Offshore flexible direct current transmission platform converter valve cooling system and layout method

Abstract

The invention provides an offshore flexible direct-current power transmission platform converter valve cooling system and a laying method, and is applied to the technical field of power electronic direct-current power transmission of a power system. The system comprises a converter valve cooling loop, a seawater circulation loop and a heat exchanger, the converter valve cooling loop comprises a cooling medium circulation pump, and the seawater circulation loop comprises a seawater circulation pump; a fluid outlet of the cooling medium circulating pump is close to a cooling medium inlet of the heat exchanger, and a fluid outlet of the seawater circulating pump is far away from a seawater inlet of the heat exchanger, so that the cooling medium side pressure of the heat exchanger is larger than the seawater side pressure. The problem that the safety of flexible direct-current power transmission is threatened due to the fact that a cooling medium of a converter valve cooling system is polluted by seawater infiltration is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of power electronic direct current transmission of power systems, and in particular to a converter valve cooling system and a deployment method for an offshore flexible direct current transmission platform. Background Art

[0002] As an emerging direct current transmission technology, flexible direct current transmission has the characteristics of no need for AC side voltage support, flexible control, high power quality, and small footprint. It is widely used in market fields such as grid interconnection, renewable energy grid connection, island power supply, and urban power grid power supply. As the core equipment of flexible direct current transmission, the converter valve will emit huge heat during operation. The converter valve cooling system is required to take away the heat in the converter valve and dissipate it to the environment in time to ensure the normal operation of the converter valve.

[0003] The converter valve cooling system of the offshore flexible DC transmission platform generally transfers the heat in the cooling medium to the external seawater through a heat exchanger. However, due to the strong corrosiveness of seawater and the aging of pipelines, the heat exchanger may cause infiltration, resulting in high-conductivity seawater contaminating the cooling medium of the converter valve cooling system, threatening the safety of flexible DC transmission. Summary of the invention

[0004] In order to overcome the above-mentioned problem that the cooling medium of the converter valve cooling system is polluted by seawater infiltration and thus threatens the safety of flexible DC power transmission, the present invention provides a converter valve cooling system and a deployment method for an offshore flexible DC power transmission platform.

[0005] On the one hand, the present invention provides a converter valve cooling system for an offshore flexible direct current transmission platform, comprising: a converter valve cooling circuit, a seawater circulation circuit and a heat exchanger, wherein the converter valve cooling circuit comprises a cooling medium circulation pump, and the seawater circulation circuit comprises a seawater circulation pump;

[0006] The fluid outlet of the cooling medium circulation pump is close to the cooling medium inlet of the heat exchanger, and the fluid outlet of the seawater circulation pump is far away from the seawater inlet of the heat exchanger, so that the pressure on the cooling medium side of the heat exchanger is greater than the pressure on the seawater side.

[0007] Optionally, the converter valve cooling circuit further includes a pressurizing device, which is close to the fluid inlet of the cooling medium circulation pump to increase the pressure on the cooling medium side of the heat exchanger.

[0008] Optionally, the converter valve cooling circuit includes a leak detection device, which is respectively arranged at the cooling medium inlet and the cooling medium outlet of the heat exchanger.

[0009] Optionally, the converter valve cooling circuit further includes a first pressure sensor, which is arranged at a cooling medium outlet of the heat exchanger to detect the pressure on the cooling medium side of the heat exchanger;

[0010] The seawater circulation loop comprises a second pressure sensor, which is arranged at the seawater inlet of the heat exchanger to detect the pressure on the seawater side of the heat exchanger.

[0011] Optionally, the converter valve cooling circuit further includes a heater, a first filter, a converter valve and a degassing device which are sequentially arranged between the cooling medium outlet of the heat exchanger and the fluid inlet of the cooling medium circulation pump;

[0012] The seawater circulation loop further includes a sterilization device and a second filter which are sequentially arranged between the fluid outlet of the seawater circulation pump and the seawater inlet of the heat exchanger.

[0013] Optionally, the heat exchanger is a plurality of heat exchangers, and the converter valve cooling circuit and the seawater circulation circuit respectively include electric valves;

[0014] The electric valves are respectively arranged at the cooling medium outlet, cooling medium inlet, seawater inlet and seawater outlet of each heat exchanger.

[0015] Optionally, the converter valve cooling circuit includes a first safety valve, which is arranged between a cooling medium inlet of each converter and a corresponding electric valve, or the first safety valve is arranged between a cooling medium outlet of each converter and a corresponding electric valve;

[0016] The seawater circulation loop comprises a second safety valve, which is arranged between the seawater inlet of each converter and the corresponding electric valve, or the second safety valve is arranged between the seawater outlet of each converter and the corresponding electric valve.

[0017] Optionally, a controller is further included, the controller being electrically connected to the leak detection device and the electric valve respectively, so as to determine the leakage of the current heat exchanger based on the change of the physical properties of the cooling medium at the cooling medium inlet and outlet of the heat exchanger detected by the leak detection device; when it is determined that the current heat exchanger is leaking, the electric valve of any other heat exchanger is controlled to be opened, and the electric valve of the current heat exchanger is closed;

[0018] The other heat exchangers are heat exchangers other than the current heat exchanger.

[0019] On the other hand, the present invention also provides a method for laying out a converter valve cooling system of an offshore flexible DC transmission platform, comprising:

[0020] Arrange a converter valve cooling circuit to cool the converter valve by using a cooling medium in the converter valve cooling circuit;

[0021] Arrange a seawater circulation loop and a heat exchanger to perform heat exchange between the seawater in the seawater circulation loop and the cooling medium in the converter valve cooling loop through the heat exchanger;

[0022] A cooling medium circulation pump is arranged at a cooling medium inlet of the heat exchanger in the converter valve cooling circuit, and a seawater circulation pump is arranged at a seawater inlet of the heat exchanger in the seawater circulation circuit, so that the pressure on the cooling medium side of the heat exchanger is greater than the pressure on the seawater side.

[0023] Optionally, the method further includes: arranging a pressurizing device at a fluid inlet close to the cooling medium circulation pump to increase the pressure on the cooling medium side of the heat exchanger.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] The present invention provides a converter valve cooling system and a layout method for an offshore flexible direct current transmission platform. By placing a cooling medium inlet of a heat exchanger close to a fluid outlet of a cooling medium circulation pump and a fluid outlet of a seawater circulation pump away from a seawater inlet of the heat exchanger, when the cooling medium of a converter valve cooling circuit and the seawater of a seawater circulation circuit are heat exchanged while flowing through the heat exchanger, the pressure on the cooling medium side of the heat exchanger is greater than the pressure on the seawater side, thereby preventing the seawater on the low-pressure side from infiltrating into the cooling medium on the high-pressure side by forming a pressure difference between the seawater side and the cooling medium side, thereby solving the problem of flexible direct current transmission safety caused by seawater infiltration. No additional equipment is required, and the system is highly feasible. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is one of the structural schematic diagrams of a converter valve cooling system for an offshore flexible DC power transmission platform of the present invention;

[0027] Figure 2 This is a second structural schematic diagram of a converter valve cooling system for an offshore flexible DC power transmission platform of the present invention;

[0028] Figure 3 This is a third structural schematic diagram of a converter valve cooling system for an offshore flexible DC power transmission platform of the present invention;

[0029] Among them, 1. cooling circuit of the converter valve; 101. cooling medium circulation pump; 102. pressurizing device; 103. leak detection device; 104. first pressure sensor; 105. heater; 106. first filter; 107. converter valve; 108. degassing device; 109. first safety valve; 2. seawater circulation circuit; 201. seawater circulation pump; 202. second pressure sensor; 203. sterilization device; 204. second filter; 205. second safety valve; 3. heat exchanger; 4. electric valve. DETAILED DESCRIPTION

[0030] The specific implementation modes of the present invention are further described in detail below with reference to the accompanying drawings.

[0031] Example 1

[0032] The present invention provides a converter valve cooling system for an offshore flexible DC transmission platform, the structural schematic diagram of which is shown in FIG. Figure 1 As shown, it includes: a converter valve cooling circuit 1, a seawater circulation circuit 2 and a heat exchanger 3, wherein the converter valve cooling circuit 1 includes a cooling medium circulation pump 101, and the seawater circulation circuit 2 includes a seawater circulation pump 201;

[0033] The fluid outlet of the cooling medium circulation pump 101 is close to the cooling medium inlet of the heat exchanger 3, and the fluid outlet of the seawater circulation pump 201 is far away from the seawater inlet of the heat exchanger 3, so that the pressure on the cooling medium side of the heat exchanger 3 is greater than the pressure on the seawater side.

[0034] In this example implementation, the converter valve cooling circuit 1 refers to a cooling medium circulation circuit for cooling the converter valve 107 of the offshore flexible DC power transmission platform; the seawater circulation circuit 2 refers to a seawater circulation circuit 2 for cooling the cooling medium in the converter valve cooling circuit 1; the cooling medium in the converter valve cooling circuit 1 and the seawater in the seawater circulation circuit 2 are heat exchanged by the heat exchanger 3 to achieve the cooling of the cooling mechanism by the seawater, and in particular, the heat exchanger 3 is a plate heat exchanger 3. In order to enable the cooling medium and seawater to circulate, the converter valve cooling circuit 1 includes a cooling medium circulation pump 101, and the seawater circulation circuit 2 includes a seawater circulation pump 201. By arranging the cooling medium circulation pump 101 as close as possible to the cooling medium inlet of the heat exchanger 3, the pressure on the cooling medium side of the heat exchanger 3 is ensured to be as high as possible. At the same time, by arranging the seawater circulation pump 201 as far as possible from the seawater inlet side of the heat exchanger 3, the pressure on the seawater side of the heat exchanger 3 is reduced as much as possible, so that the pressure on the cooling medium side of the heat exchanger 3 is greater than the pressure on the seawater side, thereby avoiding the safety hazard on the side of the converter valve 107 caused by the infiltration of seawater into the cooling medium in the heat exchanger 3.

[0035] In some embodiments, Figure 2As shown, the converter valve cooling circuit 1 further includes a pressurizing device 102 , and the pressurizing device 102 is close to the fluid inlet of the cooling medium circulation pump 101 to increase the pressure on the cooling medium side of the heat exchanger 3 .

[0036] In this example implementation, by providing a pressurizing device 102 in the converter valve cooling circuit 1, and by providing the pressurizing device 102 close to the fluid inlet of the cooling medium circulation pump 101, the pressure on the cooling medium side of the heat exchanger 3 can be increased as much as possible. When the pressure of the converter valve cooling circuit 1 is lower than a certain value, the cooling medium can be pressurized by the pressurizing device 102 to ensure that the pressure on the cooling medium side of the heat exchanger 3 is higher than the seawater side. Exemplarily, the pressurizing device 102 can be an expansion tank, and the closed expansion tank can realize automatic pressurization of the converter valve cooling circuit 1 by nitrogen pressurization, avoid problems such as control delays and control failures, and improve pressurization efficiency. The pressurizing device 102 ensures that the pressure on the deionization side of the plate heat exchanger 3 is greater than the pressure on the seawater side throughout the heat exchange process, so as to reduce the risk of seawater infiltration into the deionization cycle.

[0037] In some embodiments, Figure 3 As shown, the converter valve cooling circuit 1 includes a leak detection device 103, and the leak detection device 103 is respectively arranged at the cooling medium inlet and the cooling medium outlet of the heat exchanger 3.

[0038] In this example implementation, when the cooling medium in the converter valve cooling circuit 1 is deionized water, the leak detection device 103 can be a conductivity meter, and the conductivity of the deionized water at the cooling medium inlet and outlet of the heat exchanger 3 is detected by respectively setting a conductivity meter at the cooling medium inlet and outlet, and determining whether leakage (seawater infiltration) currently occurs by the conductivity difference between the inlet and outlet. When the cooling medium in the converter valve cooling circuit 1 is oil, that is, the converter valve cooling circuit 1 is oil circulation cooling, the leak detection device 103 can be a water content detector, and the water content at the cooling medium inlet and outlet of the heat exchanger 3 is detected, and determining whether leakage (seawater infiltration) currently occurs by the water content difference between the inlet and outlet. When a liquid leakage is detected, an alarm can be issued and the heat exchanger 3 can be switched to avoid damage to the valve cooling system by the leakage.

[0039] In an example implementation, Figure 3 As shown, the converter valve cooling circuit 1 further includes a first pressure sensor 104, which is disposed at the cooling medium outlet of the heat exchanger 3 to detect the cooling medium side pressure of the heat exchanger 3;

[0040] The seawater circulation loop 2 includes a second pressure sensor 202 . The second pressure sensor 202 is disposed at the seawater inlet of the heat exchanger 3 to detect the pressure on the seawater side of the heat exchanger 3 .

[0041] In this example implementation, pressure sensors are provided on both the converter valve cooling loop 1 and the seawater circulation loop 2. A first pressure sensor 104 is provided at the cooling medium outlet of the heat exchanger 3 to detect the pressure on the cooling medium side of the heat exchanger 3. A second pressure sensor 202 is provided at the seawater inlet of the heat exchanger 3 to detect the pressure on the seawater side of the heat exchanger 3. For plate heat exchangers, countercurrent heat exchange is generally adopted. Therefore, by detecting the outlet pressure of the cooling medium side of the heat exchanger and the inlet pressure of the seawater side, the pressure difference on both sides can be obtained. When the pressure difference does not meet the requirements, the pressurizing device is controlled to open so that the cooling medium outlet pressure is greater than the seawater side inlet pressure, so as to ensure the pressure difference throughout the heat exchange process. By way of example, the first pressure sensor 104 can also be provided at both the cooling medium inlet and outlet of the heat exchanger 3, such as Figure 3 A second pressure sensor 104 may also be provided at the seawater inlet and outlet of the heat exchanger 3, such as Figure 3 The first pressure sensor 104 and the second pressure sensor 202 may be pressure transmitters, and the first pressure sensor 104 and the second pressure sensor 202 may be used to monitor the pressure of the cooling medium side and the seawater side of the heat exchanger 3 in real time, so that leakage problems of the heat exchanger 3 can be discovered in time, and an alarm signal can be sent to the control side of the converter valve cooling system.

[0042] In an example implementation, Figure 3 As shown, the converter valve cooling circuit 1 further includes a heater 105, a first filter 106, a converter valve 107 and a degassing device 108 which are sequentially arranged between the cooling medium outlet of the heat exchanger 3 and the fluid inlet of the cooling medium circulation pump 101;

[0043] The seawater circulation loop 2 further includes a sterilization device 203 and a second filter 204 which are sequentially arranged between the fluid outlet of the seawater circulation pump 201 and the seawater inlet of the heat exchanger 3 .

[0044] In this exemplary embodiment, the cooling medium in the converter valve cooling circuit 1 comes out of the heat exchanger 3 and passes through the heater 105, the first filter 106, the converter valve 107 (i.e., the cooled device) and the degassing device 108 in sequence, and then circulates into the heat exchanger 3 through the cooling medium circulation pump 101. The heater 105 is used to start emergency heating of the cooling medium when the temperature of the cooling medium is too low to prevent condensation on the pipeline. The first filter 106 is used to remove pollutants that may be generated when the cooling medium system circulates, the converter valve 107 is the cooling object of the cooling medium, and the degassing device 108 is used to continuously remove gases that may be generated when the cooling medium system circulates. The normal operation and safety of the converter valve cooling circuit 1 are ensured by the heater 105, the first filter 106, the converter valve 107 and the degassing device 108. The seawater in the seawater circulation loop 2 passes through the seawater circulation pump 201 and passes through the second filter 204 and the sterilizing device 203 in sequence, and then enters the heat exchanger 3 to exchange heat with the cooling medium and then is discharged into the sea. The second filter 204 is used to filter impurities such as mud and sand in the seawater, and the sterilization device 203 is used to kill microorganisms in the seawater, prevent the growth of microorganisms in the pipeline, maintain the patency of the pipeline, and extend the service life of the seawater circulation loop 2. In particular, the sterilization device 203 is a sodium hypochlorite generator, which is used to produce sodium hypochlorite to kill microorganisms in seawater.

[0045] In an example implementation, Figure 3 As shown, the heat exchanger 3 is a plurality of heat exchangers 3, and the converter valve cooling loop 1 and the seawater circulation loop 2 respectively include an electric valve 4;

[0046] The electric valve 4 is respectively arranged at the cooling medium outlet, cooling medium inlet, seawater inlet and seawater outlet of each heat exchanger 3 .

[0047] In this exemplary embodiment, a plurality of heat exchangers 3 may be provided, and an electric valve 4 may be provided at the cooling medium outlet, cooling medium inlet, seawater inlet and seawater outlet of each heat exchanger 3, such as Figure 3 By opening and closing the electric valves 4 corresponding to different heat exchangers 3, the cooling medium and seawater can flow through different heat exchangers 3, thereby realizing the switching of different heat exchangers 3. Figure 3 As shown, QM0001, QM0002, QM0005, QM0006 can be used to open QM0003, QM0004, QM0007, and QM0008 to switch the plate heat exchanger A to the plate heat exchanger B. The heat exchanger 3 with the corresponding heat exchange efficiency can be selected for heat exchange according to the actual cooling medium and seawater temperature to improve the heat exchange efficiency; when the heat exchanger 3 fails, the normal operation of the equipment can be ensured by switching the heat exchanger 3, and the inlet and outlet electric valves 4 on the cooling medium side and the seawater side of the failed heat exchanger 3 can be closed to prevent the seawater from further polluting the entire valve cooling system.

[0048] In an example implementation, Figure 3 As shown, the converter valve cooling circuit 1 includes a first safety valve 109, which is arranged between the cooling medium inlet of each converter and the corresponding electric valve 4, or the first safety valve 109 is arranged between the cooling medium outlet of each converter and the corresponding electric valve 4;

[0049] The seawater circulation loop 2 includes a second safety valve 205 , which is disposed between the seawater inlet of each converter and the corresponding electric valve 4 , or between the seawater outlet of each converter and the corresponding electric valve 4 .

[0050] In this exemplary embodiment, a first safety valve 109 is provided between the cooling medium inlet and outlet of the heat exchanger 3 of the converter valve cooling circuit 1 and the corresponding electric valve 4, that is, a first safety valve 109 is provided between the cooling medium outlet of the heat exchanger 3 and the electric valve 4 at the outlet, or a first safety valve 109 is provided between the cooling medium inlet of the heat exchanger 3 and the electric valve 4 at the inlet, and the first safety valve 109 is used to relieve the pressure of the heat exchanger 3 to prevent the cooling medium remaining in the cooling medium circuit from damaging the heat exchanger 3 due to volume expansion caused by temperature change after the heat exchanger 3 is switched. A second safety valve 205 is provided between the seawater inlet and outlet of the heat exchanger 3 of the seawater circulation circuit 2 and the corresponding electric valve 4, that is, a second safety valve 205 is provided between the seawater outlet of the heat exchanger 3 and the electric valve 4 at the outlet, or a second safety valve 205 is provided between the seawater inlet of the heat exchanger 3 and the electric valve 4 at the inlet, and the function of the second safety valve 205 is similar to that of the first safety valve 109, which will not be described in detail here.

[0051] In an example implementation, Figure 3 As shown, the controller is further included, and the controller is electrically connected to the leakage detection device 103 and the electric valve 4 respectively, so as to determine the leakage of the current heat exchanger 3 based on the change of the physical properties of the cooling medium at the cooling medium inlet and outlet of the heat exchanger 3 detected by the leakage detection device 103; when it is determined that the current heat exchanger 3 is leaking, the electric valve 4 of any other heat exchanger 3 is controlled to be opened, and the electric valve 4 of the current heat exchanger 3 is closed;

[0052] The other heat exchanger 3 is a heat exchanger 3 other than the current heat exchanger 3 .

[0053] In this exemplary embodiment, the controller determines whether leakage occurs currently by receiving data from the leakage detection device 103. If leakage occurs, the controller controls to open the four electric valves 4 of other heat exchangers 3 and close the four electric valves 4 corresponding to the current heat exchanger 3 to achieve the switching of the heat exchanger 3. The other heat exchangers 3 are heat exchangers 3 other than the current heat exchanger 3, that is, other normal heat exchangers 3. For example, Figure 3 As shown, taking the case where plate heat exchanger A is running and plate heat exchanger B is shut down for standby, the control finds that seawater infiltration occurs in heat exchanger A through the difference in conductivity between the inlet and outlet water of conductivity meters QT0001 and QT0002, and the control issues a command to close the inlet and outlet water electric valves 4 on both sides of plate heat exchanger A, and cuts off and isolates plate heat exchanger A to prevent the infiltrated seawater from further contaminating the deionization cycle. At the same time, the electric valves 4 on both sides of plate heat exchanger B are opened, and the standby plate heat exchanger B is switched. The conductivity meters QT0003 and QT0004 are used to detect the inlet and outlet water conductivity of plate heat exchanger B, respectively.

[0054] For example, the structure of the converter valve cooling system of the offshore flexible DC transmission platform of the present invention is as follows: Figure 3As shown, its working principle is as follows: the cooling medium circulation pump 101 and the seawater circulation pump 201 are turned on, the cooling medium and seawater in the converter valve cooling loop 1 and the seawater circulation loop 2 circulate in the corresponding pipelines, the cooling medium is sequentially passed through the heater 105 and the first filter 106 for medium temperature adjustment and medium impurity process, and then the converter valve 107 is cooled, and then the gas that may be generated during the system circulation is continuously removed by the degassing device 108 to avoid gas accumulation and affect the subsequent heat dissipation effect, and then enters the heat exchanger 3 from the cooling medium inlet of the heat exchanger 3 through the pressurizing device 102 (such as an expansion tank) and the cooling medium circulation pump 101. At the same time, seawater is sucked into the pipeline of the seawater circulation loop 2 through the seawater circulation pump 201, and the sucked seawater is sequentially filtered for impurities and sterilized for microorganisms by the second filter 204 and the sterilizing device 203, and then enters the heat exchanger 3 from the seawater inlet of the heat exchanger 3. After the seawater entering the heat exchanger 3 and the cooling medium undergo heat exchange, they flow out of the corresponding circulation loop from the seawater outlet and the cooling medium outlet of the heat exchanger 3 respectively to continue the above process. In this example, on the one hand, the fluid outlet of the cooling medium circulation pump 101 is set as close as possible to the cooling medium inlet of the heat exchanger 3, and the fluid outlet of the seawater circulation pump 201 is set away from the seawater inlet of the heat exchanger 3, so as to ensure that the pressure on the cooling medium side of the heat exchanger 3 is as large as possible and the pressure on the seawater side is as small as possible. Under the premise of not changing other heat exchange conditions and equipment, the pressure on the cooling medium side is made greater than the pressure on the seawater side to avoid seawater infiltration. On the other hand, the cooling medium side is pressurized by the expansion tank to ensure the pressure condition of the cooling medium side under various conditions, to ensure that the pressure on the cooling medium side of the heat exchanger 3 is higher than the seawater side, and to ensure that seawater infiltration does not occur. Furthermore, in case of seawater infiltration into the cooling medium side (deionized water side) of the plate heat exchanger 3, the leakage detection device 103 (such as a conductivity meter) at the cooling medium inlet and outlet of the heat exchanger 3 can also be used to timely discover the fault, and the heat exchanger 3 can be switched by controlling the electric valve 4 at the fluid inlet and outlet of each heat exchanger 3 to avoid further contamination of the valve cooling system by seawater. The present invention ensures the equipment operation safety and reliability of the converter valve cooling system of the offshore flexible DC transmission platform through a multi-level and all-round system design.

[0055] Example 2

[0056] Based on the same inventive concept, the present invention also provides a method for laying out a converter valve cooling system for an offshore flexible DC transmission platform, comprising:

[0057] Arrange a converter valve cooling circuit to cool the converter valve by using a cooling medium in the converter valve cooling circuit;

[0058] Arrange a seawater circulation loop and a heat exchanger to perform heat exchange between the seawater in the seawater circulation loop and the cooling medium in the converter valve cooling loop through the heat exchanger;

[0059] A cooling medium circulation pump is arranged at a cooling medium inlet of the heat exchanger in the converter valve cooling circuit, and a seawater circulation pump is arranged at a seawater inlet of the heat exchanger in the seawater circulation circuit, so that the pressure on the cooling medium side of the heat exchanger is greater than the pressure on the seawater side.

[0060] In a possible implementation manner, the method further includes: disposing a pressurizing device near a fluid inlet of the cooling medium circulation pump to increase the pressure on the cooling medium side of the heat exchanger.

[0061] In a possible implementation, the method further includes: arranging leak detection devices at the cooling medium inlet and the cooling medium outlet of the heat exchanger respectively.

[0062] In a possible implementation, the method further includes: disposing a first pressure sensor at a cooling medium outlet of the heat exchanger to detect a pressure on a cooling medium side of the heat exchanger;

[0063] A second pressure sensor is arranged at the seawater inlet of the heat exchanger to detect the pressure on the seawater side of the heat exchanger.

[0064] In a possible implementation, the method further includes: sequentially arranging a heater, a first filter, a flow conversion valve, and a degassing device between the cooling medium outlet of the heat exchanger and the fluid inlet of the cooling medium circulation pump;

[0065] A sterilizing device and a second filter are arranged in sequence between the fluid outlet of the seawater circulation pump and the seawater inlet of the heat exchanger.

[0066] In a possible implementation manner, the heat exchanger is a plurality of heat exchangers, further comprising:

[0067] The electric valves are respectively arranged at the cooling medium outlet, the cooling medium inlet, the seawater inlet and the seawater outlet of each heat exchanger.

[0068] In a possible implementation manner, the method further includes: arranging a first safety valve between a cooling medium inlet of each converter and a corresponding electric valve, or arranging a first safety valve between a cooling medium outlet of each converter and a corresponding electric valve;

[0069] The second safety valve is arranged between the seawater inlet of each converter and the corresponding electric valve, or the second safety valve is arranged between the seawater outlet of each converter and the corresponding electric valve.

[0070] In a possible implementation manner, a controller is arranged, and the controller is electrically connected to the leak detection device and the electric valve respectively;

[0071] Determining the current leakage of the heat exchanger based on the change in the physical properties of the cooling medium at the cooling medium inlet and outlet of the heat exchanger detected by the leakage detection device;

[0072] When it is determined that the current heat exchanger is leaking, the electric valve of any other heat exchanger is controlled to open, and the electric valve of the current heat exchanger is closed;

[0073] The other heat exchangers are heat exchangers other than the current heat exchanger.

[0074] The present invention designs a preventive and detection measure for the internal leakage problem that may occur in the plate heat exchanger of the current converter valve cooling equipment. The water inlet of the plate heat exchanger is arranged at the outlet of the circulation pump, and the filter and the converter valve are arranged downstream of the outlet of the plate heat exchanger; a nitrogen expansion tank is set at the suction port of the circulation pump to control the system pressure. In the seawater circulation, the plate heat exchanger is arranged at the end of the circulation, and the filter and other equipment are arranged upstream of the water inlet of the plate heat exchanger. The plate heat exchanger is set up as one in use and one in standby. Electric valves are installed at all the inlets and outlets of each plate heat exchanger for switching and isolating the heat exchanger; a conductivity meter is installed at the inlet and outlet of each plate heat exchanger on the deionization circulation side to detect the status of the plate heat exchanger. The present invention designs an offshore platform valve cooling system (Valve Cooling System) with seawater internal leakage prevention and monitoring functions. By optimizing the layout design of the circulation system on both sides of the plate heat exchanger, it is ensured that the pressure on the cold side of the plate heat exchanger is higher than the measured pressure of seawater, so as to prevent the contamination of the cooling medium of the valve cooling system by seawater during internal leakage as much as possible. At the same time, by arranging a conductivity meter at the inlet and outlet of the plate heat exchanger and detecting the change of the inlet and outlet conductivity, the plate heat exchanger internal leakage fault is discovered as early as possible, and the operation and maintenance personnel are reminded to repair the heat exchanger in time, so as to avoid the corrosion of the polluted medium to damage the valve cooling system equipment and pipelines, thereby improving the reliability of the valve cooling system.

[0075] Obviously, the described embodiments are only some embodiments of the present invention, but not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0076] The above are merely embodiments of the present application and are not intended to limit the present application. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present application are included in the scope of the claims of the present application.

Claims

1. A converter valve cooling system for an offshore flexible DC transmission platform, characterized in that: include: A converter valve cooling circuit, a seawater circulation circuit and a heat exchanger, wherein the converter valve cooling circuit includes a cooling medium circulation pump, and the seawater circulation circuit includes a seawater circulation pump; The fluid outlet of the cooling medium circulation pump is close to the cooling medium inlet of the heat exchanger, and the fluid outlet of the seawater circulation pump is far away from the seawater inlet of the heat exchanger, so that the pressure on the cooling medium side of the heat exchanger is greater than the pressure on the seawater side.

2. The method according to claim 2, characterized in that: The converter valve cooling circuit also includes a pressurizing device, which is close to the fluid inlet of the cooling medium circulation pump to increase the pressure on the cooling medium side of the heat exchanger.

3. The method according to claim 1, characterized in that The converter valve cooling circuit comprises a leak detection device, which is respectively arranged at the cooling medium inlet and the cooling medium outlet of the heat exchanger.

4. The method according to claim 2, characterized in that: The converter valve cooling circuit further includes a first pressure sensor, which is disposed at a cooling medium outlet of the heat exchanger to detect a cooling medium side pressure of the heat exchanger; The seawater circulation loop comprises a second pressure sensor, which is arranged at the seawater inlet of the heat exchanger to detect the pressure on the seawater side of the heat exchanger.

5. The method according to claim 1, characterized in that: The converter valve cooling circuit also includes a heater, a first filter, a converter valve and a degassing device which are sequentially arranged between the cooling medium outlet of the heat exchanger and the fluid inlet of the cooling medium circulation pump; The seawater circulation loop further includes a sterilization device and a second filter which are sequentially arranged between the fluid outlet of the seawater circulation pump and the seawater inlet of the heat exchanger.

6. The method according to claim 3, characterized in that The heat exchanger is a plurality of heat exchangers, and the converter valve cooling circuit and the seawater circulation circuit respectively include electric valves; The electric valves are respectively arranged at the cooling medium outlet, cooling medium inlet, seawater inlet and seawater outlet of each heat exchanger.

7. The method according to claim 6, characterized in that The converter valve cooling circuit includes a first safety valve, which is arranged between the cooling medium inlet of each converter and the corresponding electric valve, or the first safety valve is arranged between the cooling medium outlet of each converter and the corresponding electric valve; The seawater circulation loop comprises a second safety valve, which is arranged between the seawater inlet of each converter and the corresponding electric valve, or the second safety valve is arranged between the seawater outlet of each converter and the corresponding electric valve.

8. The method according to claim 6, characterized in that The device further comprises a controller, which is electrically connected to the leak detection device and the electric valve, respectively, so as to determine the leakage of the current heat exchanger based on the change of the physical properties of the cooling medium at the cooling medium inlet and outlet of the heat exchanger detected by the leak detection device; when it is determined that the current heat exchanger is leaking, the controller controls to open the electric valve of any other heat exchanger and close the electric valve of the current heat exchanger; The other heat exchangers are heat exchangers other than the current heat exchanger.

9. A method for laying out a converter valve cooling system for an offshore flexible DC transmission platform, characterized in that: include: Arrange a converter valve cooling circuit to cool the converter valve by using a cooling medium in the converter valve cooling circuit; Arrange a seawater circulation loop and a heat exchanger to perform heat exchange between the seawater in the seawater circulation loop and the cooling medium in the converter valve cooling loop through the heat exchanger; A cooling medium circulation pump is arranged at a cooling medium inlet of the heat exchanger in the converter valve cooling circuit, and a seawater circulation pump is arranged at a seawater inlet of the heat exchanger in the seawater circulation circuit, so that the pressure on the cooling medium side of the heat exchanger is greater than the pressure on the seawater side.

10. The method according to claim 9, characterized in that Also includes: A pressurizing device is arranged near the fluid inlet of the cooling medium circulation pump to increase the pressure on the cooling medium side of the heat exchanger.

Images