to find the new power flow and the process is continuous
till the convergence is achieved.
This method requires less computer memory and it
involves only the evaluation of simple algebraic equations of