A method, medium and system for evaluating cooling capacity of a converter valve cooling system

Abstract

The application discloses a kind of evaluation method, medium and system of cooling capacity of converter valve cooling system, comprising: establishing the evaluation model of cooling capacity of converter valve cooling system;Every other preset time collects actual temperature rise value of converter valve cooling system under actual working condition;Multiple actual temperature rise values of converter valve cooling system under the actual working condition are substituted into the evaluation model, and evaluation index of converter valve cooling system under the actual working condition is fitted;According to the evaluation index of converter valve cooling system under the actual working condition, the cooling capacity of converter valve cooling system is evaluated.The evaluation model is established to obtain evaluation index, and the cooling capacity of cooling system can be comprehensively and quantitatively evaluated by different evaluation indexes, and the cooling capacity of different actual working conditions and different cooling systems is compared to guide the regulation and use of converter valve cooling system, and ensure the safe operation of converter valve.

Description

Technical Field

[0001] This invention relates to the field of converter valve cooling technology, and in particular to a method, medium, and system for evaluating the cooling capacity of a converter valve cooling system. Background Technology

[0002] In high-voltage and ultra-high-voltage direct current (HVDC) transmission projects, converter valves are key equipment for energy conversion. The thyristor elements within the converter valve generate significant heat during operation, necessitating a circulating cooling system. In existing technologies, this cooling system includes circulating cooling water. The cooling water flows through the converter valve, its temperature rises, and it carries away the generated heat, exchanging heat with an outdoor air cooler. This cools the cooling water to a suitable temperature range before it flows back to the converter valve, thus forming a closed-loop internal circulation system for the cooling water.

[0003] The cooling system operates in the power grid for a long time, and the dust and dirt can easily reduce its cooling capacity. If it is not dealt with in time, the temperature rise of the converter valve will exceed the limit and cause overheating failure.

[0004] Current methods for evaluating the cooling capacity of cooling systems involve monitoring the inlet and outlet water temperatures of the converter valve and controlling the inlet water temperature within a certain range; the lower the inlet water temperature, the better the cooling capacity. However, this method provides a rather one-sided assessment of the cooling system's cooling capacity. Summary of the Invention

[0005] This invention provides a method, medium, and system for evaluating the cooling capacity of a converter valve cooling system, in order to address the problem that the existing technology provides a rather one-sided evaluation of the cooling capacity of a cooling system.

[0006] Firstly, a method for evaluating the cooling capacity of a converter valve cooling system is provided, including:

[0007] Establish an evaluation model for the cooling capacity of the converter valve cooling system;

[0008] The actual temperature rise of the converter valve cooling system under actual operating conditions is collected at preset time intervals.

[0009] Substitute the collected actual temperature rise values ​​of the converter valve cooling system under the actual operating conditions into the evaluation model to obtain the evaluation index of the converter valve cooling system under the actual operating conditions.

[0010] The cooling capacity of the converter valve cooling system is evaluated based on the evaluation indicators of the converter valve cooling system under this actual operating condition.

[0011] In a second aspect, a computer-readable storage medium is provided, wherein computer program instructions are stored thereon; when executed by a processor, the computer program instructions implement the method for evaluating the cooling capacity of a converter valve cooling system as described in the first aspect embodiment above.

[0012] Thirdly, a system for evaluating the cooling capacity of a converter valve cooling system is provided, comprising: a computer-readable storage medium as described in the second aspect embodiment above.

[0013] Thus, in this embodiment of the invention, the cooling capacity of the cooling system is evaluated from the perspective of the thermodynamic performance of the converter valve. Based on the principle of energy conservation and the heat exchange principle between the converter valve and the cooling system, an evaluation model is established to obtain evaluation indicators. Through different evaluation indicators, the cooling capacity of the cooling system can be comprehensively and quantitatively evaluated. By comparing the cooling capacity of different actual operating conditions and different cooling systems, the regulation and use of the converter valve cooling system can be guided to ensure the safe operation of the converter valve. Attached Figure Description

[0014] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments of the present invention will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0015] Figure 1 This is a flowchart of a method for evaluating the cooling capacity of a converter valve cooling system according to an embodiment of the present invention. Detailed Implementation

[0016] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0017] This invention discloses a method for evaluating the cooling capacity of a converter valve cooling system. For example... Figure 1 As shown, the method includes the following steps:

[0018] Step S101: Establish an evaluation model for the cooling capacity of the converter valve cooling system.

[0019] Assuming the heat generation power of the converter valve per unit time is P, the total heat generated by the converter valve can be expressed as Pdt. A portion of the total heat generated by the converter valve is cmdθ, which is stored in the converter valve and cooling system, causing the converter valve temperature to rise. The other portion of the total heat is μΔθdt, which is dissipated into the environment through the converter valve and cooling system. Here, we assume C is the overall equivalent specific heat capacity of the converter valve and cooling system, m is the overall mass of the converter valve and cooling system, dθ is the overall temperature change of the converter valve, μ is the heat dissipated into the environment per unit temperature rise and per unit time through the various surfaces of the converter valve and cooling system, and Δθ is the temperature rise difference between the actual temperature of the converter valve and the ambient temperature. Therefore, the temperature rise change within time dt is Δθdt, assuming the ambient temperature is θ. amb Then the temperature rise Δθ = θ - θ amb .

[0020] The above description is expressed mathematically as: Pdt=cmdθ+μ(θ-θ amb By simplifying it mathematically into a first-order linear differential equation and solving it, we can obtain:

[0021] According to the thermoelectric equivalence principle, if the heat generation power P is equivalent to current and the temperature rise Δθ is equivalent to voltage, then the thermal resistance can be equivalent to resistance R. Therefore, μ can represent the conductivity coefficient of heat transfer to the outside world, which is the reciprocal of the real-time thermal resistance. Its mathematical expression is: Where W represents the total heat transferred.

[0022] Therefore, the temperature rise function is transformed into Where C1 represents a constant.

[0023] Based on the initial conditions of the converter valve, the constant C1 is solved:

[0024] When the cooling system is in a cold start state, i.e., before the cooling system starts operating and the temperature of the converter valve is the same as the ambient temperature, the initial conditions are as follows: t = 0, Δθ = 0. Substituting these into the temperature rise function above, we get C1 = -PR. At this time, the temperature rise function can be expressed as... When the cooling system is not cold-started, assuming the initial conditions are: t = 0, Δθ = K, substituting the initial conditions into the above temperature rise function yields:

[0025] Therefore, based on the above analysis, it can be seen that the temperature rise function is an exponential function. (Introducing...) This represents the time constant.

[0026] Based on the above analysis of the temperature rise function, an evaluation model is established, as shown in the following equation:

[0027]

[0028] Where a represents the steady-state temperature rise, b represents the time constant, c represents the initial temperature difference between the environment and the converter valve, x represents the acquisition time, and y represents the actual temperature rise value acquired at acquisition time x.

[0029] Step S102: Collect the actual temperature rise value of the converter valve cooling system under actual operating conditions at preset time intervals.

[0030] Specifically, a monitoring device can be installed at a specific location on the converter valve to collect temperature data. This specific location can be selected based on experience and actual conditions.

[0031] Step S103: Substitute the collected actual temperature rise values ​​of the converter valve cooling system under the actual operating conditions into the evaluation model, and fit to obtain the evaluation index of the converter valve cooling system under the actual operating conditions.

[0032] Specifically, the evaluation index can be obtained by fitting the parameters of the evaluation model using the nonlinear least squares fitting method of the cftool fitting tool in the MATLAB environment.

[0033] Specifically, the evaluation indicators include at least one of the following: steady-state temperature rise and time constant.

[0034] Step S104: Evaluate the cooling capacity of the converter valve cooling system based on the evaluation indicators of the converter valve cooling system under this actual operating condition.

[0035] I. Specifically, if the evaluation index is the steady-state temperature rise value, the method for evaluating cooling capacity through the steady-state temperature rise value is as follows:

[0036] For two steady-state temperature rise values ​​under preset comparison conditions, the maximum temperature that the converter valve cooling system with a smaller steady-state temperature rise value can raise is lower than the maximum temperature that the converter valve cooling system with a larger steady-state temperature rise value can raise.

[0037] The preset comparison conditions can include the following two types:

[0038] (1) Comparison of two converter valve cooling systems under the same actual operating conditions.

[0039] Thus, the two steady-state temperature rise values ​​are the steady-state temperature rise values ​​obtained by the two converter valve cooling systems under the same actual operating conditions.

[0040] Under these pre-defined comparison conditions, the difference in cooling capacity between the two converter valve cooling systems is evaluated.

[0041] (2) The same converter valve cooling system is compared under two actual operating conditions.

[0042] Thus, the two steady-state temperature rise values ​​are the steady-state temperature rise values ​​obtained by the converter valve cooling system under two actual operating conditions.

[0043] Under these preset comparison conditions, the evaluation assesses the cooling capacity of the same converter valve cooling system under different actual operating conditions.

[0044] According to the comparison results, the maximum temperature that the converter valve cooling system with a smaller steady-state temperature rise can raise is lower than that of the converter valve cooling system with a larger steady-state temperature rise. This indicates that the converter valve cooling system with a smaller steady-state temperature rise raises the temperature of the converter valve lower than that of the converter valve cooling system with a larger steady-state temperature rise, and has stronger cooling capacity.

[0045] II. Specifically, if the evaluation metric is the time constant, the method for evaluating cooling capacity using the time constant is as follows:

[0046] For two time constants under preset comparison conditions, the time it takes for the converter valve cooling system with the larger time constant to reach the maximum temperature that can be raised is longer than the time it takes for the converter valve cooling system with the smaller time constant to reach the maximum temperature that can be raised.

[0047] Similarly, preset comparison conditions can also include the following two types:

[0048] (1) Comparison of two converter valve cooling systems under the same actual operating conditions.

[0049] Thus, the two time constants are obtained for the two converter valve cooling systems under the same actual operating conditions.

[0050] Under these pre-defined comparison conditions, the difference in cooling capacity between the two converter valve cooling systems is evaluated.

[0051] (2) The same converter valve cooling system is compared under two actual operating conditions.

[0052] Thus, the two time constants are the time constants obtained by the converter valve cooling system under two actual operating conditions.

[0053] Under these preset comparison conditions, the evaluation assesses the cooling capacity of the same converter valve cooling system under different actual operating conditions.

[0054] According to the comparison results, the time it takes for the converter valve cooling system with a larger time constant to reach the maximum temperature that can be raised is longer than that of the converter valve cooling system with a smaller time constant. This indicates that the converter valve cooling system with a larger time constant raises the temperature of the converter valve more slowly and has a stronger cooling capacity.

[0055] It should be understood that in step S103, the steady-state temperature rise and time constant are obtained simultaneously during the solution of the evaluation model. Depending on the specific requirements, step S104 can choose to evaluate the cooling capacity independently using either the steady-state temperature rise or the time constant, or it can use both the steady-state temperature rise and the time constant together. Generally, when the cooling capacity obtained from the steady-state temperature rise and the time constant evaluations are contradictory, the evaluation result of the steady-state temperature rise shall prevail.

[0056] By evaluating the cooling capacity of the converter valve cooling system, guidance can be provided for the regulation and use of the converter valve cooling system.

[0057] Furthermore, before performing the evaluation in step S104, it is necessary to determine whether the cooling system is faulty. The evaluation will only proceed if the cooling system is not faulty. Therefore, the method also includes the following steps:

[0058] (1) Collect the actual temperature rise of the converter valve cooling system under the maximum and minimum operating conditions at preset time intervals.

[0059] (2) Substitute the collected actual temperature rise values ​​of the converter valve cooling system under the maximum operating condition into the evaluation model and fit to obtain the maximum steady-state temperature rise value of the converter valve cooling system under the maximum operating condition.

[0060] (3) Substitute the collected actual temperature rise values ​​of the converter valve cooling system under minimum operating conditions into the evaluation model and fit to obtain the minimum steady-state temperature rise value of the converter valve cooling system under the minimum operating conditions.

[0061] (4) Compare the steady-state temperature rise of the actual operating conditions of the converter valve cooling system with the maximum and minimum steady-state temperature rise.

[0062] Depending on the comparison results, the following two steps are performed:

[0063] (5) If the steady-state temperature rise under the actual operating conditions of the converter valve cooling system is not greater than the maximum steady-state temperature rise, and the steady-state temperature rise under the actual operating conditions of the converter valve cooling system is not less than the minimum steady-state temperature rise, then the step of evaluating the cooling capacity of the converter valve cooling system based on the evaluation index of the converter valve cooling system under the actual operating conditions shall be performed.

[0064] This step indicates that the converter valve cooling system is functioning correctly, therefore, further evaluation steps can be performed.

[0065] (6) If the steady-state temperature rise under the actual operating conditions of the converter valve cooling system is greater than the maximum steady-state temperature rise, and the steady-state temperature rise under the actual operating conditions of the converter valve cooling system is less than the minimum time constant, then the converter valve cooling system is determined to be faulty.

[0066] This step indicates a malfunction in the converter valve, and the converter valve cooling system should be stopped immediately.

[0067] This invention also discloses a computer-readable storage medium storing computer program instructions; when executed by a processor, the computer program instructions implement the method for evaluating the cooling capacity of the converter valve cooling system as described in the above embodiments.

[0068] This invention also discloses an evaluation system for the cooling capacity of a converter valve cooling system, comprising: a computer-readable storage medium as described in the above embodiments.

[0069] In summary, the embodiments of the present invention evaluate the cooling capacity of the cooling system from the perspective of the thermodynamic performance of the converter valve. Based on the principle of energy conservation and the heat exchange principle between the converter valve and the cooling system, an evaluation model is established to obtain evaluation indicators. Through different evaluation indicators, the cooling capacity of the cooling system can be comprehensively and quantitatively evaluated. By comparing the cooling capacity of different actual operating conditions and different cooling systems, the regulation and use of the converter valve cooling system can be guided to ensure the safe operation of the converter valve.

[0070] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A method for evaluating the cooling capacity of a converter valve cooling system, characterized in that, include: Establish an evaluation model for the cooling capacity of the converter valve cooling system; The actual temperature rise of the converter valve cooling system under actual operating conditions is collected at preset time intervals. Substitute the collected actual temperature rise values ​​of the converter valve cooling system under the actual operating conditions into the evaluation model to obtain the evaluation index of the converter valve cooling system under the actual operating conditions. The cooling capacity of the converter valve cooling system is evaluated based on the evaluation indicators of the converter valve cooling system under this actual operating condition. The evaluation model is as follows: ； in, a This represents the steady-state temperature rise. b Represents the time constant. c This indicates the initial temperature difference between the environment and the converter valve. x Indicates the collection time. y Indicates the collection time x The actual temperature rise value collected.

2. The evaluation method according to claim 1, characterized in that, The evaluation index is the steady-state temperature rise value. Therefore, the step of evaluating the cooling capacity of the converter valve cooling system based on the evaluation index under this actual operating condition includes: For two steady-state temperature rise values ​​under preset comparison conditions, the maximum temperature that the converter valve cooling system with a smaller steady-state temperature rise value can raise is lower than the maximum temperature that the converter valve cooling system with a larger steady-state temperature rise value can raise.

3. The evaluation method according to claim 1, characterized in that, If the evaluation index is a time constant, then the step of evaluating the cooling capacity of the converter valve cooling system based on the evaluation index of the converter valve cooling system under this actual operating condition includes: For two time constants under preset comparison conditions, the time it takes for the converter valve cooling system with the larger time constant to reach the maximum temperature that can be raised is longer than the time it takes for the converter valve cooling system with the smaller time constant to reach the maximum temperature that can be raised.

4. The evaluation method according to claim 2 or 3, characterized in that: The preset comparison condition is to compare two converter valve cooling systems under the same actual operating conditions.

5. The evaluation method according to claim 2 or 3, characterized in that: The preset comparison conditions are to compare the same converter valve cooling system under two actual operating conditions.

6. The evaluation method according to claim 1, characterized in that, Before the step of evaluating the cooling capacity of the converter valve cooling system based on the evaluation indicators of the converter valve cooling system under the actual operating conditions, the method further includes: The actual temperature rise of the converter valve cooling system under maximum and minimum operating conditions is collected at preset time intervals. Substitute the collected actual temperature rise values ​​of the converter valve cooling system under maximum operating conditions into the evaluation model to obtain the maximum steady-state temperature rise value of the converter valve cooling system under the maximum operating conditions. Substitute the collected actual temperature rise values ​​of the converter valve cooling system under minimum operating conditions into the evaluation model to obtain the minimum steady-state temperature rise value of the converter valve cooling system under the minimum operating conditions. The steady-state temperature rise of the converter valve cooling system under actual operating conditions is compared with the maximum steady-state temperature rise and the minimum steady-state temperature rise. If the steady-state temperature rise of the converter valve cooling system under actual operating conditions is not greater than the maximum steady-state temperature rise, and the steady-state temperature rise of the converter valve cooling system under actual operating conditions is not less than the minimum steady-state temperature rise, then the step of evaluating the cooling capacity of the converter valve cooling system based on the evaluation index of the converter valve cooling system under actual operating conditions is performed.

7. The evaluation method according to claim 6, characterized in that, Also includes: If the steady-state temperature rise of the converter valve cooling system under actual operating conditions is greater than the maximum steady-state temperature rise, or if the steady-state temperature rise of the converter valve cooling system under actual operating conditions is less than the minimum steady-state temperature rise, then the converter valve cooling system is determined to be faulty.

8. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores computer program instructions; when the computer program instructions are executed by a processor, they implement the method for evaluating the cooling capacity of the converter valve cooling system as described in any one of claims 1 to 7.

9. A system for evaluating the cooling capacity of a converter valve cooling system, characterized in that, include: The computer-readable storage medium as described in claim 8.

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