A method for installing a main transformer of a marine booster station

Abstract

The application relates to the technical field of offshore installation, in particular to a kind of offshore booster station main transformer installation method, through pre-positioning inspection, foundation verification, positive center point confirmation and scribe positioning, body installation, after pre-positioning inspection is completed, foundation verification is carried out, after foundation verification is completed, positive center point confirmation is carried out, after positive center point confirmation, scribe positioning is carried out, after scribe positioning, body installation is carried out, realize the stable installation of offshore booster station main transformer on sea, through construction preparation, oil removal to remove the pressure of custody, accessory installation, internal inspection and wiring, vacuum treatment, vacuum oil injection, vacuum breaking exhaust, hot oil circulation, cable secondary wiring, on-site inspection and test, quality acceptance, realize the installation and test of main transformer equipment.

Description

A method for installing the main transformer in an offshore booster station Technical Field

[0001] This invention relates to the field of offshore installation technology, and more specifically to a method for installing the main transformer of an offshore booster station. Background Technology

[0002] The Guangdong Electric Power Yangjiang Qingzhou I and II offshore wind power projects are located in the sea area near Shaba Town, Yangxi County, Yangjiang City, Guangdong Province. The planned installed capacity of the projects is 400MW, with 11MW wind turbine units planned. The Qingzhou II offshore wind power project is also located in the sea area near Shaba Town, Yangxi County, Yangjiang City, Guangdong Province. The planned installed capacity of the projects is 600MW, with 11MW wind turbine units planned. Both projects will jointly construct an onshore control center and a 500kV offshore substation. The electricity generated by the wind turbines will be connected to the offshore substation via a 66kV submarine cable, and after being stepped up, it will be connected to the onshore control center via a 500kV submarine cable.

[0003] Both projects involve the installation of a common offshore substation main transformer. The sea conditions in the equipment installation area are complex, and ocean currents and sea breezes have a significant impact on the installation environment of the main transformer. In order to ensure the normal lifting and installation of the equipment, we propose an installation method and control method for the offshore substation main transformer to solve the above problems. Summary of the Invention

[0004] To address the aforementioned problems, this invention provides a method for installing the main transformer in an offshore substation, which improves upon existing equipment.

[0005] The specific technical method is as follows: An installation method for the main transformer of an offshore substation includes: pre-positioning inspection, foundation verification, confirmation of the center point and marking for positioning, body installation, foundation verification after pre-positioning inspection, confirmation of the center point after foundation verification, marking for positioning after center point confirmation, and body installation after marking for positioning.

[0006] Preferably, the pre-positioning checks include: personnel checks to confirm the presence of safety officers, operators, and commanders; equipment checks to inspect and test the installation equipment, command intercom equipment, and monitoring equipment to ensure they are in normal working order at all times; reporting any malfunctioning equipment for repair and conducting a re-inspection after repair; and site checks to confirm the site's enclosure, flatness, cleanliness of debris at the installation location, and whether non-staff members have left the site. These three checks are conducted simultaneously, and the next step is carried out only after all three checks have been confirmed to be passed.

[0007] Preferably, the basic verification includes two aspects: the offset of the steel column, the butt weld, the support surface, and the center of the reserved hole; steel column:

[0008] The deviation between the centerline of the steel column and the positioning axis is 0-5cm.

[0009] The elevation of the benchmark point has an error range of +5 to -8 cm.

[0010] Verticality: The verticality of the bottom column is 10cm, and the total height of the column is 35cm.

[0011] Butt weld:

[0012] The weld reinforcement height b is less than or equal to 20mm;

[0013] The weld seam misalignment error should be controlled within the range of 0.1 to 3 mm.

[0014] Support surface: Elevation error range is ±3.0cm, levelness is L / 1000;

[0015] Center offset of reserved hole: The error range of offset is 10cm;

[0016] During verification, each set of parameters is measured and recorded, and the recorded data is compared with the specified data range to ensure that each set of measured values ​​is within the specified range before proceeding to the next step; otherwise, the next step is not allowed.

[0017] Preferably, after the basic verification data is passed, the center point of the placement position corresponding to the steel column is determined by connecting four points using the measured steel column data, and the installation position is marked with a line based on the measured center point.

[0018] Preferably, after the center point is confirmed, the main body is installed:

[0019] The four-point hook and four-point lug lifting method is adopted, with a crossbeam, a steel wire rope of 16 meters in length, and 8 meters in a ring. The spacing between the lifting points of the balance beam is 11 meters.

[0020] Calculation of wire rope diameter and permissible lifting weight:

[0021] The weight of the lifting component is G = 301 tons. Using the 4-point method, F = 301000 / 4 / cosl5° = 77.58 tons.

[0022] Wire rope diameter * wire rope diameter * 50 / 1000 = 1 / safety factor 3-8;

[0023] Currently, 65mm diameter lifting slings are selected;

[0024] All lifting lugs should be used during hoisting;

[0025] When the transformer body is transported and placed in position, the horizontal tilt angle along the major axis shall not exceed 150°.

[0026] After the crane lifts the transformer 200-300mm off the ground, stop for 5 minutes, then direct the crane to move the transformer to the vicinity of the foundation. After slowly raising it to a sufficient height, slowly and reliably lower the transformer back to the pre-installation position.

[0027] Preferably, the installation of the main body includes: construction preparation, draining oil and releasing the storage air pressure, accessory installation, internal inspection and wiring, vacuuming, vacuum oil injection, vacuum breaking and venting, hot oil circulation, secondary wiring of cables, on-site inspection and testing, and quality acceptance.

[0028] Preferably, between the oil draining or releasing the storage air pressure and the accessory installation, a set of pre-installation inspection and testing procedures is added; between the internal inspection and wiring and the vacuuming process, a set of insulating oil extraction procedures is added.

[0029] Preferably, the construction preparation includes transformer oil filtration facilities, vacuum pumps, compressed dry air and related accessories, oil storage tanks, a dedicated temporary power supply for transformer installation, transformer accessories, and fire extinguishing equipment.

[0030] Preferably, during the installation of the transformer accessories, the transformer body is exposed to the air with an ambient relative humidity of less than 75%, and dry air is supplied to maintain positive pressure in the installation environment and keep the body dry. During installation, only one installation point is opened at a time and covered with plastic film. The continuous exposure time does not exceed 8 hours. When the atmospheric humidity exceeds 75%, work is stopped.

[0031] Preferably, the hot oil circulation includes confirming the power supply and circuit of the oil filter, grounding the oil tank, oil filter, metal pipes, etc., inspecting the prepared oil storage tank, draining the residual oil inside, and cleaning it with transformer insulating oil. Before entering the oil tank, the oxygen content in the oil tank is checked and must not be lower than 18%. The oil filter, oil pipes, tees, and valves used in the transformer installation process are cleaned with insulating oil. The oil extraction and cleaning operations are carried out in a dry environment. After cleaning, the corresponding electrical tests are performed. After the tests are passed, the transformer insulating oil is sequentially passed through the oil filter and injected into the oil storage tank. The pipeline between the oil filter and the oil tank is connected. The volume and number of oil tanks are determined according to the actual needs on site. After the pipeline connection is completed and confirmed, the insulating oil in the oil tank is subjected to circulating vacuum degassing treatment.

[0032] Preferably, the vacuum oil injection includes: before vacuuming, the valve between the oil tank and the main oil tank should be closed, and the exhaust valve at the top of the oil tank or the drain valve at the bottom should be opened. The transformer is vacuumed using a vacuum pump. Every hour, the valve in front of the vacuum residual pressure gauge is opened to measure and record the vacuum degree of the transformer. After each measurement, the valve is closed. When the vacuum degree inside the transformer body reaches the vacuum leakage test standard required by the manufacturer's instructions, a vacuum leakage test is performed on the transformer. The transformer is vacuumed from the main breather interface or from the dedicated vacuum valve of the oil conservator. After evacuating to 1.0 mbar (100 Pa), the vacuum pump valve is closed, and the time and vacuum degree 1 at this time and vacuum degree 2 after 1 hour are recorded. The leakage rate is calculated as: leakage rate = (vacuum degree 2 - vacuum degree 1) × oil tank volume. The leakage rate shall not exceed 10 mbar / s. The vacuum pump is turned on again until the vacuum degree reaches below 1.0 mbar and is maintained for 48 hours.

[0033] The beneficial effects of this invention are: through pre-positioning inspection, foundation verification, center point confirmation and marking positioning, body installation, foundation verification after pre-positioning inspection, center point confirmation after foundation verification, marking positioning after center point confirmation, and body installation after marking positioning, the stable installation of the main transformer of the offshore booster station at sea is achieved.

[0034] Through construction preparation, draining oil to release storage pressure, accessory installation, internal inspection and wiring, vacuuming, vacuum oil injection, vacuum breaking and venting, hot oil circulation, secondary cable wiring, on-site inspection and testing, and quality acceptance, the installation and testing of the main transformer equipment are completed. Attached Figure Description

[0035] Figure 1 is a schematic diagram of the lifting method of the present invention;

[0036] Figure 2 is a schematic diagram of the installation sequence of the present invention;

[0037] Figure 3 is a schematic diagram of vacuuming and vacuum oil injection according to the present invention;

[0038] Figure 4 is a schematic diagram of the hot oil circulation of the present invention. Detailed Implementation

[0039] The technical solution of the present invention will now be clearly and completely described with reference to the embodiments and accompanying drawings. Obviously, the described embodiments are merely one embodiment of the present invention, and not all embodiments. Based on this embodiment, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Specific embodiments are as follows:

[0040] As shown in Figures 1-4, a method for installing a main transformer in an offshore substation includes: pre-positioning inspection, foundation verification, confirmation of the center point and marking for positioning, and main body installation. After the pre-positioning inspection is completed, foundation verification is performed. After the foundation verification is completed, the center point is confirmed. After the center point is confirmed, the marking for positioning is performed. After the marking for positioning, the main body is installed.

[0041] Pre-positioning checks include: personnel check, confirming the presence of safety officers, operators, and commanders; equipment check, inspecting and testing the installation equipment, command intercom equipment, and monitoring equipment to ensure they are in normal working order; reporting any malfunctioning equipment for repair and conducting a re-inspection after repair; and site check, confirming the site's enclosure, levelness, cleanliness of debris at the installation location, and whether unauthorized personnel have left the site. These three checks are conducted simultaneously, and the next step can only proceed after all three checks have been confirmed as passed.

[0042] The basic verification includes two aspects: the offset of the center of the steel column, the butt weld, the support surface, and the reserved hole;

[0043] Steel columns:

[0044] The deviation between the centerline of the steel column and the positioning axis is 0-5cm.

[0045] The elevation of the benchmark point has an error range of +5 to -8 cm.

[0046] Verticality: The verticality of the bottom column is 10cm, and the total height of the column is 35cm.

[0047] Butt weld:

[0048] The weld reinforcement height b is less than or equal to 20mm;

[0049] The weld seam misalignment error should be controlled within the range of 0.1 to 3 mm.

[0050] Support surface: Elevation error range is ±3.0cm, levelness is L / 1000;

[0051] Center offset of reserved hole: The error range of offset is 10cm;

[0052] During verification, each set of parameters is measured and recorded, and the recorded data is compared with the specified data range to ensure that each set of measured values ​​is within the specified range before proceeding to the next step; otherwise, the next step is not allowed.

[0053] After the basic verification data is passed, the center point of the steel column corresponding to the placement position is determined by connecting four points using the measured steel column data. Based on the measured center point, a line is drawn at the installation position to determine the installation center point.

[0054] After the center point is confirmed, the main unit is installed:

[0055] The four-point hook and four-point lug lifting method is adopted, with a crossbeam, a steel wire rope of 16 meters in length, and 8 meters in a ring. The spacing between the lifting points of the balance beam is 11 meters.

[0056] Calculation of wire rope diameter and permissible lifting weight:

[0057] The weight of the lifting component is G = 301 tons. Using the 4-point method, F = 301000 / 4 / cosl5° = 77.58 tons.

[0058] Wire rope diameter * wire rope diameter * 50 / 1000 = 1 / safety factor 3-8;

[0059] Currently, 65mm diameter slings are selected;

[0060] All lifting lugs should be used during hoisting;

[0061] When the transformer body is transported and placed in position, the horizontal tilt angle along the major axis shall not exceed 150°.

[0062] After the crane lifts the transformer 200-300mm off the ground, stop for 5 minutes, then direct the crane to move the transformer to the vicinity of the foundation. After slowly raising it to a sufficient height, slowly and reliably lower the transformer back to the pre-installation position.

[0063] The main body installation includes: construction preparation, draining oil and releasing storage air pressure, accessory installation, internal inspection and wiring, vacuuming, vacuum oil injection, vacuum breaking and venting, hot oil circulation, secondary cable wiring, on-site inspection and testing, and quality acceptance.

[0064] Between draining oil or releasing the storage air pressure and installing accessories, add a set of pre-installation inspection and testing procedures; between internal inspection and wiring and vacuuming, add a set of insulating oil extraction procedures.

[0065] Construction preparation includes transformer oil filtration facilities, vacuum pumps, compressed dry air and related accessories, oil storage tanks, a dedicated temporary power supply for transformer installation, transformer accessories, and fire extinguishing equipment.

[0066] During the installation of transformer accessories, the transformer body should be exposed to the air with the relative humidity of the environment less than 75%. Dry air should be added to maintain positive pressure in the installation environment and keep the transformer body dry. During installation, only one installation point should be opened at a time and covered with plastic film. The continuous exposure time should not exceed 8 hours. When the atmospheric humidity exceeds 75%, work should be stopped.

[0067] Hot oil circulation includes confirming the power supply and circuit of the oil filter, grounding the oil tank, oil filter, metal pipes, etc., inspecting the prepared oil storage tank, draining the residual oil inside, and cleaning it with transformer insulating oil. Before entering the oil tank, the oxygen content in the oil tank is checked and must not be lower than 18%. The oil filter, oil pipes, tees, and valves used in the transformer installation process are cleaned with insulating oil. Oil extraction and cleaning operations are carried out in a dry environment. After cleaning, the corresponding electrical tests are performed. After the tests are passed, the transformer insulating oil is sequentially passed through the oil filter and injected into the oil storage tank. The pipeline between the oil filter and the oil tank is connected. The volume and number of oil tanks are determined according to the actual needs on site. After the pipeline connection is completed and confirmed, the insulating oil in the oil tank is circulated and vacuum degassed.

[0068] Vacuum oil filling includes: Before vacuuming, the valve between the oil tanker and the main oil tank should be closed. At the same time, the exhaust valve at the top of the oil tanker or the drain valve at the bottom should be opened. Vacuum treatment of the transformer is carried out by a vacuum pump. Every hour, the valve in front of the vacuum residual pressure gauge is opened to measure and record the vacuum degree of the transformer. After each measurement, the valve is closed. When the vacuum degree in the transformer body reaches the vacuum leakage test standard required by the manufacturer's instructions, a vacuum leakage test is carried out on the transformer. The transformer is evacuated from the main breather interface or from the special vacuum valve of the oil conservator. After evacuating to 1.0 mbar (100 Pa), the vacuum pump valve is closed. The time and vacuum degree 1 at this time and vacuum degree 2 after 1 hour are recorded. The leakage rate is calculated as follows: Leakage rate = (vacuum degree 2 - vacuum degree 1) × oil tank volume. The leakage rate shall not exceed 10 mbar / s. The vacuum pump is turned on again until the vacuum degree reaches below 1.0 mbar and is maintained for 48 hours.

[0069] Before hot oil circulation, the oil pipes should be evacuated to remove all air. Hot oil circulation should then be performed simultaneously on the transformer body and cooler. During hot oil circulation, the temperature of the oil entering the transformer from the oil filter should not be lower than 50℃, and the temperature inside the oil tank should not be lower than 40℃. Generally, the temperature in the heating and dehydration tank of the oil filter should be controlled within the range of 65 ± 5℃. When the average daily ambient temperature is lower than 10℃, insulation measures should be taken for the oil tank. During hot oil circulation, the outlet temperature of the oil filter should be controlled between 55-65℃, the oil flow rate should be 6000 L / h, and five times the total oil volume should be circulated. After circulating three times the total oil volume, oil samples should be taken from the oil tank, radiator, and oil conservator for testing. If the test results do not meet the requirements (withstand voltage higher than 70kV, trace water lower than 10ppm, air content lower than 1.0%), the oil should be treated until it meets the requirements. For a forced oil circulation transformer, half of the unit should be started to participate in the circulation during the hot oil circulation process, and the oil should be replaced every 8 hours. 。

[0070] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A method for installing the main transformer in an offshore substation, characterized in that: include: Pre-positioning checks; Basic verification; Confirmation and marking of the exact center point; The main body installation process includes: pre-positioning inspection followed by foundation verification, then center point confirmation, followed by marking and positioning, and finally main body installation. The pre-positioning inspection includes: personnel inspection (confirming the presence of safety officers, operators, and commanders); equipment inspection (inspecting and testing the installation equipment, command intercom equipment, and monitoring equipment to ensure they are in normal working order, reporting any malfunctioning equipment for repair, and conducting a re-inspection after repair); and site inspection. Confirm the site's enclosure status, flatness, and the cleanliness of debris at the installation location, and ensure all non-staff members have left the site; these three checks should be conducted simultaneously, and proceed to the next step only after all three checks are confirmed to be passed. The foundation verification includes two aspects: steel columns, butt welds, and the offset of the center of the reserved hole. Steel columns: the deviation between the centerline of the steel column and the positioning axis, with a deviation range of 0-5cm; benchmark elevation, with an elevation error range of +5 to -8cm; verticality, with the bottom column having a verticality of 10cm and a total column height of 35cm; butt welds: weld reinforcement, with a height b less than or equal to 20mm; weld misalignment, with an misalignment error range controlled between 0.1 and 3mm; support surface: elevation error range of ±3.0cm, levelness of L / 1000; reserved hole center offset: offset error range of 10cm; during verification, each set of parameters should be measured and recorded, and the recorded data should be compared with the defined data range. The measurements are compared to ensure that each set of measurements is within the specified range before proceeding to the next step; otherwise, the next step is not allowed. After the basic verification data is passed, the center point of the placement position corresponding to the steel column is determined by connecting four points using the measured steel column data. Based on the measured center point, a line is drawn at the installation position for positioning. After the center point is confirmed, the main body is installed: a four-point hook and four-point lifting lug method is used, with a crossbeam, a steel wire rope of 16 meters in length, and a ring method is used. The spacing between the lifting points of the balance beam is 11 meters. The steel wire rope diameter and allowable lifting weight are calculated as follows: the weight of the lifting part G = 301 tons, using the 4-point method, F = 301000 / 4 / cosl5° = 77.58 tons; a 65mm diameter sling is selected; all lifting lugs are used during lifting; the horizontal tilt angle of the transformer body in the long axis direction does not exceed 150° when transported and placed in place; when the crane lifts the transformer off the ground; 200-300mm After a 5-minute test stop, the crane was directed to move the transformer to the vicinity of the foundation. Once it was slowly raised to a sufficient height, the transformer was slowly and reliably lowered back to its pre-installed position.

2. The method for installing the main transformer of an offshore substation according to claim 1, characterized in that: The installation of the main body includes: construction preparation; draining oil and releasing storage air pressure; accessory installation; internal inspection and wiring; vacuuming; vacuum oil injection; vacuum breaking and venting; hot oil circulation; secondary wiring of cables; on-site inspection and testing; and quality acceptance.

3. The method for installing the main transformer of an offshore substation according to claim 2, characterized in that: Between the oil draining and release of storage air pressure and accessory installation, a set of pre-installation inspection and testing procedures is added. Between internal inspection and wiring and vacuuming, a set of insulating oil extraction procedures is added.

4. The method for installing the main transformer in an offshore substation according to claim 2, characterized in that: The construction preparation includes: transformer oil filtration facilities, vacuum pump, compressed dry air and supporting accessories, oil storage tank, special temporary power supply for transformer installation, transformer accessories, fire extinguishing equipment. During the installation of the transformer accessories, the transformer body is exposed to the air, the relative humidity of the environment is less than 75%, and dry air is added to maintain the positive pressure of the installation environment and keep the body dry. During installation, only one installation point is opened at a time and covered with plastic film. The continuous exposure time does not exceed 8 hours. When the atmospheric humidity exceeds 75%, work is stopped.

5. The method for installing the main transformer of an offshore substation according to claim 2, characterized in that: The hot oil circulation process includes confirming the power supply and circuit of the oil filter, grounding the oil tank, oil filter, and metal pipes, inspecting the prepared oil storage tank, draining residual oil, and cleaning it with transformer insulating oil. Before entering the oil tank, the oxygen content in the tank is checked and must not be lower than 18%. The oil filter, oil pipes, tees, and valves used during transformer installation are cleaned with insulating oil. Oil extraction and cleaning operations are carried out in a dry environment. After cleaning, corresponding electrical tests are performed. After passing the tests, the transformer insulating oil is sequentially injected into the oil storage tank through the oil filter. The pipeline between the oil filter and the oil tank is connected. The volume and number of oil tanks are determined according to actual site needs. After the pipeline connection is completed and confirmed, the insulating oil in the oil tank is circulated and vacuum degassed. During the degassed process, the insulating oil in each oil tank is degassed one by one through the valves until the oil sample test is qualified. Before injecting the insulating oil in the oil tank into the transformer, an oil sample should be taken from the bottom of the oil storage tank and the insulating oil sample should be subjected to corresponding electrical tests.

6. The method for installing the main transformer in an offshore substation according to claim 2, characterized in that: The vacuum oil injection process includes: before vacuuming, closing the valve between the oil tanker and the main oil tank, and simultaneously opening the exhaust valve at the top of the oil tanker or the drain valve at the bottom. Vacuuming the transformer using a vacuum pump, and every hour, opening the valve before the vacuum residual pressure gauge to measure and record the transformer's vacuum level, closing the valve after each measurement. When the vacuum level inside the transformer reaches the vacuum leakage test standard required by the manufacturer's instructions, a vacuum leakage test is performed on the transformer. Vacuuming is performed on the transformer from the main breather interface or from the dedicated vacuum valve of the oil conservator until it reaches 1.0 mbar. The vacuum pump valve is then closed, and the time and vacuum level 1 at this point, and the vacuum level 2 one hour later, are recorded. The leakage rate is calculated as: Leakage rate = (Vacuum level 2 - Vacuum level 1) × oil tank volume. The leakage rate must not exceed 10 mbar / s. The vacuum pump is then restarted until the vacuum level reaches below 1.0 mbar and maintained for 48 hours.

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