Verification ground settlement

 

As measures to ensure electrical safety in LC and the operation of the equipment in the event of contact with live parts of metallic equipment become live due to the breakdown of the insulation of the grounding station equipment.

As a natural process using a metal grounding design, partially submerged in the ground, its calculated resistance spreading R = 49 ohms (water or other metal pipes). Grounding is supposed to perform the rod electrodes of the vertical length l m, a diameter of 5.6 mm or 40x40 mm steel angle, the upper ends of which are interconnected by a horizontal electrode length l m - steel strip section 4x12 mm, laid in the ground at a depth of 0.8 m. Specific earth resistance is 6 ohms:

 

р= 140 Ohm*m

 

The soil is clay, soil category 2.

Required spreading resistance grounding for the station should not exceed 2.4 ohms:

=125/I_g (4.10)

 

where - current ground fault current is equal to:

 

=

Define the required grounding resistance artificial:

 

(4.11)

 

where - the spreading resistance of the natural grounding, the Ohm.

 

Ohm

Grounding switch type is selected in-line placed along the building where the station is located and LATS. Thus vertical electrodes arranged at a distance a = 5 m from each other.

Specify the parameters of the grounding switch by checking calculations. From the preliminary scheme it shows that we have adopted the total value of the grounding electrode of the horizontal and vertical number of electrodes n = 12. We calculate the estimated horizontal electrode resistance value (combined resistance) .

One vertical electrode according to the following formulas:

 

(4.12)

 

Where , d = 0,5 * b for band width b.

For a selected electrode t = ½ + t o

 

t = 5/2+0,8=3,3 м

 

 

Then we determined by the formula 4.3

Calculate R1 according to formula 4.5

 

 

Furthermore, bearing in mind that the earthing is adopted in a row that

n = 12 units, define the tables use the coefficients of earth (9).

 

 

We calculate the estimated resistance of the group earthing R th, according to the formula:

 

 

Rh =

where Rv and Rh - spreading resistance of the vertical and horizontal electrodes, Ohm; n - number of vertical electrodes.

This resistance is less than a given r and Ri= 2.85 ohms; that provides security.

And so the projected grounding is located in one row consists of 12 vertical rod electrode length of 5 m and a diameter of 5-6 mm. And a horizontal electrode of the steel strip section length 60 m 4 * 12 mm, buried in the ground of 0.8 m. The ground conductor is attached to the apparatus reliable bolting and welding, to the earth electrode.

 

 

Environmental protection

General

 

When designing the building and reconstruction of cable lines must be carried out environmental safety requirements and protect public health, prescribe measures for nature conservation, sustainable use of natural resources, improvement of the environment.

To eliminate and redress the damage caused to the natural environment and the occurrence of adverse environmental impacts, particularly in the most vulnerable and dangerous areas (national parks and national parks, the migration places of animals, spawning fish of valuable species, coastal sea areas, rivers, permafrost, mountain terrain with scree and stone-fall events, etc.), in the construction of outside plant communication shall be provided environmental measures or means to compensate for the damage caused.

In the absence of local road communications cable line runs should, if possible, be placed on non-agricultural land or unsuitable for agriculture, as well as on forest land due to uncovered areas of forest plantations occupied little value, with the maximum use of existing firebreaks. For the construction of cable lines is permitted to provide a higher quality of land. In cases where the cabling is provided internally on arable land, the construction project should take into account the time limit production work for the period required for harvesting.

In the development of trenches and pits for installation on agricultural land (arable land, pastures, etc..) And forestry land by agreement with land users should be provided remediation activities temporarily allocated land for the construction period and the funds for the restoration of topsoil. In the projects construction of cable crossings over water barriers must be provided by measures which exclude the possibility of environmental pollution, as well as ensuring the preservation of fish stocks.

In the design of telecommunication and communication facilities should provide for economical land use and effective means of protecting the environment from pollution. Technical solutions should include the reduction of contamination to an acceptable level or eliminate harmful emissions into the atmosphere. The highest concentration of each harmful substance emissiruemogo now, should not exceed the maximum allowable concentration, to set standards [22].

In addition, in the construction business and communication facilities must be included issues related to recovery (reclamation) of land and bringing it to a condition suitable for further use.

Enterprises and communications facilities are a source of intense radiation fields of radio frequencies, so should be separated from the residential area of ​​sanitary - protective zones whose size is determined by the degree of adverse effects on health and sanitary - hygienic living conditions.

Thus, to address the issues in the design and construction of communication facilities for environmental protection should include technological processes and production equipment, in which there should be no or not exceed the permissible values:

- Selection in the indoor air, the atmosphere and waste water;

- Harmful substances as well as the heat and humidity in the operating room;

- Noise, vibration, ultrasound;

- Electromagnetic fields, optical and ionizing radiation and static electricity.

should be allowed in the development of industrial and technological projects:

- Replacement and production of harmful substances harmless;

- Replacement of processes and process steps associated with the occurrence of noise, vibration and other hazards processes or operations for which there is no, or reduced the intensity of these factors;

- Replacement of the solid and liquid gaseous fuel.

Solution of environmental problems requires careful analysis, a systematic approach to solving the problem, that is, the study of all aspects of their environment, but also the influence of the environment on human society.

In addition to general issues of compliance Safety (rules for the operation of electrical, maintenance, loading and unloading, fire and so on. D.) The construction and operation of fiber-optic transmission systems need to comply with the specific safety requirements, which will be discussed in this chapter.