The correct design and selection of line supports is of great importance for successful operation and safety of transmission lines. For this purpose various forces acting on the line supports must be estimated for normal and abnormal conditions of operation. The author develops algorithm and programme for optimal calculation of these forces, which the line supports should withstand. The main programme MDFLS and fourteen subroutines are constructed for calculation the forces acting on the line supports. The subroutines (FSUS, FDES, and FCSTA) are for determining the forces from line conductors and (FGWSU, FSWDE, FSWSA) from ground wires at suspension, dead end and strain/angle line supports respectively. The other eight are subsidiary subroutines. The parameters of the conductors (homogenous or non homogenous) are found by DPMPN and DPMPH. The physical-mechanical properties of the conductor are calculated using PMPL. The specific loadings are determined by RLOLC. The sag-tension calculations are prepared by subroutines CSCT, CSOP and SEQS. Subroutine FSPCB is for calculation of forces due to broken conductor at suspension support in the section. The elaborated programmes are written in FORTRAN 90 and adopted for personal computer.
The document discusses types of circuit breakers, specifically air break circuit breakers. It describes the need for circuit protection from overloads and short circuits. Then it explains the construction, types including plain air and air blast, working principle, design, ratings, advantages, and disadvantages of air break circuit breakers. Air break circuit breakers use atmospheric air to extinguish arcs by rapidly lengthening and cooling the arc to increase resistance above the supply voltage.
The document discusses different types of circuit breakers, including their origins, operation, and arc interruption methods. It describes low-voltage circuit breakers like miniature circuit breakers (MCB) and molded case circuit breakers (MCCB), as well as medium and high-voltage circuit breakers that use techniques like oil, gas, or vacuum to extinguish arcs. It also covers standard current ratings, common trip breakers, and the components and operation of thermal magnetic circuit breakers commonly found in distribution boards.
This document discusses lightning arresters, including their purpose, types, classification, ratings, and service conditions. It describes three main types of arresters - expulsion, valve, and gapless metal-oxide. Arresters are classified into four classes based on their application and ratings. Standard ratings include nominal discharge current and voltage. Normal service conditions include temperature, radiation, altitude, and frequency ranges, while abnormal conditions require special consideration.
The term high voltage characterizes electrical circuits in which the voltage used is the cause of particular safety concerns & insulation requirements. High voltage is used in electrical power distribution, in cathode ray tubes, to generate x-rays & particle beams, to demonstrate arcing, for ignition, in photomultiplier tubes & high power amplifier vacuum tubes & other industrial & scientific applications .
The document discusses considerations for sizing conductors connecting station class arresters to transformers. It states that the conductor diameter has a negligible effect on the arrester's protection, but the length can impact inductance and protection. The key factors for sizing conductors are mechanical strength to withstand fault currents without failing, limiting corona at high voltages, and minimizing voltage reflections from separation of arrester and bushing. The optimum conductor size is determined by mechanical requirements over electrical considerations.
Designing and testing of metal oxide surge arrester for EHV lineRohit Khare
Surge arresters constitute an indispensable aid to insulation coordination in electrical power systems. There the voltages which may appear in an electrical power system are given in per-unit of the peak value of the highest continuous line-to-earth voltage, depending on the duration of their appearance. The voltage or overvoltage which can be reached without the use of arresters is a value of several p.u. If instead, one considers the curve of the withstand voltage of equipment insulation (here equipment means electrical devices such as power transformers) one notices that starting in the range of switching overvoltages, and especially for lightning over voltages, the equipment insulation cannot withstand the occurring dielectric stresses. At this point, the arresters intervene. When in operation, it is certain that the voltage that occurs at the terminal of the device - while maintaining an adequate safety margin - will stay below the withstand voltage. Arresters’ effect, therefore, involves lightning and switching over voltages.
The time axis is roughly divided into the range of lightning overvoltage (microseconds), switching overvoltages (milliseconds), temporary overvoltages (seconds) – which are commonly cited by the abbreviation "TOV" – and finally the temporally unlimited highest continuous system operation voltage.
Lightning protection for overhead distribution linesGilberto Mejía
This document summarizes techniques for lightning protection of overhead power distribution lines. It discusses the types of lightning overvoltages that can occur on medium voltage (MV) and low voltage (LV) networks from direct strikes and indirect strikes. Direct strikes can cause overvoltages over 2000kV, far exceeding insulation levels and causing flashovers. Indirect strikes have lower but still significant voltages and are more common. The document reviews methods to mitigate these overvoltages, including increasing insulation, using grounded shield wires, and installing surge arresters. Shield wires and arresters are most effective at reducing faults from direct strikes, while all methods help reduce faults from indirect strikes.
The document provides an overview of circuit breakers, including:
1) Circuit breakers sense overcurrent, measure its magnitude, and trip in a timely manner to prevent damage. They can be manually reset once a fault is cleared.
2) Key components include the frame, contacts, arc chute assembly, operating mechanism, and trip unit.
3) The trip unit senses overloads and short circuits and triggers the operating mechanism to open the contacts.
The document discusses types of circuit breakers, specifically air break circuit breakers. It describes the need for circuit protection from overloads and short circuits. Then it explains the construction, types including plain air and air blast, working principle, design, ratings, advantages, and disadvantages of air break circuit breakers. Air break circuit breakers use atmospheric air to extinguish arcs by rapidly lengthening and cooling the arc to increase resistance above the supply voltage.
The document discusses different types of circuit breakers, including their origins, operation, and arc interruption methods. It describes low-voltage circuit breakers like miniature circuit breakers (MCB) and molded case circuit breakers (MCCB), as well as medium and high-voltage circuit breakers that use techniques like oil, gas, or vacuum to extinguish arcs. It also covers standard current ratings, common trip breakers, and the components and operation of thermal magnetic circuit breakers commonly found in distribution boards.
This document discusses lightning arresters, including their purpose, types, classification, ratings, and service conditions. It describes three main types of arresters - expulsion, valve, and gapless metal-oxide. Arresters are classified into four classes based on their application and ratings. Standard ratings include nominal discharge current and voltage. Normal service conditions include temperature, radiation, altitude, and frequency ranges, while abnormal conditions require special consideration.
The term high voltage characterizes electrical circuits in which the voltage used is the cause of particular safety concerns & insulation requirements. High voltage is used in electrical power distribution, in cathode ray tubes, to generate x-rays & particle beams, to demonstrate arcing, for ignition, in photomultiplier tubes & high power amplifier vacuum tubes & other industrial & scientific applications .
The document discusses considerations for sizing conductors connecting station class arresters to transformers. It states that the conductor diameter has a negligible effect on the arrester's protection, but the length can impact inductance and protection. The key factors for sizing conductors are mechanical strength to withstand fault currents without failing, limiting corona at high voltages, and minimizing voltage reflections from separation of arrester and bushing. The optimum conductor size is determined by mechanical requirements over electrical considerations.
Designing and testing of metal oxide surge arrester for EHV lineRohit Khare
Surge arresters constitute an indispensable aid to insulation coordination in electrical power systems. There the voltages which may appear in an electrical power system are given in per-unit of the peak value of the highest continuous line-to-earth voltage, depending on the duration of their appearance. The voltage or overvoltage which can be reached without the use of arresters is a value of several p.u. If instead, one considers the curve of the withstand voltage of equipment insulation (here equipment means electrical devices such as power transformers) one notices that starting in the range of switching overvoltages, and especially for lightning over voltages, the equipment insulation cannot withstand the occurring dielectric stresses. At this point, the arresters intervene. When in operation, it is certain that the voltage that occurs at the terminal of the device - while maintaining an adequate safety margin - will stay below the withstand voltage. Arresters’ effect, therefore, involves lightning and switching over voltages.
The time axis is roughly divided into the range of lightning overvoltage (microseconds), switching overvoltages (milliseconds), temporary overvoltages (seconds) – which are commonly cited by the abbreviation "TOV" – and finally the temporally unlimited highest continuous system operation voltage.
Lightning protection for overhead distribution linesGilberto Mejía
This document summarizes techniques for lightning protection of overhead power distribution lines. It discusses the types of lightning overvoltages that can occur on medium voltage (MV) and low voltage (LV) networks from direct strikes and indirect strikes. Direct strikes can cause overvoltages over 2000kV, far exceeding insulation levels and causing flashovers. Indirect strikes have lower but still significant voltages and are more common. The document reviews methods to mitigate these overvoltages, including increasing insulation, using grounded shield wires, and installing surge arresters. Shield wires and arresters are most effective at reducing faults from direct strikes, while all methods help reduce faults from indirect strikes.
The document provides an overview of circuit breakers, including:
1) Circuit breakers sense overcurrent, measure its magnitude, and trip in a timely manner to prevent damage. They can be manually reset once a fault is cleared.
2) Key components include the frame, contacts, arc chute assembly, operating mechanism, and trip unit.
3) The trip unit senses overloads and short circuits and triggers the operating mechanism to open the contacts.
This document discusses the selection of circuit breakers. It begins by defining a circuit breaker as a protective device that is used to automatically open the faulty part of a power system during a fault. There are two main factors considered when selecting a circuit breaker: 1) its normal working power level and fault level ratings, which are specified by the rated interrupting current or MVA, and 2) its momentary current and speed ratings. The momentary current rating must be higher than the maximum current during fault conditions, while the speed rating depends on transient fault currents and specified cycles. Multiplying factors are used to determine the circuit breaker's short circuit interrupting current from fault analysis calculations.
This is the simple ppt explaining about the main components of the power systems. especially we are determining the insulators and its types with real time pictures which are attractive,
study of lightning arrester ' working principal and working of lighning and construction of lightning arrester. and at the end what are the types of lightning arrester how these types are different from each other and what is their working principal and which is used mostly on 500kva substation.
A transformer transfers electrical energy between two circuits through electromagnetic induction. It has a primary winding connected to an AC source and a secondary winding connected to a load. A varying current in the primary winding induces a voltage in the secondary winding through electromagnetic induction. Transformers experience losses such as copper losses from winding resistance and core losses from hysteresis and eddy currents in the core. Methods to reduce losses include using a core made of thin laminated steel to reduce eddy currents, and using thicker conductor wire to reduce copper losses.
This document summarizes types of lightning arresters, their classification, identification, standard ratings, and service conditions. There are three main types of arresters: expulsion, valve, and gapless metal-oxide. Arresters are classified into four classes based on their nominal discharge current and use: station, intermediate, distribution, and secondary. Arresters must be properly identified and can operate under normal conditions of temperature, radiation, altitude, and frequency, but may require special consideration under abnormal conditions.
A surge arrester is a device connected to electrical conductors that protects electrical equipment from overvoltage transients such as lightning. It diverts excess current from surges to ground through changes in its internal composition. Different types of surge arresters are discussed, including rod gap, horn gap, multi-gap, expulsion, valve, silicon carbide, and metal oxide arresters. Each type has advantages and limitations in protecting equipment from damaging surges on electrical systems.
This document discusses overvoltage phenomena and insulation coordination in high voltage engineering. It covers several topics:
1) Natural causes of overvoltages like lightning and the mechanisms behind lightning strokes.
2) Classification of transmission lines and the behavior of traveling waves at transition points like reflections and successive reflections shown through lattice diagrams.
3) Causes of overvoltages from switching surges during circuit operations, system faults, and abnormal conditions. Characteristics of switching surges and issues in extra high voltage systems are described.
4) Methods to control overvoltages including stepped energization of lines, phase controlled circuit breakers, and drainage of trapped charges. Protective devices like expulsion gaps, protector tubes
This document outlines standards for transmission line grounding. It discusses the purposes of grounding systems, which are to safeguard people from electric shock during faults, dissipate fault currents and voltages within limits, provide a path for lightning and switching surges, and reduce static discharge. It covers fundamental considerations like soil properties, power system networks, grounding performance of structures, and types of disturbances. Specific sections address safety, grounding of different structure types, grounding conductors, electrodes, resistance requirements, and recommended conductor sizes.
Dampers used in electrical transmission linesadeelshafiq
This document discusses different types of dampers used in overhead transmission lines to reduce vibrations caused by wind. It describes Stockbridge, ELGRA, torsional, Haro, and various spacer dampers. Stockbridge dampers use weights to counteract vibrations and have not changed much since their development in the 1920s. ELGRA dampers from Sweden use elastomer pads and weights. Torsional dampers are designed for bundled high voltage lines. Haro dampers effectively reduced vibrations but were difficult to transport. Spacer dampers establish conductor distance and reduce amplitudes on bundled lines.
1. Surge arresters are selected with voltage ratings of 336kV, 360kV, 372kV or 390kV to account for temporary overvoltages during faults.
2. Condition monitoring techniques like third harmonic resistive current monitoring are effective for detecting failures in surge arresters due to moisture ingress or degradation.
3. Investigations found moisture entry through faulty seals or gaskets led to failures in many surge arresters, accelerated by manufacturing defects. Improved sealing methods using O-rings instead of flat gaskets and routine dip testing were implemented.
This document discusses circuit breakers, including their purpose, construction, types, sizing and selection factors. It provides information on:
- Circuit breakers are used to protect electrical systems and people from faults and overloads. They have advantages over fuses in many applications.
- The main types discussed are miniature circuit breakers (MCB), moulded case circuit breakers (MCCB), earth leakage circuit breakers (ELCB), motor protection circuit breakers (MPCB) and air circuit breakers (ACB).
- Selection of a circuit breaker depends on the load magnitude and nature, as well as the system component being protected. Standards like rated current and short circuit capacity must
Circuit breakers are installed in electrical panels to shut off power when too much current flows, such as from too many devices plugged in or a short circuit. They contain contacts that separate when a fault is detected to immediately stop the flow of electricity. Circuit breakers can be classified by voltage level—low, medium, or high voltage—or by their arc suppression method, which includes air, oil, sulfur hexafluoride, vacuum, and magnetic circuit breakers. Vacuum and sulfur hexafluoride circuit breakers are commonly used today due to their reliable and fast operation in shutting off electric current during a fault.
The document discusses the theory of circuit interruption in power systems. It begins by introducing circuit breakers, which can manually or automatically open a circuit under normal or fault conditions. When contacts within a circuit breaker open under a fault, an arc is produced that must be extinguished to interrupt current flow. There are two main methods for extinguishing arcs: the high resistance method, which lengthens and cools the arc to increase its resistance over time; and the low resistance or current zero method, used for AC circuits, which maintains a low resistance arc until current reaches zero to naturally extinguish the arc.
This document provides an overview of circuit breakers, including their operating principles, components, and classifications. Circuit breakers are mechanical switching devices that open and close electrical circuits under normal and abnormal conditions. They contain fixed and moving contacts to carry current when closed. When a fault occurs, the contacts separate, creating an arc that must be extinguished quickly. Circuit breakers use various insulating fluids or methods to cool the arc and reduce its conduction in order to interrupt the current. Common types include oil, air, sulfur hexafluoride, and vacuum circuit breakers.
Overhead line insulators are used to electrically isolate power line conductors from each other and supporting structures. They protect transmission lines from over-voltages caused by lightning and switching. The most common insulator materials are porcelain and glass. Pin insulators are used for voltages up to 33kV, while suspension insulators are preferred for higher voltages as they can be scaled more easily. Proper insulator selection and arrangement is needed to achieve uniform voltage distribution across the insulator string. Sag in overhead lines must be properly calculated to limit conductor tension within safe levels while minimizing material usage and clearance heights.
The document discusses air-blast circuit breakers and their operation. It provides details on:
- How an air-blast circuit breaker uses a high pressure air blast to extinguish the arc by cooling it and sweeping away arcing products.
- The advantages of air-blast circuit breakers like reduced size and damage to contacts due to shorter arcing time.
- The types of air-blast circuit breakers including axial-blast, cross-blast, and radial-blast.
COMPENSATION OF FAULT RESISTANCE IN DISTANCE RELAY FOR LONG TRANSMISSION LINEIRJET Journal
This document discusses distance protection for long transmission lines and the impact of fault resistance. It begins with an introduction to distance relaying and the issues caused by fault resistance. It then discusses the objectives of analyzing how fault resistance affects protection at different fault distances. The document proposes a new algorithm to estimate fault location and resistance using voltage and current measurements from two terminals. The algorithm compensates for fault resistance in mho-type distance relays by measuring apparent impedance and subtracting the estimated fault resistance. This improves the accuracy of distance protection for faults with resistance on long transmission lines.
Proposal Technique for an Static Var CompensatorIOSR Journals
This document provides details on the design process for a Static Var Compensator (SVC). It discusses key considerations like load characteristics, environmental conditions, thyristor selection and operation, reactor arrangements, harmonic filtering, and simulation of fault conditions. The design process requires thorough investigation of parameters like thyristor ratings, triggering circuits, cooling requirements, and protection against overvoltages. Fault cases are simulated using PSCAD software to analyze maximum current and voltage stresses on thyristor valves and harmonic filters. Reactor design must also account for current harmonics levels.
This document discusses the selection of circuit breakers. It begins by defining a circuit breaker as a protective device that is used to automatically open the faulty part of a power system during a fault. There are two main factors considered when selecting a circuit breaker: 1) its normal working power level and fault level ratings, which are specified by the rated interrupting current or MVA, and 2) its momentary current and speed ratings. The momentary current rating must be higher than the maximum current during fault conditions, while the speed rating depends on transient fault currents and specified cycles. Multiplying factors are used to determine the circuit breaker's short circuit interrupting current from fault analysis calculations.
This is the simple ppt explaining about the main components of the power systems. especially we are determining the insulators and its types with real time pictures which are attractive,
study of lightning arrester ' working principal and working of lighning and construction of lightning arrester. and at the end what are the types of lightning arrester how these types are different from each other and what is their working principal and which is used mostly on 500kva substation.
A transformer transfers electrical energy between two circuits through electromagnetic induction. It has a primary winding connected to an AC source and a secondary winding connected to a load. A varying current in the primary winding induces a voltage in the secondary winding through electromagnetic induction. Transformers experience losses such as copper losses from winding resistance and core losses from hysteresis and eddy currents in the core. Methods to reduce losses include using a core made of thin laminated steel to reduce eddy currents, and using thicker conductor wire to reduce copper losses.
This document summarizes types of lightning arresters, their classification, identification, standard ratings, and service conditions. There are three main types of arresters: expulsion, valve, and gapless metal-oxide. Arresters are classified into four classes based on their nominal discharge current and use: station, intermediate, distribution, and secondary. Arresters must be properly identified and can operate under normal conditions of temperature, radiation, altitude, and frequency, but may require special consideration under abnormal conditions.
A surge arrester is a device connected to electrical conductors that protects electrical equipment from overvoltage transients such as lightning. It diverts excess current from surges to ground through changes in its internal composition. Different types of surge arresters are discussed, including rod gap, horn gap, multi-gap, expulsion, valve, silicon carbide, and metal oxide arresters. Each type has advantages and limitations in protecting equipment from damaging surges on electrical systems.
This document discusses overvoltage phenomena and insulation coordination in high voltage engineering. It covers several topics:
1) Natural causes of overvoltages like lightning and the mechanisms behind lightning strokes.
2) Classification of transmission lines and the behavior of traveling waves at transition points like reflections and successive reflections shown through lattice diagrams.
3) Causes of overvoltages from switching surges during circuit operations, system faults, and abnormal conditions. Characteristics of switching surges and issues in extra high voltage systems are described.
4) Methods to control overvoltages including stepped energization of lines, phase controlled circuit breakers, and drainage of trapped charges. Protective devices like expulsion gaps, protector tubes
This document outlines standards for transmission line grounding. It discusses the purposes of grounding systems, which are to safeguard people from electric shock during faults, dissipate fault currents and voltages within limits, provide a path for lightning and switching surges, and reduce static discharge. It covers fundamental considerations like soil properties, power system networks, grounding performance of structures, and types of disturbances. Specific sections address safety, grounding of different structure types, grounding conductors, electrodes, resistance requirements, and recommended conductor sizes.
Dampers used in electrical transmission linesadeelshafiq
This document discusses different types of dampers used in overhead transmission lines to reduce vibrations caused by wind. It describes Stockbridge, ELGRA, torsional, Haro, and various spacer dampers. Stockbridge dampers use weights to counteract vibrations and have not changed much since their development in the 1920s. ELGRA dampers from Sweden use elastomer pads and weights. Torsional dampers are designed for bundled high voltage lines. Haro dampers effectively reduced vibrations but were difficult to transport. Spacer dampers establish conductor distance and reduce amplitudes on bundled lines.
1. Surge arresters are selected with voltage ratings of 336kV, 360kV, 372kV or 390kV to account for temporary overvoltages during faults.
2. Condition monitoring techniques like third harmonic resistive current monitoring are effective for detecting failures in surge arresters due to moisture ingress or degradation.
3. Investigations found moisture entry through faulty seals or gaskets led to failures in many surge arresters, accelerated by manufacturing defects. Improved sealing methods using O-rings instead of flat gaskets and routine dip testing were implemented.
This document discusses circuit breakers, including their purpose, construction, types, sizing and selection factors. It provides information on:
- Circuit breakers are used to protect electrical systems and people from faults and overloads. They have advantages over fuses in many applications.
- The main types discussed are miniature circuit breakers (MCB), moulded case circuit breakers (MCCB), earth leakage circuit breakers (ELCB), motor protection circuit breakers (MPCB) and air circuit breakers (ACB).
- Selection of a circuit breaker depends on the load magnitude and nature, as well as the system component being protected. Standards like rated current and short circuit capacity must
Circuit breakers are installed in electrical panels to shut off power when too much current flows, such as from too many devices plugged in or a short circuit. They contain contacts that separate when a fault is detected to immediately stop the flow of electricity. Circuit breakers can be classified by voltage level—low, medium, or high voltage—or by their arc suppression method, which includes air, oil, sulfur hexafluoride, vacuum, and magnetic circuit breakers. Vacuum and sulfur hexafluoride circuit breakers are commonly used today due to their reliable and fast operation in shutting off electric current during a fault.
The document discusses the theory of circuit interruption in power systems. It begins by introducing circuit breakers, which can manually or automatically open a circuit under normal or fault conditions. When contacts within a circuit breaker open under a fault, an arc is produced that must be extinguished to interrupt current flow. There are two main methods for extinguishing arcs: the high resistance method, which lengthens and cools the arc to increase its resistance over time; and the low resistance or current zero method, used for AC circuits, which maintains a low resistance arc until current reaches zero to naturally extinguish the arc.
This document provides an overview of circuit breakers, including their operating principles, components, and classifications. Circuit breakers are mechanical switching devices that open and close electrical circuits under normal and abnormal conditions. They contain fixed and moving contacts to carry current when closed. When a fault occurs, the contacts separate, creating an arc that must be extinguished quickly. Circuit breakers use various insulating fluids or methods to cool the arc and reduce its conduction in order to interrupt the current. Common types include oil, air, sulfur hexafluoride, and vacuum circuit breakers.
Overhead line insulators are used to electrically isolate power line conductors from each other and supporting structures. They protect transmission lines from over-voltages caused by lightning and switching. The most common insulator materials are porcelain and glass. Pin insulators are used for voltages up to 33kV, while suspension insulators are preferred for higher voltages as they can be scaled more easily. Proper insulator selection and arrangement is needed to achieve uniform voltage distribution across the insulator string. Sag in overhead lines must be properly calculated to limit conductor tension within safe levels while minimizing material usage and clearance heights.
The document discusses air-blast circuit breakers and their operation. It provides details on:
- How an air-blast circuit breaker uses a high pressure air blast to extinguish the arc by cooling it and sweeping away arcing products.
- The advantages of air-blast circuit breakers like reduced size and damage to contacts due to shorter arcing time.
- The types of air-blast circuit breakers including axial-blast, cross-blast, and radial-blast.
COMPENSATION OF FAULT RESISTANCE IN DISTANCE RELAY FOR LONG TRANSMISSION LINEIRJET Journal
This document discusses distance protection for long transmission lines and the impact of fault resistance. It begins with an introduction to distance relaying and the issues caused by fault resistance. It then discusses the objectives of analyzing how fault resistance affects protection at different fault distances. The document proposes a new algorithm to estimate fault location and resistance using voltage and current measurements from two terminals. The algorithm compensates for fault resistance in mho-type distance relays by measuring apparent impedance and subtracting the estimated fault resistance. This improves the accuracy of distance protection for faults with resistance on long transmission lines.
Proposal Technique for an Static Var CompensatorIOSR Journals
This document provides details on the design process for a Static Var Compensator (SVC). It discusses key considerations like load characteristics, environmental conditions, thyristor selection and operation, reactor arrangements, harmonic filtering, and simulation of fault conditions. The design process requires thorough investigation of parameters like thyristor ratings, triggering circuits, cooling requirements, and protection against overvoltages. Fault cases are simulated using PSCAD software to analyze maximum current and voltage stresses on thyristor valves and harmonic filters. Reactor design must also account for current harmonics levels.
ESA Module 1 Part-B ME832. by Dr. Mohammed ImranMohammed Imran
This document discusses electrical resistance strain gauges. It begins by introducing the principle behind how they operate, which was discovered by Lord Kelvin in 1856 using a Wheatstone bridge. Electrical resistance strain gauges have advantages like small size, negligible mass, and producing an electrical output. The document then discusses gauge factor and how a gauge's sensitivity is determined by both dimensional changes and changes in resistivity when strained. It also describes different types of gauge construction methods, including bonded wire, foil, and wrap-around styles. Key applications mentioned include experimental stress analysis of vehicles, structures, and machines.
This document discusses sheath voltage limiters (SVLs), which are surge arresters used to protect the outer jacket of underground high voltage cables. SVLs limit the voltage stress across the cable jacket during transient overvoltage events like faults, switching surges and lightning strikes to prevent puncture and moisture ingress. The document provides guidelines for selecting the proper rating for SVLs, including calculating the voltage that could appear on the cable sheath during faults based on cable characteristics, and ensuring the SVL's voltage rating is above this level so it does not conduct during faults. It also discusses using simulations and margins of protection to determine if the SVL can adequately protect the cable jacket from other transient overvoltages.
This document discusses earthing systems for cable screens in power lines with voltages of 66kV or greater. It describes two main types of screen earthing diagrams: rigid earthing systems and special earthing systems. Rigid earthing systems directly connect all three phase screens together and to earth, allowing screen currents but maintaining voltages close to zero. Special earthing systems aim to prevent or cancel screen currents to reduce losses, requiring screens to withstand small permanent voltages and current surges. One such system described is the cross bonded system, which divides the line into sections and uses crossed screen connections between sections to reduce induced electromotive forces.
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
This document outlines standards and guidelines for constructing overhead distribution lines in Saudi Arabia. It defines various pole types and spans, and provides specifications for materials, clearances, foundations, conductor installation and other aspects of overhead line design and construction. The standards are intended to promote standardization and ensure reliable and economical distribution lines are built.
This document discusses short-circuit currents in electrical power systems. It defines a short circuit as any accidental contact between points that normally have different voltages. Short-circuit currents are analyzed to adequately size protection devices, check circuit breaker capacities, and modify network structures. There are various types of short circuits, including phase-to-earth, phase-to-phase, and three-phase faults. Short circuits can damage insulation, weld conductors, and cause fires. They also cause voltage dips, instability, and loss of synchronization. Short-circuit currents contain subtransient, transient, and steady-state periods. Near-generator and far-generator faults result in different short-circuit current waveforms. Key quantities include
Calculation and comparison of circuit breaker parameters in Power World Simul...IJERA Editor
A circuit breaker has ratings that an engineer uses for their application. These ratings define circuit breaker
performance characteristics. A good understanding of Ratings allow the electrical engineer to make a proper
comparison of various circuit breaker designs.
In this research work, the different ratings of circuit breaker were calculated. The other objective of this work
was comparison between ratings of existing circuit breaker and calculated ratings in POWER WORLD
SIMULATOR. Further, the impact of time delay in circuit breaker was studied. These calculations were
performed for rated current of 400 & 630 Amps. The results performed in POWER WORLD SIMULATOR
were shown better and information gained from the analysis can be used for proper relay selection, settings,
performances and coordination.
Calculation and comparison of circuit breaker parameters in Power World Simul...IJERA Editor
A circuit breaker has ratings that an engineer uses for their application. These ratings define circuit breaker
performance characteristics. A good understanding of Ratings allow the electrical engineer to make a proper
comparison of various circuit breaker designs.
In this research work, the different ratings of circuit breaker were calculated. The other objective of this work
was comparison between ratings of existing circuit breaker and calculated ratings in POWER WORLD
SIMULATOR. Further, the impact of time delay in circuit breaker was studied. These calculations were
performed for rated current of 400 & 630 Amps. The results performed in POWER WORLD SIMULATOR
were shown better and information gained from the analysis can be used for proper relay selection, settings,
performances and coordination.
1) ENMAX faced the challenge of monitoring clearance between a 138kV transmission line and a 25kV distribution line that crossed paths for 9.3 km. Determining dynamic clearance is difficult using traditional methods as the lines experience different loading profiles.
2) ENMAX installed LiDAR sensors on the two lines to directly measure the distance between them in real-time. The sensors measure the distance from each line to ground, and the difference provides the inter-line clearance.
3) Four sensors were installed and communicate wirelessly to monitor clearance over two spans. The sensors provide critical clearance data to ensure sufficient spacing as loads on the lines change over time.
The document discusses short circuits (faults) in electrical systems. It defines a short circuit as a low resistance path allowing current to flow along an unintended path. Short circuits can damage equipment and endanger safety if fault currents exceed ratings. The document then provides details on types of short circuits including shunt faults like line-to-ground and line-to-line, and series faults like open circuits. Short circuit studies are important to ensure protection devices and equipment can withstand fault currents.
The document discusses short circuit currents and testing of transformers to withstand short circuits. It defines short circuits and short circuit current, and differentiates short circuits from overloads. Symmetrical and asymmetrical short circuit currents are calculated. Short circuit tests are done on distribution and power transformers to demonstrate their ability to withstand thermal and dynamic effects of short circuits without damage. The document outlines test procedures, current calculations, and setup for short circuit testing in the lab.
Reducing Induced Voltages on Parallel Facilities in Shared Transmission Corri...Power System Operation
Routing, siting, and environmental constraints are pushing more transmission lines and other linear facilities such as pipelines and railroads into shared corridors. The future power system will see a greater number of these situations, often coupled with transmission lines with heavier loading than historic lines have experienced. When a transmission line is parallel or semi-parallel to an adjacent linear facility, the magnetic fields will induce voltages onto these facilities proportionally to the line loading and length of parallelism.
This paper briefly explores the general mechanisms of magnetic induction, a summary of some traditional mitigation approaches, and non-traditional designs to reduce the induction. These methods include shield wire and aerial counterpoise conductor configurations on a sampling of typical voltage levels and transmission line configurations.
Load centers get generated electricity from power
stations that are usually far; uninterrupted consumption or usage
of power has increased in last few years. Transmission system is
the system by means of which electricity is transferred from place
of generation to the consumers. Overhead wires or conductors
are the medium used for transmission of power. These wires are
visible to wind, heat and ice. The efficiency of the power system
increases if the losses of these overhead wires are minimal. These
losses are based on the resistive, magnetic and capacitive nature
of the conductor. It is necessary to create or make proper design
of these conductors accompanied by proper installation. To
balance the working and strength of overhead transmission line
and to minimize its capacitive effect the conductors must be
installed in catenary shape. The sag is required in transmission
line for conductor suspension. The conductors are appended
between two overhead towers with ideal estimation of sag. It is
because of keeping conductor safety from inordinate tension. To
permit safe tension in the conductor, conductors are not
completely extended; rather they are allowed to have sag. For
same level supports this paper provides sag and tension
estimation with different wind speeds under low operating
temperature 2 °C. To calculate sag-tension estimation of ACSR
(Aluminum Conductor Steel Reinforced) overhead lines three
different cases are provided with normal and high wind speed
effects. Four different span lengths are taken for equal level
supports. ETAP (Electrical Transient and Analysis Program) is
used for simulation setup. The results shows that wind speed has
great impact upon line tension and with addition of wind speed
the sag of line remains unaltered while tension changes.
Moreover tension gets increase while increase in wind speed.
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The International Journal of Engineering & Science is aimed at providing a platform for researchers, engineers, scientists, or educators to publish their original research results, to exchange new ideas, to disseminate information in innovative designs, engineering experiences and technological skills. It is also the Journal's objective to promote engineering and technology education. All papers submitted to the Journal will be blind peer-reviewed. Only original articles will be published.
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Power system is the transfer of electricity from generation to the point of user location. Power system is composed of generation of power, its transmission and distribution. Transmission system is the main part out of these three in which mostly losses occur. The unchanging factors of the transmission line on which these losses depend are inductance, resistance and capacitance. These constants or unchanging factors play a vital role in the performance of transmission line. For example the capacitance effect will be more and its performance will be affected if the height of transmission line is less from the ground. On the other hand its capacitance will be less but tension will be high if the height of the transmission is high. For this reason a transmission line is connected in a curved or catenary shape known as sag. To minimize tension sag is provided in a transmission line. Sag and tension must be adjusted in safe limits. This immediate paper gives a simulation structure to calculate sag and tension of AAAC (All Aluminum Alloy Conductors of overhead transmission lines with same span length for minimum operating temperature. Three different cases are presented with different towers height and are explained in detail for unequal level span. The results show that the tension and sag increased with height. So great the height difference, higher tensions upon higher towers.
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Algorithem Algorithem and Programme for Computation of Forces Acting on line Supports
1. Abdulaziz Salem Bahaidara
International Journal of Computer Science and Security (IJCSS), Volume (6) : Issue (1) : 2012 53
Algorithem and Programme for Computation
of Forces Acting on Line Supports
Abdulaziz Salem Bahaidara abdulaziz_bahaidara@yahoo.com
Faculty of engineering/Electrical Engg. Departt.
University of Aden
Aden, Republic of Yemen
Abstract
The correct design and selection of line supports is of great importance for successful operation
and safety of transmission lines. For this purpose, various forces acting on the line supports must
be estimated for normal and abnormal conditions of operation. The author develops algorithm
and programme for optimal calculation of these forces, which the line supports should withstand.
The main programme MDFLS and fourteen subroutines are constructed for calculation the forces
acting on the line supports. The subroutines (FSUS, FDES, and FCSTA) are for determining the
forces from line conductors and (FGWSU, FSWDE, FSWSA) from ground wires at suspension,
dead end and strain/angle line supports respectively. The other eight are subsidiary subroutines.
The parameters of the conductors (homogenous or non-homogenous) are found by DPMPN and
DPMPH. The physical-mechanical properties of the conductor are calculated using PMPL. The
specific loadings are determined by RLOLC. The sag-tension calculations are prepared by
subroutines CSCT, CSOP and SEQS. Subroutine FSPCB is for calculation of forces due to
broken conductor at suspension support in the section. The elaborated programmes are written in
FORTRAN 90 and adopted for personal computer.
Keywords: Line Support, Operating Condition, Forces, Tension, Span, Sag.
1. INTRODUCTION
This paper deals with, computation forces acting on line supports, a part of future proposed
compound package of programmes related to mechanical design of transmission lines. Line
supports of overhead lines ensure the necessary clearances.They should be cheap and stable to
loadings, caused from atmospheric conditions and from operating conditions of the phase
conductors and ground wires. [1, 9]
The phase conductors and ground wires are unequal loaded when in one or several spans from
the section the specific loads are less or greater from these in the remaining spans. The reason
of unequaled loading of the conductors is their ice covered. Usually at ice-covered conductors are
covered uniformly with ice, but their release from ice may not occur simultaneously for all
conductors and ground wires in all spans of the section. The conductor may be released from ice
in one or several spans, while in other spans remains ice covered.
The unequaled loading of the conductors' causes: Approach of the conductors situated one
above other phases. Approach of the phase conductors near ground wires; release of a
conductor from skip terminals at large deflection of insulator strings by axis of electrical line;
approach of a conductor near the cross arm of a support at deflection of insulator string.[3,4]
At broken off conductor operating conditions of electrical line are sharply varied. In normal
operating condition suspension and strain supports are loaded with forces from the weight of a
conductor and from wind pressure in the direction of electrical line , forces are approximately
equal to zero. At broken off conductor appreciable forces are raised, which loaded the line
2. Abdulaziz Salem Bahaidara
International Journal of Computer Science and Security (IJCSS), Volume (6) : Issue (1) : 2012 54
supports. These forces are the biggest for the supports, which confined the span with broken off
conductor.
If the conductor is broken off in one span of the section, the insulator strings are deflected and the
supports are bended to direction of the spans, at which the entire conductor is preserved. By
moving away from the location of the damage, the quantity of the support deformation and the
deflection of the insulator strings are reduced. The forces in the conductor at abnormal operating
condition are considerably less from its previous normal operating condition; the damages of a
conductor are so high. [1, 5]
The overhead electrical lines are computed for abnormal operating condition with broken off
conductor due to the following reason: In order to determine the forces, with which the conductors
loaded the supports in abnormal operating condition; to determine the sag of a conductor in
spans, in which the conductor is healthy. This sag is required, in order to calculate the distances
between the conductors and the equipments located under them. [5, 6]
2. LINE CONDUCTOR INDEXES [2, 7]
The physical-mechanical properties of the line conductor are determined. These are: cross-
sectional area, weight of the conductor, modulus of elasticity, temperature coefficient of linear
expansion, permissible tensile stress, the stress at minimum temperature and the stress at
maximum loading. The forces, which are loading the conductors of an overhead line are, their
weight, wind pressure, weight of ice and combinations between these forces. Depending up on
the given value of operating voltage of the line, the standard clearances are selected and the
specific loadings (G1-G7) are calculated.
Critical span and temperature are calculated for finding operating condition for maximum stress in
the conductor and maximum sag. The operating condition, at which maximum tension occurs in
the conductor, is determined by a comparison of the actual span (given) with critical span. When
actual span (la) is greater than or equal to critical span (lcr), maximum tension in the conductor
occurs at the operating condition of maximum loading and at actual span less than critical span,
maximum tension in the conductor occurs at the operating condition of minimum temperature.
With criteria, critical temperature (tcr), operating condition is determined at which maximum sag
occurs in the conductor in the span. When critical temperature is less than maximum temperature
(tmax), maximum sag occurs at maximum temperature and at critical, temperature greater than or
equal to maximum temperature, maximum sag occurs at ice covered conductor load (G3) and air
temperature-5
°
C.
3. MAXIMUM LOADING AND TENSION AT ABNORMAL CONDITIONS [1, 5]
At normal operating conditions, suspension and tension supports are loaded with the conductor
weight and wind pressure while tension in the direction of electrical line are almost equal and their
resultant is zero. When one of the conductors is broken off, the operating conditions of the
electrical line will vary sharply and abnormal tension in the direction of the electrical line will load
the supports and these tensile forces will gradually increase towards the nearest support to the
damaged span, therefore, insulators will be deflected and supports will be bended to the direction
of span at which whole conductors are preserved. The deformation of supports is gradually
reduces towards the farest support from the location of broken off conductor.
Forces at abnormal condition must be calculated in order to determine loadings on the line
supports, when the conductors are broken off. However the new sag must be calculated to
determine the clearances between conductors and equipments located under the electrical line.
Calculation of abnormal forces can be done in analytical manner by using Shanfer Pharmakovski
method [1, 2]. The magnitude of the influenced force (Tab) is calculated depending on critical
span.
At la≥lcr Tab=σG3 S (3.1)
3. Abdulaziz Salem Bahaidara
International Journal of Computer Science and Security (IJCSS), Volume (6) : Issue (1) : 2012 55
At la<lcr Tab=σtmin S (3.2)
Where
σtmin , σG3 - permissible tension in the conductor at minimum temperature and load G3
(loading due to conductor weight when covered with ice).
S - The cross-sectional area of the conductor.
4. OPERATING CONDITIONS OF OVERHEAD LINES [5, 8]
The line supports are determined in normal and abnormal operating conditions. Normal operating
condition is that at which phase and ground wire conductors in all spans of the section are
healthy and parameters of an overhead electrical line are within permissible limits. All types of
supports are determined for forces conditioned by the following two normal operating conditions:
1. Normal operating condition I, which is described with: phase and ground wire conductors with
no ice; maximum wind pressure (perpendicular to the axis of the electrical line); air temperature
15
º
C.
2. Normal operating condition II, which is described with: ice covered phase and ground wire
conductors; 25% of maximum wind pressure; air temperature-5ºC. In an abnormal operating
condition such as broken off phase conductor or ground wire, wind pressure is assumed to be
zero. The location and number of broken off conductors is standardized and depending upon the
type of line supports [3,4]
3. Abnormal operating condition, broken off phase conductors provoked maximum bend
moment in the elements of the line support.
4. Abnormal operating condition, broken off phase conductors provoked maximum torsion
moment in the line support.
5. Abnormal operating condition with broken off ground wires and healthy phase conductors.
In the normal operating condition the following forces act on the suspension line support; vertical-
from the weight of the conductors ground wires, insulators, cross arms and support itself;
horizontal, perpendicular to the axis of electrical line from influence of wind; horizontal coincided
with axis of electrical line-from forces of straining conductors from the two sides of suspension
support; in normal operating condition this forces is equal to zero, since the conductors are pulled
out for the entire section.
In the abnormal operating condition the following forces act on the suspension line support ;
vertical-from the weight of the equipments of electrical line ; horizontal, coincided with axis of
electrical line-caused from unbalanced forces in the conductors of individual spans ; suspension
insulators with pin type insulators are not determined in abnormal condition, but they should stand
loadings by axis of electrical line up to 150 Newton (at this force broken off the dressing is
occurred; breakdown the insulator or hook). Horizontal, perpendicular to axis of electrical line
force does not exist, because the velocity of the wind at abnormal condition is assumed to be
equal zero.
The forces, which act strain supports in normal condition, are equal in magnitude and direction
with these, which act on suspension supports. For abnormal condition more heavy computational
conditions for strain supports-it is assumed a greater number of broken off conductors. Strain
supports are calculated also in stringing condition with forces at side strained conductors.
In the normal condition the following forces act on the conductors, insulators, cross arms, support
and others; horizontal, by axis y-from the strain force of conductors 2T sin (χ/2) is assumed that
in this direction the wind acts with maximum force on the conductors and the elements of the
support; horizontal, by axis X-in normal condition this force does not act.
In the abnormal condition the following forces act on angle support: vertical, by axis Z-from
weights of elements of electrical line ; horizontal, by axis X-from the component of the straining
force of healthy conductors-Fx=Tabcos(χ/2) ; horizontal and coincided with axis Y-from the
component of straining forces of healthy conductors Fy=Tabsin(χ/2).
4. Abdulaziz Salem Bahaidara
International Journal of Computer Science and Security (IJCSS), Volume (6) : Issue (1) : 2012 56
On dead end supports more high forces act on from straining of the conductors and ground wires.
In the normal operating condition vertical forces act on them from weights of conductor elements.
Coincided with axis of electrical line, straining forces of conductors and ground wires act on them.
The straining of the conductors from the side of distribution outfit is small and its opposed force is
neglected. Perpendicular to the electrical line it is assumed that, forces are acted from wind
pressure on the conductors and the elements of support. Forces, which loaded support in
abnormal condition, are less from forces acting at normal condition. In some cases enclosed
points of these forces are such that the support subjected to high torsion moments, which should
be taken into consideration during its design.
5. FORCES ACTING ON LINE SUPPORTS [3, 4]
The forces, with which the conductors loaded the line supports of overhead transmission line, are
computed at construction of new supports or for check of the loading on the existing support. The
forces, which loaded a support are determined by their components along the axis of the three
coordinate system X,Y and Z, where-axis X is along the direction of electrical line ; axis Y is
perpendicular to the direction of the electrical line, and axis Z is along the axis of the support in
the downward direction.
The forces, with which the conductors act on the specified support (say A) at flat terrain, are the
following [5]:
(5.1)
(5.2)
(5.3)
Where
Tо and Tо are the strain forces in the conductor in the spans (adjacent to the specified support)
number 1 and number 2 respectively ; P1y =GSl1 and P2y =GSl2 -the forces from conductors at
influence of wind on no-ice covered (G=G4) or ice covered conductors (G=G5) for spans number 1
and number 2 respectively; P1z=GSl1 and P2z=GSl2 -force from the weight of not iced (G=G1) or
ice covered conductors (G=G3)for spans number 1 and number 2 respectively.
The forces from the weight and the wind pressure are distributed equally between the two
supports, which are restricted the span. Therefore the specified support (say A) is loaded with
half of forces from spans number 1 and number 2. The reactions of the forces in the attachment
points of the conductor at the support (say A) are equal and opposite acting forces.
At normal operating condition of electrical line with suspension insulators horizontal component of
tensile stress in the conductors is same for all spans of section. Therefore Fx=0 At conductors
with pin type insulators in normal operating condition horizontal component of the tensile stress in
5. Abdulaziz Salem Bahaidara
International Journal of Computer Science and Security (IJCSS), Volume (6) : Issue (1) : 2012 57
conductor for the spans of the section is different, but the differences are small and can be
neglected and therefore Fx ≈ 0 .
In abnormal operating condition of electrical line the component F2x is equal to zero, if the
conductor is broken off in the second span. The component F1x =Tab.
The suspension and strain line supports are determined for forces (5.3). For dead end line
supports, forces from the conductors of one span are equal to zero. The forces, with which the
conductors act on dead end line supports, are determined by (5.1).
At inclined terrain, for calculation the result force acting of the conductors in the attachment point,
all acting forces are projected on coordinate axis and their projections are summing. It is obtained
that
(5.4)
Where
φ is the angle of inclination of the conductor due to wind pressure ;
α2 is the angle of the slop of conventional horizontal span.
The angle α2 can be calculated by
tan α2 = tan ψ2 sin φ ( 5.5)
Where ψ2 is the inclination of the terrain from the right side of the support.
By similar way the components of the force for span number 1 can calculated:
(5.6)
The result force, which is acted on the support:
(5.7)
The reactions of the forces, with which the conductor acts for the support, are equal and opposite
the acting forces in the attachment point of the conductor. The acting forces are calculated for
equivalent spans of the specified support le1 and le2 [4, 5]. They are large and small equivalent
spans if the specified support is located higher and lower than the adjacent supports respectively.
Small and large equivalent spans if the specified support is lower from the left side support and
higher from the right side support or vice versa. The result force from the conductors on dead end
support are determined by (5.7) for F2=0.
6. Abdulaziz Salem Bahaidara
International Journal of Computer Science and Security (IJCSS), Volume (6) : Issue (1) : 2012 58
At angle support the electrical line changes its direction with angle χ. For calculation forces,
acting on angle support coordinate system is introduced with inception in the attachment point at
specified angle support. It is assumed, that the direction of the wind is coincided with axis Y. The
force, with which wind pressure acts on the conductors in the span with length l, is calculated by
Py=G S l cos (χ/2) (5.8)
The confront with the direction of the conductors, the component of wind is put with strain force T’
or T”
The forces in the conductor in its attachment points to specified support are determined
separately for spans number 1 and number 2. For that aim subsidiary coordinate systems are
introduced with start point specified support and with axis: axis X1, X2 -with direction of the
conductors in span number 1; and span number 2 respectively. Axis Y1 and Y2 are perpendicular
to X1 and X2 respectively. For subsidiary coordinate systems forces are calculated, as at
supports, located in straight line at flat terrain, and only the force from wind introduces its
component on axis Y-equation (5.9).
The forces from conductor from spans number 1 and number 2 are respectively
(5.9)
The result force from conductor in the attachment point is found by projection of the forces F1 and
F2 on the axis of the basic coordinate system X Y Z.
(5.10)
The forces, with which the conductors act on angle support in inclined terrain, are calculated, as
for angle support in flat terrain. The components of the forces from conductor are calculated by
(5.4) and (5.6). The difference is only in the direction of wind pressure, which is at angle χ/2 with
respect to axis of the electrical line, and its component is determined by (5.8).
The components of the force F on the basic coordinate system are
(5.11)
6. COMPUTER PROGRAMME
The synthesis algorithm has been written in FORTRAN – 90, and run on a personal computer.
Figure 1. shows the flow chart of the programme, which consists of one main programme MDFLS
and fourteen subroutines.
The input data : Nominal voltage kv; climatic area – TEP is equal to one for specified
standardized or equal to two for special climatic area; length of the span l; STC1 and STC2 are
7. Abdulaziz Salem Bahaidara
International Journal of Computer Science and Security (IJCSS), Volume (6) : Issue (1) : 2012 59
codes for the phase conductor and ground wire respectively; λ is the length of insulator string; Gi
is the weight of the insulator; χ is the angle of deflection of the trace; ψ1 and ψ2 is the inclination
of the terrain from the right side and left side of the line support respectively; l1 and l2 are the
length of the spans adjacent to the specified line support.
The parameters of the line conductors are found by subroutines DPMPH and DPMPN [2]. The
subroutine PMPL is used for calculation of physical-mechanical properties of the phase
conductors (PF=1) and ground wires (PF=2).The specific loadings are determined by subroutine
RLOLC. Subroutine CSCT is for calculation of critical values of span and temperature and CSOP
is for determination of operating condition. SEQS is for solution equation of state and it is a
subsidiary function to CSCT.
The forces acting from phase conductor on suspension, strain or angle and dead end towers are
determined by FCSUS, FCSTA and FCDES respectively. The forces acting from ground wires on
suspension ,strain or angle and dead end towers are determined by FGWSU, FGWSA and
FGWDE.The subroutine FSPCB is used for calculation of the force loading line support at broken
off conductors in the section.
8. Abdulaziz Salem Bahaidara
International Journal of Computer Science and Security (IJCSS), Volume (6) : Issue (1) : 2012 60
FIGURE 1: Flow chart of programme MDFLS
7. CONCLUSION
For selection and design of the line supports, loadings due to the conductors and wind pressure
must be estimated for normal and abnormal conditions of operation. The selected supports
should be mechanically strong to withstand these forces.
The elaborated programme enable obtaining the optimum solution of the problem, aiming to
increase reliability of transmission lines and the calculated forces to be in consistent with the
specified regulations within the permissible limits.Our country began construction of national
system high voltage transmission lines 132 kv and in future 220 kv and 400 kv will be erected.
1
λ≤ 0
9. Abdulaziz Salem Bahaidara
International Journal of Computer Science and Security (IJCSS), Volume (6) : Issue (1) : 2012 61
Such programmes are needed and necessary and their use have great benefits. They will give a
precise solution, in short time, for one of the problems of mechanical design of an overhead
transmission line.
There are some specific areas in our country, which are with high humidity. The future research
direction in this field of the existing research paper is to investigate the effect of humidity in the
design of line supports for these areas, e.g. the change in the clearances of line supports due to
high humidity. This change results to different values of forces, distinguished from standard
permissible range, acting on line supports. Therefore, new methodologies should be created and
applied for design of line supports and computation of forces acting on them.
8. REFERENCES
[1] Vadhera S. S. "Power system analysis and stability", Khana Publishers Delhi, India, 1987,
pp 142-163.
[2] Bahaidara A. S. "A new algorithm for mechanical design of overhead conductor". Journal
for natural and applied sciences, vol.2 No 3 University of Aden, pp 33-40, 1997.
[3] Coombs R.D., "Pole and Tower Lines for electric power transmissions ". London Hill
Publishing CO.Ltd. , 1963, pp 29-42.
[4] Cotton H., Barber H. "The Transmission and Distribution of electrical energy", The English
Universities Press LTD, St Paul's House Warwick Lane London EC4, Third edition, 1970,
pp 205-220.
[5] Nicolai Genkov. "Mechanical part of an overhead transmission lines". Public House
"Technics", Sofia, 1974, pp 211-271.
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