Transformer substation accident oil pool expansion method without pool body expansion and transformer substation accident oil pool

Abstract

The invention discloses a transformer substation accident oil pool expansion method without pool body expansion and a transformer substation accident oil pool, and belongs to the technical field of accident oil pool expansion, and the transformer substation accident oil pool expansion method comprises the steps: calculating the effective volume of the transformer substation accident oil pool after obtaining the size data of the transformer substation accident oil pool; if the effective volume is larger than the oil volume of the transformer, a partition wall for separating an oil area and a water area in the transformer substation accident oil pool is partially dismantled; and plugging an original drainage pipe in the transformer substation accident oil pool, and installing an oil-water separation device and an air flotation device on the transformer substation accident oil pool to complete expansion of the transformer substation accident oil pool. The effective volume of the accident oil pool is enlarged by transforming the oil-water separation device, the oil-water separation effect is improved by additionally arranging the air flotation device, the existing structure is fully utilized, land is saved, the transformation cost is low, the oil-water separation effect is good, the construction period is short, the influence on operation of the transformer substation is small, and safety is high.

Description

Technical Field

[0001] The invention relates to a method for expanding a transformer substation accident oil pool without expanding a pool body and the transformer substation accident oil pool, belonging to the technical field of expanding accident oil pools. Background Art

[0002] Substations equipped with oil-immersed transformers must be equipped with emergency oil pools according to relevant regulations to prevent large amounts of oil from entering sewers and contaminating the environment during accidents (firefighting) and to reduce fire risks. Typically, substations are built according to long-term or near-term plans. Substations typically reserve space for multiple main transformers (hereinafter referred to as "main transformers"). During the construction phase, a general emergency oil pool is constructed. Its capacity is designed for a single accident (fire) at the same time, meaning the amount of waste oil stored in the emergency oil pool is calculated based on the capacity of one main transformer. As power load continues to increase, the reserved main transformers in the substation will be gradually expanded and installed. Furthermore, for some substations where power load increases exceed the planned increase, the main transformer capacity will be increased by replacing the main transformer. Standardized design specifies a uniform effective volume for the emergency oil pool for each substation type. Substations of the same voltage level are designed based on the most unfavorable conditions at the time (based on the largest oil-volume equipment available on the market). In actual projects, the effective volume of the emergency oil pool is greater than 60% but less than 100% of the main transformer oil volume.

[0003] In order to solve the problem of insufficient effective volume of the accident oil pool, the existing technology usually adopts the method of expanding the pool body. The specific solution is usually as follows: Figure 1 and Figure 2 As shown in the figure, the main technical points are: (1) a new oil pool is built in the area adjacent to the original accident oil pool. The volume of the oil pool is the insufficient volume of the original accident oil pool, and the pool body adopts reinforced concrete structure; (2) at least two upper and lower connecting pipes are added to connect with the original pool to ensure the free flow of oil and water; (3) the connection between the connecting pipe and the original accident oil pool requires excavation of the original pool body.

[0004] However, the existing technology still has the following defects: (1) Space limitations, limited land in the station area, and difficulty in selecting a site for a new oil pool; (2) Reduced oil-water separation effect; (3) Long construction period, especially during the construction phase, which increases safety risks to the operation of existing substations. Summary of the Invention

[0005] The purpose of the present invention is to provide a method for expanding the capacity of a substation accident oil pool without expanding the pool body and a substation accident oil pool, so as to solve the problems existing in the prior art such as limited space making it difficult to implement, reduced oil-water separation effect, long construction period and reduced safety.

[0006] To achieve the above objectives, the present invention is implemented by adopting the following technical solutions: In a first aspect, the present invention provides a method for expanding the capacity of a substation accident oil pool without expanding the pool body, comprising: After obtaining the size data of the substation accident oil pool, calculate the effective volume of the substation accident oil pool; If the effective volume is greater than the transformer oil volume, a partition wall separating the oil area and the water area in the substation accident oil pool is partially demolished; Seal the original drainage pipe in the substation accident oil pool, install an oil-water separation device and a flotation device on the substation accident oil pool, and complete the expansion of the substation accident oil pool.

[0007] Furthermore, after obtaining the size data of the substation accident oil pool, the effective volume of the substation accident oil pool is calculated using the following formula: V=SH; Wherein, V is the effective volume of the substation accident oil pool, S is the inner net area of the substation accident oil pool, which includes the inner net area of the oil zone and the inner net area of the water zone, 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 demolition includes: opening a plurality of 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, wherein the top elevation of the square holes located 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 located in the lower layer is the same as the bottom elevation of the bottom of the substation accident oil pool.

[0010] Furthermore, the installation of the oil-water separation device and the flotation device on the substation accident oil pool includes installing the oil-water separation device on the substation accident oil pool by the following method: The oil-water separation device includes a drainage elbow and a drainage horn, which are installed in a large open area of the substation accident oil pool. The diameter of the drainage elbow is the same as the diameter of the oil inlet pipe in the substation accident oil pool. The distance between the drainage horn and the bottom of the substation accident oil pool is 50mm to 100mm. The diameter of the horn mouth of the drainage horn is not less than 0.005d², where d is the diameter of the oil inlet pipe. The drainage horn and the oil inlet pipe in the substation accident oil pool 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 substation accident oil pool.

[0011] Furthermore, the installation of the oil-water separation device and the flotation device on the substation accident oil pool includes installing the flotation device on the substation accident oil pool by the following method: The flotation device includes multiple flotation aeration heads, multiple gas pipelines and a gas source. The number of flotation aeration heads and gas pipelines is the same. The multiple flotation aeration heads are installed at the bottom of the substation accident oil pool, and the gas source is installed above the substation accident oil pool. One flotation aeration head is connected to the gas source using a gas pipeline until all the flotation aeration heads are connected to the gas source.

[0012] In a second aspect, the present invention provides a substation emergency oil pool, which is obtained by expanding the capacity according to any one of the methods described in the first aspect, and comprises: an emergency oil pool body, a partition wall, an oil-water separation device, and an air flotation device; 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 configured to allow the oil area and the water area to communicate with each other. The oil-water separation device includes a drainage elbow and a drainage bell pipe, and the drainage elbow and the drainage bell pipe are both installed in the large open area of the accident oil pool body; The flotation device includes multiple flotation aeration heads, multiple gas pipelines and an air source. The number of flotation aeration heads and gas pipelines is the same. Each flotation aeration head is connected to the air source through a gas pipeline. The flotation aeration head is installed at the bottom of the accident oil pool body, and the air source is installed above the accident oil pool body.

[0013] Furthermore, the partition wall is provided with a plurality of square holes, and the plurality of square holes are divided into three layers from top to bottom, wherein the top elevation of the square holes located 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 located in the lower layer is the same as the bottom elevation of the bottom of the substation accident oil pool.

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

[0015] Furthermore, the gas source includes a compressed gas bottle, a starting valve port and a pressure reducing device. The starting valve port is arranged at the outlet of the compressed gas bottle and is used to control the switch of the compressed gas bottle. The pressure reducing device is arranged between the starting valve port and the gas transmission pipeline and is used to reduce the pressure of the high-pressure gas provided by the compressed gas bottle and transport it to each gas transmission pipeline.

[0016] Compared with the prior art, the present invention has the following beneficial effects: The present invention provides a method for expanding a substation accident oil pool without expanding the pool body and a substation accident oil pool. The main body does not need to be expanded, but the effective volume of the accident oil pool is expanded by modifying an oil-water separation device, and the oil-water separation effect is improved by adding an air flotation device. The existing structure is fully utilized, land is saved, the modification cost is low, the oil-water separation effect is good, the construction period is short, the impact on the substation operation is small, and the safety is high. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a schematic plan view of an emergency oil pool after expansion according to the prior art provided by an embodiment; Figure 2 1 is a cross-sectional schematic diagram of an emergency oil pool after expansion according to the prior art provided in an embodiment; Figure 3 This is a flow chart of a method for expanding the capacity of a substation accident oil pool without expanding the pool body, corresponding to Example 1; Figure 4 This is a schematic plan view of a substation accident oil pool corresponding to Example 3; Figure 5 It is a cross-sectional schematic diagram of a substation accident oil pool corresponding to Example 3.

[0018] In the figure: 1.1, drainage bell; 1.2, flange; 1.3, steel pipe; 1.4, elbow; 2.1, flotation aeration head; 2.2, gas transmission pipeline; 2.3, pressure reducing device; 2.4, starting valve; 2.5, compressed gas cylinder. DETAILED DESCRIPTION

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

[0020] Example 1 like Figure 3 As shown, this embodiment provides a method for expanding the capacity of a substation accident oil pool without expanding the pool body, including: After obtaining the size data of the substation accident oil pool, calculate the effective volume of the substation accident oil pool; If the effective volume is greater than the transformer oil volume, a partition wall separating the oil area and the water area in the substation accident oil pool is partially demolished; Seal the original drainage pipe in the substation accident oil pool, install an oil-water separation device and a flotation device on the substation accident oil pool, and complete the expansion of the substation accident oil pool.

[0021] The present invention expands the effective volume of the accident oil pool by modifying the oil-water separation device, improves the oil-water separation effect by adding a flotation device, fully utilizes 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 present invention is further described by taking a main transformer expansion project of a 220kV substation as an example.

[0023] A 220kV substation has an emergency oil drainage system, including an emergency oil pool with an effective volume of 60m³, which is divided into oil and water areas by a partition wall. The substation plans to add a main transformer in the reserved space. According to the main transformer equipment data, the total oil content of the main transformer in this expansion phase is designed to be approximately 65t, with an oil density of 0.895t / m 3 According to the "Standard for Fire Protection Design of Thermal Power Plants and Substations" (GB50229-2019), the effective volume of the oil section of the emergency oil pool must be 73 m³. The previously constructed emergency oil pool (with an effective volume of 60 m³) could not accommodate 100% of the oil volume of the main transformer to be expanded during this phase, and the emergency oil pool needed to be expanded.

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

[0025] Calculate the effective volume of the accident oil pool: V=SH; Among them, S is the net area of the accident oil pool (oil area and 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, which indicates that the capacity expansion can be carried out without expanding the pool body.

[0027] Step 2: Renovate the accident oil pool.

[0028] This embodiment allows for the complete removal of the wall separating the oil and water areas to expand the oil area. Because construction within the accident oil pool is inconvenient, and considering the sufficient effective volume of the accident oil pool, retaining the wall does not affect the oil storage capacity, this embodiment employs a method of breaking through the wall. Specifically, six 300mm x 300mm square holes are drilled in the wall, arranged in three layers: upper, middle, and lower, with three holes per layer. The top elevation of the holes in the upper layer is the same as the bottom elevation of the accident oil inlet pipe, while the bottom elevation of the holes in the lower layer is the same as the bottom elevation of the accident oil pool. After the holes are drilled, oil and water can flow freely within the wall.

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

[0030] Because the dividing wall between the oil and water areas was not completely removed in this embodiment, constructing an oil-water separation device using the existing drainage pipes presents construction difficulties. Therefore, this embodiment blocks the existing drainage pipe openings and adds a new drainage elbow and drainage horn in the large open area to construct the oil-water separation device. The drainage elbow has the same diameter as the accident oil pool inlet pipe (DN300) and the same elevation as the existing drainage pipe. The newly added drainage horn is located on a separate side from the accident oil pool inlet pipe, and the relative distance between them is ≥ 2 / 3L = 4m (L is the long side of the accident oil pool). The drainage horn inlet is 100mm from the bottom of the accident oil pool, and the horn diameter D (mm) is ≥ 0.005d² (d = 300mm), with D being 450mm. It should be noted that the pipes are metal pipes with flange connections. They are pre-installed on the ground before installation in the accident oil pool to prevent the use of open flames in the accident oil pool.

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

[0032] After the transformation, the accident oil pool has only one cavity. When the oil and water separation path is short (the distance between the oil inlet pipe and the drainage elbow is close), in order to prevent flow turbulence during accident oil discharge and the oil and water cannot be completely separated, a prefabricated flotation device is added to the accident oil pool.

[0033] Flotation technology involves injecting a large number of microbubbles into oily wastewater. The microbubbles absorb oil droplets and, under buoyancy, carry the emulsified oil to the surface, achieving separation. Several gas pipelines and flotation aeration heads are installed at the bottom of the accident oil pool. A compressed gas cylinder (in this example, a compressed nitrogen cylinder) is located on the ground to provide the gas source. A starter valve and a pressure reducer are installed at the outlet of the compressed nitrogen cylinder to release the gas at a constant pressure. The flotation device is activated simultaneously with the oil discharge during the accident. The designed flotation time is the same as the oil discharge time, set at 20 minutes.

[0034] The main logic of starting the flotation device: Automatic start: When a fire occurs in the transformer, the substation fire alarm system will start the flotation device; Remote control start: After the personnel at the substation control center discovered a fire and transformer oil leakage, they manually opened the flotation device through the fire alarm system control panel; On-site manual start-up: When a fire accident occurs in the transformer, rescue workers manually open the valve of the flotation device to start the system.

[0035] Example 3 like Figure 4 and Figure 5 As shown, this embodiment provides a substation accident oil pool, including an accident oil pool 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 set to allow the oil area and the water area to communicate with each other; The oil-water separation device includes a drainage elbow and a drainage horn pipe, both of which are installed in the large open area of the accident oil pool body; The flotation device includes multiple flotation aeration heads 2.1, multiple gas pipelines 2.2 and an air source. The number of flotation aeration heads 2.1 and gas pipelines 2.2 is the same. Each flotation aeration head 2.1 is connected to the air source through a gas pipeline 2.2. The flotation aeration head 2.1 is installed at the bottom of the accident oil pool body, and the air source is installed above the accident oil pool body.

[0037] Specifically, a plurality of square holes are opened on the partition wall, and the plurality of square holes are divided into three layers from top to bottom, wherein the top elevation of the square holes located 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 located in the lower layer is the same as the bottom elevation of the bottom of the substation accident oil pool.

[0038] Specifically, the diameter of the drainage elbow is the same as the diameter of the oil inlet pipe in the accident oil pool body, the distance between the drainage bell pipe and the bottom of the accident oil pool body is 50mm to 100mm, the bell mouth diameter of the drainage bell pipe is not less than 0.005d², d is the diameter of the oil inlet pipe, the drainage bell pipe and the oil inlet pipe in the accident oil pool body are not on the same side and the relative distance is not less than 2 / 3L, L is the length of the long side of the accident oil pool body.

[0039] like Figure 4 and Figure 5 As shown, the drainage elbow 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 pool but does not touch it. The end of the elbow 1.4 not connected to the steel pipe 1.3 extends out of the accident oil pool.

[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 provided 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 provided 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 transmit it to each gas transmission pipeline 2.2.

[0041] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for expanding the capacity of a substation accident oil pool without expanding the pool body, characterized in that: include: After obtaining the size data of the substation accident oil pool, calculate the effective volume of the substation accident oil pool; If the effective volume is greater than the transformer oil volume, a partition wall separating the oil area and the water area in the substation accident oil pool is partially demolished; Seal the original drainage pipe in the substation accident oil pool, install an oil-water separation device and a flotation device on the substation accident oil pool, and complete the expansion of the substation accident oil pool.

2. The method for expanding the emergency oil pool of a substation without expanding the pool body according to claim 1, characterized in that: After obtaining the size data of the substation accident oil pool, the effective volume of the substation accident oil pool is calculated using the following formula: V=SH; Wherein, V is the effective volume of the substation accident oil pool, S is the inner net area of the substation accident oil pool, which includes the inner net area of the oil zone and the inner net area of the water zone, 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.

3. The method for expanding the emergency oil pool of a substation without expanding the pool body according to claim 1, characterized in that: The partial demolition includes: opening a plurality of holes in the partition wall.

4. The method for expanding the emergency oil pool of a substation without expanding the pool body according to claim 3, characterized in that: The holes are square holes, and the multiple square holes are divided into three layers from top to bottom, wherein the top elevation of the square holes located 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 located in the lower layer is the same as the bottom elevation of the bottom of the substation accident oil pool.

5. The method for expanding the emergency oil pool of a substation without expanding the pool body according to claim 1, characterized in that: The installation of the oil-water separation device and the flotation device on the substation accident oil pool includes installing the oil-water separation device on the substation accident oil pool by the following method: The oil-water separation device includes a drainage elbow and a drainage horn, which are installed in a large open area of the substation accident oil pool. The diameter of the drainage elbow is the same as the diameter of the oil inlet pipe in the substation accident oil pool. The distance between the drainage horn and the bottom of the substation accident oil pool is 50mm to 100mm. The diameter of the horn mouth of the drainage horn is not less than 0.005d², where d is the diameter of the oil inlet pipe. The drainage horn and the oil inlet pipe in the substation accident oil pool 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 substation accident oil pool.

6. The method for expanding the emergency oil pool of a substation without expanding the pool body according to claim 1, characterized in that: The installation of the oil-water separation device and the flotation device on the substation accident oil pool includes installing the flotation device on the substation accident oil pool by the following method: The flotation device includes multiple flotation aeration heads, multiple gas pipelines and a gas source. The number of flotation aeration heads and gas pipelines is the same. The multiple flotation aeration heads are installed at the bottom of the substation accident oil pool, and the gas source is installed above the substation accident oil pool. One flotation aeration head is connected to the gas source using a gas pipeline until all the flotation aeration heads are connected to the gas source.

7. A substation accident oil pool, characterized in that: The substation accident oil pool is obtained by expanding the capacity according to the method according to any one of claims 1 to 6, and comprises: an accident oil pool body, a partition wall, an oil-water separation device and an air flotation device; 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 configured to allow the oil area and the water area to communicate with each other. The oil-water separation device includes a drainage elbow and a drainage bell pipe, and the drainage elbow and the drainage bell pipe are both installed in the large open area of the accident oil pool body; The flotation device includes multiple flotation aeration heads, multiple gas pipelines and an air source. The number of flotation aeration heads and gas pipelines is the same. Each flotation aeration head is connected to the air source through a gas pipeline. The flotation aeration head is installed at the bottom of the accident oil pool body, and the air source is installed above the accident oil pool body.

8. The substation accident oil pool according to claim 7, characterized in that: The partition wall is provided with a plurality of square holes, and the plurality of square holes are divided into three layers from top to bottom, wherein the top elevation of the square holes located 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 located in the lower layer is the same as the bottom elevation of the bottom of the substation accident oil pool.

9. The substation accident oil pool according to claim 7, characterized in that: The diameter of the drainage bend pipe is the same as the diameter of the oil inlet pipe in the accident oil pool body. The distance between the drainage bell pipe and the bottom of the accident oil pool body is 50mm to 100mm. The bell mouth diameter of the drainage bell pipe is not less than 0.005d², d is the diameter of the oil inlet pipe, the drainage bell pipe and the oil inlet pipe in the accident oil pool body are not on the same side and the relative distance is not less than 2 / 3L, L is the length of the long side of the accident oil pool body.

10. The substation accident oil pool according to claim 7, characterized in that: The gas source includes a compressed gas bottle, a starting valve port and a pressure reducing device. The starting valve port is arranged at the outlet of the compressed gas bottle and is used to control the switch of the compressed gas bottle. The pressure reducing device is arranged between the starting valve port and the gas transmission pipeline and is used to reduce the pressure of the high-pressure gas provided by the compressed gas bottle and transport it to each gas transmission pipeline.

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