Micro-positive pressure cooling system for converter station of offshore flexible DC transmission project

Abstract

The present invention relates to a micro-positive pressure cooling system for a converter station of an offshore flexible direct current transmission project to ensure the normal operation of the equipment, including a seawater circulation module, a freshwater circulation module and a heating equipment circulation cooling module, a heat exchanger I is provided between the seawater circulation module and the freshwater circulation module, and a heat exchanger II is provided between the freshwater circulation module and the heating equipment circulation cooling module; the freshwater circulation module is connected with a pressure instrument II for collecting the freshwater operating pressure F2 in the freshwater circulation module, the heating equipment circulation cooling module is connected with a pressure instrument III for collecting the coolant operating pressure F3 in the heating equipment circulation cooling module and a booster pump II for increasing the coolant operating pressure; the pressure instrument II, the pressure instrument III and the booster pump II are all electrically connected to a control module, and the control module controls the action of the booster pump II according to the freshwater operating pressure F2 and the coolant operating pressure F3 obtained by the pressure instrument II and the pressure instrument III, ensuring that F3>F2. The present invention is applicable to the field of direct current transmission.

Description

Technical Field

[0001] The present invention relates to a micro-positive pressure cooling system for a converter station of an offshore flexible direct current transmission project, and is applicable to the field of direct current transmission. Background Art

[0002] With the rapid development of the new energy industry, the scale of offshore wind power construction is expanding, and the problem of transmitting the generated electric energy to the corresponding power consumption area is faced. According to past experience, the traditional wind power transmission method generally adopts the high-voltage AC grid connection method, but this method is limited to small-scale, offshore wind farms. As offshore wind power development enters the deep sea and large-scale development, the high-voltage flexible direct current transmission method is more economical than the high-voltage AC transmission method, so the construction of offshore converter stations for conversion and boosting came into being.

[0003] During the operation of offshore converter stations, converter valves, connecting transformers and other electrical equipment will generate a lot of heat (10,000 kW level). Timely and reliable cooling of various heat-generating equipment is the basic prerequisite for the safe operation of offshore converter stations. Offshore converter stations are located in the open sea, where the temperature of seawater is relatively stable and inexhaustible. Considering seawater as a cooling water source according to local conditions has a very obvious cost advantage.

[0004] However, the conductivity of seawater is generally around 50,000μs / cm, the conductivity of fresh water is around 5-20μs / cm, and the conductivity of the cooling medium of the converter valve is generally required to be less than 0.5μs / cm. If seawater is used to directly exchange heat with the cooling medium in the heating equipment, once leakage occurs, the high-conductivity seawater will enter the low-conductivity internal cooling circulation system, which will seriously affect the normal operation of the equipment and even cause the equipment to stop operating or be damaged. In addition, due to the complex composition and strong corrosiveness of seawater, it is not suitable for direct cooling of various equipment in the converter station. Summary of the invention

[0005] The technical problem to be solved by the present invention is: in view of the above-mentioned problems, a micro-positive pressure cooling system for a converter station of an offshore flexible DC transmission project is provided to ensure the normal operation of the equipment.

[0006] The technical solution adopted by the present invention is: a micro-positive pressure cooling system for a converter station of an offshore flexible direct current transmission project, characterized in that: it comprises a seawater circulation module, a fresh water circulation module and a heat generating equipment circulation cooling module, a heat exchanger I for heat exchange between the seawater circulation module and the fresh water circulation module is provided, and a heat exchanger II for heat exchange between the fresh water circulation module and the heat generating equipment circulation cooling module is provided;

[0007] The fresh water circulation module is connected to a pressure meter II for collecting the fresh water operating pressure F2 in the fresh water circulation module, and the heating equipment circulation cooling module is connected to a pressure meter III for collecting the coolant operating pressure F3 in the heating equipment circulation cooling module and a booster pump II for increasing the coolant operating pressure;

[0008] The pressure instrument II, pressure instrument III and booster pump II are all electrically connected to the control module. The control module controls the operation of booster pump II according to the fresh water operating pressure F2 and coolant operating pressure F3 obtained by pressure instrument II and pressure instrument III to ensure that F3>F2.

[0009] The seawater circulation module is connected to a pressure instrument I for collecting the seawater operating pressure F1 in the seawater circulation module, and the fresh water circulation module is connected to a booster pump I for increasing the fresh water operating pressure;

[0010] The pressure meter I and the booster pump I are electrically connected to a control module, and the control module controls the booster pump I to operate according to the seawater operating pressure F1 and the fresh water operating pressure F2 obtained by the pressure meter I and the pressure meter II to ensure that F2>F1.

[0011] F3 is 10-15% larger than F2; F2 is 10-15% larger than F1.

[0012] The seawater circulation module has a seawater pump group, the water intake of the seawater pump group is located below the sea level, the water outlet of the seawater pump group is connected to the cold side input end of the heat exchanger I through a water pipe connected to a seawater filter and the pressure instrument I, and the cold side output end of the heat exchanger I is connected to the sea through a water outlet pipe.

[0013] The fresh water circulation module comprises a fresh water pipeline I connecting the hot side output end of the heat exchanger I and the cold side input end of the heat exchanger II, and a fresh water pipeline II connecting the cold side output end of the heat exchanger II and the hot side input end of the heat exchanger I, wherein the fresh water pipeline I is equipped with a water pump I, the booster pump I and a pressure instrument II.

[0014] The fresh water pipeline I is connected with a valve.

[0015] The heat-generating equipment circulating cooling module comprises a coolant pipeline I connecting the hot side output end of the heat exchanger II and the input end of the heat-generating equipment radiator, and a coolant pipeline II connecting the hot side input end of the heat exchanger II and the output end of the heat-generating equipment radiator, wherein the coolant pipeline I is provided with the pressure instrument III, and the coolant pipeline II is provided with a water pump II and the booster pump II.

[0016] The seawater circulation module also includes a marine life prevention device and a seawater filter.

[0017] The beneficial effects of the present invention are as follows: the present invention utilizes the heat transfer of seawater and fresh water through the seawater circulation module and the fresh water circulation module to effectively cool the various heating devices on the offshore platform. In the present invention, the area where seawater flows is located in the external cooling part, which only occupies a small part of the entire cooling system, and fresh water occupies a large proportion in the system. When the system uses fresh water to operate, the corrosion of pipes and valve accessories will be greatly reduced, the cycle requiring regular maintenance will increase significantly, the maintenance cost will be reduced, and the material requirements for pipes and accessories under fresh water operation conditions will be reduced, the range of options will be increased, and the material cost will be reduced.

[0018] The present invention controls the coolant operating pressure F3 to be greater than the fresh water operating pressure F2, and the fresh water operating pressure F2 is greater than the sea water operating pressure F1. Even if the pipeline or plate heat exchanger is corroded and leaks, it can ensure that the high-conductivity cooling medium will not leak into the low-conductivity cooling medium for a period of time, thereby preserving the safety of the core equipment. It buys time for early warning and maintenance of the equipment and improves the reliability of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a structural schematic diagram of an embodiment.

[0020] In the figure: 1. Seawater pump group; 2. Anti-marine life device; 3. Heat exchanger I; 5. Heat exchanger II; 6-1. Water pump I; 6-2. Water pump II; 7. Converter valve; 8. Transformer; 9. Air conditioner; 10-1. Pressure instrument I; 10-2. Pressure instrument II; 10-3. Pressure instrument III; 11-1. Booster pump I; 11-2. Booster pump II; 12. Valve. DETAILED DESCRIPTION

[0021] like Figure 1 As shown, this embodiment is a micro-positive pressure cooling system for a converter station of an offshore flexible DC transmission project, comprising a seawater circulation module, a fresh water circulation module and a heat generating equipment circulation cooling module, wherein a heat exchanger I is provided between the seawater circulation module and the fresh water circulation module, and a heat exchanger II is provided between the fresh water circulation module and the heat generating equipment circulation cooling module.

[0022] In this example, the seawater circulation module has a seawater pump group and an anti-marine life device. The water intake of the seawater pump group is located a certain distance below the sea level. The water outlet of the seawater pump group is connected to the cold side input end of the heat exchanger I through a water pipe. The cold side output end of the heat exchanger I is connected to the sea through the water outlet pipe, and a pressure instrument I is installed on the water pipe.

[0023] In this embodiment, the anti-marine life device uses a sodium hypochlorite generator. When seawater enters the anti-marine life device, the device generates sodium hypochlorite by electrolyzing seawater and transports it to the water intake of the seawater pump group to ensure that all pipe sections and components of the seawater circulation unit are not affected by marine life.

[0024] In this embodiment, the fresh water circulation module has a fresh water pipeline I and a fresh water pipeline II. One end of the fresh water pipeline I is connected to the hot side output end of the heat exchanger I, and the other end is connected to the cold side input end of the heat exchanger II through a valve. A water pump I, a booster pump I and a pressure instrument II are installed on the fresh water pipeline I; the fresh water pipeline II is connected to the cold side output end of the heat exchanger II and the hot side input end of the heat exchanger I.

[0025] In this example, the heat-generating equipment circulating cooling module has a coolant pipeline I connecting the hot-side output end of the heat exchanger II and the radiator input end of the heat-generating equipment (transformer, converter valve, air conditioner), and a coolant pipeline II connecting the radiator output end of the heat-generating equipment and the hot-side input end of the heat exchanger II, wherein a pressure instrument III is installed on the coolant pipeline I, and a water pump II and a booster pump II are installed on the coolant pipeline II.

[0026] In this embodiment, pressure instrument I, booster pump I, pressure instrument II, valve, booster pump II, pressure instrument III, etc. are all connected to the control module by circuits. The control module obtains the seawater operating pressure F1 in the seawater circulation module, the fresh water operating pressure F2 in the fresh water circulation module, and the coolant operating pressure F3 in the heat generating equipment circulation cooling module through pressure instruments I, II, and III, respectively, and ensures that F2 is 10-15% larger than F1, and F3 is 10-15% larger than F2 by controlling booster pump I and booster pump II. When the monitored pressure value is lower than the lower limit of the set value, the corresponding booster pump is started for pressurization; when the monitored pressure value is higher than the upper limit of the set value, the corresponding booster pump is stopped to ensure that the entire system is in a state of slight positive pressure.

[0027] The cooling method of this embodiment is as follows:

[0028] The coolant in the circulating cooling module of the heat generating device performs the first heat exchange with the cooled device to obtain high-temperature coolant;

[0029] The high-temperature coolant undergoes a second heat exchange with the low-temperature fresh water in the fresh water circulation module, and the low-temperature fresh water is converted into high-temperature fresh water;

[0030] The high-temperature fresh water undergoes a third heat exchange with the low-temperature seawater in the seawater circulation module to form high-temperature seawater, which is then discharged into the sea.

[0031] The above embodiments are only used to explain the inventive concept of the present invention, rather than to limit the protection of the rights of the present invention. Any non-substantial changes to the present invention using this concept shall fall within the protection scope of the present invention.

Claims

1. A micro-positive pressure cooling system for a converter station of an offshore flexible DC transmission project, characterized in that: It comprises a seawater circulation module, a freshwater circulation module and a heat generating equipment circulation cooling module, wherein a heat exchanger I (3) for heat exchange between the seawater circulation module and the freshwater circulation module is provided, and a heat exchanger II (5) for heat exchange between the freshwater circulation module and the heat generating equipment circulation cooling module is provided; The fresh water circulation module is connected to a pressure meter II (10-2) for collecting the fresh water operating pressure F2 in the fresh water circulation module; the fresh water circulation module is connected to a booster pump I (11-1) for increasing the fresh water operating pressure; The heat generating equipment circulation cooling module is connected with a pressure meter III (10-3) for collecting the operating pressure F3 of the coolant in the heat generating equipment circulation cooling module and a booster pump II (11-2) for increasing the operating pressure of the coolant; The seawater circulation module is connected to a pressure instrument I (10-1) for collecting the operating pressure F1 of the seawater in the seawater circulation module; The pressure meter II (10-2), the pressure meter III (10-3) and the booster pump II (11-2) are all electrically connected to the control module, and the control module controls the operation of the booster pump II (11-2) according to the fresh water operating pressure F2 and the coolant operating pressure F3 obtained by the pressure meter II (10-2) and the pressure meter III (10-3), so as to ensure that F3>F2; F3 is 10-15% larger than F2; The pressure meter I (10-1) and the booster pump I (11-1) are electrically connected to a control module, and the control module controls the booster pump I (11-1) to operate according to the seawater operating pressure F1 and the fresh water operating pressure F2 obtained by the pressure meter I (10-1) and the pressure meter II (10-2), so as to ensure that F2>F1; F2 is 10-15% greater than F1; The fresh water circulation module comprises a fresh water pipeline I connecting the hot side output end of the heat exchanger I (3) and the cold side input end of the heat exchanger II (5), and a fresh water pipeline II connecting the cold side output end of the heat exchanger II (5) and the hot side input end of the heat exchanger I (3), wherein the fresh water pipeline I is equipped with a water pump I (6-1), the booster pump I (11-1) and a pressure meter II (10-2); The heat-generating device circulating cooling module comprises a cooling liquid pipeline I connecting the hot side output end of the heat exchanger II (5) and the input end of the heat-generating device radiator, and a cooling liquid pipeline II connecting the output end of the heat-generating device radiator and the hot side input end of the heat exchanger II (5), wherein the cooling liquid pipeline I is provided with the pressure instrument III (10-3), and the cooling liquid pipeline II is provided with a water pump II (6-2) and the booster pump II (11-2).

2. The micro-positive pressure cooling system for a converter station of an offshore flexible DC power transmission project according to claim 1 is characterized in that: The seawater circulation module comprises a seawater pump group (1), the water inlet of the seawater pump group (1) is located below the sea level, the water outlet of the seawater pump group (1) is connected to the cold side input end of the heat exchanger I (3) via a water pipe connected to a seawater filter (3) and the pressure instrument I (10-1), and the cold side output end of the heat exchanger I (3) is connected to the sea via a water outlet pipe.

3. The micro-positive pressure cooling system for a converter station of an offshore flexible DC power transmission project according to claim 1 is characterized in that: The fresh water pipeline I is connected with a valve (12).

4. The micro-positive pressure cooling system for a converter station of an offshore flexible DC power transmission project according to claim 1 is characterized in that: The seawater circulation module also includes a marine life prevention device (2) and a seawater filter (3).

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