CN110208618B - Multi-condition DC cable water circulation forced cooling test platform under DC heat source - Google Patents

Abstract

the invention discloses a multi-working-condition direct-current cable water circulation forced cooling test platform under a direct-current heat source, which relates to the field of direct-current cable conveying capacity improvement and test tests, wherein the condition of a submarine cable landing section area is complex, the influence of the environment and weather is large, different laying working conditions are required to be simulated for the bottleneck section area to study the influence of environmental factors on the conveying capacity, and corresponding measures are provided to improve the conveying capacity.

Description

Multi-condition DC cable water circulation forced cooling test platform under DC heat source

technical field

The invention relates to the field of DC cable transmission capacity improvement and testing, in particular to a multi-working-condition DC cable water circulation forced cooling test platform under a DC heat source.

Background technique

High-voltage DC cables have become the first choice for submarine cable transmission projects due to their long transmission distance, good system stability, and large transmission capacity. The ambient temperature of the submarine cable on the seabed is relatively stable, generally lower than 10°C, and not higher than 20°C in the shallow sea. This temperature range can ensure a better and stable heat dissipation environment, and can transmit a larger current. The landing section from seawater to the shore is the key to measuring the transmission capacity of the entire cable. This transition cable may be exposed to sunlight for a long time, or it may be buried in soil that is not easy to dissipate heat. The heat dissipation environment is poor, and it is affected by the weather The environmental impact is greater. Therefore, it is necessary to simulate different laying conditions for this bottleneck area, and to study the influence of environmental factors such as temperature, humidity, soil thermal resistivity on the conveying capacity, and propose low thermal resistance backfill materials to replace the soil in the landing section, and water circulation for forced cooling. Capacity improvement measures, the actual improvement effect is verified through the current carrying capacity test, and the scientific means and evaluation basis are provided for the improvement of the transmission capacity of the landing section of the HVDC submarine cable.

At present, most of the DC current-carrying current tests still use the method of applying AC current by the step-up transformer. After obtaining the AC current-carrying capacity test data, the DC current-carrying capacity is deduced from the theoretical model. The equivalence between the two has not been fundamentally resolved, and there may be a certain error between the reversed DC current carrying capacity and the real value. In particular, when choosing to conduct tests outdoors, environmental factors have a great influence on the test results, sometimes it is difficult to obtain accurate and objective data, and there has been no good solution on the market.

SUMMARY OF THE INVENTION

The technical problem to be solved and the technical task proposed by the present invention are to perfect and improve the existing technical scheme, and provide a multi-condition DC cable water circulation forced cooling test platform under the DC heat source, so as to truly reflect the cable's performance under different laying conditions. The purpose of DC transmission capacity is to verify the effect of water circulation forced cooling on the improvement of transmission capacity through long-term continuous tests. Therefore, the present invention adopts the following technical solutions.

Multi-condition DC cable water circulation forced cooling test platform under DC heat source, including environmental area module to simulate different laying conditions of bipolar DC submarine cable landing section, DC current application unit, water circulation cooling unit, cable temperature measurement unit and environmental information collection unit , 2 cables laid in parallel in the environmental area are short-circuited together at the end through large-section short-circuit terminals to form a closed current loop. The DC current application unit, the water circulation cooling unit and the cable temperature measurement unit are all connected to the PLC as the lower computer. The control cabinet realizes the functions of up-current, cooling, temperature measurement and environmental information collection for the cable, and the PLC control cabinet and the environmental information collection unit are connected to the overall computer control system as the upper computer.

The DC current heat source is used to carry out the up-current test, and the obtained data can directly and truly reflect the DC current carrying capacity of the cable, and at the same time greatly reduce the capacity and power consumption of the test power supply; the test platform can carry out multi-cycle, long-term continuous tests, and Realize automatic data collection and storage. The environmental area module can effectively simulate various environmental areas in the landing section, and can simulate different working conditions of the landing section of the DC submarine cable. The equipped environmental information acquisition unit can be used for in-depth research on air temperature and humidity. , rainfall, wind speed, sunlight radiation intensity and other environmental factors on the transmission capacity, provide technical guidance for the safety, controllability and economy of the island laying cables; the use of water circulation cooling can make the cable in a constant temperature and controllable heat dissipation environment, the entire test platform can meet multiple research tests of DC cables, truly reflect the DC transmission capacity of cables under different laying conditions, and verify the effect of water circulation forced cooling on the improvement of transmission capacity through long-term continuous tests. Automatic operation High level, reduce the probability of personal injury and equipment damage, the overall structure is compact, and the action is reliable.

As the preferred technical means: the environmental area module includes the common soil backfill area, the low thermal resistance material backfill area, the cable trench area, the direct sunlight area, the water circulation forced cooling bipolar and the same tube area, the water circulation forced cooling bipolar double tube area and the parallel Lay water pipe cooling area; common soil backfill area, cable trench area and direct sunlight area simulate three conventional laying methods of soil direct burial, cable trench laying and air laying respectively; low thermal resistance material backfill area with low thermal resistance coefficient Replace ordinary soil with low thermal resistance backfill material with better thermal stability to improve the heat dissipation environment of the cable; the cooling area of parallel laying water pipes is an indirect cooling area, that is, cooling pipes are laid in parallel in the soil near the cable, and circulating cooling water is passed into the pipe to cool down. Reduce the soil temperature around the cable, thereby improving the heat dissipation environment; the water circulation forced cooling bipolar same tube area and the water circulation forced cooling bipolar double tube area are the direct cooling area, that is, the cable is directly put into the cooling pipe, and the cooling water is passed into the casing. The cable is directly immersed in water; in the area of forced cooling of water circulation, two cables laid in parallel are placed in the same cooling pipe; in the area of forced cooling by water circulation, two cables laid in parallel are placed in two different cooling pipes The pipes are cooled independently. It can effectively realize the simulation of different laying conditions of the landing section of the bipolar DC submarine cable, and take away the heat through the water circulation cooling, which can effectively improve the heat dissipation effect.

As a preferred technical means: the DC current applying unit adopts a three-phase bridge rectifier circuit and an LC filter circuit to realize DC voltage boosting, that is, applying DC voltage at both ends of the cable. Effectively realize equipment control and signal acquisition. The DC current application unit adopts the DC pressure method, that is, a DC voltage is applied at both ends of the cable, and a low-voltage and large current is generated at both ends of the cable. The DC current carrying capacity of the cable does not need to be converted, and at the same time, the capacity and power consumption of the test power supply are greatly reduced, which solves the drawbacks of the traditional alternating induced current.

As a preferred technical means: the water circulation cooling unit includes a water circulation treatment system, a water inlet pipe, a return pipe and a cooling pipe. The cooling water enters the cooling pipe where the cable is located from the water inlet pipe, and the heat generated by the current applied by the cable is taken away through the circulating water, and finally passes through the return pipe. It flows back to the water circulation treatment system for re-cooling, thus forming a closed water circulation loop. The water outlet temperature and flow sensors are provided on the water inlet pipe side of the water circulation cooling unit, and the return water temperature sensor is provided on the return pipe side of the water circulation cooling unit. , the water circulation treatment system is a standard cooling water treatment device, which is provided with a flow control module and a cooling water temperature control module. It can effectively realize forced cooling of water circulation, with good controllability and good cooling effect.

As a preferred technical means: the cable temperature measuring unit includes several temperature measuring point thermocouples evenly distributed in each area of the environmental area module and temperature measuring point thermocouples arranged inside the cable in the water environment. Through the temperature measurement point thermocouples distributed in each area and inside the cable, the temperature measurement and control of each environmental area and test cable can be effectively realized.

As the preferred technical means: the environmental information collection unit includes real-time measurement of the environmental data that affects the transmission capacity of the cable, such as atmospheric temperature, humidity, rainfall, solar radiation intensity, wind speed, and the thermal resistivity of the soil in the directly buried laying area around the cable test loop. Various sensors are connected to the storage module for environmental information data storage. Effective collection of environmental information.

Beneficial effects:

1) Using a DC heat source to carry out the current up-current test overcomes the drawbacks of using the alternating induced current method, and the obtained data can directly and truly reflect the DC current carrying capacity of the cable, and at the same time greatly reduce the capacity and power consumption of the test power supply.

2) The test platform can carry out multi-cycle and long-term continuous tests, and realize automatic data acquisition and storage, which can simulate different working conditions of the landing section of the DC submarine cable. The equipped environmental information acquisition unit can be used for in-depth research on air temperature, humidity, The influence of environmental factors such as rainfall, wind speed, and solar radiation intensity on the transmission capacity provides technical guidance for the safety, controllability and economy of laying cables on islands.

3) The use of water circulation cooling can keep the cable in a heat dissipation environment with constant temperature and controllable temperature. On the one hand, it reduces the error of the test caused by changes in external environmental conditions, improves the reproducibility of test results and the accuracy of theoretical modeling, and facilitates theoretical calculation. The mutual confirmation between the results and the test results, on the other hand, can improve the heat dissipation environment of the cable to improve the transmission capacity, and through the test to verify the effect of improving the transmission capacity, it provides a scientific basis for the application of water circulation forced cooling methods in practical projects to improve the transmission capacity. Provide support for further exploration of the ultimate transmission capacity of DC cables.

4) The entire test platform can meet the needs of carrying out a number of research experiments on DC cables, with a high degree of automation, reducing the probability of personal injury and equipment damage, compact overall structure, reliable operation and low cost.

Description of drawings

FIG. 1 is a schematic diagram of the environment area division of the present invention.

FIG. 2 is a schematic diagram of the composition of the functional units of the test platform of the present invention.

Figure 3 is a schematic diagram of the water circulation cooling unit of the present invention.

In the figure: 1- water circulation forced cooling bipolar double pipe area; 2 - cable trench area; 3 - water circulation forced cooling bipolar same pipe area; 4 - direct sunlight area; 5 - low thermal resistance material backfill area; 6 - parallel laying of water pipes Cooling area; 7- Ordinary soil backfill area; 8- DC current application unit; 9- Water circulation cooling unit; 10- Cable; 11- Cable temperature measurement unit; 901- water inlet pipe; 902- return pipe; 903- cooling pipe; 904- water circulation treatment system; 905- water temperature and flow sensor; 906- return water temperature sensor.

Detailed ways

The technical solutions of the present invention will be further described in detail below with reference to the accompanying drawings.

As shown in Figure 1-3, the multi-condition DC cable water circulation forced cooling test platform under the DC heat source includes an environmental area module for simulating different laying conditions in the landing section of the bipolar DC submarine cable 10, a DC current application unit 8, and a water circulation cooling unit. 9. The cable temperature measurement unit 11 and the environmental information collection unit 14, the two cables 10 laid in parallel in the environmental area are shorted together at the ends through the large-section short-circuit terminals to form a closed current loop, the DC current application unit 8, the water circulation Both the cooling unit 9 and the cable temperature measurement unit 11 are connected to the PLC control cabinet as the lower computer 12 to realize the functions of upflow, cooling, temperature measurement and environmental information collection for the cable 10, and the PLC control cabinet and the environmental information collection unit 14 are connected to the The overall computer control system of the upper computer 13 .

In order to simulate various environmental areas of the landing section of the cable 10, the environmental area module includes the common soil backfill area 7, the low thermal resistance material backfill area 5, the cable trench area 2, the direct sunlight area 4, the water circulation forced cooling bipolar same tube area 3, Water circulation forced cooling bipolar double pipe area 1 and parallel laying water pipe cooling area 6; common soil backfill area 7, cable trench area 2 and direct sunlight area 4 respectively simulate three conventional soil direct burial laying, cable 10 trench laying and air laying Laying method; low thermal resistance material backfill area 5 uses low thermal resistance backfill material with lower thermal resistance coefficient and better thermal stability to replace ordinary soil to improve the heat dissipation environment of cable 10; parallel laying of water pipe cooling area 6 is an indirect cooling area , that is, a cooling pipe 903 is laid in parallel in the soil near the cable 10, and circulating cooling water is introduced into the pipe to reduce the soil temperature around the cable 10, thereby improving the heat dissipation environment; The pipe area 1 is a direct cooling area, that is, the cable 10 is directly put into the cooling pipe 903, cooling water is passed into the casing, the cable 10 is directly immersed in water, and the heat is taken away through the water circulation; The cables 10 laid in parallel are placed in the same cooling pipe 903, and the bipolar double-pipe area 1 is forced to cool by water circulation. The two cables 10 laid in parallel are placed in two different cooling pipes 903 for independent cooling. It can effectively simulate the different laying conditions of the 10th landing section of the bipolar DC submarine cable, and take away heat through water circulation cooling, which can effectively take away heat and improve the heat dissipation effect.

In order to realize DC current application, the DC current application unit 8 uses a three-phase bridge rectifier circuit and an LC filter circuit to realize DC voltage compression, that is, DC voltage is applied to both ends of the cable 10 . The device control and signal acquisition are effectively realized. The DC current applying unit 8 adopts the DC pressure method, that is, a DC voltage is applied at both ends of the cable 10, and a low-voltage large current is generated at both ends of the cable 10. , It truly reflects the DC current carrying capacity of the cable 10, without conversion, and at the same time greatly reduces the capacity and power consumption of the test power supply, and solves the drawbacks of the traditional alternating induced current.

In order to achieve controllable water circulation cooling, the water circulation cooling unit 9 includes a water circulation treatment system 904, a water inlet pipe 901, a return pipe 902 and a cooling pipe 903. The cooling water enters the cooling pipe 903 where the cable 10 is located from the water inlet pipe 901, and applies current to the cable 10 to generate The heat of the water is taken away by the circulating water, and finally flows back to the water circulation treatment system 904 through the return pipe 902 for re-cooling, thereby forming a closed water circulation loop. The water inlet pipe 901 side of the water circulation cooling unit 9 is provided with water temperature and flow sensors. 905, a return water temperature sensor 906 is provided on the side of the return pipe 902 of the water circulation cooling unit 9, and the water circulation treatment system 904 is a standard cooling water treatment device with a flow control module and a cooling water temperature control module. It can effectively realize forced cooling of water circulation, with good controllability and good cooling effect.

In order to realize the temperature measurement and control of each environmental area and the test cable 10, the cable temperature measurement unit 11 includes several temperature measurement point thermocouples evenly distributed in each area of the environmental area module and the temperature measurement inside the cable 10 set in the water environment Click the thermocouple. It is used to measure the conductor, main insulation and outer skin temperature of the cable 10 in each area and the water temperature in the direct cooling area of the water circulation. Several thermocouples are arranged for each area to monitor the temperature of the temperature measurement point in real time. The cable 10 in the water environment The thermocouple at the internal temperature measurement point adopts special water blocking measures to prevent direct contact of cooling water, which can effectively realize the temperature measurement and control of each environmental area and test cable 10.

In order to realize the collection of environmental information, the environmental information collection unit 14 includes the ambient temperature, humidity, rainfall, sunlight radiation intensity, wind speed and thermal resistivity of the soil in the directly buried laying area around the test loop of the cable 10 that affect the transmission capacity of the cable 10. Sensors for real-time measurement of data, and various sensors are connected to the storage module for environmental information data storage. Effective collection of environmental information.

Using the DC current heat source to carry out the current up-current test, the obtained data can directly and truly reflect the DC current carrying capacity of the cable 10, and at the same time greatly reduce the capacity and power consumption of the test power supply; the test platform can carry out multi-cycle, long-term continuous tests, And realize the automatic data acquisition and storage, the environmental area module can effectively realize the simulation of various environmental areas in the landing section, and can simulate different working conditions of the landing section of the DC submarine cable 10. The equipped environmental information acquisition unit 14 can be used for in-depth research on air The influence of environmental factors such as temperature, humidity, rainfall, wind speed, and solar radiation intensity on the transmission capacity provides technical guidance for the safety, controllability and economy of the island-laying cable 10; the use of water circulation cooling can keep the cable 10 at a constant temperature And the controllable heat dissipation environment, the entire test platform can meet the needs of carrying out a number of research tests of the DC cable 10, truly reflect the DC transmission capacity of the cable 10 under different laying conditions, and through long-term continuous tests to verify that the forced cooling of water circulation is effective in transmission. The ability to improve the effect, the high degree of automatic operation, reduce the probability of personal injury and equipment damage, the overall structure is compact, and the action is reliable.

The multi-condition DC cable water circulation forced cooling test platform under the DC heat source shown in the above Figures 1-3 is a specific embodiment of the present invention. Under the inspiration of , the equivalent modification of its shape, structure, etc., are all within the protection scope of this scheme.

Claims (5)

1. The multi-condition DC cable water circulation forced cooling test platform under the DC heat source is characterized in that: it includes an environmental area module that simulates different laying conditions of the bipolar DC submarine cable (10) landing section, a DC current applying unit (8), a water circulation The cooling unit (9), the cable temperature measurement unit (11) and the environmental information collection unit (14), the two cables (10) laid in parallel in the environmental area are short-circuited together at the ends through large-section short-circuit terminals to form a closed connection. The flow loop, the DC current applying unit (8), the water circulation cooling unit (9) and the cable temperature measuring unit (11) are all connected to the PLC control cabinet as the lower computer (12) to realize current up, cooling, The temperature measurement and environmental information acquisition function, the PLC control cabinet and the environmental information acquisition unit (14) are connected to the computer overall control system as the upper computer (13); The environmental area module includes an ordinary soil backfill area (7), a low thermal resistance material backfill area (5), a cable trench area (2), a direct sunlight area (4), a water circulation forced cooling bipolar same-pipe area (3), Water circulation forced cooling bipolar double pipe area (1) and parallel laying water pipe cooling area (6); common soil backfill area (7), cable trench area (2) and direct sunlight area (4) to simulate direct soil burial and cable laying respectively (10) There are 3 conventional laying methods of trench laying and air laying; low thermal resistance material backfill area (5) Use low thermal resistance backfill material with lower thermal resistance coefficient and better thermal stability to replace ordinary soil to improve the cable ( 10) cooling environment; the cooling area (6) of parallel laying water pipes is an indirect cooling area, that is, a cooling pipe (903) is laid in parallel in the soil near the cable (10), and the circulating cooling water is introduced into the pipe to reduce the surrounding area of the cable (10). Soil temperature, thereby improving the heat dissipation environment; the water circulation forced cooling bipolar and dual pipe area (3), the water circulation forced cooling bipolar double pipe area (1) is a direct cooling area, that is, the cable (10) is directly put into the cooling pipe (903), Cooling water is introduced into the casing, and the cable (10) is directly immersed in the water; the water circulation is forced to cool the bipolar same-pipe area (3) The two cables (10) laid in parallel are placed in the same cooling pipe (903), and the water circulation is forced to The cooling bipolar and double-pipe area (1) places two cables (10) laid in parallel in two different cooling pipes (903) for independent cooling. 2. The multi-condition DC cable water circulation forced cooling test platform under DC heat source according to claim 1, characterized in that: the DC current applying unit (8) adopts a three-phase bridge rectifier circuit and an LC filter circuit to realize DC Pressurizing, ie applying a DC voltage across the cable (10). 3. The multi-condition DC cable water circulation forced cooling test platform under the DC heat source according to claim 1, characterized in that: the water circulation cooling unit (9) comprises a water circulation treatment system (904), a water inlet pipe (901), a return pipe ( 902) and the cooling pipe (903), the cooling water enters the cooling pipe (903) where the cable (10) is located from the water inlet pipe (901), and the heat generated by the current applied to the cable (10) is taken away through the circulating water, and finally passes through the return pipe ( 902) flows back to the water circulation treatment system (904) for re-cooling, thereby forming a closed water circulation loop, and a water outlet temperature and flow sensor (905) is provided on the side of the water inlet pipe (901) of the water circulation cooling unit (9). A return water temperature sensor (906) is provided on one side of the return pipe (902) of the water circulation cooling unit (9), the water circulation treatment system (904) is a standard cooling water treatment device, and is provided with a flow control module and a cooling water temperature control module. 4. The multi-condition DC cable water circulation forced cooling test platform under DC heat source according to claim 1, characterized in that: the cable temperature measurement unit (11) comprises a number of temperature measurements evenly distributed in each area of the environmental area module Spot thermocouples and temperature-measuring spot thermocouples located inside the cable (10) in a water environment. 5. The multi-condition DC cable water circulation forced cooling test platform under DC heat source according to claim 1, characterized in that: the environmental information acquisition unit (14) comprises a The amount, sunlight radiation intensity, wind speed and thermal resistivity of the soil in the directly buried laying area affect the environmental data of the transmission capacity of the cable (10) to measure the environmental data in real time, and various sensors are connected to the storage module for environmental information data storage.

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