This manual will enable you to understand the level of failure-proofing that specific equipment may require, evaluate available options objectively, specify the best and most economical solution, and manage the installation, commissioning and maintenance of the distribution system.
FOR MORE INFORMATION: http://www.idc-online.com/content/emergency-power-supplies-electrical-distribution-design-installation-and-commissioning-24?id=39
Fiction is a form of narrative, one of the four rhetorical modes of discourse. Fiction-writing also has modes for fiction-writing: action, exposition, description, dialogue, summary, and transition (Morrell 2006, p. 127). Author Peter Selgin refers to methods, including action, dialogue, thoughts, summary, scene, and description (Selgin 2007, p. 38). Currently, there is no consensus within the writing community regarding the number and composition of fiction-writing modes and their uses.
Description is the fiction-writing mode for transmitting a mental image of the particulars of a story. Together with dialogue, narration, exposition, and summarization, description is one of the most widely recognized of the fiction-writing modes. As stated in Writing from A to Z, edited by Kirk Polking, description is more than the amassing of details; it is bringing something to life by carefully choosing and arranging words and phrases to produce the desired effect (Polking 1990, p. 106). The most appropriate and effective techniques for presenting description are a matter of ongoing discussion among writers and writing coaches.Fiction is a form of narrative, one of the four rhetorical modes of discourse. Fiction-writing also has modes for fiction-writing: action, exposition, description, dialogue, summary, and transition (Morrell 2006, p. 127). Author Peter Selgin refers to methods, including action, dialogue, thoughts, summary, scene, and description (Selgin 2007, p. 38). Currently, there is no consensus within the writing community regarding the number and composition of fiction-writing modes and their uses.
Description is the fiction-writing mode for transmitting a mental image of the particulars of a story. Together with dialogue, narration, exposition, and summarization, description is one of the most widely recognized of the fiction-writing modes. As stated in Writing from A to Z, edited by Kirk Polking, description is more than the amassing of details; it is bringing something to life by carefully choosing and arranging words and phrases to produce the desired effect (Polking 1990, p. 106). The most appropriate and effective techniques for presenting description are a matter of ongoing discussion among writers and writing coaches.Fiction is a form of narrative, one of the four rhetorical modes of discourse. Fiction-writing also has modes for fiction-writing: action, exposition, description, dialogue, summary, and transition (Morrell 2006, p. 127). Author Peter Selgin refers to methods, including action, dialogue, thoughts, summary, scene, and description (Selgin 2007, p. 38). Currently, there is no consensus within the writing community regarding the number and composition of fiction-writing modes and their uses.
Description is the fiction-writing mode for transmitting a mental image of the particulars of a story. Together with dialogue, narration, exposition, and summarization, description is one of the most widely recognized of the fiction-w
Fiction is a form of narrative, one of the four rhetorical modes of discourse. Fiction-writing also has modes for fiction-writing: action, exposition, description, dialogue, summary, and transition (Morrell 2006, p. 127). Author Peter Selgin refers to methods, including action, dialogue, thoughts, summary, scene, and description (Selgin 2007, p. 38). Currently, there is no consensus within the writing community regarding the number and composition of fiction-writing modes and their uses.
Description is the fiction-writing mode for transmitting a mental image of the particulars of a story. Together with dialogue, narration, exposition, and summarization, description is one of the most widely recognized of the fiction-writing modes. As stated in Writing from A to Z, edited by Kirk Polking, description is more than the amassing of details; it is bringing something to life by carefully choosing and arranging words and phrases to produce the desired effect (Polking 1990, p. 106). The most appropriate and effective techniques for presenting description are a matter of ongoing discussion among writers and writing coaches.Fiction is a form of narrative, one of the four rhetorical modes of discourse. Fiction-writing also has modes for fiction-writing: action, exposition, description, dialogue, summary, and transition (Morrell 2006, p. 127). Author Peter Selgin refers to methods, including action, dialogue, thoughts, summary, scene, and description (Selgin 2007, p. 38). Currently, there is no consensus within the writing community regarding the number and composition of fiction-writing modes and their uses.
Description is the fiction-writing mode for transmitting a mental image of the particulars of a story. Together with dialogue, narration, exposition, and summarization, description is one of the most widely recognized of the fiction-writing modes. As stated in Writing from A to Z, edited by Kirk Polking, description is more than the amassing of details; it is bringing something to life by carefully choosing and arranging words and phrases to produce the desired effect (Polking 1990, p. 106). The most appropriate and effective techniques for presenting description are a matter of ongoing discussion among writers and writing coaches.Fiction is a form of narrative, one of the four rhetorical modes of discourse. Fiction-writing also has modes for fiction-writing: action, exposition, description, dialogue, summary, and transition (Morrell 2006, p. 127). Author Peter Selgin refers to methods, including action, dialogue, thoughts, summary, scene, and description (Selgin 2007, p. 38). Currently, there is no consensus within the writing community regarding the number and composition of fiction-writing modes and their uses.
Description is the fiction-writing mode for transmitting a mental image of the particulars of a story. Together with dialogue, narration, exposition, and summarization, description is one of the most widely recognized of the fiction-w
Unit I: Introduction to Protection System:
Introduction to protection system and its elements, functions of protective relaying, protective zones, primary and backup protection, desirable qualities of protective relaying, basic terminology.
Relays:
Electromagnetic, attracted and induction type relays, thermal relay, gas actuated relay, design considerations of electromagnetic relay.
Unit-II: Relay Application and Characteristics:
Amplitude and phase comparators, over current relays, directional relays, distance relays, differential relay.
Static Relays: Comparison with electromagnetic relay, classification and their description, over current relays, directional relay, distance relays, differential relay.
Unit-III Protection of Transmission Line:
Over current protection, distance protection, pilot wire protection, carrier current protection, protection of bus, auto re-closing,
Unit-IV: Circuit Breaking:
Properties of arc, arc extinction theories, re-striking voltage transient, current chopping, resistance switching, capacitive current interruption, short line interruption, circuit breaker ratings.
Testing Of Circuit Breaker: Classification, testing station and equipments, testing procedure, direct and indirect testing.
Unit-V Apparatus Protection:
Protection of Transformer, generator and motor.
Circuit Breaker: Operating modes, selection of circuit breakers, constructional features and operation of Bulk Oil, Minimum Oil, Air Blast, SF6, Vacuum and d. c. circuit breakers.
FUNDAMENTALS OF POWER SYSTEM PROTECTION
FUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTION
Functions and Performance Requirements
Elements of an Excitation System
Types of Excitation Systems
Control and Protection Functions
Modeling of Excitation Systems
The functions of an excitation system are
to provide direct current to the synchronous generator field winding, and
to perform control and protective functions essential to the satisfactory operation of the power system
The performance requirements of the excitation system are determined by
Generator considerations:
supply and adjust field current as the generator output varies within its continuous capability
respond to transient disturbances with field forcing consistent with the generator short term capabilities:
rotor insulation failure due to high field voltage
rotor heating due to high field current
stator heating due to high VAR loading
heating due to excess flux (volts/Hz)
Power system considerations:
contribute to effective control of system voltage and improvement of system stability
Tan delta is the insulation power factor & is equal to the ratio of power dissipated in the insulation in watts to the product of effective voltage & current in volt ampere when tested under sinusoidal voltage.
Unit I: Introduction to Protection System:
Introduction to protection system and its elements, functions of protective relaying, protective zones, primary and backup protection, desirable qualities of protective relaying, basic terminology.
Relays:
Electromagnetic, attracted and induction type relays, thermal relay, gas actuated relay, design considerations of electromagnetic relay.
Unit-II: Relay Application and Characteristics:
Amplitude and phase comparators, over current relays, directional relays, distance relays, differential relay.
Static Relays: Comparison with electromagnetic relay, classification and their description, over current relays, directional relay, distance relays, differential relay.
Unit-III Protection of Transmission Line:
Over current protection, distance protection, pilot wire protection, carrier current protection, protection of bus, auto re-closing,
Unit-IV: Circuit Breaking:
Properties of arc, arc extinction theories, re-striking voltage transient, current chopping, resistance switching, capacitive current interruption, short line interruption, circuit breaker ratings.
Testing Of Circuit Breaker: Classification, testing station and equipments, testing procedure, direct and indirect testing.
Unit-V Apparatus Protection:
Protection of Transformer, generator and motor.
Circuit Breaker: Operating modes, selection of circuit breakers, constructional features and operation of Bulk Oil, Minimum Oil, Air Blast, SF6, Vacuum and d. c. circuit breakers.
FUNDAMENTALS OF POWER SYSTEM PROTECTION
FUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTION
Functions and Performance Requirements
Elements of an Excitation System
Types of Excitation Systems
Control and Protection Functions
Modeling of Excitation Systems
The functions of an excitation system are
to provide direct current to the synchronous generator field winding, and
to perform control and protective functions essential to the satisfactory operation of the power system
The performance requirements of the excitation system are determined by
Generator considerations:
supply and adjust field current as the generator output varies within its continuous capability
respond to transient disturbances with field forcing consistent with the generator short term capabilities:
rotor insulation failure due to high field voltage
rotor heating due to high field current
stator heating due to high VAR loading
heating due to excess flux (volts/Hz)
Power system considerations:
contribute to effective control of system voltage and improvement of system stability
Tan delta is the insulation power factor & is equal to the ratio of power dissipated in the insulation in watts to the product of effective voltage & current in volt ampere when tested under sinusoidal voltage.
Long & Short Interruptions: Interruptions – Definition – Difference between failures,
outage, Interruptions – causes of Long Interruptions – Origin of Interruptions – Limits for the
Interruption frequency – Limits for the interruption duration – costs of Interruption –
Overview of Reliability evaluation to power quality, comparison of observations and
reliability evaluation.Short interruptions: definition, origin of short interruptions, basic principle, fuse saving,
voltage magnitude events due to re-closing, voltage during the interruption, monitoring of
short interruptions, difference between medium and low voltage systems. Multiple events,
single phase tripping – voltage and current during fault period, voltage and current at post
fault period
International Journal of Engineering Research and DevelopmentIJERD Editor
Electrical, Electronics and Computer Engineering,
Information Engineering and Technology,
Mechanical, Industrial and Manufacturing Engineering,
Automation and Mechatronics Engineering,
Material and Chemical Engineering,
Civil and Architecture Engineering,
Biotechnology and Bio Engineering,
Environmental Engineering,
Petroleum and Mining Engineering,
Marine and Agriculture engineering,
Aerospace Engineering.
Modeling Analysis& Solution of Power Quality Problems Using DVR & DSTATCOMijsrd.com
A Power quality problem is an occurrence manifested as a nonstandard voltage, current or frequency that results in a failure or a disoperation of end use equipment. Utility distribution networks, sensitive industrial loads, and critical commercial operations all suffer from various types of outages and service interruptions which can cost significant financial loss per incident based on process down-time, lost production, idle work forces, and other factors. With the restructuring of Power Systems and with shifting trend towards Distributed and Dispersed Generation, the issue of Power Quality is going to take newer dimensions. The aim therefore, in this work, is to identify the prominent concerns in the area and thereby to recommend measures that can enhance the quality of the power, keeping in mind their economic viability and technical repercussions. In this paper electromagnetic transient studies are presented for the following two custom power controllers: the distribution static compensator (DSTATCOM), and the dynamic voltage restorer (DVR). Comprehensive results are presented to assess the performance of each device as a potential custom power solution.
Industry tech overview by golden coffee business & investment consultingSamuel Dawit
a simple discussion type training entitled ‘’Industrial System technology Overview’’ With the Objective of Creating Discussion, Creating Documented Base Knowledge, Reminding and Brainstorming ideas on industrial System technologies that constitute eight topics with includes Industrial Power System, Industrial Control & Automation, Industrial Machines, Industrial Production method & Processes, Industrial Plant infrastructure, Industrial Materials & processes, Industrial Safety & Hazards..
Electrical Substation and Switchyard DesignLiving Online
Electrical substations form important nodal points in all power networks. Substations can be of various capacities, voltages, configurations and types depending on what is the application for which the substation is being designed. Location and layout of a substation present a number of challenges to the designer due to a large variety of options available to a designer. There are ever so many constraints too that need to be kept in mind; technical, environmental and naturally financial. Arriving at an optimum design within these constraints is as much an art as it is a science. Designing a substation which will operate with utmost reliability for at the least three or four decades involves a thorough knowledge of the current state-of-the art equipment, emerging technologies, the tools for presenting and evaluating all available options and a good appreciation of power system operation and maintenance. This course will present a comprehensive capsule of all the knowledge essential for a substation designer and walk the participants through the substation design process using a set of interlinked case studies.
FOR MORE INFORMATION: http://www.idc-online.com/content/electrical-substation-and-switchyard-design-25
IRJET-Review on Power Quality Enhancement in weak Power Grids by Integration ...IRJET Journal
Prathmesh Mayekar, Mahesh Wagh, Nilkanth Shinde "Review on Power Quality Enhancement in weak Power Grids by Integration of Renewable Energy Technologies", International Research Journal of Engineering and Technology (IRJET), Volume2,issue-01 April 2015.e-ISSN:2395-0056, p-ISSN:2395-0072. www.irjet.net
Abstract
During Last decade power quality problems has become more complex at all level of power system. With the increased use of sophisticated electronics, high efficiency variable speed drive, power electronic controllers and also more & more non-linear loads, Power Quality has become an increasing concern to utilities and customers. The modern sensitive, Non-linear and sophisticated load affects the power quality. This paper deals with the issues of low power quality in weak power grids. Initially the various power quality issues are discussed with their definition or occurrence and then finally the solution to mitigate this power quality issues are discussed. The innovative solutions like integration of renewable energy systems along with energy storage to enhance power quality by interfacing with custom power devices are explained in detail. Nearly all sorts of solution for mitigating power quality issue require some sort of DC source for providing active power, which can be supplied by renewable energy source. Also the various energy storage systems are studied.
THE WORKSHOP:
This practical workshop covers all the essentials of process control and tools to optimise the operation of your plant and process, including the ability to perform effective loop tuning.
Practical process control is aimed at engineers and technicians who wish to have a clear, practical understanding of the essentials of process control and loop tuning, as well as how to optimise the operation of their particular plant or process. These persons would typically be primarily involved in the design, implementation and upgrading of industrial control systems. Mathematical theory has been kept to a minimum with the emphasis throughout on practical applications and useful information.
Inspection, Testing and Commissioning of Electrical Switchboards, Circuit Bre...Living Online
THE WORKSHOP:
Whether you are designing, specifying, installing, testing or commissioning electrical equipment from small to large commercial and industrial installations, you need to have a thorough understanding of switchboards, switchgear, circuit breakers and associated protective relays.
The overall focus of this workshop is on electrical inspection, testing and commissioning and will commence with a detailed examination of switchgear (and circuit breakers). Circuit breakers are critical components in electrical distribution systems and their operation significantly affects the overall operation of the system. Protection relays are then discussed. These are used in power systems to maximise continuity of supply and are found in both small and large power systems from generation, through transmission, distribution and utilisation of power in plant, industrial and commercial equipment.
We cover commissioning and periodic inspection of cables and their various failure modes and how to detect these faults. The often neglected topic of switchboards will be detailed next, followed by the interesting topic of interfacing to the control system (either PLC’s or other control devices).
Case studies and practical sessions are used throughout to illustrate key practical principles.
This workshop covers key elements in a practical and project focused way. Many people assume (wrongly) that inspecting, testing and commissioning is a fairly straightforward process and is simply a rubber stamp confirmation of a so-called outstanding design. Our experience in the field demonstrates quite the opposite; where the litany of problems ranges from design and installation errors to equipment manufacturing defects. It is best that these problems are identified and corrected before the inevitable downtime comes in an operational installation where many thousands of dollars are lost in correcting the faults. The situation today is made more challenging by the heightened safety requirements and interfacing to low powered electronic control and monitoring devices (such as PLC’s) using software that has to also be verified.
Hands on Data Communications, Networking & TCP/IP TroubleshootingLiving Online
THE WORKSHOP:
Data communication is given high priority in today’s industrial environment. This workshop is designed to be hands-on, providing the participants with essential knowledge and helping them to understand and troubleshoot systems.
This is a comprehensive two-day hands-on workshop that covers practical aspects of data communication such as serial communications, Ethernet networking, TCP/IP, Modbus, wireless communications and security.
This workshop is for enthusiastic engineers and technicians who wish to develop and enhance their practical knowledge in the field of data communications and networking. It will help them to understand the concepts behind data transmission, the various protocols involved, and the topologies that govern data exchange among various systems in industry. It will also equip them with the skills and tools to design and/or maintain these systems on an ongoing basis.
Fundamentals of Instrumentation, Process Control, PLCs and SCADA for Plant Op...Living Online
THE WORKSHOP:
This course represents a tremendous opportunity to gain expertise in all the key areas of the fast growing area of industrial automation in two days. Presented by an expert in the area but who is passionate with getting the key chunks of know-how and expertise across to you in a simple understandable manner which you can immediately apply to your job. This is most definitely not a boring lecture style presentation but an intensive learning experience where you will walk away with real skills as a result of the hands-on practical exercises, calculations, case studies and group sessions to ensure an understanding of the concepts and ideas discussed. You will undertake practical sessions at approximately 20 to 30 minute intervals to maximise the absorption rate.
Hierarchical Digital Twin of a Naval Power SystemKerry Sado
A hierarchical digital twin of a Naval DC power system has been developed and experimentally verified. Similar to other state-of-the-art digital twins, this technology creates a digital replica of the physical system executed in real-time or faster, which can modify hardware controls. However, its advantage stems from distributing computational efforts by utilizing a hierarchical structure composed of lower-level digital twin blocks and a higher-level system digital twin. Each digital twin block is associated with a physical subsystem of the hardware and communicates with a singular system digital twin, which creates a system-level response. By extracting information from each level of the hierarchy, power system controls of the hardware were reconfigured autonomously. This hierarchical digital twin development offers several advantages over other digital twins, particularly in the field of naval power systems. The hierarchical structure allows for greater computational efficiency and scalability while the ability to autonomously reconfigure hardware controls offers increased flexibility and responsiveness. The hierarchical decomposition and models utilized were well aligned with the physical twin, as indicated by the maximum deviations between the developed digital twin hierarchy and the hardware.
Water scarcity is the lack of fresh water resources to meet the standard water demand. There are two type of water scarcity. One is physical. The other is economic water scarcity.
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
Final project report on grocery store management system..pdfKamal Acharya
In today’s fast-changing business environment, it’s extremely important to be able to respond to client needs in the most effective and timely manner. If your customers wish to see your business online and have instant access to your products or services.
Online Grocery Store is an e-commerce website, which retails various grocery products. This project allows viewing various products available enables registered users to purchase desired products instantly using Paytm, UPI payment processor (Instant Pay) and also can place order by using Cash on Delivery (Pay Later) option. This project provides an easy access to Administrators and Managers to view orders placed using Pay Later and Instant Pay options.
In order to develop an e-commerce website, a number of Technologies must be studied and understood. These include multi-tiered architecture, server and client-side scripting techniques, implementation technologies, programming language (such as PHP, HTML, CSS, JavaScript) and MySQL relational databases. This is a project with the objective to develop a basic website where a consumer is provided with a shopping cart website and also to know about the technologies used to develop such a website.
This document will discuss each of the underlying technologies to create and implement an e- commerce website.
Industrial Training at Shahjalal Fertilizer Company Limited (SFCL)MdTanvirMahtab2
This presentation is about the working procedure of Shahjalal Fertilizer Company Limited (SFCL). A Govt. owned Company of Bangladesh Chemical Industries Corporation under Ministry of Industries.
2. 1
Emergency Power Needs
1.1 Problems of power failure in industries
The primary intention of any power utility is to provide uninterrupted power supply to its
consumers. Unfortunately, interruptions can and do happen occasionally. There are
several causes for interruption such as:
• Equipment failures and line faults
• System instability leading to tripping
• Deliberate tripping (usually automatically) to save a system from collapse
• Human errors
• Natural causes such as hurricane, earthquakes and floods
No power system, regardless of how well it is designed or maintained, can be guaranteed
to be free from interruptions. While a high degree of continuity can be ensured, it is quite
impossible to guarantee that there will be no interruption of power in the whole of a
system.
System instability usually follows a major disturbance such as loss of a generating unit,
tie-line tripping etc. Installation and use of adequate reserves in the system may mitigate
such events. Deliberate tripping by islanding schemes is also sometimes done to save at
least part of a system during major system failures thus enabling faster restoration.
Failures due to natural calamities are not preventable, but with adequate warning, steps
can be taken to mitigate the effects by advance preparations.
Equipment failures and line faults can be reduced to an appreciable extent by proper
selection of equipment and their maintenance. In the event of tripping on faults, power
supply can be restored using several options, some of these being:
• Auto-reclose operations (for self clearing of transient faults)
• Switching to redundant feeders
• Starting standby generating sources
3. 2
Emergency Power Supplies
System outages are more likely in a system without adequate generation reserve.
Electrical energy is something that is consumed as it is being generated. No buffer storage
is possible in a transmission or distribution network. When there is a sudden load
increase, which is beyond the capacity of the system to meet, the frequency of the system
falls. Increasing the generation from available spinning reserve can halt the frequency
drop, but where this is not possible (due to inadequate reserve availability) a complete
system collapse is likely. When the load change is anticipated and is gradual, it is possible
to start standby capacity and synchronize them with the system so that excess load can be
taken up. Engine generators and gas turbines are capable of quick start and can start
supplying load almost immediately, thus taking up peak demands in the system.
It is necessary to understand the effect, a sudden power interruption can have on an
industrial facility. An interruption can have costs associated with it, some of which are
direct and others indirect. This provides a justification for planning special equipment
such as UPS systems to ensure that there are no unscheduled interruptions of supply. The
higher the costs associated with an interruption, the more reliable the supply should be
and the higher the investment that is justifiable to ensure reliability.
A power failure can result in one or more of the following:
• Accidents involving death or injury
• Damage to equipment
• Creation of potentially hazardous conditions
• Loss of production (not only for the duration of the interruption but also
during the time required to bring the process to its pre-failure state)
What kinds of accidents can result from a sudden interruption? The following are some of
the possible scenarios.
• Dropping of loads lifted by electromagnets
• Release of toxic materials
• Spillage of chemicals or hot metal
• Explosions
• Runaway reactions
All these can result in accidents. In some cases, though there may be no injury to human
beings, such sudden failures of power supply can cause extensive damage to equipment.
Following are some examples of such situations:
• Lubrication failures
• Solidification of molten material
• Failure of cooling water flow
In many cases, the equipment affected by the power failure itself may be very minor such
as a lubrication pump. But when the power supply to this equipment fails, it puts a much
a larger and critical equipment (such as a large compressor) at risk of damage. The
resulting disruption to a process as a result of the failure can be substantial and so would
be the cost of putting the system back on stream.
4. Emergency Power Needs 3
In some cases, failure of power supply can cause potentially hazardous situations. Some
examples for such situations are:
• Loss of control power
• Loss of lighting in operational areas or exit routes
• Loss of ventilation/exhaust systems
• Loss of signaling and alarms
• Loss of fire-fighting systems
In many cases, the equipment involved is relatively minor. But under specific conditions
such as a total supply failure, they may create hazardous situations. For example, lighting
failure during a power outage may result in accidents because exit routes are not
illuminated or control room operations may get affected due to delayed restoration or safe
shutdown activities.
A common result of an interruption is the stoppage of a process which results in lost
production. If the production loss is confined to the period of power interruption, it may
not be serious. Often the process takes much longer time to attain its original pre-failure
status with consequent higher loss of production. Refer to Figure 1.1.
Figure 1.1
Production behavior as a result of power interruption
In Figure 1.1, axis E denotes the production efficiency, ta the time of interruption and ts
the restarting time. It may be noted that:
• Restarting itself is not instantaneous and takes a finite amount of time
• Efficiency does not catch up at the end of restarting time, with the value
existing prior to interruption
If the interruption also results in equipment damage, the time required to repair the
damage and restart the production can be much higher and so will be the production loss.
Now consider the aspect of cost of interruption. As stated earlier there can be direct costs
as well as indirect costs. Some of the examples of direct costs are:
5. 4
Emergency Power Supplies
• Costs due to lost man-hours
• Direct expenses due to death/injury
• Cost of repairs to damaged equipment
• Lost production
In some cases, the costs may be indirect as well. The following examples will illustrate
this:
• Legal costs in the case of accidents involving third parties/quality
problems/non-fulfillment of contract commitments
• Loss of good will
Hence a power interruption can cost an industry considerably in financial terms. Planning
of an electrical system to achieve the desired degree of continuity of power and the
investment required must therefore relate to the direct and indirect costs of power
interruption in a facility.
One of the solutions that is increasingly being adopted is the installation of distributed
generation capacity in a system. Utilities either own such capacity themselves or permit
industrial consumers/other third parties to set up this capacity and operate them in tandem
with the system. This has several advantages.
• They are usually close to the load and are not affected by transmission
circuit problems
• They are usually capable of being started and brought up to load faster
• When owned by industrial consumers they also serve as standby sources
• When run as base-load generators synchronized with the utility system they
can serve as uninterrupted power source for the consumer
• They improve the voltage profile in remote end-of-line distribution circuits
Often, cleaner energy technologies are used in these equipment (such as biomass power
plants and fuel cell generation units)
A typical standby generation scheme of an industrial plant is shown in Figure 1.2. The
scheme is based on an engine driven generator and has the capacity to feed critical loads
only. Normally all the plant loads including the critical loads are supplied by the electric
utility. When the utility supply fails, the critical loads are transferred to generator supply
using the open transition changeover switch. Since the switch is break before make type,
a transfer from one supply to another is accompanied by a power interruption. Where
such interruption is unacceptable, other types of schemes will be needed.
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Figure 1.2
Industrial plant - Standby generation
1.2 Tolerance for interruptions and voltage/frequency
excursions
Any electrical equipment is designed with certain tolerances for their input supply
voltage. Also, the design may have in-built features which take care of voltage variations
to some extent. Many modern office equipment including desktop computer systems can
tolerate voltage fluctuations to some extent by virtue of large capacitances (in relation to
load currents) and internal regulation circuitry and can ride through voltage sag or even a
momentary interruption.
The tolerance range for voltage fluctuations for general industrial equipment is normally
in the range of –10 to +6% for slow/sustained variations (sag/swells) and considerably
more for short time disturbances.
1.2.1 CBEMA, ITIC and ANSI Voltage Sensitivity Curves
The topic of voltage sensitivity has received a lot of attention in relation to computers, as
the early computer designs were very susceptible to voltage variations and a number of
random data errors used to happen because of this. The studies resulted in the
development of standard curves indicating the voltage limits plotted against the time for
which the limits can be reached without causing ill effects. The earliest of these curves
7. 6
Emergency Power Supplies
were developed by the Computer and Business Equipment Manufacturers Association
(CBEMA) and is shown in Figure 1.3.
Figure 1.3
CBEMA voltage sensitivity curves
The curve defines the limit of voltage variation from 100 microseconds for positive
variations and 20 milliseconds for negative variations. It can be seen that 100% sag
(supply interruption) can be safely tolerated for duration up to 20 milliseconds. A voltage
of 375% of rated value can be tolerated for duration of 100 microseconds.
Note that such a short duration of voltage rise is what happens during a surge induced by
lightning with the safe withstand value defined by the Basic impulse Level (BIL).
In can be said that the upper and lower curves taken together represent the envelope
within which the equipment should continue to function without interruption or data loss.
As far as dips are concerned, it is the lower limit line that is of interest. This line
represents the boundary between survivable and non-survivable dips.
It should be noted that these curves are based on voltage sensitivity exhibited by
computer equipment and may not be directly applicable to power equipment. The
CBEMA curves have been further refined by Information Technology Industry Council
(ITIC) and by ANSI (as IEEE 446) and the curves suggested by these bodies are shown in
Figures 1.4 and 1.5 respectively.
8. Emergency Power Needs 7
Figure 1.4
ITIC voltage sensitivity curves
Figure 1.5
ANSI voltage sensitivity curves
In contrast to CBEMA curves, the ITIC and ANSI curves define the limits starting from 1
millisecond. A single curve may not fit all equipments and the designer may choose to
apply a particular set of curves, which would best suit the equipment in question. In many
cases, it is however the power system which may prove to be the problem. The variations
that occur in a system where a particular item of equipment has to be located may not fall
within the envelope defined by the sensitivity curves applicable for that equipment.
Figure 1.6 below illustrates this point by superimposing the negative side envelope of the
ITIC curve with the voltage dips that commonly occur in a system. It may be seen that a
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Emergency Power Supplies
substantial part of the curve, representing system voltage dips, falls outside the ITIC
lower limit envelope. In this case the equipment tolerance that is to be adopted by the
design should correspond to the curve marked as ‘Required tolerance’.
Figure 1.6
Practical system limits superimposed over ITIC lower envelope
It may or may not be possible to design equipment to match the ‘required tolerance’
curve. The alternative is to use various correction measures, which either deal with the
effect of voltage variations or correct the voltage variations so that the input voltage to the
equipment meets the requirements.
1.3 Uninterrupted power, emergency power and standby power
Certain critical processes and operations like computer installations, life support systems
will not tolerate even momentary power interruptions. These kinds of processes require a
reliable and continuous power supply in the event of failure of utility power supply. Such
processes need to be supplied power by means of uninterrupted power supply source. As
the name suggests, an uninterrupted power supply system guarantees continuous power
without even a momentary break to the connected loads.
Emergency power is the minimum backup power required for emergency applications
like emergency lighting, emergency shut down systems in petrochemical processes, alarm
systems, elevators, life safety and security systems. The term ‘emergency equipment’ is
used for those loads where a brief interruption can be tolerated but to which power should
be restored as quickly as possible.
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Standby power refers to the provision of substantial power to maintain all the production
and business processes during power outages either for short period of time or an
extended period of time. Examples of facilities that need standby power are
semiconductor manufacturing plants, airports, hospitals, apartments, telecommunication
establishments and office complexes.