A cooling water temperature control system for high-voltage direct current transmission converter valves

Abstract

The present invention discloses a cooling water temperature control system for a high-voltage direct current transmission converter valve, which relates to the technical field of temperature control and regulation systems. The system comprises a converter valve hall and a heat exchanger, wherein the converter valve hall and the heat exchanger are connected via a cooling pipe and a return pipe, a heating component and a three-way valve are fixedly arranged on the return pipe in sequence from the converter valve hall to the heat exchanger, a water tank is fixedly arranged on the cooling pipe, and the three-way valve and the water tank are connected via a first branch pipe; the system also comprises a controller and a temperature and humidity monitoring module; the controller intelligently controls the ratio of the water output of the two output ports of the three-way valve and the heating power of the heating component in real time according to the temperature and power of the converter valve hall, the temperature of the cooling pipe and the temperature of the return pipe, so as to meet the temperature requirements of the cooling water, effectively utilize the temperature of the return water, reduce the heat required for heating, and quickly adjust the temperature of the cooling water to the required temperature, thereby effectively avoiding the generation of condensation.

Description

Technical Field

[0001] The present application relates to the technical field of temperature control and regulation systems, and in particular to a cooling water temperature control system for a high-voltage direct current (HVDC) transmission converter valve. Background Art

[0002] Converter valves perform the crucial function of AC / DC conversion in HVDC transmission. Their internal power devices, such as thyristors, experience significant power losses during operation, which convert into heat. For example, under high voltage and high current conditions, the thyristors generate heat during their on- and off-states, leading to elevated operating temperatures. If this heat is not dissipated promptly, the converter valve's temperature will continue to rise. Furthermore, converter valves require not only cooling but also insulation at low temperatures. The cooling water temperature must be controlled to prevent condensation that could damage the valve's insulation.

[0003] In existing technology, testing of new HVDC converter valves requires a maximum cooling water temperature of 90°C (conventional cooling water has a maximum temperature of around 55°C) and avoids condensation that could damage insulation. Furthermore, the cooling water temperature must be adjustable over a wide range, with experimental requirements specifying a supply water temperature range of 23°C to 90°C (conventional cooling water has a temperature adjustment range of 18°C ​​to 25°C). If the valve temperature rises too quickly while the cooling water heats up slowly, condensation can easily form on the outer wall of the cooling water pipe, creating a risk of short circuits and damage to the valve circuits. Because new HVDC converter valves operate over a wide power range and experience rapid power changes, high requirements are placed on the speed at which the cooling water heats up and cools. In low-temperature environments, a cooling water system is also required to insulate the valve to ensure its proper operation. Currently, conventional automatic cooling systems need to heat room-temperature cooling water to the required temperature when higher-temperature cooling water is needed. This results in a slow heating speed, high energy consumption, and slow cooling speed. It is difficult to control the cooling water temperature in a timely manner when the power of the converter valve changes rapidly, and it is difficult to avoid the formation of condensation.

[0004] Therefore, it is necessary for the inventor to design a new HVDC converter valve cooling water temperature control system to overcome the above problems. Summary of the Invention

[0005] The main purpose of this application is to provide a high-voltage direct current transmission converter valve cooling water temperature control system to solve the problem in the related art that it is difficult to timely control the temperature of cooling water and difficult to avoid the generation of condensation in the laboratory.

[0006] To achieve the above objectives, the present application provides a HVDC converter valve cooling water temperature control system, comprising a converter valve hall and a heat exchanger, wherein the converter valve hall and the heat exchanger are connected via a cooling pipe and a return pipe, wherein a heating assembly and a three-way valve are fixedly mounted on the return pipe in a direction from the converter valve hall toward the heat exchanger, wherein a water tank is fixedly mounted on the cooling pipe, and the three-way valve and the water tank are connected via a first branch pipe;

[0007] It also includes a water replenishing tank, the water replenishing tank is connected to the return pipe through a second branch pipe, and the second branch pipe is connected between the heating component and the three-way valve;

[0008] The system further includes a controller and a temperature and humidity monitoring module, wherein the temperature and humidity monitoring module is used to monitor the water temperature of the converter valve hall, the return pipe, and the cooling pipe, and the controller is used to dynamically control the ratio of the water output of the two output ports of the three-way valve according to the temperature of the converter valve hall, the water temperature of the return pipe, and the water temperature of the cooling pipe measured by the temperature and humidity monitoring module;

[0009] The controller is used to dynamically control the power of the heating component according to the temperature and humidity of the valve hall of the converter valve, the water temperature of the return pipe, and the water temperature of the cooling pipe measured by the temperature and humidity monitoring module.

[0010] Optionally, the controller is further configured to:

[0011] Save the corresponding relationship between the preset temperature of the converter valve hall and the required temperature of the cooling water in the cooling pipe, and adjust the ratio of the water output of the two output ports of the three-way valve according to the water temperature of the cooling pipe and the water temperature of the return pipe corresponding to the real-time temperature of the converter valve hall, and then adjust the ratio of the return water in the return pipe flowing to the heat exchanger and the first branch pipe, so as to control the ratio of water entering the water tank from the first branch pipe and the heat exchanger, and then control the temperature of the water in the cooling pipe.

[0012] Optionally, the controller is further configured to:

[0013] The preset dew point temperatures corresponding to the valve hall of the converter valve at different temperatures and humidities are saved, and the temperature threshold of the cooling water is determined based on the real-time dew point temperatures at the temperature and humidity. It is then determined whether the water temperature in the return pipe is lower than the temperature threshold. When the water temperature is lower than the temperature threshold, the heating power of the heating component is controlled to heat the return water in the return pipe to within the temperature threshold.

[0014] A low-temperature protection threshold of the converter valve hall is preset. When it is determined that the temperature of the converter valve hall is lower than the low-temperature protection threshold, the heating component is controlled to heat the return water in the return pipe to above the low-temperature protection threshold.

[0015] Optionally, the system further includes a plurality of cooling branches, both ends of which are respectively connected to the ends of the cooling pipe and the return pipe, and all the cooling branches are connected in parallel in the converter valve hall. The temperature and humidity monitoring module includes a plurality of first temperature probes for monitoring the converter valve hall, and each first temperature probe corresponds to a cooling branch.

[0016] A flow valve is fixedly arranged in each cooling branch pipe.

[0017] Optionally, the controller is further configured to:

[0018] A preset maximum temperature difference threshold between the first temperature probes is saved, and the opening of each flow valve is controlled according to the temperatures measured by all the first temperature probes so that the temperature difference between any two of the first temperature probes does not exceed the maximum temperature difference threshold.

[0019] Optionally, an overflow valve and a water level sensor are fixedly installed in the water tank.

[0020] Optionally, the controller is also used to control the amount of water supplied by the water replenishment tank to the return pipe and the power of the heating component or the ratio of the water output of the two output ports of the three-way valve according to the water level of the water tank measured by the water level sensor.

[0021] Optionally, a degassing tank is fixedly provided on the return pipe between the converter valve hall and the heating assembly.

[0022] Optionally, a buffer tank is further included, and the buffer tank is fixedly connected to the return pipe between the degassing tank and the heating assembly through a third branch pipe.

[0023] Optionally, an ion exchanger is further fixedly arranged between the buffer tank and the water replenishment tank.

[0024] The present invention provides a high-voltage direct current transmission converter valve cooling water temperature control system, which has the following beneficial effects compared with the prior art:

[0025] The controller intelligently controls the ratio of the water output from the two output ports of the three-way valve and the heating power of the heating component in real time according to the temperature and power of the converter valve hall, the temperature of the cooling pipe, and the temperature of the return pipe, so that the temperature of the cooling water meets the usage requirements. This not only effectively utilizes the temperature of the return water and reduces the heat demand for heating the cooling water, but also can quickly adjust the temperature of the cooling water to the required temperature according to the actual situation of the converter valve hall, effectively avoiding the formation of condensation. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The drawings that constitute part of this application are used to provide a further understanding of this application and make other features, objects and advantages of this application more apparent. The illustrative embodiment drawings of this application and their descriptions are used to explain this application and do not constitute an improper limitation of this application. In the drawings:

[0027] Figure 1 It is a system flow chart of the present invention;

[0028] Figure 2 It is a control structure diagram of the present invention;

[0029] Figure 3 This is a diagram of the parallel structure of cooling branches in the valve hall of the converter valve of the present invention. DETAILED DESCRIPTION

[0030] In order to enable those skilled in the art to better understand the present invention, the following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of this application.

[0031] It should be noted that the terms "first", "second", etc. in the specification of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequential order. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present application described here. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0032] In this application, terms such as "upper," "lower," "left," "right," "front," "back," "top," "bottom," "inner," "outer," "center," "vertical," "horizontal," "transverse," and "longitudinal" indicate positions or locations based on the positions or locations shown in the accompanying drawings. These terms are primarily intended to better describe this application and its embodiments and are not intended to limit the devices, elements, or components indicated to having a specific orientation, or to being constructed or operated in a specific orientation.

[0033] Furthermore, some of the above terms may be used to express other meanings besides indicating a position or location. For example, the term "on" may also be used to indicate a dependency or connection in certain circumstances. Those skilled in the art will understand the specific meanings of these terms in this application based on the specific circumstances.

[0034] Additionally, the term "plurality" shall mean two or more.

[0035] It should be noted that, in the absence of conflict, the embodiments and features of the embodiments in this application can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0036] like Figure 1 、 2 As shown, a high-voltage direct current transmission converter valve cooling water temperature control system includes a converter valve hall and a heat exchanger, the converter valve hall and the heat exchanger are connected via a cooling pipe and a return pipe, a heating assembly and a three-way valve are fixedly installed on the return pipe in sequence from the converter valve hall toward the heat exchanger, a water tank is fixedly installed on the cooling pipe, and the three-way valve and the water tank are connected via a first branch pipe; the system also includes a water supply tank, which is connected to the return pipe via a second branch pipe, and the second branch pipe is connected between the heating assembly and the three-way valve;

[0037] The system further includes a controller and a temperature and humidity monitoring module, wherein the temperature and humidity monitoring module is used to monitor the water temperature of the converter valve hall, the return pipe, and the cooling pipe, and the controller is used to dynamically control the ratio of the water output of the two output ports of the three-way valve according to the temperature of the converter valve hall, the water temperature of the return pipe, and the water temperature of the cooling pipe measured by the temperature and humidity monitoring module;

[0038] The controller is used to dynamically control the power of the heating component according to the temperature and humidity of the valve hall of the converter valve, the water temperature of the return pipe, and the water temperature of the cooling pipe measured by the temperature and humidity monitoring module.

[0039] Specifically, under normal cooling conditions, cooling water flows from the heat exchanger through the cooling pipe and the valve hall of the flow converter valve into the return pipe, then flows into the heat exchanger, undergoes heat exchange and cooling in the heat exchanger, and then flows back into the cooling pipe to achieve circulation (a circulation pump should be provided in the pipeline loop, and the specific location can be set according to actual needs, which will not be described here). Setting a three-way valve can control the ratio of the amount of water that needs to be cooled and the amount of water that does not need to be cooled, and thus regulate the return water to the appropriate cooling temperature. When it is necessary to avoid condensation or the power of the heat exchange valve load body drops too quickly or the real-time temperature drops too quickly, resulting in the need to increase the temperature of the real-time cooling water, and the temperature of the return water cannot meet the demand, the cooling water is heated by the heating component until the temperature of the cooling water meets the demand.

[0040] The controller is also used to: save the corresponding relationship between the preset temperature of the converter valve hall and the required temperature of the cooling water in the cooling pipe, adjust the ratio of the water output of the two output ports of the three-way valve according to the water temperature of the cooling pipe and the water temperature of the return pipe corresponding to the real-time temperature of the converter valve hall, and then adjust the ratio of the return water in the return pipe flowing to the heat exchanger and the first branch pipe, so as to control the ratio of water entering the water tank from the first branch pipe and the heat exchanger, and then control the temperature of the water in the cooling pipe. Specifically, for example, when the temperature of the valve hall of the converter valve is preset to 70 degrees, 60-degree cooling water is used for cooling, that is, the required cooling water temperature is 60°C, while the actual temperature of the return water is 70 degrees. At the same time, half of the 70-degree water in the cooling pipe can be reduced to 50°C after passing through the heat exchanger. At this time, half of the water can be controlled by the three-way valve to enter the heat exchanger for cooling, and the other half is directly passed into the water tank through the first branch pipe. In this way, equal volumes of 50-degree water and 70-degree water will be mixed in the water tank to obtain the required 60°C cooling water, thereby realizing the effect of converting the 70-degree return water into 60-degree cooling water.

[0041] The controller dynamically controls the power of the heating component according to the temperature and humidity of the converter valve hall, the water temperature of the return pipe, and the water temperature of the cooling pipe measured by the temperature and humidity monitoring module, including: presetting the dew point temperature of the converter valve hall under different temperatures and humidities, determining the temperature threshold of the cooling water according to the real-time dew point temperature under the temperature and humidity, judging whether the water temperature in the return pipe is lower than the temperature threshold, and when the water temperature is lower than the temperature threshold, controlling the heating power of the heating component, thereby heating the return water in the return pipe to within the temperature threshold; specifically, the dew point temperature (T dew ) is determined by the ambient air temperature (T air ) and relative humidity (RH), and the calculation formula is: T dew =T air −(100−RH) / 5, for example, valve hall temperature T air When the temperature is 70℃ and the relative humidity is 40, T dew =70-(100-40) / 5=58°C, that is, the dew point temperature at this time is 58°C. Cooling with cooling water above 58°C will not produce condensed water. The cooling water temperature threshold can be set to greater than 60°C. If the converter valve hall temperature rises from 60°C to 70°C in a short period of time, the return water in the return pipe is still at a maximum of 60°C due to hysteresis, which is lower than the preset cooling threshold of 60°C and may even be close to or lower than the dew point temperature of 58°C. At this time, the heating component is controlled to quickly heat the return water, and the water temperature in the cooling pipe is monitored in real time until it reaches above 60°C.

[0042] A low-temperature protection threshold for the converter valve hall is preset. When the temperature of the converter valve hall is determined to be below the threshold, the heating component is controlled to heat the return water in the return pipe to above the threshold. Specifically, the low-temperature protection threshold for the converter valve hall can be preset to 10°C. When the temperature of the converter valve hall is below 10°C, the heating component can be controlled to heat the return water to above 10°C, for example, to 20°C, to protect the converter valve hall.

[0043] like Figure 3 As shown, it also includes a plurality of cooling branches, the two ends of the cooling branches are respectively connected to the ends of the cooling pipe and the return pipe, and all the cooling branches are connected in parallel in the valve hall of the converter valve, and the temperature and humidity monitoring module includes a plurality of first temperature probes for monitoring the valve hall of the converter valve, each of the first temperature probes corresponds to a cooling branch; a flow valve is fixedly arranged in each of the cooling branches; the controller is also used to: save the preset maximum temperature difference threshold between the first temperature probes, and control the opening of each flow valve according to the measured temperatures of all the first temperature probes so that the temperature difference between any two first temperature probes does not exceed the maximum temperature difference threshold.

[0044] Specifically, a converter valve hall contains multiple converter valve loads. Each load operates under different specific operating conditions, resulting in different heat dissipation rates and amounts. Each converter valve load requires cooling by a cooling branch. If the temperature or temperature rise rate of a particular converter valve load is significantly higher than that of the other converter valve loads (for example, one converter valve load is at 72 degrees Celsius, while the other converter valve loads are at 70 degrees Celsius, and the 72-degree converter valve load continues to heat up), and if the cooling pipe still uses 60-degree cooling water to cool it, condensation may form on the outer wall of the cooling branch used to cool the 72-degree converter valve load due to the continued temperature increase of the converter valve load), the amount of cooling water in the cooling branch used to cool the converter valve load needs to be increased to reduce the temperature of the converter valve load to the same level as the other converter valve loads, thereby preventing condensation. Therefore, multiple first temperature probes are set to monitor the real-time temperature of each converter valve load in the converter valve hall. When the temperature of one converter valve load is higher than that of the other converter valve loads, the controller controls the flow valve in the cooling pipe corresponding to the converter valve load to open wider, so that the amount of cooling water for cooling the converter valve load increases, thereby reducing the temperature of the area where the converter valve load is located to a temperature close to that of the areas where the other converter valve loads are located.

[0045] The water tank is fixedly equipped with an overflow valve and a water level sensor. The controller is also used to control the amount of water supplied from the water supply tank to the return pipe, as well as the power of the heating component or the ratio of the water output from the two output ports of the three-way valve, based on the water level in the water tank measured by the water level sensor. Specifically, the cooling system will produce cooling water loss during operation, necessitating timely water replenishment throughout the pipeline. However, the water temperature in the water supply tank differs from that in the return pipe, so to balance the temperature difference, the heating component or the three-way valve is required to adjust the temperature.

[0046] A degassing tank is fixedly mounted on the return pipe between the converter valve hall and the heating assembly. Specifically, the degassing tank separates water vapor from the return water to reduce the air pressure in the pipe.

[0047] The system also includes a buffer tank, which is fixedly connected to the return pipe between the degassing tank and the heating assembly via a third branch pipe. Specifically, the buffer tank is used to absorb fluid pressure fluctuations, suppress water hammer effects, stabilize pipeline pressure, and protect equipment from impact.

[0048] An ion exchanger is fixedly installed between the buffer tank and the water replenishment tank. Specifically, the ion exchanger optimizes water quality, balances ions in the pipeline, and protects the entire system.

[0049] This embodiment uses a controller to intelligently control the ratio of the water output of the two output ports of the three-way valve and the heating power of the heating component in real time according to the temperature and power of the converter valve hall, the temperature of the cooling pipe, and the temperature of the return pipe, so that the temperature of the cooling water meets the usage requirements. It effectively utilizes the temperature of the return water and reduces the heat demand for heating the cooling water. It can also quickly adjust the temperature of the cooling water to the required temperature according to the actual situation of the converter valve hall, effectively avoiding the formation of condensation.

[0050] The above description is merely a preferred embodiment of the present application and is not intended to limit the present application. Various modifications and variations are possible for those skilled in the art. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present application shall be included within the scope of protection of the present application.

Claims

1. A cooling water temperature control system for a high-voltage direct current (HVDC) converter valve, characterized by: The heat exchanger comprises a valve hall of a converter valve and a heat exchanger, wherein the valve hall of the converter valve and the heat exchanger are connected via a cooling pipe and a return pipe, a heating assembly and a three-way valve are fixedly installed on the return pipe in sequence from the valve hall of the converter valve to the heat exchanger, a water tank is fixedly installed on the cooling pipe, and the three-way valve and the water tank are connected via a first branch pipe; It also includes a water replenishing tank, the water replenishing tank is connected to the return pipe through a second branch pipe, and the second branch pipe is connected between the heating component and the three-way valve; The system further includes a controller and a temperature and humidity monitoring module, wherein the temperature and humidity monitoring module is used to monitor the water temperature of the converter valve hall, the return pipe, and the cooling pipe, and the controller is used to dynamically control the ratio of the water output of the two output ports of the three-way valve according to the temperature of the converter valve hall, the water temperature of the return pipe, and the water temperature of the cooling pipe measured by the temperature and humidity monitoring module; The controller is used to dynamically control the power of the heating component according to the temperature and humidity of the valve hall of the converter valve, the water temperature of the return pipe, and the water temperature of the cooling pipe measured by the temperature and humidity monitoring module.

2. The HVDC converter valve cooling water temperature control system according to claim 1, characterized in that: The controller is also used to: Save the corresponding relationship between the preset temperature of the converter valve hall and the required temperature of the cooling water in the cooling pipe, and adjust the ratio of the water output of the two output ports of the three-way valve according to the water temperature of the cooling pipe and the water temperature of the return pipe corresponding to the real-time temperature of the converter valve hall, and then adjust the ratio of the return water in the return pipe flowing to the heat exchanger and the first branch pipe, so as to control the ratio of water entering the water tank from the first branch pipe and the heat exchanger, and then control the temperature of the water in the cooling pipe.

3. The HVDC converter valve cooling water temperature control system according to claim 1, characterized in that: The controller is also used to: The preset dew point temperatures corresponding to the valve hall of the converter valve at different temperatures and humidities are saved, and the temperature threshold of the cooling water is determined based on the real-time dew point temperatures at the temperature and humidity. It is then determined whether the water temperature in the return pipe is lower than the temperature threshold. When the water temperature is lower than the temperature threshold, the heating power of the heating component is controlled to heat the return water in the return pipe to within the temperature threshold. A low-temperature protection threshold of the converter valve hall is preset. When it is determined that the temperature of the converter valve hall is lower than the low-temperature protection threshold, the heating component is controlled to heat the return water in the return pipe to above the low-temperature protection threshold.

4. The HVDC converter valve cooling water temperature control system according to claim 1, characterized in that: It also includes a plurality of cooling branches, both ends of which are respectively connected to the ends of the cooling pipe and the return pipe, and all the cooling branches are connected in parallel in the converter valve hall. The temperature and humidity monitoring module includes a plurality of first temperature probes for monitoring the converter valve hall, and each first temperature probe corresponds to a cooling branch. A flow valve is fixedly arranged in each cooling branch pipe.

5. The HVDC converter valve cooling water temperature control system according to claim 4, characterized in that: The controller is also used to: A preset maximum temperature difference threshold between the first temperature probes is saved, and the opening of each flow valve is controlled according to the temperatures measured by all the first temperature probes so that the temperature difference between any two of the first temperature probes does not exceed the maximum temperature difference threshold.

6. The HVDC converter valve cooling water temperature control system according to claim 1, characterized in that: An overflow valve and a water level sensor are fixedly arranged in the water tank.

7. The HVDC converter valve cooling water temperature control system according to claim 6, characterized in that: The controller is also used to control the amount of water supplied by the water replenishment tank to the return pipe and the power of the heating component or the ratio of the water output from the two output ports of the three-way valve according to the water level of the water tank measured by the water level sensor.

8. The HVDC converter valve cooling water temperature control system according to claim 7, characterized in that: A degassing tank is also fixedly provided on the return pipe between the converter valve hall and the heating assembly.

9. The HVDC converter valve cooling water temperature control system according to claim 8, characterized in that: It also includes a buffer tank, which is fixedly connected to the return pipe between the degassing tank and the heating component through a third branch pipe.

10. The HVDC converter valve cooling water temperature control system according to claim 9, characterized in that: An ion exchanger is also fixedly arranged between the buffer tank and the water replenishment tank.

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