This document provides an introduction to electrical distribution systems. It discusses the history of electrical power systems and how they evolved from direct current to alternating current systems. It also describes the key components of electrical power systems, including generation, transmission, distribution, control, conversion, and measurement. Distribution system planning is discussed, with the goal being to satisfy growing electricity demand in an optimal way through technically adequate and economically feasible additions to the distribution system. Customer load characteristics must be determined and factored into distribution planning.
We are providing info about power transformer parts and their functions. Power transformer is very useful in transmission network of higher voltage for step-up and step down.
transmission versus distribution planning, long term versus short term planning,issues in transmission planning,generation planning,capacity resource planning, transmission planning,national and regional planning, integrated resource planning
this slide shows what is smart grid ,its comparison between the electromechanical grids . smart meters and devises for the smart grid . benefit of smart grid . and a conclution
We are providing info about power transformer parts and their functions. Power transformer is very useful in transmission network of higher voltage for step-up and step down.
transmission versus distribution planning, long term versus short term planning,issues in transmission planning,generation planning,capacity resource planning, transmission planning,national and regional planning, integrated resource planning
this slide shows what is smart grid ,its comparison between the electromechanical grids . smart meters and devises for the smart grid . benefit of smart grid . and a conclution
A power system control is required to maintain a continuous balance between power generation and load demand. Load Frequency Controller and Automatic Voltage Regulator play an important role in maintaining constant frequency and voltage in order to ensure the reliability of electric power.
We had made a working model on static VAR compensator which is made by power electronic switch and mechanically switched. We had chosen mechanically switched capacitor method to improved receiving end voltage as well as power factor.
Energy Community: Yasuyuki Watanabe - Battery Energy Storage Systems (BESS)ENGIE Italia
Presentazione "Energy Community: Battery Energy Storage Systems (BESS)".
A cura di Yasuyuki Watanabe per il Forum #energYnnovation su
"Energy Community: un nuovo paradigma per l'innovazione energetica nel nostro Paese" - 2° osservatorio GDF SUEZ Energia Italia
Milano, 31 marzo 2014.
Museo della scienza e della tecnologia Leonardo da Vinci.
http://www.gdfsuez.it/energy_Community
Electrical substation (one and half breaker scheme)Sourabh sharma
Double Bus One and Half Breaker Scheme is mostly adopted in high voltage electrical substations (220 KV or 400KV, 700 KV). Due to many advantages of this arrangement like high selectivity, reliability and less cost as compare to other bus arrangements for power stations or switch yards
The Function of Electric Power SystemsAhmed Nassar
circuit breaker, conductors, distribution, electric power system, electrical, electromechanical, engineering, feeders, generators, insulators, lightning arresters, non-renewable energy, renewable energy, substation, substations, transformers
1. ABSTRACT
This Research Article speaks about electrical power systems which consist of three main phases: generation, transmission, and distribution. generators produce electricity from power sources at power plants. then power is delivered to customers through transmissions which stepping power up or down According to the distance that the energy travels. then power moves through distribution lines that carry electricity to homes and businesses.
2. INTRODUCTION
Typically, electricity is provided to homes and industries as AC. The electrons do not travel overhead along the power lines but vibrate in these lines 60 times per second. The electricity outlet plugs in your home does not produce electrons, but energy. If an appliance is attached, the outlet plugs provide the power for electrons to be moved around a closed circuit which is already in the wire. The energy is supplied as voltage to your home via a large, very complex distribution network. The energy is generated in a power plant and transmitted to the consumer via a network of power lines. In several steps, this is done. With a power voltage of several thousand volts, electricity leaves the power station at very high levels. The voltage is increased to several hundreds of thousand volts due to the loss of energy on high voltages at the overhead power lines. The voltage is decreased again to several thousand volts before power is distributed to industrial users. The voltage is decreased to 110 volts for home use. A transformer is used every time the voltage is down. Transformers are devices that only work with alternating current flows to either increase or decrease voltages.
Electric power systems (Figure 1) are real-time energy supply systems. Real-time means that power is generated, transported, transmitted, and distributed now of consumption. Electric power systems do not store electricity for the time of need as water and gas systems. Instead, generators produce the energy needed by demand It transforms other sources of energy (Such as wind, mechanical, solar, chemical, hydraulic, heat, geothermal, nuclear …etc.) into electrical power. Six main components of the power system are the power stations, transformer, transmission line, substations, distribution lines, distribution transformers. Also, there are many other devices connected to the network such as circuit breakers, conductors, etc. The system starts with a power plant generator where electrical energy is produced. Then power station transformers transformed to high-voltage electrical energy that is more suitable for efficient far distances transportation. High-voltage power lines in the electric power transmission system efficiently transport electricity over long distances to the
A power system control is required to maintain a continuous balance between power generation and load demand. Load Frequency Controller and Automatic Voltage Regulator play an important role in maintaining constant frequency and voltage in order to ensure the reliability of electric power.
We had made a working model on static VAR compensator which is made by power electronic switch and mechanically switched. We had chosen mechanically switched capacitor method to improved receiving end voltage as well as power factor.
Energy Community: Yasuyuki Watanabe - Battery Energy Storage Systems (BESS)ENGIE Italia
Presentazione "Energy Community: Battery Energy Storage Systems (BESS)".
A cura di Yasuyuki Watanabe per il Forum #energYnnovation su
"Energy Community: un nuovo paradigma per l'innovazione energetica nel nostro Paese" - 2° osservatorio GDF SUEZ Energia Italia
Milano, 31 marzo 2014.
Museo della scienza e della tecnologia Leonardo da Vinci.
http://www.gdfsuez.it/energy_Community
Electrical substation (one and half breaker scheme)Sourabh sharma
Double Bus One and Half Breaker Scheme is mostly adopted in high voltage electrical substations (220 KV or 400KV, 700 KV). Due to many advantages of this arrangement like high selectivity, reliability and less cost as compare to other bus arrangements for power stations or switch yards
The Function of Electric Power SystemsAhmed Nassar
circuit breaker, conductors, distribution, electric power system, electrical, electromechanical, engineering, feeders, generators, insulators, lightning arresters, non-renewable energy, renewable energy, substation, substations, transformers
1. ABSTRACT
This Research Article speaks about electrical power systems which consist of three main phases: generation, transmission, and distribution. generators produce electricity from power sources at power plants. then power is delivered to customers through transmissions which stepping power up or down According to the distance that the energy travels. then power moves through distribution lines that carry electricity to homes and businesses.
2. INTRODUCTION
Typically, electricity is provided to homes and industries as AC. The electrons do not travel overhead along the power lines but vibrate in these lines 60 times per second. The electricity outlet plugs in your home does not produce electrons, but energy. If an appliance is attached, the outlet plugs provide the power for electrons to be moved around a closed circuit which is already in the wire. The energy is supplied as voltage to your home via a large, very complex distribution network. The energy is generated in a power plant and transmitted to the consumer via a network of power lines. In several steps, this is done. With a power voltage of several thousand volts, electricity leaves the power station at very high levels. The voltage is increased to several hundreds of thousand volts due to the loss of energy on high voltages at the overhead power lines. The voltage is decreased again to several thousand volts before power is distributed to industrial users. The voltage is decreased to 110 volts for home use. A transformer is used every time the voltage is down. Transformers are devices that only work with alternating current flows to either increase or decrease voltages.
Electric power systems (Figure 1) are real-time energy supply systems. Real-time means that power is generated, transported, transmitted, and distributed now of consumption. Electric power systems do not store electricity for the time of need as water and gas systems. Instead, generators produce the energy needed by demand It transforms other sources of energy (Such as wind, mechanical, solar, chemical, hydraulic, heat, geothermal, nuclear …etc.) into electrical power. Six main components of the power system are the power stations, transformer, transmission line, substations, distribution lines, distribution transformers. Also, there are many other devices connected to the network such as circuit breakers, conductors, etc. The system starts with a power plant generator where electrical energy is produced. Then power station transformers transformed to high-voltage electrical energy that is more suitable for efficient far distances transportation. High-voltage power lines in the electric power transmission system efficiently transport electricity over long distances to the
Understanding Electrical Engineering and Safety for Non-ElectriciansLiving Online
Electrical engineering is often considered to be a mysterious science, because electricity cannot be seen. However, we are all aware of its existence and usefulness in our daily lives. While many of us work on electrical systems, we do not fully appreciate the dangers, which we get exposed to when doing so. All it takes is a few simple precautions to avoid getting hurt. This manual teaches you about the dangers of careless handling of electrical appliances and prevention of electrical accidents.
This manual is not meant for electrical engineers and other qualified technicians. It is for those who are not formally trained as electricians but often have to handle and maintain electrical appliances in the course of their work. Readers will have an opportunity to understand how the appliances they see everyday actually function.
MORE INFORMATION: http://www.idc-online.com/content/understanding-electrical-engineering-and-safety-non-electricians-23?id=145
High voltage electricity refers to electrical potential large enough to cause injury or damage. In certain industries, high voltage refers to voltage above a certain threshold. Equipment and conductors that carry high voltage warrant special safety requirements and procedures.
Detail of the insulators (the vertical string of discs) and conductor vibration dampers (the weights attached directly to the cables) on a 275,000 volt suspension pylon near Thornbury, South Gloucestershire, England. In some countries, pylons for high and extra-high voltage are usually designed to carry two or more electric circuits. For double circuit lines in Germany, the “Danube” towers or more rarely, the “fir tree” towers, are usually used. If a line is constructed using pylons designed to carry several circuits, it is not necessary to install all the circuits at the time of construction. Medium voltage circuits are often erected on the same pylons as 110 kV lines. Paralleling circuits of 380 kV, 220 kV and 110 kV-lines on the same pylons is common. Sometimes, especially with 110 kV-circuits, a parallel circuit carries traction lines for railway electrification
Human population of the world and its Electrical
power demand is increasing day by day. The available fossil
fuel energy resources are being depleted day by day. So it is a
wise decision to absorb the natural renewable energy
resources. Among the other natural resources, solar energy is
also a precious available energy source. In Pakistan abundance
solar energy can be easily extracted.
In this research work, impacts of solar generation system are
analyzed while integrated with 11kV radial distribution feeder.
PV system is integrated with feeder in three different ways by
using SINCAL software and its impacts in terms of the power
loss, voltage profile and short circuit level are analyzed. When
PV system is integrated with HT side it results negligible
increment in voltage, no change in LT losses, negligible
decrement in HT losses and no change in short circuit level.
When PV system is connected with LT bus-bar of each
transformer, there is significant increment in voltage, small
decrement in LT losses, significant decrement in HT losses and
smaller increment in short circuit level. When PV system is
connected with each load, there is significant increment in
voltage, large decrement in LT losses, significant decrement in
HT losses and smaller increment in short circuit level.
Building services engineering, technical building services, architectural engineering, building engineering, or facilities and services planning engineering refers to the implementation of the engineering for the internal environment and environmental impact of a building.
Overview of the fundamental roles in Hydropower generation and the components involved in wider Electrical Engineering.
This paper presents the design and construction of hydroelectric dams from the hydrologist’s survey of the valley before construction, all aspects and involved disciplines, fluid dynamics, structural engineering, generation and mains frequency regulation to the very transmission of power through the network in the United Kingdom.
Author: Robbie Edward Sayers
Collaborators and co editors: Charlie Sims and Connor Healey.
(C) 2024 Robbie E. Sayers
NO1 Uk best vashikaran specialist in delhi vashikaran baba near me online vas...Amil Baba Dawood bangali
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Forklift Classes Overview by Intella PartsIntella Parts
Discover the different forklift classes and their specific applications. Learn how to choose the right forklift for your needs to ensure safety, efficiency, and compliance in your operations.
For more technical information, visit our website https://intellaparts.com
Hybrid optimization of pumped hydro system and solar- Engr. Abdul-Azeez.pdffxintegritypublishin
Advancements in technology unveil a myriad of electrical and electronic breakthroughs geared towards efficiently harnessing limited resources to meet human energy demands. The optimization of hybrid solar PV panels and pumped hydro energy supply systems plays a pivotal role in utilizing natural resources effectively. This initiative not only benefits humanity but also fosters environmental sustainability. The study investigated the design optimization of these hybrid systems, focusing on understanding solar radiation patterns, identifying geographical influences on solar radiation, formulating a mathematical model for system optimization, and determining the optimal configuration of PV panels and pumped hydro storage. Through a comparative analysis approach and eight weeks of data collection, the study addressed key research questions related to solar radiation patterns and optimal system design. The findings highlighted regions with heightened solar radiation levels, showcasing substantial potential for power generation and emphasizing the system's efficiency. Optimizing system design significantly boosted power generation, promoted renewable energy utilization, and enhanced energy storage capacity. The study underscored the benefits of optimizing hybrid solar PV panels and pumped hydro energy supply systems for sustainable energy usage. Optimizing the design of solar PV panels and pumped hydro energy supply systems as examined across diverse climatic conditions in a developing country, not only enhances power generation but also improves the integration of renewable energy sources and boosts energy storage capacities, particularly beneficial for less economically prosperous regions. Additionally, the study provides valuable insights for advancing energy research in economically viable areas. Recommendations included conducting site-specific assessments, utilizing advanced modeling tools, implementing regular maintenance protocols, and enhancing communication among system components.
Cosmetic shop management system project report.pdfKamal Acharya
Buying new cosmetic products is difficult. It can even be scary for those who have sensitive skin and are prone to skin trouble. The information needed to alleviate this problem is on the back of each product, but it's thought to interpret those ingredient lists unless you have a background in chemistry.
Instead of buying and hoping for the best, we can use data science to help us predict which products may be good fits for us. It includes various function programs to do the above mentioned tasks.
Data file handling has been effectively used in the program.
The automated cosmetic shop management system should deal with the automation of general workflow and administration process of the shop. The main processes of the system focus on customer's request where the system is able to search the most appropriate products and deliver it to the customers. It should help the employees to quickly identify the list of cosmetic product that have reached the minimum quantity and also keep a track of expired date for each cosmetic product. It should help the employees to find the rack number in which the product is placed.It is also Faster and more efficient way.
NUMERICAL SIMULATIONS OF HEAT AND MASS TRANSFER IN CONDENSING HEAT EXCHANGERS...ssuser7dcef0
Power plants release a large amount of water vapor into the
atmosphere through the stack. The flue gas can be a potential
source for obtaining much needed cooling water for a power
plant. If a power plant could recover and reuse a portion of this
moisture, it could reduce its total cooling water intake
requirement. One of the most practical way to recover water
from flue gas is to use a condensing heat exchanger. The power
plant could also recover latent heat due to condensation as well
as sensible heat due to lowering the flue gas exit temperature.
Additionally, harmful acids released from the stack can be
reduced in a condensing heat exchanger by acid condensation. reduced in a condensing heat exchanger by acid condensation.
Condensation of vapors in flue gas is a complicated
phenomenon since heat and mass transfer of water vapor and
various acids simultaneously occur in the presence of noncondensable
gases such as nitrogen and oxygen. Design of a
condenser depends on the knowledge and understanding of the
heat and mass transfer processes. A computer program for
numerical simulations of water (H2O) and sulfuric acid (H2SO4)
condensation in a flue gas condensing heat exchanger was
developed using MATLAB. Governing equations based on
mass and energy balances for the system were derived to
predict variables such as flue gas exit temperature, cooling
water outlet temperature, mole fraction and condensation rates
of water and sulfuric acid vapors. The equations were solved
using an iterative solution technique with calculations of heat
and mass transfer coefficients and physical properties.
1. INTRODUCTION TO DISTRIBUTION SYSTEMS.
DISTRIBUTION SYSTEM PLANNING
ELECRTICAL DISTRIBUTION SYSTEMS
IV B.TECH II SEMESTER EEE
S K B PRADEEPKUMAR CH
ASSISTANT PROFESSOR
EEE
2. BRIEF HISTORY OF ELECTRICAL POWER SYSTEMS
Electrical power systems have been in existence for many years. The applications of power
systems have expanded rapidly since their development. At the present time, applications
continue to increase, placing additional requirements on power production, distribution
systems and associated systems. Thomas Edison is given credit for developing the concept of
widespread generation and distribution of electrical power. He performed developmental
work on direct-current (DC) generators which were driven by steam engines. Edison’s work
with electrical lights and power production led the way to development of electric motors,
distribution systems and associated control equipment. Most early discoveries related to
electrical power dealt with direct current (DC) systems. Alternating-current power generation
became widespread a short time later. The primary reason for converting to AC power
production and distribution was that transformers could be used to increase AC voltage levels
for long-distance distribution of electrical power.
3.
4.
5. Thus the discovery of transformers allowed the conversion of electrical power from DC to AC
systems. Presently, almost all electrical power systems produce and distribute three-phase
alternating current. Transformers allow the voltage produced by AC generators to be increased
while decreasing current level by a corresponding amount. This allows long-distance
electrical power distribution at a reduced current level, reduces power losses, and increases
overall power system efficiency. The increased use of electrical motors for home appliances
and industrial and commercial equipment has increased the need for electrical
power to be distributed to various locations. In the early days of electrical power, the
distribution systems were only an extension of the power generating plant. There was little
planning for the efficient transfer of energy from the generating plant to the limited number of
consumers. The expansion of electrical energy use has placed greater demands on the
distribution system. Not only are more customers served, but today’s equipment requires
closer attention to voltage variation and little toleration of service interruption. The design and
operation of electrical power distribution systems has become a very important science..
6. Well-engineered power systems of today are connected together in such a way that if a
problem occurs in one system, it can be supplemented by another system. Electrical loads can
be transferred easily from one system to another. The United States has a very reliable “grid”
system which maintains electrical power to customers at the proper voltage level without
interruption. It is extremely rare for “blackouts” or “brownouts” to occur. These conditions
are avoided by proper planning for situations of extremely high demand. A blackout is a
complete interruption of electrical power, while a brownout is a reduction of voltage level to
the consumer. A brownout could be purposely done in order to deliver available power at a
reduced voltage to avoid a blackout during a problem of extremely high demand. High
demand usually occurs during abnormally hot or cold temperatures over an extended period
of time Early power distribution systems supplied direct current (DC) at low voltage levels
over relatively short distances. The invention of the transformer and the problems associated
with delivering power over long distances brought about a change to the use of alternating
current (AC) power systems.
7. Today, greater electrical power demand can be supplied with long-distance, high voltage
transmission. Voltage levels may be easily increased and reduced by transformers in order to
supply electrical energy. Not only has the efficiency of the electrical power distribution
system been improved, but also the materials, equipment, and associated control systems have
been continually updated. Examples of such improvement include the quality of steel towers,
wood poles of long lasting design, better conductors and insulators, and more reliable
computer systems for monitoring and controlling the electrical distribution
system.
8. THE ELECTRICAL POWER SYSTEM
The block diagram of an electrical power system is shown in Figure 1-3. The first block or
the electrical power production section is an important part of the complete electrical power
system. However, once electrical power is produced, it must be distributed to the location
where it will be used, so electrical power distribution systems (block 2) transfer electrical
power from one location to another. Electrical power control systems (block 3) are probably
the most complex of all the parts of the electrical power system as there are unlimited types
of devices and equipment used to control electrical power. Then, the electrical power
conversion systems (block 4), also called loads, convert the electrical power into some
other form of energy, such as light, heat, or mechanical energy. Thus, conversion systems
are an extremely important part of the electrical power system. Another part of the
electrical power system is power measurement (block 5). Without electrical power
measurement systems, control of electrical power would be almost impossible.
9. Each of the blocks shown in Figure 1-3 represents one important part of the electrical power
system. Thus, we should be concerned with each part of the electrical power system rather
than only with isolated parts. In this way, we can develop a more complete understanding of
how electrical power systems operate. This type of understanding is needed to help us solve
our energy problems that are related to electrical power. We cannot consider only the
distribution aspect of electrical power systems. We must understand and consider each pan of
the system. The “Electrical Power System” model will be used in this book to help
understand electrical distribution systems. Refer to Figure 1-3 as a reference as you study the
chapters of this book. Figure 1-4 shows the generation and transmission of electrical power
as an example. Power is produced at a generating plant (source). Distribution occurs between
the plant and the consumer by power lines. Transformers are used to control the voltage and
current levels. Conversion of electrical power to another form (light, heat, mechanical)
occurs at the home.
10.
11. An understanding of the terms energy, work, and power is necessary in the study of
electrical power systems. The first term, energy, means the capacity to do work. For
example, the capacity to light a light bulb, to heat a home, or to move something requires
energy. Energy exists in many forms, such as electrical, mechanical, chemical, and heat. If
energy exists because of the movement of some item, such as a ball rolling down a hill, it
is called kinetic energy. If energy exists because of the position of something, such as a
ball that is at the top of the hill but not yet rolling, it is called potential energy. Energy has
become one of the most important factors in our society. A second important term is work.
Work is the transferring or transforming of energy. Work is done when a force is exerted to
move something over a distance against opposition, such as when a chair is moved from
one side of a room to the other. An electrical motor used to drive a machine performs
work.
ENERGY, WORK, AND POWER
12. Work is performed when motion is accomplished against the action of a force that tends
to oppose the motion. Work is also done each time energy changes from one form into
another. A third important term is power. Power is the rate at which work is done. It
considers not only the work that is performed but the amount of time in which the work
is done. For instance, electrical power is the rate at which work is done as electrical
current flows through a wire. Mechanical power is the rate at which work is done as an
object is moved against opposition over a certain distance. Power is either the rate of
production or the rate of use of energy. The watt is the unit of measurement of electrical
power.
13.
14. INTRODUCTION TO DISTRIBUTION SYSTEMS
To achieve a good understanding of electric distribution systems, it is necessary to first get
acquainted with the appropriate background. A description of the main concepts of electric
distribution systems is given in this chapter followed by a more detailed discussion of the
various aspects in the following chapters.
Power System Arrangements
A power system contains all electric equipment necessary for supplying the consumers
with electric energy. This equipment includes generators, transformers (step - up and step
- down), transmission lines, sub transmission lines, cables and switchgear [1] . As shown
in Figure 1.1 , the power system is divided mainly into three parts. The first part is the
generation system in which the electricity is produced in power plants owned by an
electric utility or an independent supplier. The generated power is at the generation
voltage level. The voltage is increased by using step - up power transformers to transmit
the power over long distances under the most economical conditions.
15. The second part is the transmission system that is responsible for the delivery of power to
load centers through cables or overhead transmission lines. The transmitted power is at
extra high voltage (EHV) (transmission network) or high voltage (HV) (sub transmission
network). The third part is the distribution system where the voltage is stepped down at the
substations to the medium voltage (MV) level. The power is transmitted through the
distribution lines (or cables) to the local substations (distribution transformers) at which the
voltage is reduced to the consumer level and the power lines of the local utility or
distribution company carry electricity to homes or commercial establishments. The physical
representation given in Figure 1.1 needs to be expressed by a schematic diagram adequate
for analyzing the system. This is done by drawing a single - line diagram (SLD) as shown
in Figure 1.2 . This figure illustrates two power systems connected together by using tie -
links as they exist in real practice to increase system reliability and decrease the probability
of load loss. The voltage values shown in this figure are in accordance with the standards of
North American power systems.
18. Each system contains generators delivering power at generation voltage level, say 13.8 kV.
By using step - up transformers, the voltage is stepped up to 345 kV and the power is
transmitted through the transmission system. The transmission lines are followed by 138
kV sub transmission lines through terminal substations. The sub transmission lines end at
the zone substations where the voltage is stepped down to 13.8 kV to supply the MV
distribution network at different distribution points (DPs) as primary feeders. Then the
electricity is delivered to the consumers by secondary feeders through local distribution
transformers at low voltage (LV) [3, 4] . To get a better understanding of the physical
arrangement of the power system, consider how electricity is supplied to a big city. In the
first part of the arrangement, the power stations are often located far away from the city
zones and sometimes near the city border. According to how big the city is, the second part
of the arrangement (transmission and sub transmission systems) is determined.
19. Overhead transmission lines and cables can be used for both systems. They are spanned
along the boundary of the city where the terminal and zone substations are located as well.
This allows the planner to avoid the risk of going through the city by lines that operate at
HV or EHV. For the third part, the distribution system, the total area of the city is divided
into a number of subareas depending on the geographic situation and the load (amount and
nature) within each subarea. The distribution is fed from the zone substation and designed
for each subarea to provide the consumers with electricity at LV by using local transformers.
As an illustrative example, consider the total area of a big city is divided into three
residential areas and two industrial areas as shown in Figure 1.3 . Power station #1, terminal
substations #2 (345/138/69 kV), and the zone substations #3 (138/69/13.8 kV) are located at
the boundary of the city. The transmission system operates at 138 and 69 kV. Both of these
systems are around the city and do not go through the city subareas.
20. Of course, the most economical voltage for the transmission and sub transmission systems
is determined in terms of the transmitted power and the distance of power travel. Also, the
supply network to the industrial zones is operating at 69 kV because of the high power
demand and to avoid the voltage drop violation at the MV level [5] . Substation #4
(69/13.8 kV) is located at a certain distance inside the city boundary where the distribution
system starts to feed the loads through DPs. The outgoing feeders from DPs are connected
to local distribution transformers to step down the MV to LV values.
21. System planning is essential to assure that the growing demand for electricity can be
satisfied by distribution system additions that are both technically adequate and
reasonably economical. Even though considerable work has been done in the past on the
application of some types of systematic approach to generation and transmission system
planning, its application to distribution system planning has unfortunately been
somewhat neglected. In the future, more than in the past, electric utilities will need a fast
and economical planning tool to evaluate the consequences of different proposed
alternatives and their impact on the rest of the system to provide the necessary
economical, reliable, and safe electric energy to consumers.
Distribution System Planning
22.
23. The objective of distribution system planning is to assure that the growing demand for
electricity, in terms of increasing growth rates and high load densities, can be satisfied in an
optimum way by additional distribution systems, from the secondary conductors through the
bulk power substations, which are both technically adequate and reasonably economical. All
these factors and others, for example, the scarcity of available land in urban areas and
ecological considerations, can put the problem of optimal distribution system planning
beyond the resolving power of the unaided human mind.
Distribution system planners must determine the load magnitude and its geographic location.
Then the distribution substations must be placed and sized in such a way as to serve the load
at maximum cost effectiveness by minimizing feeder losses and construction costs, while
considering the constraints of service reliability. In the past, the planning for other portions
of the electric power supply system and distribution system frequently has been authorized
at the company division level without the review of or coordination with long-range plans.
24. As a result of the increasing cost of energy, equipment, and labor, improved system planning
through use of efficient planning methods and techniques is inevitable and necessary. The
distribution system is particularly important to an electrical utility for two reasons: (1) Its
close proximity to the ultimate customer and (2) its high investment cost. Since the
distribution system of a power supply system is the closest one to the customer, its failures
affect customer service more directly than, for example, failures on the transmission and
generating systems, which usually do not cause customer service interruptions. Therefore,
distribution system planning starts at the customer level. The demand, type, load factor, and
other customer load characteristics dictate the type of distribution system required. Once the
customer loads are determined, they are grouped for service from secondary lines Connected
to distribution transformers that step down from primary voltage.
25.
26.
27.
28. The distribution transformer loads are then combined to determine the demands on the
primary distribution system. The primary distribution system loads are then assigned to
substations that step down from transmission voltage. The distribution system loads, in
turn, determine the size and location, or siting, of the substations as well as the routing and
capacity of the associated transmission lines. In other words, each step in the process
provides input for the step that follows. The distribution system planner partitions the total
distribution system planning problem into a set of sub problems that can be handled by
using available, usually ad hoc, methods and techniques. The planner, in the absence of
accepted planning techniques, may restate the problem as an attempt to minimize the cost
of sub transmission, substations, feeders, laterals, etc., and the cost of losses. In this
process, however, the planner is usually restricted by permissible voltage values, voltage
dips, flicker, etc., as well as service continuity and reliability.
29. In pursuing these objectives, the planner ultimately has a significant influence on additions
to and/or modifications of the sub transmission network, locations and sizes of substations,
service areas of substations, location of breakers and switches, sizes of feeders and laterals,
voltage levels and voltage drops in the system, the location of capacitors and voltage
regulators, and the loading of transformers and feeders. There are, of course, some other
factors that need to be considered such as transformer impedance, insulation levels,
availability of spare transformers and mobile substations, dispatch of generation, and the
rates that are charged to the customers. Furthermore, there are factors over which the
distribution system planner has no influence but which, nevertheless, have to be
considered in good long-range distribution system planning, for example, the timing and
location of energy demands; the duration and frequency of outages; the cost of equipment,
labor, and money; increasing fuel costs; increasing or decreasing prices of alternative
energy sources;
30. changing socioeconomic conditions and trends such as the growing demand for goods and
services; unexpected local population growth or decline; changing public behavior as a
result of technological changes; energy conservation; changing environmental concerns of
the public; changing economic conditions such as a decrease or increase in gross national
product (GNP) projections, inflation, and/or recession; and regulations of federal, state, and
local governments.