Foreword With the increasing development of the power system, the requirements for the safe operation and power supply reliability of transmission lines are getting higher and higher. Transmission lines play an important role in the power grid. Their safe and stable operation plays a decisive role in ensuring the integrity of the power grid structure. Due to the erection of overhead transmission lines in the field, the divisions are wide, and there are great differences in the regional environment. There are many components in the structure of the line, and there are many factors that cause failures. It is difficult to operate and maintain and it is prone to failure. Once the transmission line fails, it may affect the security of the power supply in the area. It may even cause incalculable losses. Therefore, prevention of transmission line fault prevention has always been an important task for power supply companies. In order to ensure the safe operation of transmission lines, it is necessary to dig deep into the source of the failure to take effective preventive measures. The common failures of overhead transmission lines in operation include lightning failures, insulator failures, wire breakage failures, external failure failures, bird damage failures, and design error failures.
1. Causes of lightning damage and preventive measures 1.1 Causes of lightning damage Lightning is the most common type of overhead transmission line, with complex causes and difficulties in prevention. In Guangdong Province, the climate is humid, there are many mountains and forests, and there are more thunderstorms. The density of lightning on the ground is high, and the probability of lightning strikes on the lines is high.
1.2 Lightning Prevention Measures For the prevention of lightning hazards, the integrated prevention and control method is adopted, ie, strengthening electrical insulation, installing lightning conductors, reducing the tower grounding resistance, installing automatic reclosing devices, and strengthening the inspection and maintenance of grounding devices. To deal with the poor grounding in the line, use scientific methods to detect lightning subdivisions, and install lightning arresters on lightning-intensive sections. Among them, it is most important to strengthen electrical insulation. This will be discussed in detail in the breakdown of insulators.
2. Insulator fault causes and preventive measures 2.1 Insulator faults are mainly caused by poor quality insulators, insulator flashes, and low effective dry arc distances. The main causes are poor porcelain (glass) body roasting during the manufacturing process of insulators and cement adhesives. Dry shrinkage is relatively large, resulting in voids in the ceramics; dampening of the porcelain (glass) body, uneven pressure, poor cooling and internal stress, and internal stress due to the difference in thermal expansion coefficient of the porcelain body, cement, and metal fittings. Cracks; manufacturing process defects; aging during storage, transportation, installation, and operation, external mechanical stress, and electrical effects. Due to the presence of poor quality insulators, extreme conditions can cause insulators to break strings. When the string of insulators is subjected to extreme electrical conditions, it will lead to a complete breakdown of the deteriorating insulator head. The system's ground short-circuit current passes through the interior of the steel cap. During the off time, the gas in the micro-cracks expands rapidly, causing the steel cap to burst, causing the insulator to break down.
When the effective dry arc distance is small, it is easy to break through the insulation and cause line failure when the line is struck by a lightning strike.
2.2 Insulator Failure Prevention Measures (1) Try to avoid misuse of unqualified insulators.
(2) To reduce the damage to the external force during the installation process of the insulator and to perform the quality inspection before the installation.
(3) Strengthen circuit inspection, regularly clean insulators or replace problem insulators.
(4) Understand the development history of insulators and use them properly.
Porcelain insulators have a history of more than 100 years. Due to their good insulation properties and flexible assembly, they have been widely used in overhead transmission lines and have made important contributions to the development of the power industry. However, when the qualification insulator produces a zero value, there is no difference in appearance, and the concealment is large. Therefore, it is necessary to periodically detect the zero value, and it takes a lot of manpower and material resources, and a missed detection is likely to occur in the detection. With the continuous expansion of the power grid, this type of insulator has gradually been phased out.
Tempered glass insulators have excellent electromechanical properties, and their tensile and impact resistance capabilities are far greater than those of porcelain insulators. They are superior to porcelain insulators in terms of vibration fatigue resistance, arc burn resistance, and resistance to cold and heat shock. They have zero self-burst characteristics and are easy to use. Found in the line inspection, timely replacement, is widely used in transmission lines. However, such bell-type insulators are subject to certain limitations due to factors such as difficulty in cleaning and poor self-cleaning properties.
The composite insulator has the advantages of light weight, high strength, high anti-fouling ability, convenient operation and maintenance, no breakage, and no manual cleaning (due to its hydrophobic type on the surface of the silicone rubber, it can keep it dry and adhere to the umbrella skirt. Things are easy to be washed by water and other advantages, greatly reducing the cost of operation and maintenance, can receive good economic benefits, a large number of popular use in transmission lines.
3. Reasons for the breakage of overhead lines and preventive measures 3.1 Causes of breakage of overhead lines During the operation of overhead lines, the overhead line breaks due to the influence of breeze vibration, galloping, electrical action and aging. Among them, breeze vibration is the most common and the threat is particularly prominent.
The time during which the wire generates breeze vibration in one year accounts for about a year-round vibration. As a result, the overhead line is repeatedly folded at the suspension point, causing the wire to fatigue, resulting in broken strand breakage. The wind speed required for this vibration is relatively small, usually in the range of 0.5-10 m/s. The wire dancing is usually generated under the conditions of winter wire icing and wind excitation, and the cause is complex. It is almost impossible to occur in the Guangdong area.
3.2 Preventive measures for breakage of overhead lines Reasonably install anti-vibration hammers or damping wires, strictly control the installation quality, and strictly check and accept to prevent the occurrence of anti-vibration hammers or damping line movement and drop. Conduct scientific inspection and maintenance of the line and timely supplement the dropped anti-vibration hammer or damping wire.
4. Causes of external force damage failure and preventive measures 4.1 Causes of external force damage failure The operating environment of overhead transmission lines is very special, it will inevitably be subjected to mechanical impact foundation or towers, flood erosion foundation and cable, construction machinery bump line, tower material cable stolen, etc. External forces destroy the situation. In severe cases, it will lead to failure of the tower collapse. Once the collapse of the tower collapse occurs, it takes a long time to repair and is difficult, resulting in serious consequences.
4.2 Failure Prevention Measures for External Force Failure (1) Protective measures such as anti-collision and anti-rainwater flushing facilities shall be provided in accordance with the site conditions at each stage of the line construction and operation.
(2) Reasonable application of anti-theft bolt technology.
(3) Strengthen circuit inspection, maintenance and comprehensive management.
(4) Do not miss the opportunity to do a good job in line protection and propaganda work, such as setting up warning signs at excavation and large-scale machinery operations near the line.
(5) Timely rectification of poles and towers that have been difficult to meet operational requirements for a long time.
5. Causes of bird damage and preventive measures 5.1 Bird damage Causes Bird damage is also an important cause of line failure. Since overhead transmission lines are mostly located in the wild, it is easy to incur birds to nest or inhabit on poles and towers. Birds or debris that birds bring to poles and poles and bird droppings on insulators of poles and towers can easily cause line tripping.
5.2 Bird damage prevention measures (1) Increase the number of line inspections in the bird gathering area and handle the bird nest at any time.
(2) Set up bird-fighting measures, such as selecting a part of a tower to install bird thorns or an artificial bird's nest on a transmission line.
6. Causes of failures caused by design reasons and preventive measures The designer's negligence or the quality of personnel caused the design to be unreasonable, or the lack of understanding of micro-topography and micro-meteorology, and the failure to adopt conventional design methods in micro-meteorological micro-meteorological points caused line failures. . Although there are few micro-meteorological meteorological points on overhead transmission lines passing through the micro-topography, once passed, if the design is incorrect, it may bring about the failure of inverted towers.
The micro-meteorological micro-meteorological point can be understood as that in the atmosphere near the surface, under the influence of systemic weather patterns, due to the influence of terrain and other factors, the climatic factors of a certain location are particularly enhanced, exceeding the ice and wind conditions in the design area of ​​the area, and thus Locations that may jeopardize the safe operation of transmission lines, such as dugouts of mountain formations, high mountain watersheds, waterways of larger rivers and lakes, sudden elevations of terrain, and mountain valleys.
In addition to the strict control of design, the timely implementation of technological reform measures found after the operation can not meet the design due to design reasons improve.
7. Concluding remarks In summary, the safety of operation and maintenance of overhead transmission lines requires unremitting efforts in all aspects. With the extensive exchanges between domestic and foreign industries, constant exploration and practice of professionals, the reliability indicators for operation and maintenance of overhead transmission lines will be raised to a higher level.
1. Causes of lightning damage and preventive measures 1.1 Causes of lightning damage Lightning is the most common type of overhead transmission line, with complex causes and difficulties in prevention. In Guangdong Province, the climate is humid, there are many mountains and forests, and there are more thunderstorms. The density of lightning on the ground is high, and the probability of lightning strikes on the lines is high.
1.2 Lightning Prevention Measures For the prevention of lightning hazards, the integrated prevention and control method is adopted, ie, strengthening electrical insulation, installing lightning conductors, reducing the tower grounding resistance, installing automatic reclosing devices, and strengthening the inspection and maintenance of grounding devices. To deal with the poor grounding in the line, use scientific methods to detect lightning subdivisions, and install lightning arresters on lightning-intensive sections. Among them, it is most important to strengthen electrical insulation. This will be discussed in detail in the breakdown of insulators.
2. Insulator fault causes and preventive measures 2.1 Insulator faults are mainly caused by poor quality insulators, insulator flashes, and low effective dry arc distances. The main causes are poor porcelain (glass) body roasting during the manufacturing process of insulators and cement adhesives. Dry shrinkage is relatively large, resulting in voids in the ceramics; dampening of the porcelain (glass) body, uneven pressure, poor cooling and internal stress, and internal stress due to the difference in thermal expansion coefficient of the porcelain body, cement, and metal fittings. Cracks; manufacturing process defects; aging during storage, transportation, installation, and operation, external mechanical stress, and electrical effects. Due to the presence of poor quality insulators, extreme conditions can cause insulators to break strings. When the string of insulators is subjected to extreme electrical conditions, it will lead to a complete breakdown of the deteriorating insulator head. The system's ground short-circuit current passes through the interior of the steel cap. During the off time, the gas in the micro-cracks expands rapidly, causing the steel cap to burst, causing the insulator to break down.
When the effective dry arc distance is small, it is easy to break through the insulation and cause line failure when the line is struck by a lightning strike.
2.2 Insulator Failure Prevention Measures (1) Try to avoid misuse of unqualified insulators.
(2) To reduce the damage to the external force during the installation process of the insulator and to perform the quality inspection before the installation.
(3) Strengthen circuit inspection, regularly clean insulators or replace problem insulators.
(4) Understand the development history of insulators and use them properly.
Porcelain insulators have a history of more than 100 years. Due to their good insulation properties and flexible assembly, they have been widely used in overhead transmission lines and have made important contributions to the development of the power industry. However, when the qualification insulator produces a zero value, there is no difference in appearance, and the concealment is large. Therefore, it is necessary to periodically detect the zero value, and it takes a lot of manpower and material resources, and a missed detection is likely to occur in the detection. With the continuous expansion of the power grid, this type of insulator has gradually been phased out.
Tempered glass insulators have excellent electromechanical properties, and their tensile and impact resistance capabilities are far greater than those of porcelain insulators. They are superior to porcelain insulators in terms of vibration fatigue resistance, arc burn resistance, and resistance to cold and heat shock. They have zero self-burst characteristics and are easy to use. Found in the line inspection, timely replacement, is widely used in transmission lines. However, such bell-type insulators are subject to certain limitations due to factors such as difficulty in cleaning and poor self-cleaning properties.
The composite insulator has the advantages of light weight, high strength, high anti-fouling ability, convenient operation and maintenance, no breakage, and no manual cleaning (due to its hydrophobic type on the surface of the silicone rubber, it can keep it dry and adhere to the umbrella skirt. Things are easy to be washed by water and other advantages, greatly reducing the cost of operation and maintenance, can receive good economic benefits, a large number of popular use in transmission lines.
3. Reasons for the breakage of overhead lines and preventive measures 3.1 Causes of breakage of overhead lines During the operation of overhead lines, the overhead line breaks due to the influence of breeze vibration, galloping, electrical action and aging. Among them, breeze vibration is the most common and the threat is particularly prominent.
The time during which the wire generates breeze vibration in one year accounts for about a year-round vibration. As a result, the overhead line is repeatedly folded at the suspension point, causing the wire to fatigue, resulting in broken strand breakage. The wind speed required for this vibration is relatively small, usually in the range of 0.5-10 m/s. The wire dancing is usually generated under the conditions of winter wire icing and wind excitation, and the cause is complex. It is almost impossible to occur in the Guangdong area.
3.2 Preventive measures for breakage of overhead lines Reasonably install anti-vibration hammers or damping wires, strictly control the installation quality, and strictly check and accept to prevent the occurrence of anti-vibration hammers or damping line movement and drop. Conduct scientific inspection and maintenance of the line and timely supplement the dropped anti-vibration hammer or damping wire.
4. Causes of external force damage failure and preventive measures 4.1 Causes of external force damage failure The operating environment of overhead transmission lines is very special, it will inevitably be subjected to mechanical impact foundation or towers, flood erosion foundation and cable, construction machinery bump line, tower material cable stolen, etc. External forces destroy the situation. In severe cases, it will lead to failure of the tower collapse. Once the collapse of the tower collapse occurs, it takes a long time to repair and is difficult, resulting in serious consequences.
4.2 Failure Prevention Measures for External Force Failure (1) Protective measures such as anti-collision and anti-rainwater flushing facilities shall be provided in accordance with the site conditions at each stage of the line construction and operation.
(2) Reasonable application of anti-theft bolt technology.
(3) Strengthen circuit inspection, maintenance and comprehensive management.
(4) Do not miss the opportunity to do a good job in line protection and propaganda work, such as setting up warning signs at excavation and large-scale machinery operations near the line.
(5) Timely rectification of poles and towers that have been difficult to meet operational requirements for a long time.
5. Causes of bird damage and preventive measures 5.1 Bird damage Causes Bird damage is also an important cause of line failure. Since overhead transmission lines are mostly located in the wild, it is easy to incur birds to nest or inhabit on poles and towers. Birds or debris that birds bring to poles and poles and bird droppings on insulators of poles and towers can easily cause line tripping.
5.2 Bird damage prevention measures (1) Increase the number of line inspections in the bird gathering area and handle the bird nest at any time.
(2) Set up bird-fighting measures, such as selecting a part of a tower to install bird thorns or an artificial bird's nest on a transmission line.
6. Causes of failures caused by design reasons and preventive measures The designer's negligence or the quality of personnel caused the design to be unreasonable, or the lack of understanding of micro-topography and micro-meteorology, and the failure to adopt conventional design methods in micro-meteorological micro-meteorological points caused line failures. . Although there are few micro-meteorological meteorological points on overhead transmission lines passing through the micro-topography, once passed, if the design is incorrect, it may bring about the failure of inverted towers.
The micro-meteorological micro-meteorological point can be understood as that in the atmosphere near the surface, under the influence of systemic weather patterns, due to the influence of terrain and other factors, the climatic factors of a certain location are particularly enhanced, exceeding the ice and wind conditions in the design area of ​​the area, and thus Locations that may jeopardize the safe operation of transmission lines, such as dugouts of mountain formations, high mountain watersheds, waterways of larger rivers and lakes, sudden elevations of terrain, and mountain valleys.
In addition to the strict control of design, the timely implementation of technological reform measures found after the operation can not meet the design due to design reasons improve.
7. Concluding remarks In summary, the safety of operation and maintenance of overhead transmission lines requires unremitting efforts in all aspects. With the extensive exchanges between domestic and foreign industries, constant exploration and practice of professionals, the reliability indicators for operation and maintenance of overhead transmission lines will be raised to a higher level.
Potassium Binoxalate another name is Potassium Hydrogen Oxalate, PBO.
It is white crystals,soluble in water, slightly soluble in ethanol, produced by excess Oxalic Acid and potassium carbonate or potassium chloride and other potassium salts.The commonly crystal size include 0.1mm - 0.8 mm, 0.5 m -2.17 mm, 0.5 mm- 3 mm,2mm-4mm, 2 mm- 15 mm etc.
Uses:
Potassium Binoxalate mainly used for Marble & Granite polishing, environmental Coatings manufacture, metal polishing and rust cleaning, chemical reagent.
Hydrogen Oxalate,Potassium Binoxalate,Potassium Bioxalate,Potassium Hydrogen Oxalate
Yucheng Jinhe Industrial Co.,Ltd , https://www.hntitaniumdioxide.com