Cooling water temperature control system for high-voltage direct-current transmission converter valve

Abstract

The invention discloses a high-voltage direct-current transmission converter valve cooling water temperature control system, which relates to the technical field of temperature control adjusting systems and comprises a converter valve hall and a heat exchanger which are communicated through a cooling pipe and a return pipe. A heating assembly and a three-way valve are sequentially and fixedly arranged on the backflow pipe in the direction from the converter valve hall to the heat exchanger, a water tank is fixedly arranged on the cooling pipe, and the three-way valve is connected with the water tank through a first branch pipe. The system further comprises a controller and a temperature and humidity monitoring module. The controller intelligently controls the proportion of the water yield of the two output ports of the three-way valve and the heating power of the heating assembly 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 backflow pipe so that the temperature of cooling water can meet the requirement, the temperature of backflow water is effectively utilized, and heat needed by heating is reduced; and the temperature of the cooling water can be quickly adjusted to the required temperature, so that condensation is effectively avoided.

Description

Technical Field

[0001] This application relates to the technical field of temperature control systems, and more particularly, to a cooling water temperature control system for a high-voltage direct current (HVDC) converter valve. Background Art

[0002] The converter valve plays an important role in the AC / DC conversion in HVDC transmission. When the power devices such as thyristors inside it are working, there will be relatively large power losses, and these losses will be converted into heat. For example, in the case of high voltage and large current, heat losses will occur during the on and off processes of thyristors, resulting in an increase in the operating temperature. If these heats are not dissipated in time, the temperature of the converter valve will continue to rise. In addition to cooling down the converter valve, it is also necessary to keep it warm under low-temperature conditions and control the temperature of the cooling water to avoid the formation of condensation in the converter valve, which may damage the insulation effect.

[0003] In the prior art, the experimental requirements for the new HVDC converter valve stipulate that the maximum temperature of the cooling water reaches 90°C (the maximum temperature of the conventional cooling water is about 55°C), and condensation damage to the insulation should be avoided. At the same time, the adjustable range of the cooling water temperature is large, and the experimental requirements propose a water supply temperature range of 23°C to 90°C (the conventional cooling water temperature adjustment range is 18°C to 25°C). When the temperature of the converter valve rises too fast and the cooling water warms up slowly, condensation is very likely to occur on the outer wall of the cooling water pipe. After the condensation occurs, there is a risk of short circuit and damage to the circuit of the converter valve. Due to the large working power range and fast power change speed of the new HVDC converter valve, there are also relatively high requirements for the heating and cooling speeds of the cooling water. In a low-temperature environment, a cooling water system is also required to keep the converter valve warm to ensure its normal operation. Currently, the conventional automatic cooling system needs to heat the normal-temperature cooling water to the required temperature when higher-temperature cooling water is needed. The heating speed is slow, the energy consumption is large, and the cooling speed is also slow. It is difficult to control the temperature of the cooling water in time 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 cooling water temperature control system for the HVDC converter valve to overcome the above problems. Summary of the Invention

[0005] The main object of this application is to provide a cooling water temperature control system for an HVDC converter valve to solve the problems in the related art that it is difficult to control the temperature of the cooling water in time in the laboratory and it is difficult to avoid the formation of condensation.

[0006] To achieve the above object, the present application provides a cooling water temperature control system for a high-voltage DC transmission converter valve, including a converter valve hall and a heat exchanger. The converter valve hall and the heat exchanger are connected through 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 direction. A water tank is fixedly arranged on the cooling pipe. The three-way valve and the water tank are connected through a first branch pipe; It further includes a water replenishing tank. The water replenishing tank is connected to the return pipe through a second branch pipe. The second branch pipe is connected between the heating component and the three-way valve; It further includes a controller and a temperature and humidity monitoring module. 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. The controller is used to dynamically control the proportion of the water flow rate at 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 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.

[0007] Optionally, the controller is further used for: Saving the corresponding relationship between the preset temperature of the converter valve hall and the required temperature of the cooling water in the cooling pipe. Adjusting the proportion of the water flow rate at 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, thereby adjusting the proportion of the return water flowing from the return pipe to the heat exchanger and the first branch pipe, realizing the control of the proportion of the water entering the water tank from the first branch pipe and the heat exchanger, and further controlling the water temperature in the cooling pipe.

[0008] Optionally, the controller is further used for: Saving the preset dew point temperature corresponding to 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 this temperature and humidity. Judging whether the water temperature in the return pipe is lower than this temperature threshold. When the water temperature is lower than this temperature threshold, controlling the heating power of the heating component, and heating the return water in the return pipe to within this temperature threshold; Presetting the low-temperature protection threshold of the converter valve hall. When the temperature of the converter valve hall is lower than the low-temperature protection threshold, controlling the heating component to heat the return water in the return pipe to above the low-temperature protection threshold.

[0009] Optionally, it further includes a plurality of cooling branch pipes, both ends of the cooling branch pipes are respectively connected to the ends of the cooling pipe and the return pipe, and all the cooling branch pipes 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 pipe; A flow valve is fixedly arranged in each of the cooling branch pipes.

[0010] Optionally, the controller is further configured to: Save the preset maximum temperature difference threshold between the first temperature probes, and control the opening degree of each flow valve according to the temperatures measured by all the first temperature probes so that the temperature difference between any two first temperature probes does not exceed the maximum temperature difference threshold.

[0011] Optionally, an overflow valve and a water level sensor are fixedly arranged in the water tank.

[0012] Optionally, the controller is further configured to control the water volume replenished by the water replenishing tank to the return pipe, 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.

[0013] Optionally, a degassing tank is fixedly arranged on the return pipe between the converter valve heating component and the heating component.

[0014] Optionally, it further includes a buffer tank, and the buffer tank is fixedly connected to the return pipe between the degassing tank and the heating component through a third branch pipe.

[0015] Optionally, an ion exchanger is fixedly arranged between the buffer tank and the water replenishing tank.

[0016] A cooling water temperature control system for a high-voltage direct current transmission converter valve provided by the present invention has the following beneficial effects compared with the prior art: 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, power of the converter valve hall, temperature of the cooling pipe, and temperature of the return pipe, so that the temperature of the cooling water meets the use requirements. It not only effectively utilizes the temperature of the returned 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 generation of condensation. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The drawings forming a part of this application are used to provide a further understanding of this application, making other features, objects, and advantages of this application more obvious. The schematic embodiments and descriptions of the drawings of this application are used to explain this application and do not constitute an improper limitation of this application. In the drawings: Figure 1 is the system flowchart of the present invention; Figure 2 is the control structure diagram of the present invention; Figure 3 is the parallel structure diagram of the cooling branch pipes in the converter valve hall of the present invention. Detailed implementation manners

[0018] In order to enable those skilled in the art to better understand the solution of this application, the technical solutions in the embodiments of this application will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of this application. Obviously, the described embodiments are only a part of the embodiments of this application, rather than all the embodiments. Based on the embodiments in this application, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of this application.

[0019] It should be noted that the terms "first", "second", etc. in the description of this application and the above-mentioned drawings are used to distinguish similar objects, and do not have to be used to describe a specific order or sequence. It should be understood that such data can be interchanged under appropriate circumstances so as to describe the embodiments of this application here. In addition, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device including a series of steps or units does not necessarily have to be limited to those clearly listed steps or units, but may include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0020] In this application, the orientation or positional relationship indicated by the terms "upper", "lower", "left", "right", "front", "rear", "top", "bottom", "inner", "outer", "middle", "vertical", "horizontal", "lateral", "longitudinal", etc. is based on the orientation or positional relationship shown in the drawings. These terms are mainly used to better describe this application and its embodiments, and are not used to limit that the indicated devices, elements or components must have a specific orientation, or be constructed and operated in a specific orientation.

[0021] Moreover, in addition to being able to represent the orientation or positional relationship, some of the above-mentioned terms may also be used to represent other meanings. For example, the term "upper" may also be used to represent a certain attachment relationship or connection relationship in some cases. For those of ordinary skill in the art, the specific meanings of these terms in this application can be understood according to specific circumstances.

[0022] In addition, the meaning of the term "plurality" should be two or more.

[0023] It should be noted that, without conflict, the embodiments in the present application and the features in the embodiments 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.

[0024] As Figure 1 、 2 shown, a cooling water temperature control system for a high-voltage DC transmission converter valve includes a converter valve hall and a heat exchanger. The converter valve hall and the heat exchanger are connected and communicated through 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 direction. A water tank is fixedly arranged on the cooling pipe. The three-way valve and the water tank are connected through a first branch pipe; A water replenishing tank is further included. The water replenishing tank is connected to the return pipe through a second branch pipe. The second branch pipe is connected between the heating component and the three-way valve; A controller and a temperature and humidity monitoring module are further included. 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. The controller is used to dynamically control the proportion of the water flow rates at 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 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.

[0025] Specifically, under normal cooling conditions, the cooling water flows from the heat exchanger through the cooling pipe through the converter valve hall and then into the return pipe, and then flows into the heat exchanger and is cooled by heat exchange of the heat exchanger and then flows back into the cooling pipe to realize circulation (a circulation pump should be provided in the pipeline loop, and the specific position can be set according to actual needs, which will not be elaborated here). The three-way valve can be set to control the proportion of the water volume that needs to be cooled and the water volume that does not need to be cooled, and then regulate the return water to a suitable cooling temperature. When it is necessary to avoid condensation, or the power of the heat exchange valve load body drops too fast, or the real-time temperature drops too fast, resulting in the need to increase the real-time temperature of the cooling water, and the temperature of the return water cannot meet the requirements, the heating component is used to heat the cooling water until the temperature of the cooling water meets the requirements.

[0026] The controller is further configured to: store the correspondence between the preset temperature of the converter valve hall and the temperature of the cooling water in the required cooling pipe, and adjust the proportion of the water flow rates at the two output ports of the three-way valve according to the water temperature of the cooling pipe corresponding to the real-time temperature of the converter valve hall and the water temperature of the return pipe, so as to further adjust the proportion of the return water flowing from the return pipe to the heat exchanger and the first branch pipe, thereby controlling the proportion of the water entering the water tank from the first branch pipe and the heat exchanger, and further controlling the temperature of the water in the cooling pipe. Specifically, for example, when the preset temperature of the converter valve hall is 70 degrees, cooling water at 60 degrees is used for cooling, that is, the required temperature of the cooling water is 60 °C, and 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 cooled to 50 °C after flowing through the heat exchanger. At this time, the three-way valve can be used to control half of the water to enter the heat exchanger for cooling, and the other half directly enters the water tank through the first branch pipe. In this way, there will be equal volumes of 50-degree water and 70-degree water mixed in the water tank to obtain the required 60 °C cooling water, that is, the effect of converting 70-degree return water into 60-degree cooling water is achieved.

[0027] The controller dynamically controls the power of the heating component according to the temperature and humidity of the converter valve hall measured by the temperature and humidity monitoring module, the water temperature of the return pipe, and the water temperature of the cooling pipe, 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 this temperature and humidity, and judging whether the water temperature in the return pipe is lower than this temperature threshold. When the water temperature is lower than this temperature threshold, control the heating power of the heating component, and then heat the return water in the return pipe to within this temperature threshold; specifically, the dew point temperature (T dew ) is jointly determined by the temperature (T air ) of the ambient air and the relative humidity (RH), and its calculation formula is: T dew =T air −(100−RH) / 5. For example, when the valve hall temperature T air is 70 °C and the relative humidity RH is 40, T dew =70-(100−40) / 5=58 °C, that is, the dew point temperature at this time is 58 °C. At this time, using cooling water above 58 °C for cooling will not generate condensate, and the cooling water temperature threshold at this time can be set to be greater than 60 °C. If the temperature of the converter valve hall rises from 60 °C to 70 °C in a short time, the return water in the return pipe is still in a state where it does not exceed 60 °C at most due to hysteresis, lower than the preset cooling threshold of 60 °C, and even close to or lower than the dew point temperature of 58 °C. At this time, control the heating component to quickly heat the return water and monitor the water temperature in the cooling pipe in real time until it reaches above 60 °C.

[0028] Preset the low-temperature protection threshold of the converter valve hall. When it is determined that the temperature of the converter valve hall is lower than the low-temperature protection threshold, control the heating component to heat the return water in the return pipe to above the low-temperature protection threshold. Specifically, the low-temperature protection threshold of the converter valve hall can be preset to 10°C. When the temperature of the converter valve hall is lower than 10°C, the heating component can be controlled to heat the return water, heating it to above 10°C, for example, heating it to 20°C to protect the converter valve hall.

[0029] As Figure 3 shown, it further includes a plurality of cooling branch pipes. Both ends of each cooling branch pipe are respectively connected to the ends of the cooling pipe and the return pipe, and all the cooling branch pipes 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 pipe; a flow valve is fixedly arranged in each cooling branch pipe; the controller is further configured to: save the preset maximum temperature difference threshold between the first temperature probes, and control the opening degree of each flow valve according to the temperatures measured by all the first temperature probes so that the temperature difference between any two first temperature probes does not exceed the maximum temperature difference threshold.

[0030] Specifically, there are multiple converter valve loads in the converter valve hall, and the specific working conditions of each load during operation are not exactly the same. Their heat dissipation rates and heat dissipation amounts during operation are different. Each converter valve load requires a cooling branch pipe to cool it. When the temperature or temperature rise rate of a certain converter valve load is significantly higher than that of other converter valve loads (for example, one of them is 72°C, and the other converter valve loads are 70°C, and the converter valve load at 72°C is still rising. At this time, if the water in the cooling pipe still uses 60°C cooling water to cool it, the outer wall of the cooling branch pipe for the converter valve load at 72°C is likely to condense due to the continuous increase in the temperature of this converter valve load). At this time, it is necessary to increase the cooling water volume in the cooling branch pipe used to cool this converter valve load to lower the temperature of this converter valve load to the same level as other converter valve loads, thereby avoiding condensation. Therefore, a plurality of 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 other converter valve loads, the controller controls the opening degree of the flow valve in the cooling pipe corresponding to this converter valve load to become larger, so that the cooling water volume for cooling this converter valve load increases, and thus the temperature of the area where this converter valve load is located is reduced to be close to the temperature of the areas where other converter valve loads are located.

[0031] An overflow valve and a water level sensor are fixedly arranged in the water tank; the controller is further configured to control the water supply amount of the water replenishing tank to the return pipe and the power of the heating assembly or the ratio of the water output amounts 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. Specifically, during the operation of the cooling system, cooling water loss will occur, so it is necessary to replenish water to the entire pipeline in a timely manner. However, the water temperature in the water replenishing tank is different from that in the return pipe. Therefore, to balance the temperature difference between the two, it is necessary to adjust through the heating assembly or the three-way valve.

[0032] A degassing tank is also fixedly arranged on the return pipe between the converter valve heating assembly and the heating assembly. Specifically, the degassing tank separates water vapor from the returned water to reduce the air pressure in the pipeline.

[0033] 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. Specifically, the buffer tank is used to absorb fluid pressure fluctuations, suppress the water hammer effect, stabilize the pipeline pressure, and protect the equipment from impact.

[0034] An ion exchanger is also fixedly arranged between the buffer tank and the water replenishing tank. Specifically, the water quality is optimized through the ion exchanger to balance the ions in the pipeline and protect the entire system.

[0035] In this embodiment, the controller intelligently controls the ratio of the water output amounts of the two output ports of the three-way valve and the heating power of the heating assembly 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 not only effectively utilizes the temperature of the returned water and reduces the heat demand required 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 generation of condensation.

[0036] The above are only the preferred embodiments of the present application and are not used to limit the present application. For those skilled in the art, various changes and modifications can be made to the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A cooling water temperature control system for a HVDC converter valve, characterized in that: It includes a converter valve hall and a heat exchanger. The converter valve hall is connected to the heat exchanger through 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 direction. A water tank is fixedly arranged on the cooling pipe. The three-way valve is connected to the water tank through a first branch pipe; It further includes a water replenishing tank. The water replenishing tank is connected to the return pipe through a second branch pipe. The second branch pipe is connected between the heating component and the three-way valve; It further includes a controller and a temperature and humidity monitoring module. 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. The controller is used to dynamically control the proportion 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 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.

2. The cooling water temperature control system for a high-voltage DC transmission converter valve according to claim 1, characterized in that: The controller is further used for: Saving the corresponding relationship between the preset temperature of the converter valve hall and the required water temperature of the cooling water in the cooling pipe. Adjusting the proportion 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, so as to adjust the proportion of the return water flowing from the return pipe to the heat exchanger and the first branch pipe, and realize the control of the proportion of the water entering the water tank from the first branch pipe and the heat exchanger, and further control the water temperature in the cooling pipe.

3. The cooling water temperature control system for a HVDC converter valve as claimed in claim 1, wherein: The controller is further used for: Saving the preset dew point temperature corresponding to 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 this temperature and humidity. Judging whether the water temperature in the return pipe is lower than this temperature threshold. When the water temperature is lower than this temperature threshold, controlling the heating power of the heating component, and heating the return water in the return pipe to within this temperature threshold; Presetting the low temperature protection threshold of the converter valve hall. When judging that the temperature of the converter valve hall is lower than the low temperature protection threshold, controlling the heating component to heat the return water in the return pipe to above the low temperature protection threshold.

4. The cooling water temperature control system for a high-voltage DC transmission converter valve according to claim 1, characterized in that: It further includes a plurality of cooling branch pipes. The two ends of the cooling branch pipes are respectively connected to the ends of the cooling pipe and the return pipe, and all the cooling branch pipes 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. Each first temperature probe corresponds to a cooling branch pipe; A flow valve is fixedly arranged in each cooling branch pipe.

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

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

7. The temperature control system for the cooling water of a high-voltage DC transmission converter valve according to claim 6, characterized in that: The controller is further configured to control the water replenishing amount of the water replenishing tank to the return pipe, the power of the heating assembly, or the water output ratio 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.

8. A cooling water temperature control system for a high-voltage DC transmission converter valve according to claim 7, characterized in that: An air removal tank is fixedly arranged on the return pipe between the converter valve heating assembly and the heating assembly.

9. The cooling water temperature control system for a high-voltage DC transmission converter valve according to claim 8, wherein: It further includes a buffer tank, and the buffer tank is fixedly connected to the return pipe between the air removal tank and the heating assembly through a third branch pipe.

10. A high-voltage DC transmission converter valve cooling water temperature control system according to claim 9, characterized in that: An ion exchanger is fixedly arranged between the buffer tank and the water replenishing tank.

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