Free technical library

Section 2. Electrical equipment and electrical installations for general purposes

Chapter 2.4. cable lines

Encyclopedia of radio electronics and electrical engineering / Rules for the technical operation of consumer electrical installations (PTE)

Comments on the article

2.4.1. This chapter applies to power cable lines with voltages from 0,4 to 220 kV.

2.4.2. When commissioning cable lines with voltages up to and above 1000 V, in addition to the documentation provided for by building codes and regulations and industry acceptance rules, the following technical documentation must be drawn up and transferred to the customer:

In addition to the above documentation, upon acceptance into operation of cable lines with a voltage of 110 kV and above, the installation organization must additionally transfer to the customer:

2.4.3. Upon acceptance into operation of a newly constructed cable line, tests must be carried out in accordance with the requirements of the rules for the installation of electrical installations.

2.4.4. The consumer who owns the cable lines (operating organization) must conduct technical supervision of the laying and installation of cable lines of all voltages constructed by installation organizations.

When supervising the laying and operating unarmored hose-covered cables, special attention must be paid to the condition of the hoses. Cables with rips, tears, and cracks in hoses must be repaired or replaced.

2.4.5. Each CL must have a passport, including the documentation specified in clause 2.4.2, dispatch number or name.

Openly laid cables, as well as all cable boxes, must be tagged; cable tags at the beginning and end of the line must indicate the brand, voltage, section, number or name of the line; on the tags of the couplings - the number of the coupling, the date of installation.

Labels must be resistant to environmental influences. They should be located along the length of the line every 50 m on openly laid cables, as well as on the turns of the route and in places where cables pass through fire-resistant partitions and ceilings (on both sides).

2.4.6. For each CL during commissioning, the highest permissible current loads must be set. Loads must be determined for a section of the route with a length of at least 10 m with the worst cooling conditions. An increase in these loads is allowed on the basis of thermal tests, provided that the core temperature is not higher than the long-term permissible temperature given in state standards or technical conditions. At the same time, the heating of the cables should be checked in sections of the routes with the worst cooling conditions.

2.4.7. In cable structures and other premises, systematic monitoring of the thermal regime of cables, air temperature and the operation of ventilation devices should be organized.

The air temperature inside cable tunnels, channels and shafts in the summer should be no more than 10 degrees. With higher outdoor temperature.

2.4.8. For the period of liquidation of the accident, overcurrent is allowed for cables with impregnated paper insulation with a voltage of up to 10 kV by 30% for a duration of not more than 6 hours per day for 5 days, but not more than 100 hours per year, if in the remaining periods of these days the load does not exceed long-term acceptable.

For cables that have been in operation for more than 15 years, overloads should be reduced to 10%.

Overloading of cables with impregnated paper insulation with a voltage of 20 and 35 kV is not allowed.

2.4.9. For the period of liquidation of the accident, current overloads are allowed for cables with insulation made of polyethylene and PVC by 15% and for cables with insulation made of rubber and vulcanized polyethylene by 18% for a duration of not more than 6 hours per day for 5 days, but not more than 100 hours per year, if in the remaining periods of these days the load does not exceed the long-term allowable.

For cables that have been in operation for more than 15 years, overloads should be reduced to 10%.

2.4.10. Overloading of 110 - 220 kV low and high pressure oil-filled cables must be established by local regulations, taking into account the requirements of national standards.

2.4.11. For each CL of oil-filled cables or its section with a voltage of 110 - 220 kV, depending on the profile of the line, local instructions must establish permissible limit values ​​​​of oil pressure, in case of deviations from which the CL should be turned off and turned on only after identifying and eliminating the causes of violations.

2.4.12. Oil samples from oil-filled cables and liquid from the terminations of cables with plastic insulation with a voltage of 110 kV and above should be taken before putting a new line into operation, 1 year after switching on, then after 3 years and thereafter every 6 years. The values ​​of the controlled parameters of oil and liquid must comply with the standards for testing electrical equipment (Appendix 3).

2.4.13. In the event of a single-phase ground fault in networks with an isolated or compensated neutral, the personnel must immediately inform the person on duty at the supply substation or the person on duty at the network of the power supply organization and continue to act on their instructions.

2.4.14. The CL loads must be measured periodically within the time limits established by the electrical equipment testing standards (Appendix 3). Based on the data of these measurements, the modes and schemes of CL operation should be specified.

2.4.15. Inspections of cable lines with voltage up to 35 kV should be carried out within the following periods:

2.4.16. Inspections of cable lines with a voltage of 110 - 220 kV should be carried out:

For cable lines laid openly, inspection of cable boxes with voltages above 1000 V should be carried out at each inspection of electrical equipment.

2.4.17. Periodically, but at least once every 1 months, selective inspections of the CL should be carried out by administrative and technical personnel.

During the period of floods, after showers and when the CL is turned off by relay protection, extraordinary inspections should be carried out.

Information about faults discovered during inspections should be recorded in the log of defects and malfunctions. Faults must be rectified as soon as possible.

2.4.18. Inspection of tunnels (collectors), shafts and channels at substations with constant personnel duty must be carried out at least once a month, inspection of these structures at substations without constant personnel duty - according to local instructions within the time limits established by the Consumer responsible for electrical facilities.

2.4.19. Local instructions should establish terms for checking the operability of fire alarm and fire extinguishing devices located in cable structures.

2.4.20. Tunnels, collectors, channels and other cable structures must be kept clean, metal non-galvanized armor of cables laid in cable structures, and metal structures with a non-metallized coating along which cables are laid must be periodically coated with non-combustible anti-corrosion compounds.

Storage in cable structures of any materials is not allowed.

Cable structures into which water enters must be equipped with means for draining soil and storm water.

2.4.21. In areas with electrified rail transport or aggressive soils, stray current measurements should be carried out on the cable lines, potential diagrams of the cable line (or its individual sections) and maps of soil corrosion zones should be compiled and systematically corrected. In cities where joint anti-corrosion protection is organized for all underground utilities, the removal of potential diagrams is not required.

Cable potentials should be measured in stray current zones, places where power cables approach pipelines and communication cables with cathodic protection, and in cable sections equipped with corrosion protection installations. On cables with hose protective covers, the state of the anti-corrosion coating should be monitored.

2.4.22. The consumer, in charge of the cable lines, must control the implementation by the departments and services of electrified rail transport of measures to reduce the values ​​​​of stray currents in the ground in accordance with the established requirements.

If a danger of destruction of metal shells due to electrical, soil or chemical corrosion is detected on the cable, measures must be taken to prevent it.

Protective devices on cable lines must be monitored in accordance with local regulations.

2.4.23. Excavation of cable routes or earthworks near them should be carried out only after obtaining the appropriate permission from the management of the organization through which the cable line passes, and the organization operating the cable line. The permit must be accompanied by a plan (scheme) indicating the placement and depth of the cable lines. The location of the CL must be indicated by appropriate signs or inscriptions both on the plan (scheme) and at the place of work. At the same time, the contractor must ensure the safety of the cables for the entire period of work, and strengthen the opened cables to prevent them from sagging and protect them from mechanical damage. Signal lights and warning posters must be installed at the work site.

2.4.24. Before the start of excavations, the cable line should be drilled (control opening) under the supervision of the electrical personnel of the Consumer operating the cable lines to clarify the location of the cables and their depth.

If pipelines, unknown cables or other communications not indicated in the diagram are discovered during the excavation of an earthen trench, it is necessary to suspend work and notify the person responsible for electrical facilities about this. Digging trenches and pits at the locations of cables and underground structures should be done with extreme caution, and at a depth of 0,4 m or more - only with shovels.

2.4.25. In winter, excavations to a depth of more than 0,4 m in places where cables pass should be carried out with soil heating. At the same time, it is necessary to ensure that a layer of soil with a thickness of at least 0,15 m remains from the surface of the heated layer to the cables. The thawed soil should be discarded with shovels.

The use of crowbars and similar tools is not allowed.

2.4.26. Excavation by earthmoving machines at a distance closer than 1 m from the cable, as well as the use of jackhammers, crowbars and picks to loosen the soil above the cables to a depth at which a soil layer of less than 0,3 m remains before the cable, is not allowed.

The use of impact and vibro-submersible mechanisms is allowed at a distance of at least 5 m from the cables.

Additional specifications must be issued for blasting operations.

2.4.27. The owner (balance holder) of the cable lines and the operating organization must periodically notify the organizations and the population of the area where the cable routes pass, about the procedure for earthworks near these routes.

2.4.28. CLs must be periodically subjected to preventive tests with increased DC voltage in accordance with the standards for testing electrical equipment (Appendix 3).

The need for extraordinary testing of cable lines, for example, after repair work or excavations related to the opening of routes, as well as after automatic shutdown of cable lines, is determined by the management of the Consumer in charge of the cable line.

Testing of cable lines with a voltage of 110 - 220 kV is carried out only with the permission of the power supply organization.

2.4.29. To prevent electrical breakdowns on vertical sections of cables with a voltage of 20 - 35 kV due to drying of the insulation, it is necessary to periodically replace them or install locking couplings.

For cable lines with a voltage of 20 - 35 kV with cables having a non-draining impregnating mass and plastic insulation, or with gas-filled cables, additional monitoring of the insulation of vertical sections and their periodic replacement is not required.

2.4.30. Samples of damaged cables and damaged cable boxes during electrical breakdown of insulation in operation or during preventive tests should be subjected to laboratory studies to determine the causes of damage and develop measures to prevent them. When claims are made to manufacturers, damaged samples with factory defects must be kept for examination by experts.

See other articles Section Rules for the technical operation of consumer electrical installations (PTE).

Read and write useful comments on this article.

<< Back

Latest news of science and technology, new electronics:

Machine for thinning flowers in gardens 02.05.2024

In modern agriculture, technological progress is developing aimed at increasing the efficiency of plant care processes. The innovative Florix flower thinning machine was presented in Italy, designed to optimize the harvesting stage. This tool is equipped with mobile arms, allowing it to be easily adapted to the needs of the garden. The operator can adjust the speed of the thin wires by controlling them from the tractor cab using a joystick. This approach significantly increases the efficiency of the flower thinning process, providing the possibility of individual adjustment to the specific conditions of the garden, as well as the variety and type of fruit grown in it. After testing the Florix machine for two years on various types of fruit, the results were very encouraging. Farmers such as Filiberto Montanari, who has used a Florix machine for several years, have reported a significant reduction in the time and labor required to thin flowers. ... >>

Advanced Infrared Microscope 02.05.2024

Microscopes play an important role in scientific research, allowing scientists to delve into structures and processes invisible to the eye. However, various microscopy methods have their limitations, and among them was the limitation of resolution when using the infrared range. But the latest achievements of Japanese researchers from the University of Tokyo open up new prospects for studying the microworld. Scientists from the University of Tokyo have unveiled a new microscope that will revolutionize the capabilities of infrared microscopy. This advanced instrument allows you to see the internal structures of living bacteria with amazing clarity on the nanometer scale. Typically, mid-infrared microscopes are limited by low resolution, but the latest development from Japanese researchers overcomes these limitations. According to scientists, the developed microscope allows creating images with a resolution of up to 120 nanometers, which is 30 times higher than the resolution of traditional microscopes. ... >>

Air trap for insects 01.05.2024

Agriculture is one of the key sectors of the economy, and pest control is an integral part of this process. A team of scientists from the Indian Council of Agricultural Research-Central Potato Research Institute (ICAR-CPRI), Shimla, has come up with an innovative solution to this problem - a wind-powered insect air trap. This device addresses the shortcomings of traditional pest control methods by providing real-time insect population data. The trap is powered entirely by wind energy, making it an environmentally friendly solution that requires no power. Its unique design allows monitoring of both harmful and beneficial insects, providing a complete overview of the population in any agricultural area. “By assessing target pests at the right time, we can take necessary measures to control both pests and diseases,” says Kapil ... >>

Random news from the Archive A device that mimics the brain 09.12.2018 Emulation of the human brain is one of the cornerstones of the development of artificial intelligence. The new study by scientists from the Department of Applied Science and Technology of the Polytechnic University of Turin is a step forward in this direction. Experts have created a new device of minimal size to artificially reproduce the connection between neurons. Brain emulation is the process of full-scale simulation of the main organ of the central nervous system, in other words, "uploading the mind into a computer." One of the greatest challenges scientists have ever faced is trying to artificially replicate signal processing in the human brain. Typically, neural networks can only be modeled in a very cumbersome and inefficient way using sophisticated hardware. The work of Italian scientists has shown how it is possible to artificially simulate the activity of synapses (that is, contacts between neurons that regulate learning processes in our brain) in a single nanowire, more than a thousand times thinner than a human hair. An expert-designed nanowire made from zinc oxide crystals takes the memristor (an electronic device capable of artificially reproducing the functions of biological synapses) to a new level of performance. Thanks to the use of nanotechnology, which allows you to control matter at the atomic level, for the first time it became possible to combine in one device synaptic functions that were previously reproduced only individually through separate devices. The nanowire makes it possible to significantly minimize the size of the memristor, reducing the complexity and power consumption of the electronic circuits required to implement learning algorithms. According to scientists, the new technology paves the way for the development of neuromorphic chips that can mimic the functioning of the human brain, while being small and energy efficient.

Other interesting news:

▪ Magnetic GPS in salmon noses

▪ Spent spacecraft stages are returning

▪ Smell dementia

▪ The effectiveness of exercise depends on the time of day

▪ Indian village of twins

News feed of science and technology, new electronics

Interesting materials of the Free Technical Library:

▪ section of the Electrician website. Article selection

▪ article by Amos Bronson Alcott. Famous aphorisms

▪ article What is life? Detailed answer

▪ article Automotive flameless combustion heater. Personal transport

▪ article Theory: 3H preamplifiers. Encyclopedia of radio electronics and electrical engineering

▪ article Power transformers Chamber of Commerce and Industry addition. Encyclopedia of radio electronics and electrical engineering

Leave your comment on this article:

All languages ​​of this page

Arabic	Hebrew	Polish
Bengali	Hindi	Portuguese
Chinese	Italian	Spanish
English	Japanese	Turkish
French	Korean	Ukrainian
German	Malay	Vietnamese

Home page | Library | Articles | Website map | Site Reviews

www.diagram.com.ua
2000-2024