Power box anti-condensation heating and dehumidifying method

Abstract

The present application relates to the technical field of electric power, and particularly relates to a power box anti-condensation heating and dehumidification method. The method comprises the following steps: obtaining atmospheric humidity through weather forecast, and obtaining box humidity through a humidity sensor in the power box; when the humidity sensor is in a normal state, controlling a PID heating strategy according to the box humidity; when the humidity sensor is damaged, controlling a heating strategy according to the atmospheric humidity. The present application gives a method for determining whether the humidity sensor is abnormal or not in the case of using only the humidity sensor. For the normal and abnormal states of the humidity sensor, dehumidification and heating strategies are respectively formulated, which significantly increases the stability of the power system. When the humidity sensor is normal, the PID heating control strategy can quickly dehumidify in the case of high humidity, and prolong the dehumidification time in the case of low humidity, thereby avoiding frequent start and stop of the heater.

Description

Technical Field

[0001] This invention relates to the field of power technology, and in particular to a method for preventing condensation and dehumidifying power distribution boxes through heating. Background Technology

[0002] In southern regions, outdoor power system facilities are exposed to high humidity for extended periods, inevitably leading to condensation. For some equipment, especially in 220kV and above substations, condensation can cause safety hazards such as secondary circuit grounding and corrosion of internal equipment.

[0003] The most common way to solve the condensation problem is to install a heater inside the enclosure. When the humidity is too high, the heater is turned on to dehumidify. To implement this solution, a humidity sensor is currently installed inside the enclosure. When the humidity sensor collects data exceeding a threshold, the heater is automatically or remotely activated.

[0004] Its major shortcomings are: 1. When the outdoor humidity is high for a long time, the heater will be frequently turned on and off, which can easily lead to heater failure; 2. When the humidity sensor is damaged, the power box cannot effectively dehumidify, causing safety hazards; 3. It cannot optimize the heater heating strategy for different humidity environments, resulting in dehumidification that is too fast or ineffective. Summary of the Invention

[0005] This invention discloses a method for preventing condensation and dehumidifying electrical boxes through heating, characterized by the following specific method:

[0006] Atmospheric humidity is obtained through weather forecasts, and humidity inside the electrical box is obtained through a humidity sensor.

[0007] If the atmospheric humidity is higher than the first threshold and the cabinet humidity is lower than the second threshold, or if the cabinet humidity data is lost, it is determined that the cabinet humidity sensor is faulty. At this time, the current condensation atmospheric humidity threshold is predicted. When the atmospheric humidity is higher than the current condensation atmospheric humidity threshold, the first atmospheric humidity heating control strategy is activated.

[0008] If the humidity of the chamber is higher than the second threshold, the heater will be activated, and the heating power of the heater will be controlled by a PID heating control algorithm.

[0009] The advantage of this embodiment is that it provides a method for determining whether the humidity sensor is abnormal when using only a humidity sensor. Dehumidification and heating strategies are formulated for both normal and abnormal humidity sensor states, significantly increasing the stability of the power system. When the humidity sensor is normal, the PID heating control strategy can quickly dehumidify under high humidity conditions and extend the dehumidification time under low humidity conditions, avoiding frequent start-up and shutdown of the heater.

[0010] Furthermore, the first threshold is the highest atmospheric condensation humidity corresponding to condensation on the power box within the calibrated temperature range;

[0011] The second threshold is the first threshold minus the maximum humidity deviation between the atmosphere and the box when condensation occurs on the power box under non-heating conditions.

[0012] The advantage of this embodiment is that when the atmospheric humidity is at its lowest condensation level, condensation will inevitably form inside the chamber without heating. If the humidity sensor has not yet reached the dehumidification activation threshold (the second threshold) at this time, the humidity sensor is deemed to be damaged. The second threshold is determined by the maximum deviation between the atmospheric humidity and the chamber humidity when the chamber is best sealed.

[0013] Furthermore, when the heater is controlled by the PID heating control algorithm, if the rate of change of humidity in the chamber is less than the first speed threshold, it is determined that the chamber door is not closed and the chamber door alarm is activated.

[0014] When the heater is controlled by the PID heating control algorithm, if the rate of change of humidity in the chamber is less than the second speed threshold or the humidity in the chamber is lost, it is determined that the humidity sensor is faulty and the first atmospheric humidity heating control strategy is activated.

[0015] The advantage of this embodiment is that it provides a method for determining whether the cabinet door is closed by relying solely on a humidity sensor, and a method for determining humidity sensor malfunction by heating, thus saving dehumidification costs.

[0016] Furthermore, if the cabinet door was not closed after the last maintenance and the humidity sensor is currently determined to be faulty, the second atmospheric heating control strategy will be activated.

[0017] The advantage of this embodiment is that it provides an independent heating control strategy for the case where the cabinet door is not closed and the humidity sensor is faulty, so as to differentiate the heating control strategy when the cabinet door is closed.

[0018] Furthermore, the first atmospheric humidity heating control strategy uses atmospheric humidity as the decision-making basis to control the heater heating, and the specific method is as follows:

[0019] Obtain the current ambient temperature, determine the current atmospheric condensation humidity based on the current ambient temperature, and start the heater at the first power when the current atmospheric humidity is greater than the current atmospheric condensation humidity until the calibration time.

[0020] The advantage of this embodiment is that when the humidity sensor is damaged and the cabinet door is closed, heating with constant power for a fixed time can extend the heating time while ensuring the dehumidification effect and avoiding frequent opening and closing of the heater.

[0021] Furthermore, the second atmospheric heating control strategy uses atmospheric humidity as the decision-making basis to control the heater heating, and the specific method is as follows:

[0022] Obtain the current ambient temperature, determine the current atmospheric condensation humidity based on the current ambient temperature, and when the current atmospheric humidity is greater than the current atmospheric condensation humidity, start the heater at a constant second power until the current atmospheric humidity is less than the current atmospheric condensation humidity.

[0023] The advantage of this embodiment is that condensation is particularly likely to occur when the humidity sensor is damaged and the cabinet door is not closed, requiring continuous heating with lower power to ensure the safety of the electrical equipment.

[0024] Furthermore, the current atmospheric condensation humidity is determined based on the current ambient temperature, using the following specific method:

[0025] The current ambient temperature and time are input into the condensation humidity prediction model established for this power box, and the condensation humidity prediction model outputs the current atmospheric condensation humidity.

[0026] The advantage of this embodiment is that it establishes a condensation humidity prediction model for different ambient temperatures and different electrical box locations, which can improve the accuracy of the condensation humidity threshold and help to effectively dehumidify.

[0027] Furthermore, the first power and calibration time are determined through an optimization algorithm, the specific method of which is as follows:

[0028] Several parameter combinations with different initial power and different calibration time are randomly generated;

[0029] Exclude parameter combinations that cannot reduce the humidity of the enclosure below the target level;

[0030] Determine the work and time required to reduce the humidity of the chamber to below the target level using the remaining parameter combinations;

[0031] The fitness function is constructed based on the least amount of work done and the longest work time, and the parameter combinations that are ranked before a preset number are retained.

[0032] Using the first power and calibration time corresponding to each retained parameter combination as the center of a two-dimensional coordinate circle, a preset radius is set, and new parameter combinations are randomly generated within the preset radius;

[0033] Repeatedly calculate the fitness function of the new parameter combination, filter and retain the new parameter combination, and randomly generate parameter combinations until the preset number of calculations is completed. Select the first power and calibration time parameter combination corresponding to the optimal fitness function as the final result.

[0034] The advantage of this embodiment is that, in the case of a closed cabinet door and a malfunctioning humidity sensor, it optimizes the heating time and heating power, extending the heating time while reducing the heating power, thus saving energy.

[0035] Furthermore, the second power determination method is as follows:

[0036] Determine the minimum heating power corresponding to different atmospheric humidity levels when the power box is not closed; when the heater is driven with the minimum heating power, the humidity of the box decreases at a preset rate.

[0037] A lookup table was constructed based on different atmospheric humidity levels and their corresponding minimum heating power.

[0038] Based on the current atmospheric condensation humidity and the lookup table, determine the current second power.

[0039] The advantage of this embodiment is that, in the case of an open door and a malfunctioning humidity sensor, it ensures that condensation does not occur inside the enclosure for an extended period of time with low power consumption, thus guaranteeing the safe operation of the power grid.

[0040] Furthermore, the heating power is controlled using a PID heating control algorithm, as detailed below:

[0041] Calculate the humidity deviation between the current humidity level in the enclosure and the target humidity level;

[0042] The current heating power is controlled by using the humidity deviation as a feedforward input.

[0043] Heating will stop when the humidity deviation is less than the target deviation and the duration exceeds the time threshold.

[0044] The advantage of this embodiment is that, when the humidity sensor is in normal condition, it can quickly dehumidify in the early stage to ensure equipment safety, and can dehumidify at low power in the later stage to extend the dehumidification time and prevent the heater from frequently starting and stopping.

[0045] Other advantages, objectives, and features of the invention will be set forth in part in the description which follows, and in part will be apparent to those skilled in the art from the following examination, or may be learned from practice of the invention. The objectives and other advantages of the invention can be realized and obtained through the following description. Attached Figure Description

[0046] The accompanying drawings of this invention are described below.

[0047] Figure 1 This is a schematic diagram of the overall process of the present invention.

[0048] Figure 2 This is a schematic diagram of the PID heating control process.

[0049] Figure 3 This is a schematic diagram of the first atmospheric humidity heating control strategy. Detailed Implementation

[0050] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0051] A method for preventing condensation and dehumidifying electrical boxes using heating, such as... Figure 1 As shown, the specific steps are as follows:

[0052] S1. Obtain atmospheric humidity h from weather forecasts. a The humidity h inside the power box is obtained through a humidity sensor. b .

[0053] S2. If the humidity of the chamber is higher than the second threshold The heater is started, and its heating power is controlled by a PID heating control algorithm.

[0054] Second threshold The first threshold Subtract the maximum humidity deviation Δh between the atmosphere and the enclosure when condensation occurs on the electrical box under non-heating conditions. max ,Right now First threshold The calibration temperature is the highest atmospheric humidity corresponding to condensation on the power box within the calibrated temperature range. The calibrated temperature is the average ambient temperature range.

[0055] In step S2, when the heater is controlled to heat using the PID heating control algorithm, if the rate of change of humidity in the chamber is less than the first speed threshold... If the cabinet door is determined to be open, the cabinet door alarm will be activated.

[0056] When the heater is controlled by a PID heating control algorithm, if the rate of change of humidity in the chamber is less than the second speed threshold... If the humidity of the enclosure is lost, it is determined to be a humidity sensor malfunction, and the first atmospheric humidity heating control strategy is activated.

[0057] The heating power is controlled using a PID heating control algorithm, such as... Figure 2 As shown, the specific steps are as follows:

[0058] S21. Calculate the humidity deviation e(t) between the current humidity of the chamber and the target humidity;

[0059] S22. Using humidity deviation as a feedforward input, control the current heating power using the following formula:

[0060] u(t)=kp*e(t)+ki*∫e(t)+kd*de(t) / dt

[0061] S23. When the humidity deviation is less than the target deviation and the duration exceeds the time threshold, stop heating.

[0062] S3. If the atmospheric humidity is higher than the first threshold. And the humidity of the enclosure is below the second threshold. If the humidity data of the enclosure is lost, it is determined that the humidity sensor of the enclosure is faulty; at this time, the current condensation atmospheric humidity threshold th is predicted. ccWhen the atmospheric humidity is higher than the current condensation humidity threshold, i.e. h a >th cc Activate the first atmospheric humidity heating control strategy, such as Figure 3 As shown.

[0063] In step S3, the first atmospheric humidity heating control strategy uses atmospheric humidity as the decision basis to control the heater to heat. Specifically, the method is as follows: obtain the current ambient temperature T, and determine the current atmospheric condensation humidity th based on the current ambient temperature T. cc When the current atmospheric humidity is greater than the current atmospheric condensation humidity, i.e., h a >th cc The heater is started with the first power p1 until the calibrated time t1.

[0064] In step S3, the first power and calibration time are determined through an optimization algorithm, and the specific steps are as follows:

[0065] S31. Randomly generate several parameter combinations {p1,t1} with different first powers and different calibration times;

[0066] S32. Exclude parameter combinations that cannot reduce the humidity of the enclosure below the target level;

[0067] S33. Determine the work and time required to reduce the humidity of the chamber to below the target using the remaining parameter combinations;

[0068] S34. Construct a fitness function based on the minimum work done and the longest work time, retaining the parameter combinations ranked before a preset number. The specific formula for the fitness function is as follows:

[0069]

[0070] In the formula, a and b are preset weights.

[0071] S35. Using the first power and calibration time corresponding to each retained parameter combination as the center of a two-dimensional coordinate circle, set a preset radius, and randomly generate new parameter combinations within the preset radius;

[0072] S36. Repeatedly calculate the fitness function of the new parameter combination, filter and retain the new parameter combination, and randomly generate parameter combinations until the preset number of calculations is completed. Select the first power and calibration time parameter combination corresponding to the optimal fitness function as the final result.

[0073] S4. If the cabinet door was not closed after the last maintenance and the humidity sensor is currently determined to be faulty, the second atmospheric heating control strategy will be activated.

[0074] In step S4, the second atmospheric heating control strategy uses atmospheric humidity as the decision-making basis to control the heater heating. Specifically, the method is as follows: obtain the current ambient temperature T, and determine the current atmospheric condensation humidity th based on the current ambient temperature T. cc When the current atmospheric humidity is greater than the current atmospheric condensation humidity, i.e., h a >th cc The heater is started at a constant second power p2 until the current atmospheric humidity is lower than the current atmospheric condensation humidity.

[0075] In step S4, the second power determination steps are as follows:

[0076] S41. Determine the minimum heating power corresponding to different atmospheric humidity levels when the power box is not closed; when the heater is driven with the minimum heating power, the humidity of the box decreases at a preset rate.

[0077] S42. Construct a lookup table based on different atmospheric humidity levels and corresponding minimum heating power;

[0078] S43. Determine the current second power based on the current atmospheric condensation humidity and the lookup table.

[0079] In steps S3 and S4, the current atmospheric condensation humidity is determined based on the current ambient temperature. Specifically, the current ambient temperature and current time are input into the condensation humidity prediction model established for the power box, and the condensation humidity prediction model outputs the current atmospheric condensation humidity.

[0080] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A method for preventing condensation and dehumidifying electrical boxes using heating, characterized in that, The specific method is as follows: Atmospheric humidity is obtained through weather forecasts, and humidity inside the electrical box is obtained through a humidity sensor. If the atmospheric humidity is higher than the first threshold and the cabinet humidity is lower than the second threshold, or if the cabinet humidity data is lost, it is determined that the cabinet humidity sensor is faulty. At this time, the current condensation atmospheric humidity threshold is predicted. When the atmospheric humidity is higher than the current condensation atmospheric humidity threshold, the first atmospheric humidity heating control strategy is activated. If the humidity of the chamber is higher than the second threshold, the heater will be activated, and the heating power of the heater will be controlled by a PID heating control algorithm. The first threshold is the highest atmospheric humidity corresponding to condensation on the power box within the calibrated temperature range; The second threshold is the first threshold minus the maximum humidity deviation between the atmosphere and the box when condensation occurs on the power box under non-heating conditions; When the heater is controlled by the PID heating control algorithm, if the rate of change of humidity in the chamber is less than the first speed threshold, it is determined that the chamber door is not closed and the chamber door alarm is activated. When the heater is controlled by the PID heating control algorithm, if the rate of change of humidity in the chamber is less than the second speed threshold or the humidity in the chamber is lost, it is determined that the humidity sensor is faulty and the first atmospheric humidity heating control strategy is activated. If the cabinet door was not closed after the last maintenance and the humidity sensor is currently diagnosed as faulty, the second atmospheric heating control strategy will be activated. The first atmospheric humidity heating control strategy uses atmospheric humidity as the decision-making basis to control the heater heating, and the specific method is as follows: Obtain the current ambient temperature, determine the current atmospheric condensation humidity based on the current ambient temperature, and start the heater at the first power when the current atmospheric humidity is greater than the current atmospheric condensation humidity until the calibration time is reached. The second atmospheric heating control strategy uses atmospheric humidity as the decision-making basis to control the heater heating, and the specific method is as follows: Obtain the current ambient temperature, determine the current atmospheric condensation humidity based on the current ambient temperature, and when the current atmospheric humidity is greater than the current atmospheric condensation humidity, start the heater at a constant second power until the current atmospheric humidity is less than the current atmospheric condensation humidity.

2. The method for preventing condensation and dehumidifying electrical boxes as described in claim 1, characterized in that, Determine the current atmospheric condensation humidity based on the current ambient temperature, using the following method: The current ambient temperature and time are input into the condensation humidity prediction model established for this power box, and the condensation humidity prediction model outputs the current atmospheric condensation humidity.

3. The method for preventing condensation and dehumidifying electrical boxes as described in claim 1, characterized in that, The first power and calibration time are determined through an optimization algorithm, the specific method of which is as follows: Several parameter combinations with different initial power and different calibration time are randomly generated; Exclude parameter combinations that cannot reduce the humidity of the enclosure below the target level; Determine the work and time required to reduce the humidity of the chamber to below the target level using the remaining parameter combinations; The fitness function is constructed based on the least amount of work done and the longest work time, and the parameter combinations that are ranked before a preset number are retained. Using the first power and calibration time corresponding to each retained parameter combination as the center of a two-dimensional coordinate circle, a preset radius is set, and new parameter combinations are randomly generated within the preset radius; Repeatedly calculate the fitness function of the new parameter combination, filter and retain the new parameter combination, and randomly generate parameter combinations until the preset number of calculations is completed. Select the first power and calibration time parameter combination corresponding to the optimal fitness function as the final result.

4. The method for preventing condensation and dehumidifying electrical boxes as described in claim 1, characterized in that, The second power determination method is as follows: Determine the minimum heating power corresponding to different atmospheric humidity levels when the power box is not closed; when the heater is driven with the minimum heating power, the humidity of the box decreases at a preset rate. A lookup table was constructed based on different atmospheric humidity levels and their corresponding minimum heating power. Based on the current atmospheric condensation humidity and the lookup table, determine the current second power.

5. The method for preventing condensation and dehumidifying electrical boxes as described in claim 1, characterized in that, The heating power is controlled using a PID heating control algorithm, and the specific method is as follows: Calculate the humidity deviation between the current humidity level in the enclosure and the target humidity level; The current heating power is controlled by using the humidity deviation as a feedforward input. Heating will stop when the humidity deviation is less than the target deviation and the duration exceeds the time threshold.

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