Ultralow-frequency alternating-current ice melting device and fault protection method

Abstract

The invention relates to the technical field of intelligent power grids, in particular to an ultralow-frequency alternating-current ice melting device and a fault protection method. The method comprises the following steps: acquiring the line temperature and the output power of an ultralow-frequency alternating-current ice melting device at each moment in a preset historical time period of the current moment; further analyzing to obtain an ice melting efficiency coefficient at each moment, and constructing an ice melting efficiency coefficient sequence; obtaining all homotaxis sequence sub-segments and long-term change sub-segments; and finally, according to the change condition of the long-term change sub-segment and the local fluctuation condition of the ice melting efficiency coefficient sequence at the current moment, the output current frequency of the ultralow-frequency alternating-current ice melting device at the current moment is adjusted. By monitoring and evaluating the ice melting efficiency change condition of the ultralow-frequency alternating-current ice melting device, the ice melting effect in the adjacent time period of the current moment is analyzed and evaluated, then the output current frequency of the ultralow-frequency alternating-current ice melting device is accurately adjusted according to the ice melting effect, and the fault risk of the ice melting device is reduced while efficient and stable ice melting is kept.

Description

Technical Field

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

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

[0003] In the prior art, ultra-low frequency AC ice melting devices are usually used to melt ice on the lines. The working principle is mainly to calculate the required heat for ice melting based on the environmental thermal 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 AC current. However, the appropriate output current frequency is crucial to improving the ice melting efficiency and avoiding ice melting equipment failure. Inappropriate output current frequency may cause the electrical components in the ice melting device to wear out and age, or even break down and be damaged, and may also cause strong electromagnetic interference and cause the control system to fail; inappropriate output current frequency adjustment method will cause the ultra-low frequency AC ice melting device to wear out and fail. Summary of the invention

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

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

[0006] In a preset historical period at the current moment, 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 are obtained;

[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 AC de-icing device, an ice melting efficiency coefficient of the ultra-low frequency AC de-icing device is obtained; according to the ice melting efficiency coefficient of the ultra-low frequency AC de-icing device at all moments, an ice melting efficiency coefficient sequence is constructed;

[0008] According to the change of the ice melting efficiency coefficient sequence, the ice melting efficiency coefficient sequence is segmented to obtain all the isotropic sequence sub-segments, and the long-term change sub-segments are screened out from all the isotropic sequence sub-segments; according to the change of the long-term change sub-segments and the local fluctuation of the ice melting efficiency coefficient sequence at the current moment, the output current frequency of the ultra-low frequency AC ice melting device at the current moment is adjusted.

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

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

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

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

[0013] Furthermore, the method for obtaining the isochronous sequence sub-segments includes:

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

[0015] The ice melting efficiency coefficient sequence is divided correspondingly according to the differential coefficient sequence sub-segments to obtain all the same trend sequence sub-segments.

[0016] Furthermore, the method of segmenting the ice melting efficiency coefficient sequence according to the differential coefficient sequence sub-segments to obtain all the same trend sequence sub-segments includes:

[0017] Add 1 to the sequence number of the last sequence element in each differential coefficient sequence subsegment in the differential coefficient sequence to obtain all the segmentation point sequences in the ice melting efficiency coefficient sequence;

[0018] In the ice melting efficiency coefficient sequence, the sequence element corresponding to the segmentation point number is used as the end element of each isoconvergent sequence subsegment, and the next adjacent sequence element of the end element is used as the beginning element of the next isoconvergent sequence subsegment; based on the end element and the beginning element, the corresponding isoconvergent sequence subsegment is obtained.

[0019] Furthermore, the method for acquiring the long-term variation sub-segment includes:

[0020] Among all the iso-convergent sequence sub-segments, the longest iso-convergent sequence sub-segment is used as the long-term variation sub-segment.

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

[0022] According to the coefficient difference between all adjacent ice melting efficiency coefficients in the long-term change sub-segment, a flat growth parameter of the long-term change sub-segment is obtained; according to the length of the isotropic sequence sub-segment, a local fluctuation sequence sub-segment at the current moment is obtained; according to the sequence length of the local fluctuation sequence sub-segment and the flat growth parameter, an adjustment weight of the output current frequency at the current moment is obtained;

[0023] The output current frequency of the ultra-low frequency AC ice melting device at the previous adjacent moment before the current moment is weighted by using the adjustment weight, and the weighted result is used as the frequency adjustment amount; the output current frequency of the ultra-low frequency AC ice melting device at the current moment is added to the frequency adjustment amount to obtain the adjusted output current frequency.

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

[0025] In the long-term variation subsection, the difference between each ice-melting efficiency coefficient and the previous adjacent ice-melting efficiency coefficient is taken as the coefficient difference; the negative correlation normalization result of the variance of all the coefficient differences is obtained to obtain a flat growth parameter.

[0026] Furthermore, the method for obtaining the local fluctuation sequence subsegment includes:

[0027] The isotropic sequence subsegments whose sequence length is less than a preset threshold are taken as sequence subsegments to be merged; in the ice melting efficiency coefficient sequence, adjacent sequence subsegments to be merged are merged to obtain a fluctuation sequence subsegment; and the fluctuation sequence subsegment closest to the current moment is taken as a local fluctuation sequence subsegment.

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

[0029] The ratio of the length of the local fluctuation sequence subsegment to the length of the ice-melting efficiency coefficient sequence is used as the ice-melting effect parameter; the normalized result of the flat growth parameter of the long-term change subsegment is mapped to the product of the ice-melting effect parameter, and the mapping result is used as the adjustment weight; the value range of the adjustment weight is [-1, 1].

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

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

[0032] The present invention obtains the line temperature and the output power of the ultra-low frequency AC ice melting device at each moment within the preset historical period at the current moment, so as to provide data support for the 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 ice-melted 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, so as to provide a reference basis for the subsequent evaluation of the ice-melting effect to adjust the output current frequency; then, according to the change of the ice-melting efficiency coefficient sequence, the ice-melting efficiency coefficient sequence is segmented to obtain Take all the same trend sequence sub-segments, and filter out the long-term change sub-segments from all the same trend sequence sub-segments. The change trends of the ice melting efficiency coefficients in the same trend sequence sub-segments are similar. The long-term change sub-segments correspond to a relatively stable ice melting process. Segmentation can help evaluate the ice melting effect of the ultra-low frequency AC ice melting device; finally, according to the change of the long-term change sub-segment and the local fluctuation of the ice melting efficiency coefficient sequence at the current moment, the ice melting effect in 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, and reduce the risk of ice melting device failure caused by unreasonable frequency adjustment. The present invention monitors and evaluates the change of the ice melting efficiency of the ultra-low frequency AC ice melting device, thereby analyzing and evaluating the ice melting effect in the adjacent time 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 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 drawings required for use in the embodiments or the prior art descriptions are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0034] Figure 1 A flow chart of a fault protection method for an ultra-low frequency AC ice melting device provided by one embodiment of the present invention;

[0035] Figure 2 A flow chart of a method for adjusting output current frequency provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0036] In order to further explain the technical means and effects adopted by the present invention to achieve the predetermined invention purpose, the following is a detailed description of the specific implementation, structure, features and effects of an ultra-low frequency AC ice melting device and a fault protection method proposed by the present invention in combination with the accompanying drawings and preferred embodiments. In the following description, different "one embodiment" or "another embodiment" does not necessarily refer to the same embodiment. In addition, specific features, structures or characteristics in one or more embodiments may be combined in any suitable form.

[0037] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.

[0038] The specific scheme of an ultra-low frequency AC ice melting device and a fault protection method provided by the present invention is described in detail below with reference to the accompanying drawings.

[0039] The embodiment of the present invention proposes an ultra-low frequency AC ice-melting device, which at least includes an ultra-low frequency power supply device, a sensing device, an operation monitoring system, a control system and a remote communication system; wherein the ultra-low frequency power supply device is used to provide a low-frequency AC power supply; the sensing device is used to generate an induced current so that the line to be de-iced generates heat to melt the ice; the operation monitoring system is used to monitor the operating parameters of the ice-melting device such as cable temperature, output voltage, output current and frequency, as well as ice-melting environmental parameters such as ambient temperature and ice 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 operating 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 the collected various operating parameters of the ice-melting device to the control system for analysis or recording.

[0040] Each ice-covered transmission line in the smart grid system is regarded as a line to be melted, and an induction device is installed and laid out on each line to be melted according to actual needs. For example, a special clamp is used to fix the induction coil on the line to be melted. The laying distance needs to be determined by analysis and calculation based on the actual situation. This is an existing technology well known to those skilled in the art, and the specific laying process will not be repeated here.

[0041] It should be noted that, since the analysis and fault protection methods of each induction coil on each ice-melting line are the same, only the control method of any induction coil is used as an example for analysis and description. In the embodiment of the present invention, the output current frequency of the ultra-low frequency AC ice-melting device is adjusted to adjust the output current frequency of the induction coil therein.

[0042] See also Figure 1 , which shows a flow chart of a fault protection method for an ultra-low frequency AC ice melting device provided by an embodiment of the present invention, specifically comprising:

[0043] Step S1, 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 within a preset historical period at the current moment.

[0044] In order to adjust the output current frequency of the ultra-low frequency AC ice-melting device in real time, the frequency adjustment accuracy can be optimized without affecting the ice-melting effect, thereby reducing the loss and failure of the ultra-low frequency AC ice-melting device; therefore, in an embodiment of the present invention, firstly, within a preset historical period at the current moment, 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 are obtained, so as to provide data support for subsequent analysis and adjustment of the output current frequency of the ultra-low frequency AC ice-melting device.

[0045] As an example, the preset historical period is specifically set to within ten minutes of 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 ice melting device needs to start melting ice after reaching the preset ice melting temperature for the first time, and then the output current frequency can be analyzed and adjusted, wherein the preset ice melting temperature is set to 5°C, and the implementer can also set it to any value between 0°C and 5°C;

[0046] Then, the temperature sensor in the operation monitoring system is used to obtain the line temperature of the line to be de-iced at each moment, the output voltage of the ultra-low frequency AC de-icing device at each moment is collected by the voltage sensor, the output current at each moment is collected by the current sensor, and the power factor is evaluated by using the phase difference between the current and the voltage at each moment, thereby obtaining the output power of the ultra-low frequency AC de-icing device at each moment; wherein, the acquisition frequency of the sensor is set to 50Hz, which can also be customized by the implementer, and the acquisition of the line temperature and output power are all known technical means, which 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 coefficient of the ultra-low frequency AC de-icing device at all moments, construct an de-icing efficiency coefficient sequence.

[0048] Considering that when an ultra-low frequency AC ice melting device melts ice, the ice melting heat demand is usually calculated based on the environmental heat balance model. As the ice continues to melt, the ice gradually melts into water, and the contact area between the ice and the line changes continuously due to the influence of gravity. The heat generated by the current may dissipate into the environment. The ice environment is dynamic and complex, and the ice melting heat demand will also change continuously, so that the output current frequency of the ultra-low frequency AC ice melting device is also constantly adjusted. 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, a guiding basis can be provided for the adjustment of the output current frequency, thereby ensuring that the ice melting device always operates within an efficient frequency range, thereby reducing the risk of ice melting device failure caused by improper frequency adjustment.

[0049] Therefore, the embodiment of the present invention first obtains the ice melting efficiency coefficient of the ultra-low frequency AC ice melting device at each moment according to the line temperature of the line to be ice-melted and the output power of the ultra-low frequency AC ice melting device, and then constructs an ice melting efficiency coefficient sequence to provide a reference basis for the subsequent evaluation of the ice melting effect to adjust the output current frequency.

[0050] Preferably, in one 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 under the premise of ensuring safety, it means that the ice melting effect at this moment is better and the output current frequency is more in line with the efficient application of the current ice-covered 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, a first ice-melting efficiency parameter is obtained;

[0052] At each moment, according to the difference between the output power and the preset output power, a 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 integrated 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 time in the preset historical period of the current time; p t is the ice melting efficiency parameter at the tth moment; T t is the line temperature of the line to be de-iced at the tth moment; T L is the preset ice melting temperature; (T t -T L ) is the first ice melting efficiency parameter at the tth moment; w t is the output power of the ultra-low frequency AC ice melting device at the tth moment; w maxis the preset output power, which is also the maximum output power of the ultra-low frequency AC ice melting device; is the second ice melting efficiency parameter at the tth 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 it is, it means that the heat is sufficient to melt the ice, and the first ice melting efficiency parameter is larger; conversely, when the difference is less than 0 and the smaller it is, it means that the temperature is not enough 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, and the output power of the ultra-low frequency AC ice melting device is higher, which can provide sufficient energy to maintain the ice melting temperature and maintain effective ice melting; then the two are multiplied and combined to obtain the ice melting efficiency coefficient at the corresponding moment.

[0056] It should be noted that the preset ice-melting temperature in this example is 5°C, which can also be customized; the maximum output power is the design parameter of the ultra-low frequency AC ice-melting device, which needs to be obtained according to the specific design instructions; 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 repeated here.

[0057] In one embodiment of the present invention, the ice melting efficiency coefficient of the ultra-low frequency AC ice melting device at each moment is obtained, and the ice melting efficiency coefficients of the ultra-low frequency AC ice melting device at all moments can be sorted in time sequence to construct an ice melting efficiency coefficient sequence, so as to subsequently evaluate the efficiency change during the ice melting process and make timely adjustments. It should be noted that the construction of the time sequence is already a prior art and will not be repeated here.

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

[0059] Considering that the ice melting process is usually dynamic and divided into multiple stages, including different changes in temperature, ice thickness, ice-covered contact area, etc., these changes will cause fluctuations in ice melting efficiency, and the changing trends of ice melting efficiency in different stages are different, so the ultra-low frequency AC ice melting device automatically adjusts its output current frequency and also has certain fluctuations; therefore, the embodiment of the present invention will segment the ice melting efficiency coefficient sequence according to the change of the ice melting efficiency coefficient sequence, 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, so as to evaluate the ice melting effect later;

[0060] The changing trends of the ice-melting efficiency coefficients in each isotropic sequence sub-segment are similar, so they are called isotropic sequence sub-segments, and the long-term change sub-segment corresponds to a relatively stable ice-melting process in a preset historical period. Segmentation can help to clearly observe the different stages of the ice-melting process, thereby helping to identify the ice-melting needs at different stages, and then help evaluate the ice-melting effect of the ultra-low frequency AC ice-melting device, so as to prepare for the subsequent reasonable adjustment of the output current frequency and reduce the risk of ice-melting device failure.

[0061] Preferably, in one embodiment of the present invention, considering that the difference can help evaluate the change between adjacent data, so as to facilitate the evaluation of the same change trend; therefore, the method for obtaining the same trend sequence sub-segments includes:

[0062] The first-order difference of the ice melting efficiency coefficient sequence is performed to obtain the differential coefficient sequence; all consecutive sequence elements with the same sign in the differential coefficient sequence are divided into a differential coefficient sequence sub-segment; the ice melting efficiency coefficient sequence is divided according to the differential coefficient sequence sub-segment to obtain all the same trend sequence sub-segments, specifically including:

[0063] Add 1 to the serial number of the last sequence element in each differential coefficient sequence subsegment 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, use the sequence element corresponding to the segmentation point serial number as the last element of each isoconvergent sequence subsegment, and use the next adjacent sequence element of the last element as the head element of the next isoconvergent sequence subsegment; based on the last element and the head element, obtain the corresponding isoconvergent sequence subsegment.

[0064] As an example, assuming that 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}, the differential coefficient sequence is {-0.1, 0.2, 1.1, 0, 0.5, 0.2, 0.2, -0.2, 0.5}, and the corresponding differential coefficient sequence subsegments are {-0.1}, {0.2, 1.1}, {0}, {0.5, 0.2, 0.2}{-0.2}, {0.5}, respectively. Furthermore, all the isotropic sequence subsegments are determined to be {-1.2, -1.3}, {-1.1, 0}, {0}, {0.5, 0.7, 0.9}, {0.7}, {1.2}.

[0065] In other examples, the implementer may also fit the change curve corresponding to the ice melting efficiency coefficient sequence, identify all extreme values ​​in the change curve, and use the ice melting efficiency coefficient sequence sub-segments corresponding to the curve sub-segments between adjacent extreme values ​​as a converging sequence sub-segment; the implementer may also use other feature extraction algorithms to obtain converging sequence sub-segments with the same change trend, which are all existing technologies and will not be elaborated here.

[0066] Preferably, in one embodiment of the present invention, considering that the longer the isoconvergent sequence sub-segment is, the longer the long-term variation characteristics or the relatively stable state of the ice melting efficiency in the preset historical period is, which indirectly reflects the ice melting effect of the ultra-low frequency AC ice melting device in the preset historical period, so as to facilitate subsequent reasonable intervention and adjustment; therefore, among all the isoconvergent sequence sub-segments, the longest isoconvergent sequence sub-segment is used as the long-term variation sub-segment.

[0067] Considering that the long-term change sub-segment reflects the relatively stable state of ice melting efficiency, if the ice melting efficiency in the long-term change sub-segment shows an upward trend, the ice melting effect is better; considering that the local fluctuation of the ice melting efficiency coefficient at the current moment reflects the complex situation 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, and the ice melting effect is better;

[0068] The better the ice-melting effect is, the higher the output current frequency should be adjusted to speed up the melting speed and cope with complex ice-melting stages, so as to reduce the risk of ice-melting device failure while maintaining efficient 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 changes in the long-term change sub-segment and the local fluctuations of the ice-melting efficiency coefficient sequence at the current moment, so as to reduce the risk of ice-melting device failure while maintaining efficient and stable ice-melting.

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

[0070] See also Figure 2 , which shows a flow chart of an output current frequency adjustment method provided in one embodiment of the present invention, specifically comprising:

[0071] Step S201, obtaining a flat growth parameter of a long-term variation subsegment according to the coefficient differences between all adjacent ice melting efficiency coefficients in the long-term variation subsegment.

[0072] Taking into account the difference in changes between all adjacent ice melting efficiency coefficients in the comprehensive long-term change sub-segment, it can help evaluate its change trend or fluctuation, so the flat growth parameter is evaluated based on this.

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

[0074] In the long-term change sub-segment, the difference between each ice-melting efficiency coefficient and the previous adjacent ice-melting efficiency coefficient is taken as the coefficient difference; the negative correlation normalization result of the variance of all coefficient differences is obtained 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 9 similarly converging sequence sub-segments, and the sequence length of each similarly converging sequence sub-segment is 5, 8, 6, 10, 11, 16, 13, 7, and 9 respectively. The similarly converging sequence sub-segments with sequence lengths of 5, 8, 6, 7, and 9 are used as sequence sub-segments to be merged; then, since the three sequence sub-segments to be merged with sequence lengths of 5, 8, and 6 are adjacent, the three sequence sub-segments to be merged are merged into a fluctuation sequence sub-segment; and since the two sequence sub-segments to be merged with sequence lengths of 7 and 9 are adjacent, the two sequence sub-segments to be merged are merged into a fluctuation sequence sub-segment, and since they are close to the current moment, the fluctuation sequence sub-segment obtained by merging the two sequence sub-segments to be merged with sequence lengths of 7 and 9 is used as the local fluctuation sequence sub-segment at the current moment.

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

[0083] Considering that the larger the flat growth parameter of the long-term variation sub-segment is, the more stable the ice-melting process is and the better the effect is; considering that the longer the local fluctuation sequence sub-segment is, the more complicated the ice-melting process near the current moment is, and the ultra-low frequency AC ice-melting device is constantly and automatically adjusted, thereby improving the ice-melting efficiency, which indirectly indicates 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 based on the ice-melting process. The adjustment weight indirectly reflects the ice-melting effect at the current moment. The better the ice-melting effect is, the higher the output current frequency should be adjusted to speed up the melting speed and cope with complex ice-melting stages, so as to reduce the risk of ice-melting device failure while maintaining efficient and stable ice-melting.

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

[0086] The ratio of the length of the local fluctuation sequence sub-segment to the length of the ice-melting efficiency coefficient sequence is used as the ice-melting effect parameter; the normalized result of the flat growth parameter of the long-term variation sub-segment is mapped to the product of the ice-melting effect parameter, and the mapping result is used as the adjustment weight; the value range of the adjustment weight is [-1, 1].

[0087] As an example, the calculation formula for adjusting the weight is: Among them, t is the serial number of 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 fluctuation sequence subsegment; 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 subsegment in the preset historical period at the current moment; max(Y) is the sequence length of the long-term sequence subsegment in 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 better the ice melting effect is. Specifically, the flat growth parameter is divided by the historical maximum value for normalization. The larger the flat growth parameter in the preset historical period at the current moment, the larger the normalization result, which also indirectly indicates that the ice is efficiently melted in 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, so that the adjustment weight is in [-1, 1], so as to subsequently increase or decrease the output current frequency.

[0089] In other examples, implementers may also use other mapping functions, which are all existing technologies and are not described in detail here.

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

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

[0092] In this example, when the ice melting effect is better, the adjustment weight is relatively larger and greater than 0, and the corresponding frequency adjustment amount is greater than 0. The larger the frequency, the higher the output current frequency can be, so as to further accelerate the ice melting speed when the ice melting effect is better. At the same time, the output current can be made more stable to avoid local overheating of the equipment or unstable current and increase the risk of failure; when the ice melting effect is not good, the adjustment weight is relatively small and less than 0, and the corresponding frequency adjustment amount is less than 0, so as to reduce the output current frequency, thereby improving uneven ice melting to improve 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 manual of the ultra-low frequency AC ice melting device.

[0094] In summary, 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 de-icing device on the line to be de-iced at each moment within the preset historical period at the current moment; further analyzes and obtains the de-icing efficiency coefficient of the ultra-low frequency AC de-icing device at each moment, and constructs a de-icing efficiency coefficient sequence; then the de-icing efficiency coefficient sequence is segmented to obtain all isotropic sequence sub-segments and long-term change sub-segments; finally, according to the change of the long-term change sub-segments and the local fluctuation of the de-icing efficiency coefficient sequence at the current moment, the output current frequency of the ultra-low frequency AC de-icing device at the current moment is adjusted. The present invention monitors and evaluates the change of the de-icing efficiency of the ultra-low frequency AC de-icing device, thereby analyzing and evaluating the de-icing effect in the adjacent time period at the current moment, and then accurately adjusts the output current frequency of the ultra-low frequency AC de-icing device according to the de-icing effect, while maintaining efficient and stable de-icing, reducing the risk of failure of the de-icing device.

[0095] It should be noted that the sequence of the above embodiments of the present invention is only for description and does not represent the advantages and 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 results. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0096] The various embodiments in this specification are described in a progressive manner, and the same or similar parts between the various embodiments can be referenced to each other, and 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 comprises: In a preset historical period at the current moment, 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 are obtained; 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, an ice melting efficiency coefficient of the ultra-low frequency AC de-icing device is obtained; according to the ice melting efficiency coefficient of the ultra-low frequency AC de-icing device at all moments, an ice melting efficiency coefficient sequence is constructed; According to the change of the ice melting efficiency coefficient sequence, the ice melting efficiency coefficient sequence is segmented to obtain all the isotropic sequence sub-segments, and the long-term change sub-segments are screened out from all the isotropic sequence sub-segments; according to the change of the long-term change sub-segments and the local fluctuation of the ice melting efficiency coefficient sequence at the current moment, the output current frequency of the ultra-low frequency AC ice melting device at the current moment is adjusted.

2. 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 ice melting efficiency coefficient includes: At each moment, obtaining a first ice-melting efficiency parameter according to the difference between the line temperature and a preset ice-melting temperature; At each moment, according to the difference between the output power and the preset output power, a second ice melting efficiency parameter is obtained; The first ice-melting efficiency parameter and the second ice-melting efficiency parameter at each moment are integrated to obtain an ice-melting efficiency coefficient of the ultra-low frequency AC ice-melting device at each moment.

3. The method for protecting a fault of an ultra-low frequency AC ice melting device according to claim 1, characterized in that: The method for obtaining the isochronous sequence sub-segments comprises: Performing a first-order difference on the ice melting efficiency coefficient sequence to obtain a differential coefficient sequence; dividing all consecutive sequence elements with the same sign in the differential coefficient sequence into a differential coefficient sequence sub-segment; The ice melting efficiency coefficient sequence is divided correspondingly according to the differential coefficient sequence sub-segments to obtain all the same trend sequence sub-segments.

4. A fault protection method for an ultra-low frequency AC ice melting device according to claim 3, characterized in that: The method of segmenting the ice melting efficiency coefficient sequence according to the differential coefficient sequence sub-segments to obtain all the same trend sequence sub-segments includes: Add 1 to the sequence number of the last sequence element in each differential coefficient sequence subsegment in the differential coefficient sequence to obtain all the segmentation point sequences in the ice melting efficiency coefficient sequence; In the ice melting efficiency coefficient sequence, the sequence element corresponding to the segmentation point number is used as the end element of each isoconvergent sequence subsegment, and the next adjacent sequence element of the end element is used as the beginning element of the next isoconvergent sequence subsegment; based on the end element and the beginning element, the corresponding isoconvergent sequence subsegment is obtained.

5. The method for protecting a fault of an ultra-low frequency AC ice melting device according to claim 1, characterized in that: The method for acquiring the long-term variation sub-segment comprises: Among all the iso-convergent sequence sub-segments, the longest iso-convergent sequence sub-segment is used as the long-term variation sub-segment.

6. The method for protecting a fault of an ultra-low frequency AC ice melting device according to claim 1, characterized in that: The method for adjusting the output current frequency includes: According to the coefficient difference between all adjacent ice melting efficiency coefficients in the long-term change sub-segment, a flat growth parameter of the long-term change sub-segment is obtained; according to the length of the isotropic sequence sub-segment, a local fluctuation sequence sub-segment at the current moment is obtained; according to the sequence length of the local fluctuation sequence sub-segment and the flat growth parameter, an adjustment weight of the output current frequency at the current moment is obtained; The output current frequency of the ultra-low frequency AC ice melting device at the previous adjacent moment before the current moment is weighted by using the adjustment weight, and the weighted result is used as the frequency adjustment amount; the output current frequency of the ultra-low frequency AC ice melting device at the current moment is added to the frequency adjustment amount to obtain the adjusted output current frequency.

7. A fault protection method for an ultra-low frequency AC ice melting device according to claim 6, characterized in that: The method for obtaining the flat growth parameter includes: In the long-term variation subsection, the difference between each ice-melting efficiency coefficient and the previous adjacent ice-melting efficiency coefficient is taken as the coefficient difference; the negative correlation normalization result of the variance of all the coefficient differences is obtained to obtain a flat growth parameter.

8. The method for protecting a fault of an ultra-low frequency AC ice melting device according to claim 6, characterized in that: The method for obtaining the local fluctuation sequence subsegment comprises: The isotropic sequence subsegments whose sequence length is less than a preset threshold are taken as sequence subsegments to be merged; in the ice melting efficiency coefficient sequence, adjacent sequence subsegments to be merged are merged to obtain a fluctuation sequence subsegment; and the fluctuation sequence subsegment closest to the current moment is taken as a local fluctuation sequence subsegment.

9. A fault protection method for an ultra-low frequency AC ice melting device according to claim 6, characterized in that: The method for obtaining the adjustment weight includes: The ratio of the length of the local fluctuation sequence subsegment to the length of the ice-melting efficiency coefficient sequence is used as the ice-melting effect parameter; the normalized result of the flat growth parameter of the long-term change subsegment is mapped to the product of the ice-melting effect parameter, and the mapping result is used as the adjustment weight; the value range of the adjustment weight is [-1, 1].

10. An ultra-low frequency AC ice melting device, comprising a device body, characterized in that: The device implements the steps of a fault protection method for an ultra-low frequency AC ice melting device as claimed in any one of claims 1 to 9.

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