logging in or signing up B2 WHY STUDIES narasimharaja Download Post to : URL : Related Presentations : Share Add to Flag Embed Email Send to Blogs and Networks Add to Channel Uploaded from authorPOINT lite Insert YouTube videos in PowerPont slides with aS Desktop Copy embed code: (To copy code, click on the text box) Embed: URL: Thumbnail: WordPress Embed Customize Embed The presentation is successfully added In Your Favorites. Views: 94 Category: Entertainment License: All Rights Reserved Like it (0) Dislike it (0) Added: February 24, 2011 This Presentation is Public Favorites: 0 Presentation Description No description available. Comments Posting comment... Premium member Presentation Transcript WHY STUDIES: WHY STUDIES In recent years, the industrial and commercial systems have advanced & Their capacities have grown close to or sometimes exceeding that of small electric utility (EB = Electricity Board) system. More loads, more generators, and more redundancy means more buses/branches and, to predict the performance of the electrical system for all the possible configurations, more studies. The efforts required to evaluate the performance of the systems increases with their size and complexity.WHY STUDIES: WHY STUDIES Today’s business environment has become intensely competitive, Management personnel have to be very aware of the total owning cost of their electrical power distribution system Therefore they demand assurances of maximum return on all capital investments in the electrical power systems.WHY STUDIES: WHY STUDIES The results of each of the various electrical studies serve specific purposes in the planning, design, and operation of electrical power systems. Relays and circuit breakers are tested and calibrated according to the coordination study. Spectrum analyzers measure the harmonics present in the power system. Power flows, voltage drops, continuous and starting currents can be measured and compared to the load flow and motor starting calculations, though for many configurations this will never actually be done.WHY STUDIES: WHY STUDIES The transient performance of the system can be measured for many operating configurations to verify the calculation models, but again these tests seldom are done in a manner that should be carried out considering their importance. Short circuit tests are destructive, thus are not conducted in the field (at least, not on purpose). The fact that results of some the calculations will never be tested conclusively is reason good enough for conducting studies and for the calculations to be performed as accurately as possible.WHY STUDIES: WHY STUDIES Objectives of electrical system studies are:- To evaluate performance of system To determine effectiveness of alternatives To select cost effective solution To select adequate equipment ratings. For large and complex processes and plants, the type of technical analysis required to meet design aspects and criteria may become quite involved.WHY STUDIES: WHY STUDIES In the past electrical system analysis were performed by long hand calculations. Many simplifying assumptions were made to meet constraints of time and manpower. This limited the number of options considered and results were not adequate. Systems were built, equipment installed subsequent to which modifications were made as required resulting in expensive solutions.WHY STUDIES: WHY STUDIES Power system softwares gave engineers a quick method of simulating case studies. Introduction of digital time sharing main frame computers made it easy to evaluate many options quickly. This resulted in cost of studies to be less expensive with better confidence in the results. Identification of least cost solution became easy. Recent advances in PC technology, in terms of speed and capacity, has made computing power accessible to every person at a very affordable cost. It is important for plant engineers to be knowledgeable in the types of power system studies that are performed.WHY STUDIES: WHY STUDIES The use of digital computers with sophisticated electrical system softwares - like ETAP, CYME, SKM Power Tools, EDSA, ERACS makes it possible to study the performance of proposed and actual systems under many operating conditions. Answers to many questions regarding -impact of system expansion, -short circuit capacity, -stability, load distribution etc, can be intelligently and economically obtained .WHY STUDIES: WHY STUDIES The planning, design and operation of various industries require several studies to assist in evaluation of -the initial and future system performance -system reliability, safety -ability to grow with the production and/or operating requirements.WHY STUDIES: WHY STUDIES The studies most likely to be needed are -load flow studies -short circuit of fault studies, -relay coordination studies, -harmonic studies, - transient stability - motor start studies.WHY STUDIES: WHY STUDIES The Lead engineer or Specialist Engineer must decide which studies are needed to ensure that the system will operate safely, economically and efficiently over the expected life of the system .WHY STUDIES: WHY STUDIES 1.0 Preparation for the study To solve a power system analysis problem, the engineer must be thoroughly familiar with the fundamentals of electrical power engineering. The engineer can then analyse the problem, prepare necessary equivalent circuits and obtain appropriate data before using a power system software to perform repetitive calculationsWHY STUDIES: WHY STUDIES Failure to use valid analytical procedure to establish a sound basic approach to the problem could lead to disastrous consequences in both the design and operation of a system . A basic understanding of power engineering is essential to correctly interpret the results of the power system software calculation results . Thorough base of experience in electrical power system engineering in addition to modern, effective computing tools and software is must.WHY STUDIES: WHY STUDIES Electrical power system analysis engineering softwares (such as ETAP, CYME, SKM Power Tools, EDSA or ERACS) are excellent for studying power systems However softwares cannot be used as a substitute for knowledge and experience. So some basic fundamentals of power system engineering has to be attained or brushed before an engineer can use the software.WHY STUDIES: WHY STUDIES To set up the electrical system MODEL SLD in the software for system analysis, certain basic data must be gathered with accuracy and proper presentation. Important inputs to a meaningful system study are -The extent of system representation, -restriction in terms of nodes or buses and branches ( such as cables, lines and transformers), -balanced three phase network -single line diagram (SLD), impedance diagram, -load list at various busbars, spilt of loads as motor or lighting, -identification of harmonic generating loads, etcWHY STUDIES: WHY STUDIES 2.0 Load Flow Studies- These calculate active and reactive power flows from the source and through each of the branches along with and voltages at all the bus and nodes. Applications include: Identifying excessive voltage variations/violations under normal and contingency outage conditions. Identifying overloaded circuits and necessary plant upgrades under normal and contingency outage conditions. Identifying under load circuits for carrying out system optimisationWHY STUDIES: WHY STUDIES Checking current flows under different conditions. Estimating overall active and reactive power losses including assessment of these losses in individual branches. Estimating the range of ON LOAD AUTO TAP changers or OFF Load Tap changers required to ensure system voltages are maintained at all points to well within desired limits under both peak and minimum load conditions Specifying cables, reactors and transformers. Specifying compensation equipment such as power factor correction capacitors or reactive absorbing devices such as reactorsWHY STUDIES: WHY STUDIES Load flow study result acceptance criteria needs to developed and agreed with the CLIENT for comparison of results with criteria as required to analyse the power system load flow software results.WHY STUDIES: WHY STUDIES 3.0 Fault Level Studies- Accurate fault level assessments support the legally required safety rating of equipment to reduce dangers. Study includes comparison of evaluated fault levels like -initial AC symmetrical rms fault current, -peak making fault current -Asymmetrical break rms fault current values at any given bus in the system with corresponding switchgear and breaker peak and break fault ratings.WHY STUDIES: WHY STUDIES Each of the above fault levels of the switchgear/CB should be greater than the calculated values of each of these currents. That is:- Peak fault rating in kA peak of a switchgear/CB should be greater than the calculated Peak fault (kA peak) current at that switchgear point of the system. Initial AC symmetrical kA rms fault rating of switchgear/CB should be greater than the calculated Initial AC symmetrical kA rms fault current at that switchgear point of the system. Asymmetrical break kA rms fault rating of switchgear/CB at breaker opening time (3 cycle to 4 cycle i.e 60 to 80 milli-sec should be greater than the calculated Asymmetrical break kA rms fault current at that switchgear point of the system.WHY STUDIES: WHY STUDIES Studies Helps To : Identify equipment where ratings are exceeded. Specify ratings for plant upgrades and new plant. Contain or reduce fault levels on existing systems. Develop plant and operating procedures to limit fault current.WHY STUDIES: WHY STUDIES 4.0 Stability Studies- System disturbances are a source of instability They can cause loss of synchronisation, stalling or overloading of generators and motors. Catastrophic failure of large parts of the power system can result, along with plant damage.WHY STUDIES: WHY STUDIES Stability models & Studies are used to: Assess system susceptibility to transient events such as faults, motor starting or sudden load application and load rejection. Specify technical requirements for stable operation. Design or verify suitable protection schemes.WHY STUDIES: WHY STUDIES 5.0 Electrical protection- CAD methods to co-ordinate protection on a wide variety of electrical systems so that faulty equipment is disconnected promptly leaving functioning equipment in service wherever possible.WHY STUDIES: WHY STUDIES 6.0 Electromagnetic transients & insulation co-ordination studies- Electromagnetic transients can damage plant and cause mal-operation of equipment. These studies include: Calculating system overvoltages resulting from faults or switching operations. Calculating overvoltages caused by lightning strikes.WHY STUDIES: WHY STUDIES Calculating switchgear TRV (Transient Recovery Voltage) and RRRV (Rate of Rise of Recovery Voltage) to specify or check switchgear ratings. Specifying or checking surge arrestor ratings. Analysing faults and recommending solutions. Investigating linear and non-linear resonance You do not have the permission to view this presentation. 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B2 WHY STUDIES narasimharaja Download Post to : URL : Related Presentations : Share Add to Flag Embed Email Send to Blogs and Networks Add to Channel Uploaded from authorPOINT lite Insert YouTube videos in PowerPont slides with aS Desktop Copy embed code: (To copy code, click on the text box) Embed: URL: Thumbnail: WordPress Embed Customize Embed The presentation is successfully added In Your Favorites. Views: 94 Category: Entertainment License: All Rights Reserved Like it (0) Dislike it (0) Added: February 24, 2011 This Presentation is Public Favorites: 0 Presentation Description No description available. Comments Posting comment... Premium member Presentation Transcript WHY STUDIES: WHY STUDIES In recent years, the industrial and commercial systems have advanced & Their capacities have grown close to or sometimes exceeding that of small electric utility (EB = Electricity Board) system. More loads, more generators, and more redundancy means more buses/branches and, to predict the performance of the electrical system for all the possible configurations, more studies. The efforts required to evaluate the performance of the systems increases with their size and complexity.WHY STUDIES: WHY STUDIES Today’s business environment has become intensely competitive, Management personnel have to be very aware of the total owning cost of their electrical power distribution system Therefore they demand assurances of maximum return on all capital investments in the electrical power systems.WHY STUDIES: WHY STUDIES The results of each of the various electrical studies serve specific purposes in the planning, design, and operation of electrical power systems. Relays and circuit breakers are tested and calibrated according to the coordination study. Spectrum analyzers measure the harmonics present in the power system. Power flows, voltage drops, continuous and starting currents can be measured and compared to the load flow and motor starting calculations, though for many configurations this will never actually be done.WHY STUDIES: WHY STUDIES The transient performance of the system can be measured for many operating configurations to verify the calculation models, but again these tests seldom are done in a manner that should be carried out considering their importance. Short circuit tests are destructive, thus are not conducted in the field (at least, not on purpose). The fact that results of some the calculations will never be tested conclusively is reason good enough for conducting studies and for the calculations to be performed as accurately as possible.WHY STUDIES: WHY STUDIES Objectives of electrical system studies are:- To evaluate performance of system To determine effectiveness of alternatives To select cost effective solution To select adequate equipment ratings. For large and complex processes and plants, the type of technical analysis required to meet design aspects and criteria may become quite involved.WHY STUDIES: WHY STUDIES In the past electrical system analysis were performed by long hand calculations. Many simplifying assumptions were made to meet constraints of time and manpower. This limited the number of options considered and results were not adequate. Systems were built, equipment installed subsequent to which modifications were made as required resulting in expensive solutions.WHY STUDIES: WHY STUDIES Power system softwares gave engineers a quick method of simulating case studies. Introduction of digital time sharing main frame computers made it easy to evaluate many options quickly. This resulted in cost of studies to be less expensive with better confidence in the results. Identification of least cost solution became easy. Recent advances in PC technology, in terms of speed and capacity, has made computing power accessible to every person at a very affordable cost. It is important for plant engineers to be knowledgeable in the types of power system studies that are performed.WHY STUDIES: WHY STUDIES The use of digital computers with sophisticated electrical system softwares - like ETAP, CYME, SKM Power Tools, EDSA, ERACS makes it possible to study the performance of proposed and actual systems under many operating conditions. Answers to many questions regarding -impact of system expansion, -short circuit capacity, -stability, load distribution etc, can be intelligently and economically obtained .WHY STUDIES: WHY STUDIES The planning, design and operation of various industries require several studies to assist in evaluation of -the initial and future system performance -system reliability, safety -ability to grow with the production and/or operating requirements.WHY STUDIES: WHY STUDIES The studies most likely to be needed are -load flow studies -short circuit of fault studies, -relay coordination studies, -harmonic studies, - transient stability - motor start studies.WHY STUDIES: WHY STUDIES The Lead engineer or Specialist Engineer must decide which studies are needed to ensure that the system will operate safely, economically and efficiently over the expected life of the system .WHY STUDIES: WHY STUDIES 1.0 Preparation for the study To solve a power system analysis problem, the engineer must be thoroughly familiar with the fundamentals of electrical power engineering. The engineer can then analyse the problem, prepare necessary equivalent circuits and obtain appropriate data before using a power system software to perform repetitive calculationsWHY STUDIES: WHY STUDIES Failure to use valid analytical procedure to establish a sound basic approach to the problem could lead to disastrous consequences in both the design and operation of a system . A basic understanding of power engineering is essential to correctly interpret the results of the power system software calculation results . Thorough base of experience in electrical power system engineering in addition to modern, effective computing tools and software is must.WHY STUDIES: WHY STUDIES Electrical power system analysis engineering softwares (such as ETAP, CYME, SKM Power Tools, EDSA or ERACS) are excellent for studying power systems However softwares cannot be used as a substitute for knowledge and experience. So some basic fundamentals of power system engineering has to be attained or brushed before an engineer can use the software.WHY STUDIES: WHY STUDIES To set up the electrical system MODEL SLD in the software for system analysis, certain basic data must be gathered with accuracy and proper presentation. Important inputs to a meaningful system study are -The extent of system representation, -restriction in terms of nodes or buses and branches ( such as cables, lines and transformers), -balanced three phase network -single line diagram (SLD), impedance diagram, -load list at various busbars, spilt of loads as motor or lighting, -identification of harmonic generating loads, etcWHY STUDIES: WHY STUDIES 2.0 Load Flow Studies- These calculate active and reactive power flows from the source and through each of the branches along with and voltages at all the bus and nodes. Applications include: Identifying excessive voltage variations/violations under normal and contingency outage conditions. Identifying overloaded circuits and necessary plant upgrades under normal and contingency outage conditions. Identifying under load circuits for carrying out system optimisationWHY STUDIES: WHY STUDIES Checking current flows under different conditions. Estimating overall active and reactive power losses including assessment of these losses in individual branches. Estimating the range of ON LOAD AUTO TAP changers or OFF Load Tap changers required to ensure system voltages are maintained at all points to well within desired limits under both peak and minimum load conditions Specifying cables, reactors and transformers. Specifying compensation equipment such as power factor correction capacitors or reactive absorbing devices such as reactorsWHY STUDIES: WHY STUDIES Load flow study result acceptance criteria needs to developed and agreed with the CLIENT for comparison of results with criteria as required to analyse the power system load flow software results.WHY STUDIES: WHY STUDIES 3.0 Fault Level Studies- Accurate fault level assessments support the legally required safety rating of equipment to reduce dangers. Study includes comparison of evaluated fault levels like -initial AC symmetrical rms fault current, -peak making fault current -Asymmetrical break rms fault current values at any given bus in the system with corresponding switchgear and breaker peak and break fault ratings.WHY STUDIES: WHY STUDIES Each of the above fault levels of the switchgear/CB should be greater than the calculated values of each of these currents. That is:- Peak fault rating in kA peak of a switchgear/CB should be greater than the calculated Peak fault (kA peak) current at that switchgear point of the system. Initial AC symmetrical kA rms fault rating of switchgear/CB should be greater than the calculated Initial AC symmetrical kA rms fault current at that switchgear point of the system. Asymmetrical break kA rms fault rating of switchgear/CB at breaker opening time (3 cycle to 4 cycle i.e 60 to 80 milli-sec should be greater than the calculated Asymmetrical break kA rms fault current at that switchgear point of the system.WHY STUDIES: WHY STUDIES Studies Helps To : Identify equipment where ratings are exceeded. Specify ratings for plant upgrades and new plant. Contain or reduce fault levels on existing systems. Develop plant and operating procedures to limit fault current.WHY STUDIES: WHY STUDIES 4.0 Stability Studies- System disturbances are a source of instability They can cause loss of synchronisation, stalling or overloading of generators and motors. Catastrophic failure of large parts of the power system can result, along with plant damage.WHY STUDIES: WHY STUDIES Stability models & Studies are used to: Assess system susceptibility to transient events such as faults, motor starting or sudden load application and load rejection. Specify technical requirements for stable operation. Design or verify suitable protection schemes.WHY STUDIES: WHY STUDIES 5.0 Electrical protection- CAD methods to co-ordinate protection on a wide variety of electrical systems so that faulty equipment is disconnected promptly leaving functioning equipment in service wherever possible.WHY STUDIES: WHY STUDIES 6.0 Electromagnetic transients & insulation co-ordination studies- Electromagnetic transients can damage plant and cause mal-operation of equipment. These studies include: Calculating system overvoltages resulting from faults or switching operations. Calculating overvoltages caused by lightning strikes.WHY STUDIES: WHY STUDIES Calculating switchgear TRV (Transient Recovery Voltage) and RRRV (Rate of Rise of Recovery Voltage) to specify or check switchgear ratings. Specifying or checking surge arrestor ratings. Analysing faults and recommending solutions. Investigating linear and non-linear resonance