Method and device for monitoring temperature of flexible direct-current transmission power sub-module busbar

Abstract

The invention discloses a method and a device for monitoring the temperature of a busbar of a flexible direct-current transmission power sub-module. The method comprises the following steps: acquiring operation parameters of a converter valve under different temperature conditions; inputting the operation parameters into the busbar temperature prediction model, and outputting a corresponding busbar temperature prediction value; the busbar temperature prediction model is obtained by training a least square support vector machine model by taking historical operation parameters as input and historical busbar temperature as output; acquiring temperature values at a plurality of contact points of the surface of the busbar and the sensing optical fiber, and selecting a maximum temperature value from the temperature values at the plurality of contact points as an actual temperature value of the busbar; and calculating a temperature difference value between the busbar temperature prediction value and the busbar temperature actual value, and monitoring the temperature state of the busbar according to a temperature difference value calculation result. The operation safety and stability of the converter valve can be improved.

Description

Technical Field

[0001] The present invention relates to the technical field of direct current transmission, and in particular to a method and device for monitoring busbar temperature of a flexible direct current transmission power submodule. Background Art

[0002] This section is intended to provide a background or context to the embodiments of the invention recited in the claims. No admission is made that the description herein is prior art by inclusion in this section.

[0003] With the continuous development of modern urbanization, flexible direct current transmission technology has gradually replaced traditional alternating current transmission technology, improving the efficiency, quality and safety of current transmission, avoiding the emergence of traditional grid-connected problems, and playing an important role in the overall development of the power industry. As an indispensable part of the power submodule structure of the flexible direct current converter valve, the busbar is used for the electrical connection of various components. When the operating voltage increases, the current in the busbar will also increase accordingly, which will cause the busbar to generate more heat and the temperature will increase. High temperature will not only affect the electrical performance of the busbar, but also accelerate the aging of the insulation material and reduce the service life of the busbar. At the same time, its flow capacity will also be reduced due to the increase of conductor resistance when it is in a high temperature state for a long time, which is easy to cause electrical failures, thereby affecting the stability and safety of the power system. Therefore, it is necessary to monitor the temperature of the busbar. When the temperature exceeds a certain range, relevant personnel can detect it in time and take corresponding measures to improve the safety and stability of the converter valve operation. Summary of the invention

[0004] An embodiment of the present invention provides a method for monitoring busbar temperature of a flexible direct current transmission power submodule, which is used to monitor the busbar temperature in real time and to ensure safe operation of a converter valve based on the busbar temperature. The method includes:

[0005] Obtaining the operating parameters of the converter valve under different temperature conditions;

[0006] Inputting the operating parameters into the busbar temperature prediction model and outputting the corresponding busbar temperature prediction value; the busbar temperature prediction model is obtained by training a least squares support vector machine model using the historical operating parameters as input and the historical busbar temperature as output;

[0007] Obtaining temperature values ​​at multiple contact points between the busbar surface and the sensing optical fiber, and selecting a maximum temperature value from the temperature values ​​at the multiple contact points as the actual busbar temperature value;

[0008] Calculate the temperature difference between the predicted busbar temperature and the actual busbar temperature, and monitor the busbar temperature status based on the temperature difference calculation result.

[0009] The embodiment of the present invention further provides a monitoring device for busbar temperature of a flexible DC transmission power submodule, which is used to monitor the busbar temperature in real time and ensure the safe operation of the converter valve based on the busbar temperature. The device includes:

[0010] An operating parameter acquisition module is used to obtain operating parameters of the converter valve under different temperature conditions;

[0011] A busbar temperature prediction value output module is used to input the operating parameters into the busbar temperature prediction model and output the corresponding busbar temperature prediction value; the busbar temperature prediction model is obtained by training a least squares support vector machine model using historical operating parameters as input and historical busbar temperature as output;

[0012] A busbar temperature actual value determination module is used to obtain the temperature values ​​at multiple contact points between the busbar surface and the sensing optical fiber, and select the maximum temperature value from the temperature values ​​at the multiple contact points as the busbar temperature actual value;

[0013] The busbar temperature status monitoring module is used to calculate the temperature difference between the busbar temperature prediction value and the busbar temperature actual value, and monitor the busbar temperature status according to the temperature difference calculation result.

[0014] An embodiment of the present invention also provides a computer device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the above-mentioned method for monitoring the busbar temperature of the flexible direct current transmission power submodule when executing the computer program.

[0015] An embodiment of the present invention further provides a computer-readable storage medium, wherein the computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the method for monitoring the busbar temperature of the flexible direct current transmission power submodule is implemented.

[0016] An embodiment of the present invention further provides a computer program product, which includes a computer program. When the computer program is executed by a processor, the method for monitoring the busbar temperature of the flexible direct current transmission power submodule is implemented.

[0017] In the embodiment of the present invention, the operating parameters of the converter valve under different temperature conditions are obtained; the operating parameters are input into the busbar temperature prediction model, and the corresponding busbar temperature prediction value is output; the busbar temperature prediction model is obtained by training the least squares support vector machine model with the historical operating parameters as input and the historical busbar temperature as output; the temperature values ​​at multiple contact points between the busbar surface and the sensing optical fiber are obtained, and the maximum temperature value is selected from the temperature values ​​at multiple contact points as the actual busbar temperature value; the temperature difference between the busbar temperature prediction value and the busbar temperature actual value is calculated, and the temperature state of the busbar is monitored according to the temperature difference calculation result. In the above process, the embodiment of the present invention monitors the busbar temperature in real time, uses the busbar temperature as the judgment basis for the safe operation of the converter valve, and improves the safety and stability of the converter valve operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the prior art descriptions. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work. In the drawings:

[0019] Figure 1 It is a flow chart of a method for monitoring busbar temperature of a flexible direct current transmission power submodule in an embodiment of the present invention;

[0020] Figure 2 The IGCT power submodule half-bridge topology structure in the embodiment of the present invention;

[0021] Figure 3 A flow chart of obtaining temperature values ​​at multiple contact points between the busbar surface and the sensing optical fiber in an embodiment of the present invention;

[0022] Figure 4 Schematic diagram of a monitoring device for busbar temperature of a flexible direct current transmission power submodule in an embodiment of the present invention;

[0023] Figure 5 Schematic diagram of a computer device in an embodiment of the present invention. DETAILED DESCRIPTION

[0024] To make the purpose, technical solution and advantages of the embodiments of the present invention more clear, the embodiments of the present invention are further described in detail below in conjunction with the accompanying drawings. Here, the exemplary embodiments of the present invention and their descriptions are used to explain the present invention, but are not intended to limit the present invention.

[0025] Figure 1 The flowchart of the method for monitoring the busbar temperature of the flexible direct current transmission power submodule in an embodiment of the present invention includes:

[0026] Step 101, obtaining operating parameters of the converter valve under different temperature conditions;

[0027] Step 102, inputting the operating parameters into the busbar temperature prediction model, and outputting the corresponding busbar temperature prediction value; the busbar temperature prediction model is obtained by training a least squares support vector machine model using historical operating parameters as input and historical busbar temperature as output;

[0028] Step 103, obtaining temperature values ​​at multiple contact points between the busbar surface and the sensing optical fiber, and selecting a maximum temperature value from the temperature values ​​at the multiple contact points as the actual busbar temperature value;

[0029] Step 104, calculating the temperature difference between the predicted busbar temperature and the actual busbar temperature, and monitoring the temperature state of the busbar according to the temperature difference calculation result.

[0030] In an embodiment of the present invention, the flexible direct current transmission system is composed of a plurality of power sub-modules connected in series, and the topological structure of the power sub-modules includes a half-bridge topological structure and a full-bridge topological structure. Figure 2 The IGCT power submodule half-bridge topology structure in the embodiment of the present invention is taken as an example. Figure 2 As shown, the half-bridge power submodule includes fully controlled switching devices VD1, VD2, diodes D1, D2, and anode reactance L i , clamping diode D cl , clamping resistor R cl , clamping capacitor C cl , voltage balancing resistor R, DC capacitor C, bypass switch K. VD1 and D1 are connected in parallel, VD2 and D2 are connected in parallel, D cl , R cl and C cl The clamping circuit is formed, and the bypass switch K is connected in parallel at both ends of VD2 and D2. The two ends of the bypass switch K are connected to busbars A and B respectively. One end of busbar A is the positive electrode of the bridge port end of the power submodule, and the other end is connected to the cathode of VD1; busbar B One end of busbar A is the negative electrode of the bridge port end of the power submodule, and the other end is connected to the DC capacitor C. During operation, the flow of current at the bridge port end of each power submodule will generate heat, and the temperature of busbars A and B needs to be monitored. The following describes each step in detail.

[0031] In step 101, operating parameters of the converter valve under different temperature conditions are obtained.

[0032] In one embodiment, the operating parameters of the converter valve include: AC component, AC phase, DC component, DC phase, voltage, and current.

[0033] In step 102, the operating parameters are input into the busbar temperature prediction model, and the corresponding busbar temperature prediction value is output; the busbar temperature prediction model is obtained by training a least squares support vector machine model using historical operating parameters as input and historical busbar temperature as output.

[0034] In a specific embodiment, the least squares support vector machine model LSSVM uses the quadratic square term of the error as the target loss function, transforms the inequality constraint into an equality constraint problem, replaces the quadratic programming method used by the support vector machine, and simplifies the computational complexity. According to the optimization conditions, a suitable kernel function is selected for the LSSVM to improve the accuracy of modeling, and finally the optimized LSSVM model is obtained as the busbar temperature prediction model.

[0035] In step 103, the temperature values ​​at multiple contact points between the busbar surface and the sensing optical fiber are obtained, and the maximum temperature value is selected from the temperature values ​​at the multiple contact points as the actual value of the busbar temperature.

[0036] Figure 3 FIG. 1 is a flow chart of obtaining the temperature values ​​at multiple contact points between the busbar surface and the sensing optical fiber in an embodiment of the present invention. Figure 3 As shown, in one embodiment, obtaining the temperature values ​​at multiple contact points between the busbar surface and the sensing optical fiber includes:

[0037] Step 301, using optical fiber temperature measurement technology to measure the Brillouin frequencies at multiple contact points between the sensing optical fiber and the surface of each busbar;

[0038] Step 302: Calculate the temperature values ​​at the multiple contact points between the busbar surface and the sensing optical fiber according to the Brillouin frequencies at the multiple contact points.

[0039] In a specific embodiment, sensing optical fibers are laid on the surfaces of busbars A and B, and optical fiber temperature measurement technology is used to obtain the Brillouin frequency at the contact point between the sensing optical fiber and the surface of each resistor, and the temperature of each contact point between the busbar and the sensing optical fiber is determined based on the Brillouin frequency at the contact point between the sensing optical fiber and the surface of each resistor. The Brillouin frequency is the frequency corresponding to the maximum peak in the Brillouin scattering spectrum at the contact point between the sensing optical fiber and the surface of each resistor.

[0040] In one embodiment, the temperature value at each contact point between the busbar surface and the sensing optical fiber is calculated according to the following formula:

[0041]

[0042] In the formula, * represents the busbar number, f i,* (t) is the Brillouin frequency at the i-th contact point between the sensing optical fiber and the busbar surface at time t, f′ i,* is the Brillouin frequency at the ith contact point between the sensing optical fiber and the busbar when the busbar surface is at the reference temperature, CV,T is the temperature coefficient of the sensing fiber, T′ i,* is the reference temperature at the i-th contact point on the busbar surface.

[0043] In a specific embodiment, based on the time difference between the detection light and its corresponding scattered light, the contact point between the sensing optical fiber and the busbar surface of the power submodule can be located. The corresponding time difference t and the contact point position P conform to the following relationship:

[0044]

[0045] Where C is the speed of light in a vacuum, and n is the refractive index of the sensing optical fiber. In the embodiment of the present invention, the entire sensing optical fiber is used as a sensor, and the sensing points are continuously distributed. Temperature measurement is performed at multiple contact points, and multi-point continuous measurement of the busbar surface can be achieved. The above-mentioned distributed optical fiber temperature measurement method has strong resistance to electromagnetic interference due to its unique measurement principle, thereby ensuring the accuracy and reliability of the measurement results; in addition, during the operation of the power submodule, vibration and explosion may occur. The distributed optical fiber temperature measurement system can operate stably in harsh environments to ensure the safety of the equipment.

[0046] In step 104, the temperature difference between the predicted busbar temperature and the actual busbar temperature is calculated, and the temperature state of the busbar is monitored according to the temperature difference calculation result.

[0047] In one embodiment, monitoring the temperature state of the busbar according to the temperature difference calculation result includes:

[0048] If the temperature difference is less than or equal to the preset threshold, it is determined that the busbar temperature is normal;

[0049] If the temperature difference is greater than the preset threshold, the busbar temperature warning is triggered, and the busbar temperature status is determined to be abnormal.

[0050] In a specific embodiment, a temperature warning threshold is set. When the temperature prediction value exceeds the set threshold, a temperature warning will be triggered to remind the monitoring personnel to pay attention to the temperature and ensure the safe and reliable operation of the power submodule and the converter valve. On the other hand, if the temperature prediction value deviates significantly from the historical temperature average, the temperature prediction value will be marked as abnormal.

[0051] The present invention also provides a device for monitoring busbar temperature of a flexible DC power submodule, as described in the following embodiments. Since the principle of the device to solve the problem is similar to the method for monitoring busbar temperature of a flexible DC power submodule, the implementation of the device can refer to the implementation of the method for monitoring busbar temperature of a flexible DC power submodule, and the repeated parts will not be repeated.

[0052] Figure 4Schematic diagram of a monitoring device for busbar temperature of a flexible DC transmission power submodule in an embodiment of the present invention, the device comprises:

[0053] An operating parameter acquisition module 401 is used to acquire operating parameters of the converter valve under different temperature conditions;

[0054] The busbar temperature prediction value output module 402 is used to input the operating parameters into the busbar temperature prediction model and output the corresponding busbar temperature prediction value; the busbar temperature prediction model is obtained by training a least squares support vector machine model using historical operating parameters as input and historical busbar temperatures as output;

[0055] The busbar temperature actual value determination module 403 is used to obtain the temperature values ​​at multiple contact points between the busbar surface and the sensing optical fiber, and select the maximum temperature value from the temperature values ​​at the multiple contact points as the busbar temperature actual value;

[0056] The busbar temperature status monitoring module 404 is used to calculate the temperature difference between the predicted busbar temperature value and the actual busbar temperature value, and monitor the temperature status of the busbar according to the temperature difference calculation result.

[0057] In one embodiment, the operating parameters of the converter valve include: AC component, AC phase, DC component, DC phase, voltage, and current.

[0058] In one embodiment, the busbar temperature actual value determination module is specifically used to:

[0059] The optical fiber temperature measurement technology is used to measure the Brillouin frequency at multiple contact points between the sensing optical fiber and each busbar surface;

[0060] The temperature values ​​at the multiple contact points between the busbar surface and the sensing optical fiber are calculated according to the Brillouin frequencies at the multiple contact points.

[0061] In one embodiment, the busbar temperature actual value determination module is specifically used to:

[0062] The temperature value at each contact point between the busbar surface and the sensing optical fiber is calculated according to the following formula:

[0063]

[0064] In the formula, * represents the busbar number, f i,* (t) is the Brillouin frequency at the i-th contact point between the sensing optical fiber and the busbar surface at time t, f′ i,* is the Brillouin frequency at the ith contact point between the sensing optical fiber and the busbar when the busbar surface is at the reference temperature, C V,T is the temperature coefficient of the sensing fiber, T′ i,* is the reference temperature at the i-th contact point on the busbar surface.

[0065] In one embodiment, the busbar temperature status monitoring module is specifically used to:

[0066] If the temperature difference is less than or equal to the preset threshold, it is determined that the busbar temperature is normal;

[0067] If the temperature difference is greater than the preset threshold, the busbar temperature warning is triggered, and the busbar temperature status is determined to be abnormal.

[0068] An embodiment of the present invention further provides a computer device, Figure 5 It is a schematic diagram of a computer device in an embodiment of the present invention. The computer device 500 includes a memory 510, a processor 520, and a computer program 530 stored in the memory 510 and executable on the processor 520. When the processor 520 executes the computer program 530, the above-mentioned method for monitoring the busbar temperature of the flexible DC transmission power submodule is implemented.

[0069] An embodiment of the present invention further provides a computer-readable storage medium, wherein the computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the method for monitoring the busbar temperature of the flexible direct current transmission power submodule is implemented.

[0070] An embodiment of the present invention further provides a computer program product, which includes a computer program. When the computer program is executed by a processor, the method for monitoring the busbar temperature of the flexible direct current transmission power submodule is implemented.

[0071] In the embodiment of the present invention, the operating parameters of the converter valve under different temperature conditions are obtained; the operating parameters are input into the busbar temperature prediction model, and the corresponding busbar temperature prediction value is output; the busbar temperature prediction model is obtained by training the least squares support vector machine model with the historical operating parameters as input and the historical busbar temperature as output; the temperature values ​​at multiple contact points between the busbar surface and the sensing optical fiber are obtained, and the maximum temperature value is selected from the temperature values ​​at multiple contact points as the actual busbar temperature value; the temperature difference between the busbar temperature prediction value and the busbar temperature actual value is calculated, and the temperature state of the busbar is monitored according to the temperature difference calculation result. In the above process, the embodiment of the present invention monitors the busbar temperature in real time, uses the busbar temperature as the judgment basis for the safe operation of the converter valve, and improves the safety and stability of the converter valve operation.

[0072] Those skilled in the art will appreciate that embodiments of the present invention may be provided as methods, systems, or computer program products. Therefore, the present invention may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Moreover, the present invention may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0073] The present invention is described with reference to flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to embodiments of the present invention. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as the combination of processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0074] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0075] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0076] The specific embodiments described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for monitoring busbar temperature of a flexible direct current transmission power submodule, characterized in that: include: Obtaining the operating parameters of the converter valve under different temperature conditions; Input the operating parameters into the busbar temperature prediction model and output the corresponding busbar temperature prediction value; The busbar temperature prediction model is obtained by training a least squares support vector machine model using historical operating parameters as input and historical busbar temperature as output; Obtaining temperature values ​​at multiple contact points between the busbar surface and the sensing optical fiber, and selecting a maximum temperature value from the temperature values ​​at the multiple contact points as the actual busbar temperature value; Calculate the temperature difference between the predicted busbar temperature and the actual busbar temperature, and monitor the busbar temperature status based on the temperature difference calculation result.

2. The method according to claim 1, characterized in that The operating parameters of the converter valve include: AC component, AC phase, DC component, DC phase, voltage, and current.

3. The method according to claim 1, characterized in that Obtain the temperature values ​​at multiple contact points between the busbar surface and the sensing optical fiber, including: The optical fiber temperature measurement technology is used to measure the Brillouin frequency at multiple contact points between the sensing optical fiber and each busbar surface; The temperature values ​​at the multiple contact points between the busbar surface and the sensing optical fiber are calculated according to the Brillouin frequencies at the multiple contact points.

4. The method according to claim 3, characterized in that The temperature value at each contact point between the busbar surface and the sensing optical fiber is calculated according to the following formula: In the formula, * represents the busbar number, f i,* (t) is the Brillouin frequency at the i-th contact point between the sensing optical fiber and the busbar surface at time t, f′ i,* is the Brillouin frequency at the ith contact point between the sensing optical fiber and the busbar when the busbar surface is at the reference temperature, C V,T is the temperature coefficient of the sensing fiber, T′ i,* is the reference temperature at the i-th contact point on the busbar surface.

5. The method according to claim 1, characterized in that Monitor the temperature status of the busbar based on the temperature difference calculation results, including: If the temperature difference is less than or equal to the preset threshold, it is determined that the busbar temperature is normal; If the temperature difference is greater than the preset threshold, the busbar temperature warning is triggered, and the busbar temperature status is determined to be abnormal.

6. A monitoring device for busbar temperature of a flexible DC transmission power submodule, characterized in that: include: An operating parameter acquisition module is used to obtain operating parameters of the converter valve under different temperature conditions; A busbar temperature prediction value output module is used to input the operating parameters into the busbar temperature prediction model and output the corresponding busbar temperature prediction value; the busbar temperature prediction model is obtained by training a least squares support vector machine model using historical operating parameters as input and historical busbar temperature as output; A busbar temperature actual value determination module is used to obtain the temperature values ​​at multiple contact points between the busbar surface and the sensing optical fiber, and select the maximum temperature value from the temperature values ​​at the multiple contact points as the busbar temperature actual value; The busbar temperature status monitoring module is used to calculate the temperature difference between the predicted busbar temperature value and the actual busbar temperature value, and monitor the temperature status of the busbar according to the temperature difference calculation result.

7. The device according to claim 6, characterized in that The operating parameters of the converter valve include: AC component, AC phase, DC component, DC phase, voltage, and current.

8. The device according to claim 6, characterized in that The busbar temperature actual value determination module is specifically used for: The optical fiber temperature measurement technology is used to measure the Brillouin frequency at multiple contact points between the sensing optical fiber and each busbar surface; The temperature values ​​at the multiple contact points between the busbar surface and the sensing optical fiber are calculated according to the Brillouin frequencies at the multiple contact points.

9. The device according to claim 8, characterized in that The busbar temperature actual value determination module is specifically used for: The temperature value at each contact point between the busbar surface and the sensing optical fiber is calculated according to the following formula: In the formula, * represents the busbar number, f i,* (t) is the Brillouin frequency at the i-th contact point between the sensing optical fiber and the busbar surface at time t, f′ i,* is the Brillouin frequency at the ith contact point between the sensing optical fiber and the busbar when the busbar surface is at the reference temperature, C V,T is the temperature coefficient of the sensing fiber, T′ i,* is the reference temperature at the i-th contact point on the busbar surface.

10. The device according to claim 6, characterized in that The busbar temperature status monitoring module is specifically used for: If the temperature difference is less than or equal to the preset threshold, it is determined that the busbar temperature is normal; If the temperature difference is greater than the preset threshold, the busbar temperature warning is triggered, and the busbar temperature status is determined to be abnormal.

11. A computer device comprising a memory, a processor and a computer program stored in the memory and executable on the processor, characterized in that: When the processor executes the computer program, the method according to any one of claims 1 to 5 is implemented.

12. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the method according to any one of claims 1 to 5 is implemented.

13. A computer program product, characterized in that The computer program product comprises a computer program, and when the computer program is executed by a processor, the method according to any one of claims 1 to 5 is implemented.

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