A substation accident oil pool expansion method without expanding the pool body and a substation accident oil pool

Abstract

The application discloses a substation accident oil pool expansion method without expanding the pool body and a substation accident oil pool, and belongs to the technical field of accident oil pool expansion, which comprises the following steps: obtaining size data of the substation accident oil pool, calculating the effective volume of the substation accident oil pool, removing part of a partition wall for separating oil areas and water areas in the substation accident oil pool if the effective volume is greater than the transformer oil volume, plugging the original drainage pipe in the substation accident oil pool, installing an oil-water separation device and a gas floatation device on the substation accident oil pool, and completing the expansion of the substation accident oil pool. The application expands the effective volume of the accident oil pool by reforming the oil-water separation device, improves the oil-water separation effect by adding the gas floatation device, fully utilizes the existing structure, saves land, has low reform cost, has good oil-water separation effect, has a short construction period, has little influence on the operation of the substation, and has high safety.

Description

Technical Field

[0001] This invention relates to a method for expanding the capacity of a substation emergency oil tank without expanding the tank body, and to a substation emergency oil tank, belonging to the field of emergency oil tank expansion technology. Background Technology

[0002] Substations equipped with oil-immersed transformers should be equipped with emergency oil tanks according to relevant regulations to prevent large amounts of emergency oil from entering the sewer system and polluting the environment during accidents (fires) and to reduce fire risks. Typically, substations are planned according to long-term plans and constructed according to short-term plans. Substations generally reserve space for multiple main transformers (hereinafter referred to as main transformers). During the construction phase, a main emergency oil tank is built, with its capacity designed for one accident (fire) at a time; that is, the amount of waste oil stored in the emergency oil tank is calculated based on one main transformer. As the power load continues to increase, the main transformers planned in the substation will be gradually expanded and installed. Furthermore, for some substations whose power load exceeds the planned increase, the main transformer capacity will be increased by replacing the main transformers. Standardized design uniformly specifies the corresponding effective volume for emergency oil tanks of various types of substations. Substations of the same voltage level are designed with emergency oil tanks based on the most unfavorable conditions at the time (based on the equipment data with the largest oil volume on the market). In actual engineering projects, the effective volume of the emergency oil tank is greater than 60% but less than 100% of the main transformer's oil volume.

[0003] To address the problem of insufficient effective volume of oil spill containment tanks, existing technologies typically employ methods such as expanding the tank's capacity. Specific solutions are usually as follows: Figure 1 and Figure 2 As shown, its main technical points are: (1) A new oil tank is built in the area adjacent to the original accident oil tank. The volume of the oil tank is the volume of the insufficient part of the original accident oil tank. The tank body adopts a reinforced concrete structure; (2) At least two new connecting pipes are added to connect with the original tank to ensure the free flow of oil and water; (3) The connection between the connecting pipe and the original accident oil tank requires the original tank body to be excavated.

[0004] However, the existing technology still has the following defects: (1) Space is limited, the land in the station area is tight, and it is difficult to select a site for the new oil pool; (2) The oil-water separation effect is reduced; (3) The construction period is long, especially the construction stage increases the safety hazards to the operation of the existing substation. Summary of the Invention

[0005] The purpose of this invention is to provide a method for expanding the capacity of a substation accident oil tank without expanding the tank body, and a substation accident oil tank, which solves the problems of space constraints leading to difficulty in implementation, reduced oil-water separation effect, long construction period, and reduced safety in the prior art.

[0006] To achieve the above objectives, the present invention employs the following technical solution: In a first aspect, the present invention provides a method for expanding the capacity of a substation accident oil tank without expanding the tank body, comprising: After obtaining the dimensional data of the substation emergency oil tank, calculate the effective volume of the substation emergency oil tank; If the effective volume is greater than the transformer oil volume, then the partition wall separating the oil zone and the water zone in the substation emergency oil pool shall be partially removed. The original drainage pipe in the substation emergency oil tank was sealed off, and an oil-water separator and an air flotation device were installed on the substation emergency oil tank to complete the expansion of the substation emergency oil tank.

[0007] Furthermore, after obtaining the dimensional data of the substation emergency oil tank, the effective volume of the substation emergency oil tank is calculated using the following formula: V=SH; Wherein, V is the effective volume of the substation accident oil pool, S is the net internal area of ​​the substation accident oil pool, the net internal area includes the net internal area of ​​the oil area and the net internal area of ​​the water area, and H is the effective water depth of the substation accident oil pool. H = Height difference between the bottom of the oil inlet pipe and the bottom of the pool - 100mm.

[0008] Furthermore, the partial removal includes: making multiple holes in the partition wall.

[0009] Furthermore, the holes are square holes, and the multiple square holes are divided into three layers from top to bottom. The top elevation of the hole in the upper layer is the same as the bottom elevation of the oil inlet pipe in the substation accident oil pool, and the bottom elevation of the square hole in the lower layer is the same as the bottom elevation of the pool bottom in the substation accident oil pool.

[0010] Furthermore, the installation of an oil-water separator and an air flotation device on the substation emergency oil pool includes installing the oil-water separator on the substation emergency oil pool by the following method: The oil-water separation device includes a drain bend and a drain bell pipe. The drain bend and drain bell pipe are installed in the large open area of ​​the substation emergency oil pool. The diameter of the drain bend is the same as the diameter of the oil inlet pipe in the substation emergency oil pool. The distance between the drain bell pipe and the bottom of the substation emergency oil pool is 50mm to 100mm. The bell diameter of the drain bell pipe is not less than 0.005d², where d is the diameter of the oil inlet pipe. The drain bell pipe and the oil inlet pipe in the substation emergency oil pool are not on the same side and the relative distance between them is not less than 2 / 3L, where L is the length of the long side of the substation emergency oil pool.

[0011] Furthermore, the installation of an oil-water separator and an air flotation device on the substation emergency oil pool includes installing the air flotation device on the substation emergency oil pool by the following method: The air flotation device includes multiple air flotation aerators, multiple air supply pipes, and an air source. The number of air flotation aerators and air supply pipes are the same. Multiple air flotation aerators are installed at the bottom of the substation emergency oil tank, and the air source is installed above the substation emergency oil tank. One air flotation aerator is connected to the air source by one air supply pipe until all air flotation aerators are connected to the air source.

[0012] In a second aspect, the present invention provides a substation emergency oil tank, which is obtained by expanding the capacity according to any one of the methods in the first aspect, and includes: an emergency oil tank body, a partition wall, an oil-water separation device and an air flotation device. The accident oil tank body includes an oil area and a water area, and the original drainage pipe on the accident oil tank body is in a closed state. The partition wall is located between the oil area and the water area, and the partition wall is configured to allow the oil area and the water area to communicate with each other. The oil-water separation device includes a drain bend and a drain bell pipe, both of which are installed in the large open area of ​​the accident oil tank body. The air flotation device includes multiple air flotation aeration heads, multiple air supply pipes, and an air source. The number of air flotation aeration heads and air supply pipes are the same. Each air flotation aeration head is connected to the air source through an air supply pipe. The air flotation aeration heads are installed at the bottom of the accident oil tank body, and the air source is installed above the accident oil tank body.

[0013] Furthermore, the partition wall has multiple square holes, which are divided into three layers from top to bottom. The top elevation of the square holes in the upper layer is the same as the bottom elevation of the oil inlet pipe in the substation accident oil pool, and the bottom elevation of the square holes in the lower layer is the same as the bottom elevation of the pool bottom in the substation accident oil pool.

[0014] Furthermore, the diameter of the drain bend is the same as the diameter of the inlet pipe in the accident oil tank body, the distance between the drain bell pipe and the bottom of the accident oil tank body is 50mm to 100mm, the bell diameter of the drain bell pipe is not less than 0.005d², where d is the diameter of the inlet pipe, the drain bell pipe and the inlet pipe in the accident oil tank body are not on the same side and the relative distance is not less than 2 / 3L, where L is the length of the long side of the accident oil tank body.

[0015] Furthermore, the gas source includes a compressed gas cylinder, a start valve port, and a pressure reducing device. The start valve port is located at the outlet of the compressed gas cylinder and is used to control the opening and closing of the compressed gas cylinder. The pressure reducing device is located between the start valve port and the gas transmission pipeline and is used to reduce the pressure of the high-pressure gas provided by the compressed gas cylinder and deliver it to each gas transmission pipeline.

[0016] Compared with the prior art, the beneficial effects achieved by the present invention are: This invention provides a method for expanding the capacity of a substation emergency oil tank without expanding the tank body, and a substation emergency oil tank. The main body is not expanded, but the effective volume of the emergency oil tank is increased by modifying the oil-water separation device. The oil-water separation effect is improved by adding an air flotation device. It makes full use of the existing structure, saves land, has low modification cost, good oil-water separation effect, short construction period, little impact on substation operation, and high safety. Attached Figure Description

[0017] Figure 1 This is a plan view of the expanded emergency oil tank provided in the embodiment. Figure 2 This is a cross-sectional schematic diagram of the expanded emergency oil tank provided in the embodiment. Figure 3 This is a flowchart of a method for expanding the capacity of a substation accident oil tank without expanding the tank body, corresponding to Example 1; Figure 4 This is a plan view of a substation accident oil pool corresponding to Example 3; Figure 5 This is a cross-sectional schematic diagram of a substation accident oil pool corresponding to Example 3.

[0018] In the diagram: 1.1 Drainage bell mouth; 1.2 Flange; 1.3 Steel pipe; 1.4 Elbow; 2.1 Air flotation aerator head; 2.2 Gas transmission pipeline; 2.3 Pressure reducing device; 2.4 Start valve port; 2.5 Compressed gas cylinder. Detailed Implementation

[0019] The present invention will be further described below with reference to the accompanying drawings. The following embodiments are only used to illustrate the technical solution of the present invention more clearly, and should not be used to limit the scope of protection of the present invention.

[0020] Example 1 like Figure 3 As shown in the figure, this embodiment provides a method for expanding the capacity of a substation accident oil tank without expanding the tank body, including: After obtaining the dimensional data of the substation emergency oil tank, calculate the effective volume of the substation emergency oil tank; If the effective volume is greater than the transformer oil volume, then the partition wall separating the oil zone and the water zone in the substation emergency oil pool shall be partially removed. The original drainage pipe in the substation emergency oil tank was sealed off, and an oil-water separator and an air flotation device were installed on the substation emergency oil tank to complete the expansion of the substation emergency oil tank.

[0021] This invention expands the effective volume of the emergency oil pool by modifying the oil-water separation device, improves the oil-water separation effect by adding an air flotation device, makes full use of the existing structure, saves land, has low modification cost, good oil-water separation effect, short construction period, little impact on substation operation, and high safety.

[0022] Example 2 In this embodiment, the invention will be further described using the expansion project of a 220kV substation as an example.

[0023] A 220kV substation has an emergency oil drainage system, including an emergency oil tank with an effective volume of 60m³, which is divided into an oil zone and a water zone by a partition wall. The substation plans to add a main transformer to the originally planned location. According to the main transformer equipment data, the total oil content of the expanded main transformer is designed to be approximately 65t, with an oil density of 0.895t / m³. 3 According to the "Fire Protection Design Standard for Thermal Power Plants and Substations" (GB50229-2019), the effective volume of the oil area in the accident oil pool needs to be 73 m³. The existing accident oil pool (effective volume of 60 m³) cannot accommodate 100% of the oil volume of the main transformer to be expanded in this phase, so the accident oil pool needs to be expanded.

[0024] This embodiment provides a method for expanding the capacity of a substation accident oil tank without expanding the tank body, including: Step 1: Determine the modifiability of existing substation accident oil pools.

[0025] Calculate the effective volume of the accident oil pool: V=SH; Where S is the net area of ​​the accident oil pool (including the oil area and the water area), S = 5.8m × 4.6m = 26.68m²; H is the effective water depth, H = the height difference between the bottom of the oil inlet pipe and the bottom of the pool - 0.1m, H = 3.05m - 0.1m = 2.95m.

[0026] V = 26.68 m² × 2.95 m = 78.7 m³ > 73 m³, indicating that the expansion and renovation of the pool can be carried out without expanding the pool body.

[0027] Step 2: Modify the accident oil tank.

[0028] This embodiment allows for the complete removal of the partition wall between the oil and water zones to expand the oil zone volume. However, due to the inconvenience of construction within the emergency oil pool and the calculation that the effective volume of the emergency oil pool is sufficient, retaining the partition wall would not affect the oil storage volume. Therefore, this embodiment employs the method of opening up the partition wall. Specifically, six 300mm × 300mm square holes are made in the partition wall, arranged in three layers (upper, middle, and lower), with three holes in each layer. The top elevation of the upper layer holes is the same as the bottom elevation of the emergency oil inlet pipe, and the bottom elevation of the lower layer holes is the same as the bottom elevation of the emergency oil pool. After the holes are opened, oil and water can flow freely within the partition wall area.

[0029] Step 3: Construct an oil-water separation device.

[0030] Because the partition wall between the oil and water zones was not completely removed in this embodiment, constructing an oil-water separation device using the original drainage pipe presents construction difficulties. Therefore, this embodiment seals the original drainage pipe opening and adds a drainage bend and a drainage bell pipe to construct the oil-water separation device in the large open area. The diameter of the drainage bend is the same as the diameter of the oil inlet pipe of the emergency oil tank (DN300), and the elevation is the same as the original drainage pipe. The newly added drainage bell pipe is not on the same side as the oil inlet pipe of the emergency oil tank, and the relative distance is ≥2 / 3L=4m (L is the long side of the emergency oil tank). The inlet of the drainage bell pipe is 100mm from the bottom of the emergency oil tank, and the bell diameter D (mm) is ≥0.005d² (d=300mm), where D is taken as 450mm. It should be noted that the pipes are metal pipes with flange connections, and all are pre-installed on the ground before being installed inside the emergency oil tank to avoid the use of open flames inside the emergency oil tank.

[0031] Step 4: Add an air flotation device.

[0032] After the renovation, the accident oil tank has only one cavity. When the oil and water separation path is short (the distance between the oil inlet pipe and the drain bend is close), in order to prevent the flow turbulence during accident oil discharge and the inability of oil and water to be completely separated, a prefabricated air flotation device is added to the accident oil tank.

[0033] Air flotation technology separates oily wastewater by introducing a large number of microbubbles. These microbubbles adsorb oil droplets and, under buoyancy, carry the emulsified oil to the surface. Several gas supply pipes and air flotation aerators are installed at the bottom of the oil spill area, while a compressed gas cylinder (compressed nitrogen in this embodiment) is placed on the ground to provide the gas source. The compressed nitrogen cylinder outlet is equipped with a start valve and a pressure reducing device, releasing the gas at a constant pressure. The air flotation device is activated simultaneously during the emergency oil discharge, with a design time of 20 minutes, the same as the oil discharge time.

[0034] The main logic for starting the air flotation device: Automatic start-up: In the event of a fire in the transformer, the substation fire alarm system will activate the air flotation device in conjunction with the operation. Remote start-up: After discovering a fire and transformer oil leak, personnel at the substation's central control center manually activate the air flotation device via the fire alarm system control panel. Manual start-up on site: In the event of a transformer fire, rescuers manually open the valve of the air flotation device to start the system.

[0035] Example 3 like Figure 4 and Figure 5 As shown, this embodiment provides a substation emergency oil tank, including an emergency oil tank body, a partition wall, an oil-water separation device, and an air flotation device.

[0036] The accident oil pool body includes an oil area and a water area, and the original drainage pipe on the accident oil pool body is in a closed state. The partition wall is located between the oil area and the water area, and the partition wall is designed to allow the oil area and the water area to communicate with each other. The oil-water separation device includes a drain bend and a drain bell pipe, both of which are installed in the large open area of ​​the accident oil tank body. The air flotation device includes multiple air flotation aeration heads 2.1, multiple air supply pipes 2.2, and an air source. The number of air flotation aeration heads 2.1 and air supply pipes 2.2 are the same. Each air flotation aeration head 2.1 is connected to the air source through an air supply pipe 2.2. The air flotation aeration heads 2.1 are installed at the bottom of the accident oil tank body, and the air source is installed above the accident oil tank body.

[0037] Specifically, the partition wall has multiple square holes, which are divided into three layers from top to bottom. The top elevation of the square holes in the upper layer is the same as the bottom elevation of the oil inlet pipe in the substation accident oil pool, and the bottom elevation of the square holes in the lower layer is the same as the bottom elevation of the pool bottom in the substation accident oil pool.

[0038] Specifically, the diameter of the drain bend is the same as the diameter of the inlet pipe in the main body of the emergency oil tank. The distance between the drain bell pipe and the bottom of the emergency oil tank is 50mm to 100mm. The diameter of the bell mouth of the drain bell pipe is not less than 0.005d², where d is the diameter of the inlet pipe. The drain bell pipe and the inlet pipe in the main body of the emergency oil tank are not on the same side and the relative distance is not less than 2 / 3L, where L is the length of the long side of the emergency oil tank.

[0039] like Figure 4 and Figure 5 As shown, the drainage bend includes a drainage bell mouth 1.1, a flange 1.2, a steel pipe 1.3 and an elbow 1.4 connected in sequence. The drainage bell mouth 1.1 is close to the bottom of the accident oil tank body but does not contact it. The end of the elbow 1.4 that is not connected to the steel pipe 1.3 extends out of the accident oil tank body.

[0040] like Figure 5 As shown, specifically, the gas source includes a compressed gas cylinder 2.5, a starting valve port 2.4, and a pressure reducing device 2.3. The starting valve port 2.4 is located at the outlet of the compressed gas cylinder 2.5 and is used to control the opening and closing of the compressed gas cylinder 2.5. The pressure reducing device 2.3 is located between the starting valve port 2.4 and the gas transmission pipeline 2.2 and is used to reduce the pressure of the high-pressure gas provided by the compressed gas cylinder 2.5 and deliver it to each gas transmission pipeline 2.2.

[0041] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for expanding the capacity of a substation accident oil tank without expanding the tank body, characterized in that, include: After obtaining the dimensional data of the substation emergency oil tank, calculate the effective volume of the substation emergency oil tank; If the effective volume is greater than the transformer oil volume, then the partition wall separating the oil zone and the water zone in the substation emergency oil pool shall be partially removed. The original drainage pipe in the substation accident oil tank was blocked, and an oil-water separator and an air flotation device were installed on the substation accident oil tank to complete the expansion of the substation accident oil tank. After obtaining the dimensional data of the substation emergency oil tank, the effective volume of the substation emergency oil tank is calculated using the following formula: V=SH; Wherein, V is the effective volume of the substation accident oil pool, S is the net internal area of ​​the substation accident oil pool, the net internal area includes the net internal area of ​​the oil area and the net internal area of ​​the water area, and H is the effective water depth of the substation accident oil pool. H = Height difference between bottom of oil inlet pipe and bottom of pool - 100mm; The partial demolition includes: making multiple holes in the partition wall; The holes are square holes, and the multiple square holes are divided into three layers from top to bottom. The top elevation of the hole in the upper layer is the same as the bottom elevation of the oil inlet pipe in the substation accident oil pool, and the bottom elevation of the square hole in the lower layer is the same as the bottom elevation of the pool bottom in the substation accident oil pool.

2. The method for expanding the capacity of a substation accident oil tank without expanding the tank body according to claim 1, characterized in that, The installation of an oil-water separator and an air flotation device on the substation emergency oil pool includes installing the oil-water separator on the substation emergency oil pool by the following methods: The oil-water separation device includes a drain bend and a drain bell pipe. The drain bend and drain bell pipe are installed in the large open area of ​​the substation emergency oil pool. The diameter of the drain bend is the same as the diameter of the oil inlet pipe in the substation emergency oil pool. The distance between the drain bell pipe and the bottom of the substation emergency oil pool is 50mm to 100mm. The bell diameter of the drain bell pipe is not less than 0.005d², where d is the diameter of the oil inlet pipe. The drain bell pipe and the oil inlet pipe in the substation emergency oil pool are not on the same side and the relative distance between them is not less than 2 / 3L, where L is the length of the long side of the substation emergency oil pool.

3. The method for expanding the capacity of a substation accident oil tank without expanding the tank body according to claim 1, characterized in that, The installation of an oil-water separator and an air flotation device on the substation emergency oil pool includes installing the air flotation device on the substation emergency oil pool by the following methods: The air flotation device includes multiple air flotation aerators, multiple air supply pipes, and an air source. The number of air flotation aerators and air supply pipes are the same. Multiple air flotation aerators are installed at the bottom of the substation emergency oil tank, and the air source is installed above the substation emergency oil tank. One air flotation aerator is connected to the air source by one air supply pipe until all air flotation aerators are connected to the air source.

4. A substation accident oil tank, characterized in that, The substation emergency oil tank is obtained by expanding the capacity according to any one of claims 1 to 3, and includes: the emergency oil tank body, the partition wall, the oil-water separation device and the air flotation device; The accident oil tank body includes an oil area and a water area, and the original drainage pipe on the accident oil tank body is in a closed state. The partition wall is located between the oil area and the water area, and the partition wall is configured to allow the oil area and the water area to communicate with each other. The oil-water separation device includes a drain bend and a drain bell pipe, both of which are installed in the large open area of ​​the accident oil tank body. The air flotation device includes multiple air flotation aeration heads, multiple air supply pipes, and an air source. The number of air flotation aeration heads and air supply pipes are the same. Each air flotation aeration head is connected to the air source through an air supply pipe. The air flotation aeration heads are installed at the bottom of the accident oil tank body, and the air source is installed above the accident oil tank body.

5. The substation accident oil pool according to claim 4, characterized in that, The partition wall has multiple square holes, which are arranged in three layers from top to bottom. The top elevation of the square holes in the upper layer is the same as the bottom elevation of the oil inlet pipe in the substation accident oil pool, and the bottom elevation of the square holes in the lower layer is the same as the bottom elevation of the pool bottom in the substation accident oil pool.

6. The substation accident oil pool according to claim 4, characterized in that, The diameter of the drain bend is the same as the diameter of the inlet pipe in the accident oil pool body. The distance between the drain bell pipe and the bottom of the accident oil pool body is 50mm to 100mm. The bell diameter of the drain bell pipe is not less than 0.005d², where d is the diameter of the inlet pipe. The drain bell pipe and the inlet pipe in the accident oil pool body are not on the same side and their relative distance is not less than 2 / 3L, where L is the length of the long side of the accident oil pool body.

7. The substation accident oil pool according to claim 4, characterized in that, The gas source includes a compressed gas cylinder, a start valve port, and a pressure reducing device. The start valve port is located at the outlet of the compressed gas cylinder and is used to control the opening and closing of the compressed gas cylinder. The pressure reducing device is located between the start valve port and the gas transmission pipeline and is used to reduce the pressure of the high-pressure gas provided by the compressed gas cylinder and deliver it to each gas transmission pipeline.

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