RU238999U1 - Small-sized concrete complete transformer substation for outdoor maintenance - Google Patents

Abstract

The utility model relates to electrical engineering, namely to the designs of small-sized concrete complete transformer substations (hereinafter MCCPTS) intended for external, outdoor maintenance, which eliminates the need for operating personnel to access the enclosure and ensures increased safety during operational activities - repair, component replacement, emergency situations and operation. The technical result consists in increasing the reliability of the MCCPTS, which leads to an increase in the service life and an increase in the period between repairs. The small-sized complete transformer substation for outdoor maintenance comprises a monolithic reinforced concrete enclosure including: walls, a high-voltage equipment compartment, a low-voltage equipment compartment, a power transformer and an oil receiver compartment, the foundation part of the substation is designed as a cable compartment, wherein the cable compartment has a trapezoidal shape, blind holes are made in the walls of the cable compartment. The concrete oil receiver can be monolithically made in the cable compartment. 2 sec. fil., 4 fig.

Description

The utility model relates to electrical engineering, namely to the design of small-sized concrete complete transformer substations (hereinafter MCCTS), intended for external, outdoor maintenance, which eliminates the need for operating personnel to access the inside of the housing and ensures increased safety during operational activities - repairs, replacement of components, emergency situations and operation.

The substation is suitable for aggressive environments, difficult soils, densely populated areas, and situations where the delivery of large or heavy (over 10 tons) loads is limited and rapid installation is required. The MBKTP meets power requirements of up to 1000 kVA, making it a suitable solution for electrifying most residential, commercial, and industrial facilities. MBKTP are factory-manufactured and require minimal installation costs, significantly reducing facility electrification time.

The prior art discloses complete transformer substations made in a metal housing, for example, a complete transformer substation (see Russian Federation patent for utility model No. 172565, published 2016), comprising a high-voltage compartment, a main metal shell and a power transformer compartment located therein, a low-voltage switchgear compartment with an access door, containing devices for measuring and metering electricity, the said measuring and metering devices are enclosed in at least one additional metal shell located in the main shell and equipped with a separate access door.

The disadvantages of the known solution are due to a short service life due to the low corrosion resistance of the metal casing, and, as a result, unreliability.

An outdoor transformer substation is known (see Russian Federation patent for invention No. 2211513, published in 2003), containing a distribution device in the form of a "line - transformer" cell, in which the first load switch is located, a line connection with a load switch with an earthing switch and fuses and a transformer connection with a disconnector, connecting buses, a frame and a fence, contains a roof connected to the frame by means of a threaded connection, while in said cell opposite the first load switch a second load switch is installed, identical to the first, the upper contacts of the load switches are connected by means of connecting buses, and high voltage is supplied to the lower contacts of the load switches and through fuses and an earthing switch and through said transformer connection is supplied to the high-voltage contacts of the transformer.

The analogue is characterized by ease of operation due to external maintenance and easy access to the equipment; however, the roof of the device is connected to the frame of the transformer substation using a threaded connection, which reduces the reliability of the structure.

A small-sized block transformer substation in a reinforced concrete case is known (the closest analogue, prototype, see the Russian Federation patent for utility model No. 74012, published in 2008), installed on a cable structure, including a wall reinforced concrete block with a floor connected to the roof slab by a bolted connection, compartments for a power transformer, high and low voltage switchgear, openings for input and output of cables to switchgear and draining oil from a power transformer, in order to ensure quality, the installation of electrical equipment is carried out in production conditions, after installation of a small-sized block transformer substation in a reinforced concrete case at the operating site, the connection of the power transformer and connection of the high and low voltage feeder and outlet cables, and the external grounding circuit are carried out.

The existing solution is characterized by internal maintenance, which increases the overall size of the device; the cable compartment is designed as a separate cable structure, and the structure is not monolithic. Furthermore, substations with a service corridor increase the risk of electric shock in cramped spaces, making it difficult to respond to personnel who are electrocuted.

Known solutions use metal oil receivers, which lead to corrosion vulnerability and, as a consequence, the need for periodic renewal of the external protective anti-corrosion coating.

The objectives of the proposed technical solution are: simplifying the delivery and installation of the device, reducing the size of the device due to the absence of a service corridor, creating a functional foundation half-floor (compartment), intended, among other things, for placing an oil receiver, and convenient cable connection.

The technical result consists in increasing the reliability of the MBKTP, which leads to an increase in the service life and an increase in the period between repairs.

The technical result is achieved by a compact, packaged transformer substation for outdoor maintenance comprising a monolithic reinforced concrete enclosure, including walls, a high-voltage equipment compartment, a low-voltage equipment compartment, a power transformer compartment, and an oil receiver. The substation's foundation is designed as a cable compartment. The cable compartment has a trapezoidal shape, with blind openings in the walls of the cable compartment. The oil receiver can be made of concrete. The oil receiver can be integrated into the monolithic structure of the cable compartment.

The longevity and reliability of a substation largely depend on the robustness of its enclosure. Constructing the enclosure from reinforced concrete increases the service life and reliability of the structure due to its sufficient strength and rigidity. A monolithic reinforced concrete enclosure is virtually impervious to environmental damage.

The implementation of a cable compartment with sloping walls and blind openings for cable entry allows for the simplified installation of incoming and outgoing cables "at full height" for the installer from the street, rather than in a cramped cable mezzanine of a similar substation. This, in most cases, affects the quality of the work performed by installers in connecting cables to the elements (equipment) of the substation, which in turn affects the reliability of the equipment and the substation as a whole, and also reduces the number of emergency repairs associated with the reliability of contact connections of cables and substation equipment.

The cable compartment can be designed with a built-in concrete oil receiver (instead of an iron tank or metal oil receivers), which increases the service life of the oil receiver by over 30 years. Also, when integrated into the monolithic cable compartment structure, the concrete oil receiver can serve as a support for power transformers, increasing the structural strength of the cable compartment.

The device is explained by the following description and figures. Fig. 1 shows the external view from the front of the high-voltage switchgear compartment (HVSC), Fig. 2 is a side view of the device, Fig. 3 is a bottom view, Fig. 4 shows one of the possible design options, a sectional view,

where 1 is a monolithic body, 2 is a roof, 3 is a cable compartment, 4 is blind holes for input/output of cables, 5 is a concrete oil receiver, 6 is a power transformer, 7 is a power transformer compartment, 8 is fire partitions, 9 is a high-voltage equipment compartment, 10 is a low-voltage equipment compartment.

Designing a substation for external maintenance only requires access to equipment through external doors and control panels; there are no internal corridors for personnel. Access to switching nodes is through external doors with interlocks.

A small-sized concrete complete transformer substation consists of a monolithic body 1 made of reinforced concrete, which includes walls with openings (for installing doors, gates, gratings), a floor, a cable compartment 3, a power transformer compartment 7, a high-voltage equipment compartment 9, and a low-voltage equipment compartment 10.

The structure is a reinforced concrete shell, including:

- high-voltage equipment compartment 9 for placing vacuum circuit breakers, autogas load switches, disconnectors, fuses, arresters, current transformers;

- low-voltage equipment compartment 10 for placing distribution boards with circuit breakers, load switches, switches with fuses, metering units, and reactive power compensation;

- power transformer compartment 7 is designed for complete insulation of the transformer inside a concrete housing, natural ventilation is provided through ventilation grilles;

- cable compartment 3 (foundation half-floor).

In the compartment of power transformer 7, after the installation of the substation, power transformer 6 is installed by installation specialists.

In the low-voltage switchgear compartment and in the high-voltage (medium) switchgear compartment, the electrical panel equipment is installed at the manufacturing plant in accordance with the design solutions and technical specifications of the customer; fire partitions and electrical buses for connecting the transformer are installed in the low-voltage and high-voltage compartments.

The lower part of the substation, cable compartment 3, serves as the base and has a trapezoidal shape (with beveled corners, preferably at 45°). The walls of cable compartment 3 are designed for cable entry and exit, with recesses (blind holes 4) at least half the base wall thickness deep, allowing cable entry and exit through chrysotile cement pipes to the switchgear. Blind holes 4 are cut using a diamond- or carbide-coated installation tool. Installers insert asbestos-cement pipes into the open holes, then seal the voids. The concrete surfaces (bevels) of the MBKTP are treated with a wear-resistant, fiber-reinforced polymer waterproofing at the points of contact with the ground. This provides additional protection against moisture ingress and maintains the integrity of the waterproofing during excavation work.

When oil is discharged from the transformer, an oil receiver 5 is provided, which can be made of built-in concrete.

The interior finishing of the substation's concrete surfaces can be accomplished using water-based paint, such as E-VA-17 (GOST 281196-89), or similar coatings. Metalwork is finished using GF-021 primers (GOST 25129-82) followed by a coat of anti-corrosion enamel. Equipment painting is performed in accordance with GOST 14695-80. The customer determines the exterior finish of the substation's concrete surfaces, including the specific color and texture, during the approval process for the substation's production.

The roof of the 2nd MBT is waterproofed—it's treated with a wear-resistant, fiber-reinforced polymer waterproofing that's UV-resistant. This provides additional protection against moisture ingress and maintains the waterproofing's integrity during operation. This type of waterproofing completely prevents roof leaks during adverse weather conditions.

The substation is installed on a prepared foundation slab, whose technical parameters depend on the soil conditions at the specific installation site. Precast reinforced concrete blocks (manufactured commercially) are used for the substation installation, or it is poured on-site with a sand and gravel backfill. The weight of a modular modular substation and the contact area with the foundation slab are half the weight and contact area of a modular modular substation with a service corridor and a foundation pit.

The MBKTP design consists of sections, but is a single element, which allows unloading and installation work to be carried out with a single operation using a crane, which in turn reduces the time for unloading and installation.

The reduced contact area between the cable compartment and the base plate allows for a smaller base plate, which in turn reduces both the excavation pit size and the grounding arrangement. Given the dimensions of the foundation section of the product, the bearing area on the prepared foundation is smaller compared to similar or identical products. Furthermore, the geometry and design of the base plate allow for excavation work (trenching) during installation with a minimum slope angle without the need for reinforcement or reduced soil excavation for the installation of the product's external grounding circuit.

The substation unit is mounted on the foundation slab. The internal grounding circuit is connected to the existing external grounding circuit using the connections provided by the manufacturer. This work must be performed by a specialized installation company that installs the substation on-site. After installation is complete, commissioning of the electrical equipment must be performed by a specialized company.

Asbestos-cement pipes for cable connections are laid during foundation construction under the supervision of installers. Openings in the floor are provided for cable connections to the substation's electrical equipment.

Comparison with analogues.

Parameter Traditional BCTP Small-sized MBKTP MBKTP Dimensions 5×2.5×3.1 m +1.1 (1.6) m 3.2×2.3×3.0 m * 2.95×2.05×2.39 Weight 20 t 10 t * 9 t Wall thickness 8-10 cm 5-12 cm 7 cm Thickness of the walls of the cable floor (compartment) 12-20 cm 10 cm 7 cm Power Up to 2500 kVA Up to 1000 kVA Up to 400 kVA Note: * depending on the transformer power.

Advantages.

1. Reduction in dimensions and weight by 50% (up to 10 tons) compared to traditional concrete substations (20 tons).

2. Simplified transportation – smaller weight and dimensions reduce logistics costs and eliminate the need for special equipment for transportation.

3. Fast installation - installation takes 1-2 days instead of 5-7 days.

4. Shallow excavation depth – reduction of the volume of excavation work and time for site preparation.

5. Flexibility of placement – possibility of installation in confined spaces (urban areas, highways).

6. Reduction of capital costs – savings on materials and site preparation.

7. Environmentally friendly - 30% less concrete consumption.

8. Increased security – protection from weather conditions and vandalism.

Claims (3)

1. A small-sized complete transformer substation for outdoor maintenance, characterized by the fact that it includes a monolithic reinforced concrete body, including walls, a high-voltage equipment compartment, a low-voltage equipment compartment, a power transformer compartment and an oil receiver, the foundation part of the substation is made in the form of a cable compartment, while the cable compartment has a trapezoidal shape, blind holes are made in the walls of the cable compartment. 2. A small-sized complete transformer substation for outdoor maintenance according to paragraph 1, characterized in that the oil receiver is made of concrete. 3. A small-sized complete transformer substation for outdoor maintenance according to paragraph 1, characterized in that the oil receiver is built into the monolithic structure of the cable compartment.