During the construction of new power lines, transformer substations or reconstruction, expansion, re-equipment with new technical means, the design of electrical networks is first performed. Drawings, plans, load calculations are performed taking into account current standards. The rules provide requirements that ensure reliable operation of networks, auxiliary units and structures, reliable provision of consumers, increase of technical indicators and quality of electric energy produced. Electric networks include lines from which energy is supplied to urban and agricultural consumers, including utilities, enterprises and organizations of the production, household and cultural sectors.
Requirements for agricultural electrical networks
The direction of development of electric networks of rural consumers contains mainly questions of the construction of lines with a voltage of 35-110 kW. They are based on sectional lines with one main voltage circuit and mutual reserve, operating from transformer complex substations. Mutual reserve lines are powered by the inputs of various substations. If the power is supplied from one transformer, then the norms of technological design of electric networks allow connecting to different systems of one substation. If necessary, backup power is connected automatically.
New substations under construction are connected to the outdoor switchgear of the operating substation by dissecting the power lines or by branch circuit taking into account the capacity of the existing network. If the new and old lines follow in parallel, then the issue of converting an existing transformer to an increased voltage is considered.
Transformer Substation Requirements
Substations of transformer equipment are intended for use by complete sections of industrial manufacture and closed form made of brick, reinforced concrete panels and blocks.
The project is based on unified designs and standard units, and it is allowed to design devices that are subject to industrial development if they are delivered by the time installation begins. Design of electrical networks implies an indication in the documentation of the delivery time. A wide variety of sizes of used building structures is not allowed, the minimum amount is used.
Decisions are made on the basis of the parameters of power grids, cost-effective design schemes after comparing several options. Preference is given to the design that provides the lowest cost. Technical parameters of electrical networks are selected in accordance with the power flows in all operating modes.
Estimated losses are taken based on the acceptable values of voltage losses at the input of the receiver and the permissible voltage indicator in the central power supply system. If there are no technical data for calculating the allowable losses, then for the calculation of utility networks, voltage consumption is 8%, production lines - 6.5%, livestock complexes - 4% of the nominal indicator.
The loads are determined taking into account all consumers of electricity that are powered by the designed transformer. Loads are accepted with a prospect of 10 years, the definition of the wire and cable cross-section is made for 5 years from the moment of commissioning. If the project has lain for three years and has not been implemented, then the construction of electric networks is not carried out on it, the documentation is being reviewed.
Reliability indicators of electrical supply
Electric receivers of non-agricultural consumers powered by agricultural networks are divided into categories depending on the requirements for the reliability of electrical supply. Reliability standards for each category are set out in departmental documents and are determined by the type of consumer input device.
The design of a rural electric network depends on the category of consumers of agricultural production, municipal and household supplies. Their subdivision into categories 1 and 2 is given in the form of a list in the guidelines for providing electricity to agricultural electrical receivers.
If consumers are not included in the list, then they are assigned to 3 categories. Power supply of the first two categories is provided by two interchangeable transformers, independent of each other. The interruption of their electricity supply does not exceed the time of automatic power recovery. To do this, an automatic backup power supply is provided at the input to the consumer.
Centralized power supply provides a second power source in the form of a substation with two transformers or two bus sections of the same substation. If the consumer is in remote access, then an autonomous backup power transformer is installed for him. For unforeseen backup power supply of the receivers of the first two categories, which do not allow interruptions of more than 0.5 hours, the design of electrical networks provides a backup source of autonomous supply, regardless of the external power supply on the main lines.
General norms
The design of the structural part and the general plan is carried out taking into account the final point of development of the substation, determined by the situational perspective at the time of design. Design of electrical networks is carried out according to the norms of the Land Code. Such papers include decisions of local councils of the appropriate level on the seizure of land from owners for the construction of energy complexes.
Electrical network design uses the following information:
- customer requirements for connecting the substation to the energy system;
- requirements of electrical appliances when connected to utilities;
- requirements of land owners in relation to the transformer and networks;
- standards of architectural and planning solutions;
- loads and their distribution by stages of substation development taking into account voltages and categories of users;
- technical data on ultimate loads of the transformer;
- estimated data on the total power of transformers and their numbers;
- requirements for the construction of the connecting circuit;
- Methods for adjusting the voltage across the tires of a transformer substation.
Sources of the above data
The design of power supply to obtain the above requirements uses the following documents:
- schemes of energy development of electric lines and technical characteristics of the external power supply of the facility;
- terms of technical connection of the energy supply company;
- documentation on the alienation of land for construction;
- technical parameters of the customer’s task.
If there is no possibility of obtaining data from the primary sources or the information is outdated, then the engineering workers make the necessary calculations and determine the missing information at the preliminary stage of construction.
Design of electrical networks and systems, thermal power plants includes the following buildings and structures:
- production facilities and workshops, the main building, electrical buildings, water supply and heating systems, gas and oil installations;
- buildings and constructions for auxiliary and industrial purposes, start-up boiler houses, storage buildings, administrative and domestic premises, workshops and oil refueling;
- auxiliary facilities, railways, stations, depots, garages;
- wastewater treatment plants, fences, roads, roads, land improvement, temporary buildings and bomb shelters.
Design work is carried out by specialists of a high technical level, the project provides for highly economical devices and equipment. Technical solutions are based on ensuring reliability, saving investment and the cost of further operation.
Technological equipment is located and assembled with the condition of providing convenient maintenance and repair, the desire for complete mechanization and a decrease in the share of manual work. Instructions for the design of electrical networks prescribe the rooms of staff and change houses in rooms separated by walls from working equipment. Technological pipes are not laid inside, with the exception of water supply, sewage, heating and ventilation.
Management and automation
At modern power plants, control methods are provided using an automated control system that allows you to systematize work from a remote location, regulate the operations of calculation, alarm, protection, urgent communication. The scope of work on control is adopted in the project in accordance with the instructions of departmental guidance documents.
The volume of management operations is determined based on the direction of automation, the tasks of technological processes at startup, load changes and shutdowns of individual units or the entire system. Automatic control posts are of various types: controlling block power plants, high-voltage lines and transformers with transverse connections.
Block power plants are controlled from the central panel of compact distribution stands, control panels of auxiliary office premises, general stationary installations of the compressor substation.
Land conservation measures
Electrical substations are located on the lands of private and municipal plots in accordance with the law on land legislation, a collection of acts on the protection of natural resources, building codes and rules. The place of the future site is selected taking into account the binding to the scheme of the existing layout and general plan of the industrial enterprise.
The design of the district electric network takes into account the fact that for the location of substations and electric networks use non-agricultural land and land with low productivity. During the construction process, the fertile soil layer is cut and preserved, which subsequently restore unproductive land.
Compensation for used agricultural land is provided to the owners of the plots involved. If land is allocated for temporary use, then in the future this soil is subject to secondary cultivation. Buildings in the areas allocated for the construction of power plants are located sparingly, the arrangement of utility services in multi-storey buildings prevails. New buildings do not block existing production and domestic facilities.
Design of distribution electric networks takes place in strict accordance with the building density standards given in SNiP. The areas provided for in the project for further expansion of electric networks are determined in accordance with the design assignment and economic justification. The areas of ash and slag dumps are calculated taking into account the further use of materials for fertilizer in the national economy.
The entrances and roads to the buildings of the substation economy are designed on the same land allotment strip, utilities, heating lines, water supply and sewage channels are compactly installed, passing pipes do not violate the boundaries of agricultural land.
Airspace Protection
For this purpose, when drafting the project, measures and special devices are envisaged that ensure the reduction of the content of dust and harmful substances in the aboveground atmosphere to indicators of sanitary standards. This condition is provided in various indicators of the transformer substation, including the highest power mode.
Water protection measures
Wastewater treatment plants are being built to protect water bodies from pollution by wastewater entering them. These facilities are built taking into account sanitary standards. The method of processing waste industrial water is selected depending on the specific operating conditions of the designed station. High-voltage lines are built at distances specified in standards from water bodies.
The cleaning method is affected by the type of equipment used and its power. The mode of use, the type of fuel, the method of removing combustion products, the cooling system, climatic conditions and other technical indicators are taken into account. The designed effluent discharge is coordinated with the services of the state sanitary supervision, protection of fish ponds and other bodies.
Transport movements
Transport of external and internal movement of goods for the operation of the substation is designed based on a comparison of the technical and economic indicators of the options. Conveyor, rail, water, road or air transportation is used. Delivery of workers from the place of residence to the work area is carried out by the most efficient mode of transport, which allows spending the least amount of time.
The transportation of goods and passengers to transformer substations located in industrial areas is tied to the general scheme of existing modes of transport and the project for the development of routes for future periods. There is a mutually beneficial cooperation of transportation with neighboring operating and designed enterprises.
Reception, supply and storage of fuel oil, gas, oil
The daily need for fuel oil is calculated based on the operation of all boilers with their normal performance for 20 hours of operation. If the average temperature of the coldest month of the year is taken into account, then the calculation is carried out for 24 hours. Solid fuel power plants are designed taking into account the construction of a kindling unit. If hot water peak boilers are used, then their economy is combined with a kindling device.
The design of the electrical networks of the enterprise is made taking into account the supply of fuel to the starting boiler room from the main or secondary fuel oil unit. If the use of gas is foreseen as the main fuel, then a gas control station is designed as part of the boiler room. The distribution unit is located in the substation in a separate building or under a canopy.
Gas fuel consumption is determined from the calculation of the maximum consumption for all boilers. Gas supply is carried out separately for each distribution point; backup pipelines are not planned. The number of control devices in each distribution point is provided for one more, which is a backup.
Power plants are equipped with transformer and turbine oil facilities . The farm includes storage tanks for fresh and used product, pumping devices, drying plants, and recovery equipment. During the pouring of transformers, mobile degassing plants are used, protected by nitrogen or film material. Four substations of turbine oil and transformer are installed in the substation complex, two tanks are separately provided for storing engine oil lubrication.
Home Power Project
The project develops an external electrical supply for residential and public buildings, internal wiring is not included in its composition. Typical projects are designed to connect electrical power to consumers with a standard layout. If the location of the courtyard buildings is far from the standard solution, then the project is revised taking into account these changes.
The electricity supply project of the apartment is mainly used in new buildings, in which the construction company must make the minimum number of connection points. There is a kind of project, which is called individual, which allows you to include in the development of external, internal and economic power supply. Economic supply of electricity allows the functioning of communication and air conditioning systems.
Procedure for registration of a project
The electricity supply project of the apartment basically contains technical conditions. , . :
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