An ultra-low frequency AC ice melting device and a fault protection method

Abstract

The present invention relates to the technical field of smart grids, and particularly relates to an ultra-low frequency AC ice melting device and a fault protection method. At each moment within a preset historical period at the current moment, the present invention acquires the line temperature and the output power of the ultra-low frequency AC ice melting device; further analyzes and obtains the ice melting efficiency coefficient at each moment, and constructs an ice melting efficiency coefficient sequence; then obtains all co-trending sequence sub-segments and long-term change sub-segments; finally, according to the change situation of the long-term change sub-segment and the local fluctuation situation of the ice melting efficiency coefficient sequence at the current moment, adjusts the output current frequency of the ultra-low frequency AC ice melting device at the current moment. By monitoring and evaluating the change situation of the ice melting efficiency of the ultra-low frequency AC ice melting device, the present invention analyzes and evaluates the ice melting effect within the adjacent period at the current moment, and then accurately adjusts the output current frequency of the ultra-low frequency AC ice melting device according to the ice melting effect, while maintaining efficient and stable ice melting, reducing the fault risk of the ice melting device.

Description

Technical Field

[0001] The present invention relates to the technical field of smart grids, and particularly to an ultra-low frequency alternating current ice melting device and a fault protection method thereof. Background Art

[0002] Since the transmission lines in the smart grid are laid outdoors, their surfaces may be continuously covered with ice in the cold winter environment. Severe icing will cause the transmission towers to be unable to support these ice-covered cables and collapse, resulting in large-scale power outages, significant economic losses and social impacts. Therefore, it is crucial to melt the ice on the ice-covered cables to ensure the safe operation of the lines.

[0003] In the prior art, an ultra-low frequency alternating current ice melting device is usually used to melt the ice on the lines. Its working principle is mainly based on calculating the heat required for ice melting based on the environmental heat balance model, so as to automatically adjust the output current frequency, and then melt the ice through the thermal effect generated by the ultra-low frequency alternating current. However, a suitable output current frequency is crucial for improving the ice melting efficiency and avoiding faults of the ice melting equipment. An inappropriate output current frequency may cause the electrical components in the ice melting device to be damaged and aged due to losses, and even be broken down and damaged. It may also cause strong electromagnetic interference and lead to the failure of the control system. An inappropriate output current frequency adjustment method will lead to losses and faults of the ultra-low frequency alternating current ice melting device. Summary of the Invention

[0004] In order to solve the technical problem that an inappropriate output current frequency adjustment method in the prior art leads to device loss and faults, the purpose of the present invention is to provide an ultra-low frequency alternating current ice melting device and a fault protection method thereof. The specific technical solutions adopted are as follows:

[0005] A fault protection method for an ultra-low frequency alternating current ice melting device, the method comprising:

[0006] Within a preset historical period at the current moment, obtain the line temperature of the line to be de-iced at each moment, and the output power of the ultra-low frequency alternating current ice melting device on the line to be de-iced at each moment;

[0007] At each moment, according to the line temperature of the line to be de-iced and the output power of the ultra-low frequency alternating current ice melting device, obtain the ice melting efficiency coefficient of the ultra-low frequency alternating current ice melting device; according to the ice melting efficiency coefficients of the ultra-low frequency alternating current ice melting device at all moments, construct an ice melting efficiency coefficient sequence;

[0008] According to the change situation of the ice melting efficiency coefficient sequence, segment the ice melting efficiency coefficient sequence to obtain all the same-trend sequence sub-segments, and screen out the long-term change sub-segments from all the same-trend sequence sub-segments; according to the change situation of the long-term change sub-segments and the local fluctuation situation of the ice melting efficiency coefficient sequence at the current moment, adjust the output current frequency of the ultra-low frequency alternating current ice melting device at the current moment.

[0009] Further, the method for obtaining the ice melting efficiency coefficient includes:

[0010] At each moment, according to the difference between the line temperature and the preset ice melting temperature, obtain the first ice melting efficiency parameter;

[0011] At each moment, according to the difference between the output power and the preset output power, obtain the second ice melting efficiency parameter;

[0012] Fuse the first ice melting efficiency parameter and the second ice melting efficiency parameter at each moment to obtain the ice melting efficiency coefficient of the ultra-low frequency AC ice melting device at each moment.

[0013] Further, the method for obtaining the same-trend sequence sub-segment includes:

[0014] Perform a first-order difference on the ice melting efficiency coefficient sequence to obtain a difference coefficient sequence; divide all consecutive sequence elements with the same sign in the difference coefficient sequence into a difference coefficient sequence sub-segment;

[0015] According to the difference coefficient sequence sub-segment, correspondingly divide the ice melting efficiency coefficient sequence to obtain all same-trend sequence sub-segments.

[0016] Further, the method for correspondingly dividing the ice melting efficiency coefficient sequence according to the difference coefficient sequence sub-segment to obtain all same-trend sequence sub-segments includes:

[0017] For the last sequence element in each difference coefficient sequence sub-segment, add 1 to its serial number in the difference coefficient sequence to obtain all the segmentation point serial numbers in the ice melting efficiency coefficient sequence;

[0018] In the ice melting efficiency coefficient sequence, use the sequence element corresponding to the segmentation point serial number as the last element of each same-trend sequence sub-segment, and use the next adjacent sequence element of the last element as the first element of the next same-trend sequence sub-segment; based on the last element and the first element, obtain the corresponding same-trend sequence sub-segment.

[0019] Further, the method for obtaining the long-term change sub-segment includes:

[0020] Among all the same-trend sequence sub-segments, use the longest same-trend sequence sub-segment as the long-term change sub-segment.

[0021] Further, the method for adjusting the output current frequency includes:

[0022] Obtain the flat growth parameter of the long-term change sub-segment according to the coefficient difference between all adjacent ice melting efficiency coefficients in the long-term change sub-segment; obtain the local fluctuation sequence sub-segment at the current moment according to the length of the co-trending sequence sub-segment; obtain the adjustment weight of the output current frequency at the current moment according to the sequence length of the local fluctuation sequence sub-segment and the flat growth parameter;

[0023] Use the adjustment weight to weight the output current frequency of the ultra-low frequency AC ice melting device at the previous adjacent moment of the current moment, and take the weighted result as the frequency adjustment amount; add the frequency adjustment amount to the output current frequency of the ultra-low frequency AC ice melting device at the current moment to obtain the adjusted output current frequency.

[0024] Further, the method for obtaining the flat growth parameter includes:

[0025] In the long-term change sub-segment, take the difference between each ice melting efficiency coefficient and the previous adjacent ice melting efficiency coefficient as the coefficient difference; obtain the flat growth parameter by taking the negative correlation normalization result of the variances of all the coefficient differences.

[0026] Further, the method for obtaining the local fluctuation sequence sub-segment includes:

[0027] Take the co-trending sequence sub-segment with a sequence length less than the preset threshold as the sequence sub-segment to be merged; in the ice melting efficiency coefficient sequence, merge adjacent sequence sub-segments to be merged to obtain a fluctuation sequence sub-segment; take the fluctuation sequence sub-segment closest to the current moment as the local fluctuation sequence sub-segment.

[0028] Further, the method for obtaining the adjustment weight includes:

[0029] Take the ratio of the length of the local fluctuation sequence sub-segment to the length of the ice melting efficiency coefficient sequence as the ice melting effect parameter; map the product of the normalization result of the flat growth parameter of the long-term change sub-segment and the ice melting effect parameter, and take the mapping result as the adjustment weight; the value range of the adjustment weight is [-1, 1].

[0030] The present invention also proposes an ultra-low frequency AC ice melting device, which includes a device body, and the device implements the steps of the fault protection method for the ultra-low frequency AC ice melting device.

[0031] The present invention has the following beneficial effects:

[0032] At each moment within a preset historical period at the current moment, the present invention obtains the line temperature and the output power of the ultra-low frequency AC ice melting device, providing data support for subsequent analysis and adjustment of the output current frequency of the ultra-low frequency AC ice melting device; then at each moment, according to the line temperature of the line to be de-iced and the output power of the ultra-low frequency AC ice melting device, the ice melting efficiency coefficient of the ultra-low frequency AC ice melting device is obtained, and then an ice melting efficiency coefficient sequence is constructed, providing a reference basis for subsequent evaluation of the ice melting effect to adjust the output current frequency; then according to the change situation of the ice melting efficiency coefficient sequence, the ice melting efficiency coefficient sequence is segmented to obtain all co-trend sequence sub-segments, and long-term change sub-segments are screened out from all the co-trend sequence sub-segments. The change trends of the ice melting efficiency coefficients within the co-trend sequence sub-segments are similar, and the long-term change sub-segments correspond to relatively stable ice melting processes. Segmentation can help evaluate the ice melting effect of the ultra-low frequency AC ice melting device; finally, according to the change situation of the long-term change sub-segments and the local fluctuation situation of the ice melting efficiency coefficient sequence at the current moment, the ice melting effect within the preset historical period at the current moment is evaluated, so as to accurately adjust the output current frequency of the ultra-low frequency AC ice melting device at the current moment, reducing the risk of ice melting device failure caused by unreasonable frequency adjustment. By monitoring and evaluating the change situation of the ice melting efficiency of the ultra-low frequency AC ice melting device, the present invention analyzes and evaluates the ice melting effect within the adjacent period at the current moment, and then accurately adjusts the output current frequency of the ultra-low frequency AC ice melting device according to the ice melting effect, while maintaining efficient and stable ice melting and reducing the risk of ice melting device failure. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the technical solutions and advantages in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required to be used in the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0034] Figure 1 It is a flowchart of a method for protecting an ultra-low frequency AC ice melting device provided by an embodiment of the present invention;

[0035] Figure 2 It is a flowchart of a method for adjusting the output current frequency provided by an embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0036] To further illustrate the technical means and effects adopted by the present invention to achieve the intended invention purpose, the following, in conjunction with the accompanying drawings and preferred embodiments, details a super-low-frequency AC ice melting device and a fault protection method proposed according to the present invention, including its specific implementation manner, structure, features and effects, as follows. In the following description, different "one embodiment" or "another embodiment" do not necessarily refer to the same embodiment. In addition, the specific features, structures or characteristics in one or more embodiments can be combined in any suitable form.

[0037] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the technical field to which the present invention belongs.

[0038] The following specifically describes the specific solution of a super-low-frequency AC ice melting device and a fault protection method provided by the present invention with reference to the accompanying drawings.

[0039] An embodiment of the present invention provides a super-low-frequency AC ice melting device, which at least includes a super-low-frequency power supply device, an induction device, an operation monitoring system, a control system and a remote communication system; wherein the super-low-frequency power supply device is used to provide a low-frequency AC power supply; the induction device is used to generate an induced current to generate heat on the line to be de-iced; the operation monitoring system is used to monitor the operation parameters of the ice melting device such as the cable temperature, output voltage, output current and frequency, as well as the ice melting environment parameters such as the ambient temperature and ice coating thickness, so as to feedback and regulate the ice melting process; the control system includes a frequency conversion controller, a data analysis module and various protection devices to control the operation of the ice melting device, the frequency conversion controller is used to adjust the current frequency, and the data analysis module is used to analyze the operation parameters of the ice melting device to evaluate the adjustment method of the output current frequency; the remote communication system is used to remotely transmit various operation parameters of the ice melting device collected to the control system for analysis or recording.

[0040] Each iced transmission line in the smart grid system is regarded as a line to be de-iced. An induction device is installed and arranged on each line to be de-iced according to actual needs. For example, a special fixture is used to fix the induction coil on the line to be de-iced. The layout distance needs to be determined by analysis and calculation according to actual situations, which is already a well-known prior art to those skilled in the art, and the specific layout process is not described in detail herein.

[0041] It should be noted that since the analysis and fault protection methods for each induction coil on each line to be de-iced are the same, only the regulation method of any induction coil is taken as an example for analysis and description herein. Adjusting the output current frequency of the super-low-frequency AC ice melting device in the embodiments of the present invention is to adjust the output current frequency of the induction coil therein.

[0042] Please refer to Figure 1 , which shows a flowchart of a fault protection method for a super-low-frequency AC ice melting device provided by an embodiment of the present invention, specifically including:

[0043] Step S1, within a preset historical period at the current moment, obtain the line temperature of the line to be de-iced at each moment, and the output power of the ultra-low frequency AC de-icing device on the line to be de-iced at each moment.

[0044] To adjust the output current frequency of the ultra-low frequency AC de-icing device in real time, optimize the frequency adjustment accuracy without affecting the de-icing effect, and thus reduce the loss failure of the ultra-low frequency AC de-icing device; therefore, in the embodiment of the present invention, first, within a preset historical period at the current moment, obtain the line temperature of the line to be de-iced at each moment, and the output power of the ultra-low frequency AC de-icing device on the line to be de-iced at each moment, so as to provide data support for subsequent analysis and adjustment of the output current frequency of the ultra-low frequency AC de-icing device.

[0045] As an example, specifically set the preset historical period to the last ten minutes at the current moment, and the implementer can also set the duration of the preset historical period by himself; it should be noted that the ultra-low frequency AC de-icing device can only analyze and adjust the output current frequency after starting to de-ice when it first reaches the preset de-icing temperature, where the preset de-icing temperature is set to 5°C, and the implementer can also set it to any value between 0°C and 5°C by himself;

[0046] Then, through the temperature sensor in the operation monitoring system, obtain the line temperature of the line to be de-iced at each moment, collect the output voltage of the ultra-low frequency AC de-icing device at each moment through the voltage sensor, collect the output current at each moment using the current sensor, and at the same time evaluate the power factor using the phase difference between the current and voltage at each moment, so as to obtain the output power of the ultra-low frequency AC de-icing device at each moment; among them, the acquisition frequency of the sensors is set to 50Hz, and the implementer can also customize it. The acquisition of the line temperature and the output power are both well-known technical means and will not be elaborated here.

[0047] Step S2, at each moment, according to the line temperature of the line to be de-iced and the output power of the ultra-low frequency AC de-icing device, obtain the de-icing efficiency coefficient of the ultra-low frequency AC de-icing device; according to the de-icing efficiency coefficients of the ultra-low frequency AC de-icing device at all moments, construct a de-icing efficiency coefficient sequence.

[0048] When considering the ultra-low frequency AC ice melting device melting ice, it usually calculates the ice melting heat demand based on the environmental heat balance model. As the ice continuously melts, the ice gradually melts into water, and due to the influence of gravity, the contact area between the ice and the line continuously changes. The heat generated by the current may dissipate into the environment. The ice melting environment is dynamic and complex, and the ice melting heat demand also changes continuously, resulting in continuous adjustment and change of the output current frequency of the ultra-low frequency AC ice melting device. Also considering that the ice melting efficiency is closely related to the output current frequency, by evaluating the ice melting efficiency of the ultra-low frequency AC ice melting device at each moment, it can provide a guiding basis for adjusting the output current frequency, so as to ensure that the ice melting device always operates within an efficient frequency range, and further reduce the risk of ice melting device failure caused by improper frequency adjustment;

[0049] Therefore, in the embodiments of the present invention, first at each moment, according to the line temperature of the line to be de-iced and the output power of the ultra-low frequency AC ice melting device, the ice melting efficiency coefficient of the ultra-low frequency AC ice melting device is obtained, and then an ice melting efficiency coefficient sequence is constructed, providing a reference basis for subsequent evaluation of the ice melting effect to adjust the output current frequency.

[0050] Preferably, in an embodiment of the present invention, considering that when the line temperature is closer to the ice melting temperature and the output power of the ultra-low frequency AC ice melting device is relatively higher on the premise of ensuring safety, it indicates that the ice melting effect at this moment is better, and the output current frequency also more conforms to the efficient application of the current ice melting environment. Therefore, the method for obtaining the ice melting efficiency coefficient includes:

[0051] At each moment, according to the difference between the line temperature and the preset ice melting temperature, the first ice melting efficiency parameter is obtained;

[0052] At each moment, according to the difference between the output power and the preset output power, the second ice melting efficiency parameter is obtained;

[0053] The first ice melting efficiency parameter and the second ice melting efficiency parameter at each moment are fused to obtain the ice melting efficiency coefficient of the ultra-low frequency AC ice melting device at each moment.

[0054] As an example, the calculation formula for the ice melting efficiency coefficient is: where t is the serial number of the moment within the preset historical period of the current moment; p t is the ice melting efficiency parameter at the t-th moment; T t is the line temperature of the line to be de-iced at the t-th moment; T L is the preset ice melting temperature; (T t -T L ) is the first ice melting efficiency parameter at the t-th moment; w t is the output power of the ultra-low frequency AC ice melting device at the t-th moment; w maxis the preset output power and also the maximum output power of the ultra-low frequency AC ice melting device; is the second ice melting efficiency parameter at the t-th moment.

[0055] In the calculation formula of the ice melting efficiency coefficient, when the difference between the line temperature and the preset ice melting temperature is greater than 0 and the larger the difference, it indicates that the heat is sufficient to melt the ice coating, then the first ice melting efficiency parameter is larger. On the contrary, when the difference is less than 0 and the smaller the difference, it indicates that the temperature is not sufficient to melt the ice, and the first ice melting efficiency parameter is negative and smaller; when the output power of the ultra-low frequency AC ice melting device is closer to the maximum output power, the second ice melting efficiency parameter is closer to 1, which means the output power of the ultra-low frequency AC ice melting device is higher, and it can provide sufficient energy to maintain the ice melting temperature and keep effective ice melting; then multiply the two and fuse them to obtain the ice melting efficiency coefficient at the corresponding moment.

[0056] It should be noted that in this example, the preset ice melting temperature is taken as 5°C, which can also be customized; the maximum output power is a design parameter of the ultra-low frequency AC ice melting device and needs to be obtained according to the specific design specification; in other examples, the implementer can also fuse the first ice melting efficiency parameter and the second ice melting efficiency parameter through basic mathematical operations such as addition or weighted summation, which will not be elaborated here.

[0057] In an embodiment of the present invention, by obtaining the ice melting efficiency coefficient of the ultra-low frequency AC ice melting device at each moment, the ice melting efficiency coefficients of the ultra-low frequency AC ice melting device at all moments can be sorted in chronological order to construct an ice melting efficiency coefficient sequence, so as to evaluate the efficiency change during the ice melting process for subsequent timely adjustment. It should be noted that the construction of the chronological sequence is already an existing technology and will not be elaborated here.

[0058] Step S3, according to the change situation of the ice melting efficiency coefficient sequence, segment the ice melting efficiency coefficient sequence to obtain all same-trend sequence sub-segments, and screen out the long-term change sub-segments from all same-trend sequence sub-segments; according to the change situation of the long-term change sub-segments and the local fluctuation situation of the ice melting efficiency coefficient sequence at the current moment, adjust the output current frequency of the ultra-low frequency AC ice melting device at the current moment.

[0059] Considering that the ice melting process is usually dynamic and divided into multiple stages, including changes in different temperatures, ice layer thicknesses, ice-covered contact areas, etc., these changes will cause fluctuations in the ice melting efficiency, and the ice melting efficiency change trends in different stages are different, so the automatic adjustment of the output current frequency of the ultra-low frequency AC ice melting device also has certain fluctuations; therefore, in the embodiment of the present invention, according to the change situation of the ice melting efficiency coefficient sequence, the ice melting efficiency coefficient sequence will be segmented to obtain all same-trend sequence sub-segments, and the long-term change sub-segments will be screened out from all same-trend sequence sub-segments for subsequent evaluation of the ice melting effect;

[0060] The changing trends of the ice melting efficiency coefficients within each co-trending sequence sub-segment are similar, so it is called a co-trending sequence sub-segment, while the long-term change sub-segment corresponds to a relatively stable ice melting process within a preset historical period; segmenting can help clearly observe different stages of the ice melting process, thereby helping to identify the ice melting requirements in different stages, and further helping to evaluate the ice melting effect of the ultra-low frequency AC ice melting device, preparing for reasonably adjusting the output current frequency subsequently and reducing the failure risk of the ice melting device.

[0061] Preferably, in an embodiment of the present invention, considering that taking the difference can help evaluate the changes between adjacent data, thus facilitating the evaluation of the same changing trend; the method for obtaining the co-trending sequence sub-segment includes:

[0062] Taking the first-order difference of the ice melting efficiency coefficient sequence to obtain a difference coefficient sequence; dividing all consecutive sequence elements with the same sign in the difference coefficient sequence into a difference coefficient sequence sub-segment; correspondingly segmenting the ice melting efficiency coefficient sequence according to the difference coefficient sequence sub-segment to obtain all co-trending sequence sub-segments, specifically including:

[0063] Adding 1 to the sequence number of the last sequence element in each difference coefficient sequence sub-segment in the difference coefficient sequence to obtain the sequence numbers of all segmentation points in the ice melting efficiency coefficient sequence; in the ice melting efficiency coefficient sequence, taking the sequence element corresponding to the segmentation point sequence number as the last element of each co-trending sequence sub-segment, and taking the next adjacent sequence element of the last element as the first element of the next co-trending sequence sub-segment; based on the last element and the first element, obtaining the corresponding co-trending sequence sub-segment.

[0064] As an example, assuming an ice melting efficiency coefficient sequence is {-1.2, -1.3, -1.1, 0, 0, 0.5, 0.7, 0.9, 0.7, 1.2}, then the difference coefficient sequence is {-0.1, 0.2, 1.1, 0, 0.5, 0.2, 0.2, -0.2, 0.5}, and the corresponding difference coefficient sequence sub-segments are {-0.1}, {0.2, 1.1}, {0}, {0.5, 0.2, 0.2}, {-0.2}, {0.5} respectively, and then determining all co-trending sequence sub-segments as {-1.2, -1.3}, {-1.1, 0}, {0}, {0.5, 0.7, 0.9}, {0.7}, {1.2}.

[0065] In other examples, the implementer can also fit the corresponding change curve of the ice melting efficiency coefficient sequence, identify all the extreme values in the change curve, and take the ice melting efficiency coefficient sequence sub-segment corresponding to the curve sub-segment between adjacent extreme values as a co-trending sequence sub-segment; the implementer can also use other feature extraction algorithms to obtain co-trending sequence sub-segments with the same changing trend, which are all prior arts and will not be elaborated here.

[0066] Preferably, in an embodiment of the present invention, considering that the longer the co-trending sequence segment is, the more it indicates the long-term change characteristics or relatively stable state of the ice melting efficiency within the preset historical period, which reflects the ice melting effect of the ultra-low frequency AC ice melting device within the preset historical period, so as to make reasonable intervention and adjustment subsequently; therefore, among all the co-trending sequence segments, the longest co-trending sequence segment is used as the long-term change segment.

[0067] Considering that the long-term change segment reflects the relatively stable state of the ice melting efficiency, if the ice melting efficiency within the long-term change segment shows an upward trend, the ice melting effect is better; also considering that the local fluctuation of the ice melting efficiency coefficient at the current moment reflects the complexity of the ice melting environment at the current moment, the ice melting device may need to automatically adjust the output current frequency to adapt to the changing needs of the ice melting stage, then the ice melting effect is also better;

[0068] When the ice melting effect is better, the output current frequency should be increased to accelerate the melting speed and cope with the complex ice melting stage, so as to reduce the failure risk of the ice melting device while maintaining high-efficiency and stable ice melting; therefore, the embodiment of the present invention will adjust the output current frequency of the ultra-low frequency AC ice melting device at the current moment according to the change situation of the long-term change segment and the local fluctuation situation of the ice melting efficiency coefficient sequence at the current moment, so as to reduce the failure risk of the ice melting device while maintaining high-efficiency and stable ice melting.

[0069] Preferably, in an embodiment of the present invention, the method for adjusting the output current frequency includes:

[0070] Please refer to Figure 2 , which shows a flowchart of a method for adjusting the output current frequency provided in an embodiment of the present invention, specifically including:

[0071] Step S201, obtain the flat growth parameter of the long-term change segment according to the coefficient difference between all adjacent ice melting efficiency coefficients in the long-term change segment.

[0072] Considering that comprehensively considering the change differences between all adjacent ice melting efficiency coefficients in the long-term change segment can help evaluate its change trend or fluctuation situation, so the flat growth parameter is evaluated based on this.

[0073] In a preferred embodiment of the present invention, the method for obtaining the flat growth parameter includes:

[0074] In the long-term change segment, the difference between each ice melting efficiency coefficient and the previous adjacent ice melting efficiency coefficient is used as the coefficient difference; the negative correlation normalization result of the variance of all coefficient differences is used to obtain the flat growth parameter.

[0075] As an example, the variance of the coefficient difference is taken as the x in the exponential function exp(-x) with the natural constant e as the base, and negative correlation normalization is performed, and then the negative correlation normalization result is used as the flat growth parameter; the larger the variance of the coefficient difference, the more drastic the change in ice melting efficiency, and the negative correlation mapping logic needs to be adjusted to make the flat growth parameter smaller.

[0076] In other examples, implementers may also adopt other negative correlation mapping methods such as inverse operations, which are not described here; they may also perform linear regression analysis on the data in the long-term change sub-segment to evaluate whether it has a linear trend, and then use the two-point method to calculate its slope to evaluate whether it is growing, and then comprehensively evaluate the flat growth parameters, which are all existing technologies; implementers may also adopt other methods, which are not described here.

[0077] Step S202, obtaining the local fluctuation sequence sub-segment at the current moment according to the length of the co-converging sequence sub-segment.

[0078] Considering that the shorter the length of the isotropic sequence subsegment is, the more frequently the ice-melting efficiency coefficient changes, if the length of the isotropic sequence subsegment is shorter in the local historical time domain at the current moment, the local fluctuation sequence subsegment at the current moment can be obtained; the local fluctuation sequence subsegment reflects the fluctuation of the ice-melting efficiency coefficient near the current moment, which is used for subsequent evaluation of the complexity of ice-melting and the high efficiency of ice-melting near the current moment, and also provides a reference basis for subsequent intervention to adjust the output current frequency, thereby reducing the risk of ice-melting device failure while maintaining efficient and stable ice-melting.

[0079] Therefore, in a preferred embodiment of the present invention, the method for obtaining the local fluctuation sequence sub-segment includes:

[0080] The same trend sequence subsegments whose sequence length is less than a preset threshold are taken as the sequence subsegments to be merged; in the ice melting efficiency coefficient sequence, the adjacent sequence subsegments to be merged are merged to obtain a fluctuation sequence subsegment; the fluctuation sequence subsegment closest to the current moment is taken as the local fluctuation sequence subsegment.

[0081] As an example, the preset threshold is 10, and the implementer can also define it by himself; for example, in the ice melting efficiency coefficient sequence, there are a total of 9 same-trend sequence segments, and the sequence lengths of each same-trend sequence segment are 5, 8, 6, 10, 11, 16, 13, 7, 9 respectively. The same-trend sequence segments with sequence lengths of 5, 8, 6, 7, 9 are used as the sequence segments to be merged; then, since the three sequence segments to be merged with sequence lengths of 5, 8, 6 are adjacent, the three sequence segments to be merged are merged into a fluctuating sequence segment; and since the two sequence segments to be merged with sequence lengths of 7, 9 are adjacent, the two sequence segments to be merged are merged into a fluctuating sequence segment, and because it is close to the current moment, the fluctuating sequence segment obtained by merging the two sequence segments to be merged with sequence lengths of 7, 9 is used as the local fluctuating sequence segment at the current moment.

[0082] Step S203, according to the sequence length of the local fluctuating sequence segment and the flat growth parameter, obtain the adjustment weight of the output current frequency at the current moment.

[0083] Considering that the larger the flat growth parameter of the long-term change segment, the more stable and better the ice melting process; and considering that the longer the local fluctuating sequence segment, the more complex the ice melting process near the current moment, and the ultra-low frequency AC ice melting device is constantly automatically regulated, thereby improving the ice melting efficiency, which also shows that the ice melting effect is better;

[0084] Based on this, the adjustment weight of the output current frequency at the current moment can be determined comprehensively based on the ice melting process. The adjustment weight reflects the ice melting effect at the current moment. The better the ice melting effect, the higher the output current frequency should be adjusted to accelerate the melting speed and cope with the complex ice melting stage, so as to reduce the failure risk of the ice melting device while maintaining high-efficiency and stable ice melting.

[0085] In a preferred embodiment of the present invention, the method for obtaining the adjustment weight includes:

[0086] Take the ratio of the length of the local fluctuating sequence segment to the length of the ice melting efficiency coefficient sequence as the ice melting effect parameter; map the product of the normalization result of the flat growth parameter of the long-term change segment and the ice melting effect parameter, and take the mapping result as the adjustment weight; the value range of the adjustment weight is [-1, 1].

[0087] As an example, the calculation formula for the adjustment weight is: Wherein, t is the serial number of the moment within the preset historical period at the current moment; M is the adjustment weight of the output current frequency at the current moment; n is the sequence length of the local fluctuating sequence segment; N is the sequence length of the ice melting efficiency coefficient sequence; is the ice melting effect parameter; Y is the sequence length of the long-term sequence sub-segment within the preset historical period at the current moment; max(Y) is the sequence length of the long-term sequence sub-segment within the corresponding preset historical period at all moments including the current moment; P[] is the mapping function.

[0088] In the calculation formula for adjusting the weight, the longer the local fluctuation sequence sub-segment, the more it indicates that the ultra-low frequency AC ice melting device is continuously automatically regulated, thereby improving the ice melting efficiency, and the better the ice melting effect; specifically, the flat growth parameter is normalized by dividing it by the historical maximum value. The larger the flat growth parameter within the preset historical period at the current moment, the larger the normalization result, which also indirectly indicates that efficient ice melting is occurring within the preset historical period at the current moment; then the two are multiplied and fused, and the fusion result is mapped through the premnmx function to make the adjusted weight within [-1, 1] for subsequent increasing or decreasing the output current frequency.

[0089] In other examples, the implementer can also adopt other mapping functions, which are all existing technologies and will not be elaborated here.

[0090] Step S204, use the adjusted weight to weight the output current frequency of the ultra-low frequency AC ice melting device at the previous adjacent moment of the current moment, and take the weighted result as the frequency adjustment amount; add the frequency adjustment amount to the output current frequency of the ultra-low frequency AC ice melting device at the current moment to obtain the adjusted output current frequency.

[0091] As an example, the calculation formula for the adjusted output current frequency is: where, f ′ is the adjusted output current frequency; f is the output current frequency at the previous adjacent moment of the current moment; M is the adjusted weight; (f×M) is the frequency adjustment amount; is the floor function.

[0092] In this example, when the ice melting effect is better, the adjusted weight is relatively larger and greater than 0, and the corresponding frequency adjustment amount is greater than 0 and larger, then the output current frequency can be increased, so as to further accelerate the ice melting speed when the ice melting effect is good, and at the same time, the output current can be made more stable, avoiding local overheating or current instability of the equipment and increasing the risk of failure; when the ice melting effect is not good, the adjusted weight is relatively smaller and less than 0, and the corresponding frequency adjustment amount is less than 0, and then the output current frequency can be reduced, so as to improve uneven ice melting to enhance the ice melting efficiency, and at the same time, it can also avoid heat loss and aging of electrical components, and reduce the risk of equipment overload or damage.

[0093] It should be noted that when the adjusted output current frequency exceeds the standard output current frequency range of the ultra-low frequency AC ice melting device, such as exceeding the maximum value or being lower than the minimum value, the adjusted output current frequency at the current moment can be set to the corresponding interval value; the standard output current frequency range needs to be obtained according to the design specification of the ultra-low frequency AC ice melting device.

[0094] In summary, in the preset historical period at the current moment, the present invention obtains the line temperature of the line to be de-iced at each moment, and the output power of the ultra-low frequency AC ice melting device on the line to be de-iced at each moment; further analyzes and obtains the ice melting efficiency coefficient of the ultra-low frequency AC ice melting device at each moment, and constructs a sequence of ice melting efficiency coefficients; then segments the sequence of ice melting efficiency coefficients to obtain all the same-trend sequence sub-segments and the long-term change sub-segments; finally, adjusts the output current frequency of the ultra-low frequency AC ice melting device at the current moment according to the change situation of the long-term change sub-segment and the local fluctuation situation of the sequence of ice melting efficiency coefficients at the current moment. The present invention monitors and evaluates the change of the ice melting efficiency of the ultra-low frequency AC ice melting device, thereby analyzes and evaluates the ice melting effect in the adjacent period at the current moment, and then accurately adjusts the output current frequency of the ultra-low frequency AC ice melting device according to the ice melting effect, while maintaining high-efficiency and stable ice melting, reducing the failure risk of the ice melting device.

[0095] It should be noted that the above-mentioned sequence of the embodiments of the present invention is only for description and does not represent the advantages or disadvantages of the embodiments. The processes depicted in the accompanying drawings do not necessarily require the specific order or continuous order shown to achieve the desired result. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0096] Each embodiment in this specification is described in a progressive manner, and the same or similar parts between the embodiments can be referred to each other. Each embodiment focuses on the differences from other embodiments.

Claims

1. A fault protection method for an ultra-low frequency AC ice melting device, characterized in that The method includes: Within a preset historical period at the current moment, obtaining the line temperature of the line to be de-iced at each moment, and the output power of the ultra-low frequency AC de-icing device on the line to be de-iced at each moment; At each moment, according to the line temperature of the line to be de-iced and the output power of the ultra-low frequency AC de-icing device, obtaining the de-icing efficiency coefficient of the ultra-low frequency AC de-icing device; constructing a de-icing efficiency coefficient sequence according to the de-icing efficiency coefficients of the ultra-low frequency AC de-icing device at all moments; According to the change situation of the de-icing efficiency coefficient sequence, segmenting the de-icing efficiency coefficient sequence to obtain all same-trend sequence sub-segments, and screening out the long-term change sub-segments from all the same-trend sequence sub-segments; according to the change situation of the long-term change sub-segments and the local fluctuation situation of the de-icing efficiency coefficient sequence at the current moment, adjusting the output current frequency of the ultra-low frequency AC de-icing device at the current moment; The method for obtaining the de-icing efficiency coefficient includes: At each moment, according to the difference between the line temperature and the preset de-icing temperature, obtaining the first de-icing efficiency parameter; At each moment, according to the difference between the output power and the preset output power, obtaining the second de-icing efficiency parameter; Fusing the first de-icing efficiency parameter and the second de-icing efficiency parameter at each moment to obtain the de-icing efficiency coefficient of the ultra-low frequency AC de-icing device at each moment; The method for obtaining the long-term change sub-segments includes: Among all the same-trend sequence sub-segments, taking the longest same-trend sequence sub-segment as the long-term change sub-segment; The method for adjusting the output current frequency includes: According to the coefficient difference between all adjacent de-icing efficiency coefficients in the long-term change sub-segments, obtaining the flat growth parameter of the long-term change sub-segments; according to the length of the same-trend sequence sub-segments, obtaining the local fluctuation sequence sub-segment at the current moment; according to the sequence length of the local fluctuation sequence sub-segment and the flat growth parameter, obtaining the adjustment weight of the output current frequency at the current moment; Using the adjustment weight to weight the output current frequency of the ultra-low frequency AC de-icing device at the previous adjacent moment of the current moment, and taking the weighted result as the frequency adjustment amount; adding the frequency adjustment amount to the output current frequency of the ultra-low frequency AC de-icing device at the current moment to obtain the adjusted output current frequency; The method for obtaining the local fluctuation sequence sub-segment includes: Taking the same-trend sequence sub-segments with a sequence length less than the preset threshold as the sequence sub-segments to be merged; in the de-icing efficiency coefficient sequence, merging adjacent sequence sub-segments to be merged to obtain a fluctuation sequence sub-segment; taking the fluctuation sequence sub-segment closest to the current moment as the local fluctuation sequence sub-segment.

2. The fault protection method of an ultra-low frequency AC ice melting device according to claim 1, characterized in that, The method for obtaining the same-trend sequence sub-segments includes: Performing a first-order difference on the de-icing efficiency coefficient sequence to obtain a difference coefficient sequence; dividing all consecutive sequence elements with the same sign in the difference coefficient sequence into a difference coefficient sequence sub-segment; According to the difference coefficient sequence sub-segments, correspondingly segmenting the de-icing efficiency coefficient sequence to obtain all same-trend sequence sub-segments.

3. A fault protection method for an ultra-low frequency AC ice melting device according to claim 2, characterized in that, The method for correspondingly segmenting the ice melting efficiency coefficient sequence according to the differential coefficient sequence sub-segment to obtain all the same-trend sequence sub-segments includes: Adding 1 to the serial number of the last sequence element in each of the differential coefficient sequence sub-segments in the differential coefficient sequence to obtain all the segmentation point serial numbers in the ice melting efficiency coefficient sequence; In the ice melting efficiency coefficient sequence, taking the sequence element corresponding to the segmentation point serial number as the last element of each same-trend sequence sub-segment, and taking the next adjacent sequence element of the last element as the head element of the next same-trend sequence sub-segment; based on the last element and the head element, obtaining the corresponding same-trend sequence sub-segment.

4. A fault protection method for an ultra-low frequency AC ice melting device according to claim 1, characterized in that, The method for obtaining the flat growth parameter includes: In the long-term change sub-segment, taking the difference between each ice melting efficiency coefficient and the previous adjacent ice melting efficiency coefficient as the coefficient difference; obtaining the flat growth parameter by taking the negative correlation normalization result of the variances of all the coefficient differences.

5. A fault protection method for an ultra-low frequency AC ice melting device according to claim 1, characterized in that, The method for obtaining the adjusted weight includes: Taking the ratio of the length of the local fluctuation sequence sub-segment to the length of the ice melting efficiency coefficient sequence as the ice melting effect parameter; performing mapping on the product of the normalization result of the flat growth parameter of the long-term change sub-segment and the ice melting effect parameter, and taking the mapping result as the adjusted weight; the value range of the adjusted weight is [-1, 1].

6. An ultra-low frequency AC ice melting device, comprising a device body, characterized in that, The device implements the steps of the method for fault protection of an ultra-low frequency AC ice melting device according to any one of claims 1 to 5.

Images