Fault detection processing method and system of direct current deicing device and direct current deicing device

Abstract

The present application relates to the technical field of ice melting device fault detection processing, and discloses a fault detection processing method and system of a direct current ice melting device and the direct current ice melting device, which comprises the following steps: collecting ice layer data, valve group load data and weather data of a power transmission line in real time, inputting the ice layer data into an ice layer prediction model to obtain an ice layer thickness change rate; calculating the thyristor failure probability of each working valve group according to the ice layer thickness change rate, the valve group load data and the weather data, and selecting a risk valve group; judging whether to trigger a redundant switching strategy according to the thyristor junction temperature and the node-to-ground potential of the risk valve group; in response to the triggering of the redundant switching strategy, selecting a first backup valve group according to the priority of the backup valve group, and calculating a load distribution ratio according to the load current of the risk valve group. The present application can accurately predict the thyristor failure risk, improve the timeliness of the redundant switching of the direct current ice melting device, and improve the ice melting efficiency and operation stability of the device through the optimization of the redundant switching logic.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of fault detection processing of ice melting device, and particularly relates to a fault detection processing method and system of direct current ice melting device and the direct current ice melting device. BACKGROUND

[0002] Because icing of power transmission lines will seriously affect the stable operation of the power system, the ice melting technology based on the ice melting device is usually used to solve the icing problem of the power transmission lines. At present, the direct current ice melting device mainly used is to apply a direct current to the power transmission lines and short-circuit at the end of the power transmission lines, so that the conductor generates heat to melt the ice on the power transmission lines, thereby avoiding the pole falling and wire breaking due to icing. The direct current ice melting device adopts the thyristor control technology to realize the ablation of the ice layer by dynamically adjusting the current. The limitation of the current ice melting technology is that the dynamic change of the ice layer load caused by complex weather changes cannot be dynamically adjusted in time by the current direct current ice melting device according to the change of the complex working conditions. The problem of insufficient dynamic adaptability is particularly prominent when the thyristor fails, because the ice melting device not only has to deal with the changing load, but also has to cope with new electrical challenges such as uneven current distribution in the valve group and intensified potential difference between the valve groups. The current direct current ice melting technology is difficult to effectively coordinate the concurrent problems, which directly leads to the decrease of the ice melting efficiency and the increase of the energy consumption.

[0003] In addition, in order to cope with the sudden situation, the current direct current ice melting device also sets up a redundant backup mechanism, but its switching logic is static switching, and it lacks the ability to dynamically adjust according to the real-time ice melting progress and the current load state, which further limits the optimization configuration ability and the overall performance of the ice melting device under the sudden situation or dynamic load. SUMMARY

[0004] In order to solve the above technical problems, the present application provides a fault detection processing method and system of direct current ice melting device and the direct current ice melting device, which can solve the problem of insufficient adaptability of the current direct current ice melting device to dynamic load change, and effectively improve the ice melting efficiency and the operation stability of the direct current ice melting device.

[0005] In the first aspect, the present application provides a fault detection processing method of direct current ice melting device, which comprises:

[0006] Real-time collection of ice layer data, valve group load data and meteorological data of the power transmission lines, and inputting into a preset ice layer prediction model to obtain the ice layer thickness change rate, wherein the ice layer prediction model is built based on support vector mechanism;

[0007] According to the ice layer thickness change rate, the valve group load data and the meteorological data, a logic regression algorithm is used to calculate the thyristor failure probability of each working valve group of the direct current deicing device, and a risk valve group is selected from each working valve group according to the thyristor failure probability;

[0008] According to the risk valve group, the thyristor junction temperature and the node-to-ground potential, it is judged whether the redundancy switching strategy is triggered or not, and the risk valve group is switched;

[0009] In response to triggering the redundancy switching strategy, according to the priority of each standby valve group of the direct current deicing device, a plurality of standby valve groups are selected as the first standby valve group, and the load distribution ratio of the first standby valve group is calculated according to the load current of the risk valve group;

[0010] The first standby valve group is used to replace the risk valve group, and the first standby valve group is controlled according to the load distribution ratio.

[0011] Further, before the step of judging whether the redundancy switching strategy is triggered or not according to the risk valve group, the thyristor junction temperature and the node-to-ground potential, it further comprises:

[0012] According to the current value standard deviation of each thyristor of the risk valve group, a current balance coefficient is calculated;

[0013] It is judged whether the current balance coefficient is greater than the coefficient threshold value, if yes, the difference value between the real-time current value of each thyristor and the thyristor current average value is calculated;

[0014] According to the difference value, a to-be-adjusted thyristor is selected from each thyristor, and the conduction angle of the to-be-adjusted thyristor is adjusted;

[0015] Wherein, the current balance coefficient is expressed by the following formula:

[0016]

[0017] In the formula, N represents the total number of thyristors, I j represents the real-time current value of the jth thyristor, and μ represents the thyristor current average value.

[0018] Further, the step of judging whether the redundancy switching strategy is triggered or not according to the risk valve group, the thyristor junction temperature and the node-to-ground potential, comprises:

[0019] According to the risk valve group, the thyristor junction temperature, the real-time current value and the thyristor conduction time of each thyristor, the local overheating index of each thyristor is calculated;

[0020] judging whether the local overheating index is greater than an index threshold, and if greater than the index threshold, triggering a redundancy switching strategy;

[0021] if not greater than the index threshold, calculating a valve group potential difference according to the ground potential of each node of the risk valve group;

[0022] judging whether the valve group potential difference is greater than a potential difference threshold, and if greater than the potential difference threshold, triggering the redundancy switching strategy.

[0023] Further, the local overheating index is expressed by the following formula:

[0024]

[0025] In the formula, Q j represents the local overheating index of the jth thyristor, T j represents the junction temperature of the jth thyristor, β represents the thermal resistance coefficient, t j represents the cumulative conduction time of the jth thyristor, I j represents the real-time current value of the jth thyristor;

[0026] The valve group potential difference is expressed by the following formula:

[0027]

[0028] In the formula, V max represents the maximum node-to-ground potential, V min represents the minimum node-to-ground potential.

[0029] Further, the step of selecting a plurality of standby valve groups as the first standby valve group according to the priority of each standby valve group of the DC de-icing device comprises:

[0030] calculating the load adaptation degree of each standby valve group according to the load current of the risk valve group and the rated current of each standby valve group, and determining a weight coefficient according to the current de-icing progress of the power transmission line;

[0031] weighting and summing the load adaptation degree and the current de-icing progress according to the weight coefficient to obtain the priority of each standby valve group;

[0032] determining the valve group selection quantity according to the load current of the risk valve group and the average of the rated current of the standby valve group;

[0033] selecting the first standby valve group from each standby valve group according to the priority and the valve group selection quantity;

[0034] In the formula, the priority is expressed by the following formula:

[0035]

[0036] wherein ρ s represents the priority of the s-th backup valve group, α represents the weight coefficient, R represents the current ice-melting progress, I load represents the load current of the risk valve group, represents the rated current of the i-th backup valve group.

[0037] Further, the step of calculating the load distribution ratio of the first backup valve group according to the load current of the risk valve group comprises:

[0038] a load distribution ratio model is established with the difference between the distribution current value of each first backup valve group and the target balanced current value as an objective function, and with the total of the distribution current values of each first backup valve group not exceeding the load current of the risk valve group as a constraint condition;

[0039] a linear programming algorithm is used to solve the load distribution ratio model to obtain the distribution current value of each first backup valve group.

[0040] Further, the objective function is expressed by the following formula:

[0041]

[0042] wherein represents the maximum value parameter function, I i represents the distribution current value of the i-th first backup valve group, M represents the total number of first backup valve groups, I t represents the target balanced current value.

[0043] The constraint condition is expressed by the following formula:

[0044]

[0045] wherein I load represents the load current of the risk valve group.

[0046] Further, after the step of performing load control on the first backup valve group according to the load distribution ratio, the method further comprises:

[0047] calculating a stability index according to the current fluctuation value and the thyristor junction temperature of the working valve group of the DC ice-melting device;

[0048] judging whether the stability index is less than a stability index threshold value, and if so, selecting a working valve group with the largest current fluctuation value from each working valve group as a to-be-optimized valve group;

[0049] decrease the load current of the valve group to be optimized, select a second backup valve group according to the decreased load current and the priority of each backup valve group, and connect the second backup valve group to the DC de-icing device;

[0050] wherein the stability index is expressed by the following formula:

[0051]

[0052] wherein, △I represents the current fluctuation value, I n represents the rated total current, △T represents the maximum difference between the thyristor junction temperature and the ambient temperature, T max represents the maximum junction temperature allowed by the thyristor, λ1 represents the current weight, and λ2 represents the temperature weight.

[0053] In a second aspect, the present application provides a fault detection processing system of a DC de-icing device, the system comprising:

[0054] an ice layer prediction module configured to collect ice layer data, valve group load data and weather data of a power transmission line in real time, and input a preset ice layer prediction model to obtain an ice layer thickness change rate, the ice layer prediction model being built based on a support vector machine;

[0055] a fault detection module configured to calculate a thyristor failure probability of each working valve group of the DC de-icing device according to the ice layer thickness change rate, the valve group load data and the weather data by using a logistic regression algorithm, and select a risk valve group from each working valve group according to the thyristor failure probability;

[0056] a switching judgment module configured to judge whether to trigger a redundancy switching strategy according to the thyristor junction temperature and the node-to-ground potential of the risk valve group, and switch the risk valve group;

[0057] a redundancy switching module configured to select a plurality of backup valve groups as first backup valve groups according to the priority of each backup valve group of the DC de-icing device in response to triggering the redundancy switching strategy, and calculate a load distribution ratio of the first backup valve groups according to the load current of the risk valve group;

[0058] replace the risk valve group with the first backup valve groups, and control the load of the first backup valve groups according to the load distribution ratio.

[0059] In a third aspect, the present application further provides a DC de-icing device, which is subjected to fault detection processing by using the method as described above.

[0060] The application provides a fault detection processing method and system of a direct current ice melting device and the direct current ice melting device. The ice layer predictive model is combined with real-time meteorological data and load data to improve the accuracy of the risk prediction of thyristor failure. The analysis of the thyristor junction temperature and the node-to-ground potential of the valve group can accurately determine the working state of the valve group. The switching logic of the direct current ice melting device is optimized by the redundant switching strategy based on priority and load distribution ratio dynamic adjustment, which can improve the ice melting efficiency and operation stability of the direct current ice melting device, and further ensure the safety and stability of the power transmission line operation. BRIEF DESCRIPTION OF DRAWINGS

[0061] Figure 1 FIG. 1 is a flow diagram of the fault detection processing method of the direct current ice melting device in the embodiment of the application;

[0062] Figure 2 FIG. 2 is a structural diagram of the fault detection processing system of the direct current ice melting device in the embodiment of the application;

[0063] Reference signs:

[0064] 10, ice layer prediction module; 20, fault detection module; 30, switching judgment module; 40, redundant switching module. DETAILED DESCRIPTION

[0065] In order to make the purpose, technical scheme and advantages of the embodiments of the application clearer, the technical scheme in the embodiments of the application will be described clearly and completely below with reference to the drawings in the embodiments of the application. Obviously, the described embodiments are part of the embodiments of the application, rather than all the embodiments. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of the application.

[0066] Please refer to Figure 1 The fault detection processing method of the direct current ice melting device according to the first embodiment of the application comprises steps S10-S50.

[0067] Step S10: Real-time acquisition of ice layer data, valve group load data and meteorological data of a power transmission line, and input into a preset ice layer prediction model to obtain an ice layer thickness change rate. The ice layer prediction model is built based on a support vector machine.

[0068] Step S20: According to the ice layer thickness change rate, the valve group load data and the meteorological data, a logic regression algorithm is used to calculate the thyristor failure probability of each working valve group of the direct current ice melting device, and a risk valve group is selected from each working valve group according to the thyristor failure probability.

[0069] Step S30, according to the risk valve group thyristor junction temperature and node to ground potential, judge whether to trigger the redundant switching strategy, switch the risk valve group;

[0070] Step S40, in response to triggering the redundant switching strategy, according to the priority of each standby valve group of the DC ice melting device, select a plurality of standby valve groups as the first standby valve group, and according to the load current of the risk valve group, calculate the load distribution ratio of the first standby valve group;

[0071] Step S50, using the first standby valve group to replace the risk valve group, and according to the load distribution ratio, the first standby valve group is controlled.

[0072] The application provides a kind of for the failure detection and processing method of DC ice melting device, wherein DC ice melting device is twelve pulse DC ice melting device, twelve pulse DC ice melting device is a kind of specially used for power transmission line icing management high efficiency equipment, the heat effect generated by utilizing direct current, by delivering large current to icing conductor, make conductor heat and melt the ice layer attached to its surface.This device uses the core feature of twelve pulse wave rectification technology, compared with traditional ice melting method has higher efficiency and better security.

[0073] When carrying out transmission line ice melting, with the ice layer change on transmission line and the line load state change caused by ice layer change, all can cause thyristor in DC ice melting device to fail, in order to predict the probability of thyristor failure in DC ice melting device when carrying out ice melting, in the embodiment, first, according to current meteorological data and ice layer data and valve group load data of transmission line, the ice layer change on transmission line is predicted by ice layer prediction model, wherein ice layer prediction model preferably uses support vector machine algorithm to construct.Specifically, the input data of ice layer prediction model includes ice layer data, valve group load data and current meteorological data of transmission line, and the output data is ice layer thickness change rate, wherein the ice layer data includes ice layer thickness, the valve group load data includes load current and load voltage of each valve group in DC ice melting device, and meteorological data includes current temperature and current humidity etc.Here it needs to be explained that, since DC ice melting device is by delivering large current to icing conductor, make conductor heat and melt the ice layer attached to its surface, therefore, the valve group in DC ice melting device and the thyristor in valve group can reuse the valve group and thyristor of transmission line, thereby improving equipment utilization.

[0074] After predicting the ice layer thickness change rate on the power transmission line through the ice layer prediction model, combined with the current valve group load data and meteorological data, a logistic regression algorithm is used to calculate the thyristor failure probability of each working valve group in the DC deicing device. The working valve group refers to the valve group that is currently performing deicing work. Since the DC deicing device adopts a redundant backup mechanism, in addition to the working valve group, there are also some valve groups that have not been put into deicing work, which are standby valve groups.

[0075] In this embodiment, mainly by using the load current of the working valve group in the valve group load data, the current temperature in the meteorological data, and the ice layer thickness change rate output by the ice layer prediction model, the thyristor failure probability of the working valve group under the current environment can be calculated through the logistic regression algorithm as follows:

[0076]

[0077] In the formula, P represents the thyristor failure probability, a, b, and c represent model coefficients, which are obtained by training historical failure data, △L represents the ice layer thickness change rate, I represents the load current, and T represents the environmental temperature. It should be noted that the above failure probability formula is for calculating the thyristor failure probability of a single valve group, so the load current in the formula is the load current of the valve group, i.e. the real-time current value of the valve group. In addition, in feature engineering, each feature parameter is usually normalized before linear combination calculation to eliminate the dimensional influence between feature parameters. Therefore, the ice layer thickness change rate, load current, and environmental temperature in this embodiment will be normalized before failure probability calculation. It can be understood that the ice layer thickness change rate, load current, and environmental temperature in the above formula are all normalized parameters.

[0078] After calculating the thyristor failure probability of the working valve group, compare its thyristor failure probability with the preset probability threshold. Assuming that the probability threshold is 0.15, when P > 0.15, it means that the working valve group has a high risk of thyristor failure, so the working valve group is regarded as a risk valve group.

[0079] Since the risk valve group only indicates that the valve group has a certain risk of thyristor failure, but cannot determine whether the current working state of the valve group is normal or abnormal, it is impossible to determine whether redundancy switching is needed. In order to improve the timeliness of redundancy switching, it is also necessary to analyze the related parameters of the risk valve group to identify the current state of the risk valve group, so as to determine whether the standby valve group needs to be used to replace the risk valve group.

[0080] In the embodiment, the working state of the risk valve group is judged by the thyristor junction temperature and the node-to-ground potential of the risk valve group, wherein the thyristor junction temperature refers to the temperature of the thyristor chip, which is obtained by directly measuring the real-time temperature of the PN junction inside the thyristor and reflects the current heat accumulation state of the chip. If the thyristor junction temperature exceeds the bearing range of the thyristor, a fault will occur. Therefore, the thyristor junction temperature is an important parameter, and the working state of the valve group can be judged by the parameter. If the thyristor junction temperature is too high, it indicates that the working state of the risk valve group is abnormal.

[0081] The node-to-ground potential of the risk valve group refers to the ground voltage of the key electrical connection points in the valve group. The connection points herein include the anode and cathode of the thyristor and the auxiliary circuit nodes in the valve group, such as the voltage equalizing resistor connection point and the trigger signal line connection point. The node-to-ground potential can be obtained by measuring the ground potential between the two ends of the thyristor and the ground potential of the auxiliary circuit nodes in the valve group. The voltage fluctuation in the risk valve group can be analyzed by the node-to-ground potential, so as to judge whether the working state of the risk valve group is stable.

[0082] In a preferred embodiment, in order to improve the accuracy of identifying the working state of the risk valve group and thus timely trigger the redundancy switching strategy, the present application identifies the working state of the risk valve group by analyzing the thyristor junction temperature and the node-to-ground potential, so as to judge whether to trigger the redundancy switching strategy. The specific steps include:

[0083] According to the thyristor junction temperature, real-time current value and thyristor conduction time of each thyristor of the risk valve group, a local overheating index of each thyristor is calculated.

[0084] It is judged whether the local overheating index is greater than an index threshold. If it is greater than the index threshold, the redundancy switching strategy is triggered.

[0085] If it is not greater than the index threshold, a valve group potential difference is calculated according to the node-to-ground potential of each node of the risk valve group.

[0086] It is judged whether the valve group potential difference is greater than a potential difference threshold. If it is greater than the potential difference threshold, the redundancy switching strategy is triggered.

[0087] In the embodiment, since the thyristor junction temperature is a direct measurement of the current heat state, only the instantaneous temperature is reflected, and the dynamic heat accumulation trend of the current load and the conduction time is not included. In fact, according to the different working states of the thyristor, the future heat accumulation will also be different. In order to accurately judge whether the temperature of the thyristor will affect the working state of the valve group, the future temperature rise change is predicted by the load data of the thyristor in the embodiment, and the real-time temperature and the predicted temperature rise change are combined to calculate the local overheating index of each thyristor, and according to the local overheating index, it is judged whether the thyristor will cause overheating risk due to continuous high load.

[0088] Specifically, the local overheating index can be calculated according to the thyristor junction temperature of the thyristor, the real-time current value and the thyristor conduction time, and its formula is represented as:

[0089]

[0090] In the formula, Q j represents the local overheating index of the jth thyristor, T j represents the thyristor junction temperature of the jth thyristor, β represents the thermal resistance coefficient, t j represents the cumulative conduction time of the jth thyristor, I j represents the real-time current value of the jth thyristor.

[0091] In the local overheating index formula, the future temperature rise trend is predicted by the load data of the thyristor, and the future temperature rise trend is combined with the real-time temperature, so that the overheating risk caused by continuous high load can be warned in advance, instead of relying only on the current junction temperature threshold. If the current junction temperature of the thyristor does not exceed the junction temperature threshold, but it works in a high current environment for a long time, so after superimposing the future temperature rise trend, the thyristor has a high probability of overheating risk. Specifically, since the current conduction will generate heat, the longer the power-on time, the more heat will be generated. In order to simplify the calculation, the cumulative effect of the current is quantified by the product of the load current and the conduction time, that is, the greater the current and the longer the conduction time, the more significant the heat accumulation. And in order to convert the quantified current heat into temperature, the thermal resistance coefficient is set in the embodiment, which is determined by the thyristor material and the heat dissipation condition, and reflects the ability to resist heat flow per unit current and time. Its unit is: ℃ / (A·s). Through the thermal resistance coefficient, the accumulated heat of the current conduction can be converted into a temperature value, so that the prediction of the future temperature rise trend can be realized.

[0092] Since the DC ice melting device is controlled based on the thyristor, the working state of the thyristor needs to be analyzed and determined first. When the local overheating index of the thyristor is higher than the preset index threshold, it indicates that the thyristor has a high risk of overheating, and it is considered that the working state of the risk valve group is abnormal. At this time, the redundant switching needs to be performed. If the local overheating index of the thyristor is not higher than the index threshold, it indicates that the current working state of the thyristor is normal. At this time, the state determination of the risk threshold also needs to further refer to the node-to-ground potential.

[0093] In the embodiment, the potential difference of the valve group is calculated by the node-to-ground potential of each node of the risk valve group. The valve group potential difference is the difference between the maximum value and the minimum value of the node-to-ground potential of each node, and its formula is expressed as:

[0094]

[0095] In the formula, V max represents the maximum value of the node-to-ground potential, that is, the maximum value of the node-to-ground potential of each node, V min represents the minimum value of the node-to-ground potential, that is, the minimum value of the node-to-ground potential of each node.

[0096] If the valve group potential difference is greater than the preset potential difference threshold, it indicates that the voltage fluctuation in the risk valve group is too large, which will cause the working state of the risk valve group to be unstable. In combination with the risk threshold, the valve group itself has a risk of thyristor failure. At this time, it is considered that the standby valve group needs to be used to replace the risk valve group.

[0097] In a preferred embodiment, before triggering the determination of the redundant switching of the risk valve group, the current state of the risk valve group also needs to be analyzed and processed. The specific steps include:

[0098] According to the current value standard deviation of each thyristor of the risk valve group, the current balance coefficient is calculated;

[0099] Determine whether the current balance coefficient is greater than the coefficient threshold. If yes, the difference between the real-time current value of each thyristor and the average current value of the thyristor is calculated;

[0100] According to the difference, the thyristor to be adjusted is selected from each thyristor, and the conduction angle of the thyristor to be adjusted is adjusted.

[0101] The embodiment is the determination of the current distribution state in the risk valve group. The determination of the current distribution state is performed before the determination of the local overheating of the thyristor. The unbalanced current in the valve group can cause the subsequent local overheating and potential difference. If the local overheating is directly determined, there can be a situation that the current distribution is unbalanced but the local overheating index has not exceeded the threshold value. At this time, the current imbalance risk can be ignored. The potential difference can also be caused by the external load change and has no direct connection with the current balance. Therefore, before the determination of the local overheating index and the potential difference, the current balance coefficient is used to determine the current distribution state in the risk valve group. The current balance coefficient is calculated by using the standard deviation of the current values of the thyristors. The formula is as follows:

[0102]

[0103] In the formula, N represents the total number of the thyristors, I j represents the real-time current value of the jththyristor, and μ represents the average current value of the thyristor.

[0104] If the current balance coefficient of the risk valve group is less than or equal to the preset coefficient threshold value, it is indicated that the current distribution in the risk valve group is uniform. The local overheating and the excessive potential difference of the valve group are irrelevant to the current balance state in the valve group. Conversely, if the current balance coefficient is greater than the coefficient threshold value, it is indicated that the current distribution in the risk valve group is not uniform. At this time, the thyristors in the risk valve group need to be adjusted to achieve the current balance through the current redistribution.

[0105] There are multiple thyristors in the risk valve group. When the current is redistributed, all the thyristors are not adjusted. Instead, the thyristors to be adjusted need to be found. In the embodiment, the average current value of the thyristors is calculated according to the actual current values of the thyristors in the risk valve group. Then, the difference between the actual current value of each thyristor and the average current value of the thyristor is calculated, and the sorting is performed according to the absolute value of the difference. Since the thyristors in the valve group appear in pairs, the thyristor pair with the largest difference value needs to be selected from the sorting. Then, the conduction angle of the thyristor pair is adjusted to achieve the current redistribution. Preferably, the adjustment amount of the conduction angle can be represented as follows:

[0106]

[0107] In the formula, represents the adjustment amount of the conduction angle of the kththyristor to be adjusted, represents the adjustment coefficient, I k represents the real-time current value of the kththyristor to be adjusted, and μ represents the average current value of the thyristor.

[0108] In the embodiment, the current balance can be achieved by adjusting the conduction angle of the thyristor, thereby avoiding local overload and ensuring that the risk valve group is in a current balance state when subsequent local overheating and potential difference determination is performed, so that the determination result of the working state of the risk valve group is more accurate.

[0109] When it is confirmed that the redundancy switching strategy is triggered, the embodiment adopts a priority-based selection method to select a suitable replacement valve group from multiple backup valve groups. The priority of the backup valve group can be a preset priority, and the selection quantity can be selected according to the priority order and a preset quantity. However, this static redundancy switching strategy is not dynamically adjusted according to the actual working condition, which may lead to imbalance between the ice melting efficiency and the ice melting energy consumption. Therefore, the embodiment provides a multi-level redundancy backup switching strategy capable of dynamically adjusting according to the actual working condition to achieve switching control of the valve group. In the redundancy switching strategy of the embodiment, the priority of the backup valve group is first dynamically calculated according to the actual working condition, and the specific steps include:

[0110] According to the load current of the risk valve group and the rated current of each backup valve group, the load adaptation degree of each backup valve group is calculated, and the weight coefficient is determined according to the current ice melting progress of the power transmission line;

[0111] According to the weight coefficient, the load adaptation degree and the current ice melting progress are weighted and summed to obtain the priority of each backup valve group;

[0112] According to the load current of the risk valve group and the minimum rated current of the backup valve group, the valve group selection quantity is determined;

[0113] According to the priority and the valve group selection quantity, a first backup valve group is selected from each backup valve group.

[0114] In the embodiment, the current ice melting progress is first determined, which refers to the completion ratio of ice melting and can be determined by the ratio of the melted ice thickness to the initial ice layer thickness. Then, according to the load current of the risk valve group and the rated current of each backup valve group, the load adaptation degree of each backup valve group is calculated, wherein the load adaptation degree is the ratio between the load current of the risk valve group and the rated current of the backup valve group. The priority of the backup valve group is determined according to the ice melting progress and the load adaptation degree, and the formula is as follows:

[0115]

[0116] In the formula, p s represents the priority of the s-th backup valve group, a represents the weight coefficient, R represents the current ice melting progress, I load represents the load current of the risk valve group, represents the rated current of the i-th backup valve group.

[0117] The weight coefficients in the above priority formula can be preset, and in order to make the priority of the backup valve group match the current actual working condition, in a preferred embodiment, the weight coefficients of the two parameters are determined by the current ice melting progress. Specifically, the ice melting progress reflects the proportion of the overall ice melting task of the power transmission line completed, which is directly related to the working effect of the current working valve group. Although the ice melting progress does not directly describe the performance of the backup valve group, the demand characteristics of the backup valve group for the DC ice melting device can be evaluated through the current ice melting progress. If the ice melting progress is high, it indicates that only a small amount of time is needed to complete the ice melting, at this time the DC ice melting device can preferentially select a backup valve group that can quickly complete the remaining task, such as a valve group with high response speed but low capacity; if the ice melting progress is low, it indicates that a long time of ice melting is needed, at this time what is needed is a backup valve group with high load capacity and sustainable operation. It can be understood that when the ice melting progress is high, the backup valve group with fast response and high efficiency is preferentially selected, and when the ice melting progress is low, the backup valve group with strong stability and large capacity is preferentially selected. Therefore, in this embodiment, a progress threshold is preset, assuming that the progress threshold is 50%, in the case that the ice melting progress is less than 50%, more emphasis is placed on the load capacity, so the weight of the load adaptation degree can be increased, for example, α is set to 0.8, otherwise, more emphasis is placed on the urgency of the ice melting task, so the weight of the ice melting progress can be increased, for example, α is set to 0.4. Through dynamic weight allocation, the priority calculation can be more in line with the task stage demand.

[0118] The number of selected backup valve groups can be determined according to the load current of the risk valve group, and when the backup valve group is used to replace the risk valve group, the load current of the risk valve group needs to be shared by the backup valve group. Therefore, by comparing the load current of the risk valve group with the rated current of the backup valve group, the optimal number of selected backup valve groups can be determined. In this embodiment, the selected backup valve groups are regarded as first backup valve groups, and the total number M of the first backup valve groups can be represented as:

[0119]

[0120] In the formula, I load represents the load current of the risk valve group, I p represents the average rated current of each backup valve group, and represents the upper limit function.

[0121] In addition to determining the number of selected backup valve groups based on the average rated current, the number of selected backup valve groups can also be determined based on the minimum or maximum rated current of each backup valve group. Only preferred embodiments are given here, and no further limitation is made.

[0122] After selecting a plurality of first backup valve groups according to the priorities and the selected number of the backup valve groups, load distribution needs to be performed on the first backup valve groups according to the load current of the risk valve group, and the specific steps include:

[0123] A load distribution proportion model is established, with the difference between the distribution current value of each first backup valve group and the target balanced current value as the objective function, and the sum of the distribution current values of each first backup valve group not exceeding the load current of the risk valve group as the constraint condition.

[0124] The load distribution proportion model is solved by using a linear programming algorithm to obtain the distribution current value of each first backup valve group.

[0125] In this embodiment, the load distribution between the first backup valve groups is realized by constructing a load distribution proportion model, wherein the objective function of the model is the minimization of the difference between the distribution current value of each first backup valve group and the target balanced current value, and the target balanced current value refers to the average value of the load currents of all working valve groups at present, and the constraint condition of the model is that the sum of the distribution current values of each first backup valve group does not exceed the load current of the risk valve group, therefore, the objective function L of the load distribution proportion model can be expressed as:

[0126]

[0127] In the formula, I represents the maximum value parameter function, I i represents the distribution current value of the i-th first backup valve group, M represents the total number of the first backup valve groups, and I t represents the target balanced current value.

[0128] The constraint condition is expressed as:

[0129]

[0130] In the formula, I load represents the load current of the risk valve group.

[0131] Then, the load distribution proportion model is solved by using a linear programming algorithm, and the distribution current value of each first backup valve group can be obtained, finally, the first backup valve groups are connected to the DC ice-melting device to replace the risk valve group, and valve group control is performed according to the respective distribution current values, so that the redundant switching of the DC ice-melting device is realized.

[0132] In order to ensure that the DC ice-melting device after redundant switching can work stably, in a preferred embodiment, the application further provides a method for secondary optimization determination of the DC ice-melting device, and the specific steps include:

[0133] According to the current fluctuation value and the thyristor junction temperature of the working valve group of the DC de-icing device, a stability index is calculated;

[0134] It is judged whether the stability index is less than a stability index threshold value, and if so, a working valve group with the largest current fluctuation value is selected from each working valve group as a to-be-optimized valve group;

[0135] The load current of the to-be-optimized valve group is reduced, a second standby valve group is selected according to the reduced load current and the priority of each standby valve group, and the second standby valve group is connected to the DC de-icing device.

[0136] In the embodiment, the stability index of the device is calculated according to the current fluctuation value and the thyristor junction temperature of the working valve group of the DC de-icing device, and the formula is:

[0137]

[0138] In the formula, △I represents the current fluctuation value, I n represents the rated total current, △T represents the maximum difference between the thyristor junction temperature and the ambient temperature, T max represents the maximum junction temperature allowed by the thyristor, λ1 represents the current weight, and λ2 represents the temperature weight.

[0139] The stability index formula actually includes two parameters of current fluctuation and temperature gradient. The current fluctuation value is the total current fluctuation value of the de-icing device, which can be calculated by the standard deviation of the current of all thyristors. The calculation formula is the same as that of the current balancing coefficient, and the difference is that the current fluctuation value is calculated for all thyristor currents in the DC de-icing device. The rated total current is the rated total current of the de-icing device. The maximum difference between the junction temperature of the thyristor and the ambient temperature is determined by the difference between the maximum junction temperature of all thyristors and the ambient temperature. The current weight and the temperature weight are preset values.

[0140] Since the current fluctuation can directly reflect the balance of the thyristor current distribution, unbalance will exacerbate local loss. The temperature gradient indicates that the junction temperature of the thyristor is too high, which may cause hardware damage or efficiency decline. Therefore, the working state of the DC de-icing device after redundancy switching is judged by the current fluctuation and the temperature gradient. If the calculated stability index is less than the preset stability index threshold value, it means that the working state of the DC de-icing device after redundancy switching cannot meet the stability requirement, and secondary optimization adjustment is still needed. In this case, the to-be-optimized valve group needs to be selected from the working valve group, and the second standby valve group needs to be selected from the remaining standby valve group to replace the to-be-optimized valve group.

[0141] In the embodiment, the valve group to be optimized can be selected according to the current balance state, preferably, the working valve group with the maximum current fluctuation value is selected for optimization, which can be understood as calculating the current balance coefficient of each working valve group, and selecting the working valve group with the maximum current balance coefficient as the valve group to be optimized. For the valve group to be optimized, since its failure risk is not high, when performing secondary optimization, the valve group does not need to be replaced, but its load current is reduced, and the reduced load current can be determined according to the real-time load current of the valve group to be optimized, and the reduced load current needs to be shared by the newly accessed second standby valve group. In the embodiment, the priority, selection quantity and load distribution ratio of the second standby valve group are the same as the priority setting method, selection quantity method and load distribution method of the first standby valve group in the above-mentioned embodiment, which will not be repeated here. Finally, the selected second standby valve group is accessed to the DC ice melting device, and the load of the second standby valve group is controlled according to the calculated load distribution ratio, so as to realize the secondary optimization control of the DC ice melting device.

[0142] The fault detection processing method of the DC ice melting device provided in the embodiment improves the accuracy of the thyristor failure risk prediction by combining real-time weather data and load data with the ice layer predictive model; the working state of the valve group can be accurately determined through the analysis of the thyristor junction temperature and the node-to-ground potential of the valve group, thereby ensuring the timeliness of the redundant switching of the DC ice melting device; the switching logic of the DC ice melting device is optimized through the redundant switching strategy based on the priority and the load distribution ratio, thereby improving the ice melting efficiency and the operation stability of the device, and ensuring the safety and stability of the power transmission line operation.

[0143] Please refer to Figure 2 , based on the same inventive concept, the second embodiment of the fault detection processing system of the DC ice melting device provided by the present application comprises:

[0144] The ice layer prediction module 10 is configured to collect the ice layer data, the valve group load data and the weather data of the power transmission line in real time, and input the data into a preset ice layer prediction model to obtain an ice layer thickness change rate, wherein the ice layer prediction model is built based on a support vector machine;

[0145] The fault detection module 20 is configured to calculate the thyristor failure probability of each working valve group of the DC ice melting device by using a logistic regression algorithm according to the ice layer thickness change rate, the valve group load data and the weather data, and select a risk valve group from each working valve group according to the thyristor failure probability;

[0146] The switching judgment module 30 is configured to determine whether to trigger a redundant switching strategy according to the thyristor junction temperature and the node-to-ground potential of the risk valve group, and switch the risk valve group;

[0147] The redundancy switching module 40 is configured to select a plurality of standby valve groups as first standby valve groups according to the priorities of the standby valve groups of the DC de-icing device in response to triggering the redundancy switching strategy, and calculate load distribution ratios of the first standby valve groups according to the load currents of the risk valve groups.

[0148] The risk valve groups are replaced by the first standby valve groups, and the first standby valve groups are controlled according to the load distribution ratios.

[0149] The technical features and technical effects of the fault detection processing system of the DC de-icing device proposed in the embodiments of the present application are the same as those of the method proposed in the embodiments of the present application, and will not be repeated here. Each module in the fault detection processing system of the DC de-icing device can be realized by software, hardware, or a combination thereof, in whole or in part. Each module can be embedded in or independent of the processor in the computer device in hardware form, or stored in the memory in the computer device in software form, so as to be called and executed by the processor to perform the operations corresponding to each module.

[0150] In addition, the embodiments of the present application also propose a DC de-icing device, which adopts the method for fault detection processing as described above.

[0151] In summary, the embodiment of the present application proposes a fault detection processing method and system of a direct current deicing device and the direct current deicing device, the method acquires ice layer data, valve group load data and weather data of a power transmission line in real time, inputs a preset ice layer prediction model to obtain an ice layer thickness change rate, and the ice layer prediction model is obtained based on a support vector machine; according to the ice layer thickness change rate, the valve group load data and the weather data, a logic regression algorithm is used to calculate a thyristor failure probability of each working valve group of the direct current deicing device, and a risk valve group is selected from each working valve group according to the thyristor failure probability; whether a redundant switching strategy is triggered is judged according to the node-to-ground potential and the thyristor junction temperature of the risk valve group, and the risk valve group is switched; in response to triggering the redundant switching strategy, according to the priority of each standby valve group of the direct current deicing device, a plurality of standby valve groups are selected as first standby valve groups, and the load distribution ratio of the first standby valve groups is calculated according to the load current of the risk valve group; the risk valve group is replaced by using the first standby valve groups, and the first standby valve groups are controlled according to the load distribution ratio. The present application improves the accuracy of the thyristor failure risk prediction by combining real-time weather data and load data with the ice layer predictive model; the working state of the valve group can be accurately determined by analyzing the node-to-ground potential and the thyristor junction temperature of the valve group, ensuring the timeliness of the redundant switching of the direct current deicing device; the switching logic of the direct current deicing device is optimized by the redundant switching strategy based on priority and load distribution ratio dynamic adjustment, improving the ice melting efficiency and operation stability of the direct current deicing device, thereby ensuring the safety and stability of the power transmission line operation.

[0152] Each embodiment in the specification is described in a progressive manner, and the same or similar parts of each embodiment can be referred to each other. Each embodiment focuses on the difference from other embodiments. In particular, the system embodiment is basically similar to the method embodiment, so the description is relatively simple, and the related parts can be referred to the part of the method embodiment. It should be noted that the technical features of the above embodiments can be combined in any way. In order to make the description simple, all possible combinations of the technical features in the above embodiments are not described, but as long as the combination of the technical features does not exist contradictory, it should be considered as the scope of the description.

[0153] The above-described embodiments only express several preferred embodiments of the present application, and the description is more specific and detailed, but it should not be understood as limiting the scope of the patent. It should be noted that for ordinary skilled in the art, without departing from the technical principles of the present application, some improvements and replacements can be made, which should also be considered as the protection scope of the present application. Therefore, the protection scope of the patent of the present application should be subject to the protection scope of the claims.

Claims

1. A fault detection and handling method for a DC de-icing device, characterized in that, include: Real-time data collection of ice layer data, valve group load data, and meteorological data of transmission lines is performed and input into a preset ice layer prediction model to obtain the ice layer thickness change rate. The ice layer prediction model is constructed based on a support vector machine, and the meteorological data includes ambient temperature. Based on the ice thickness change rate, the valve group load data, and the meteorological data, a logistic regression algorithm is used to calculate the thyristor failure probability of each working valve group of the DC ice melting device, and risk valve groups are selected from each working valve group based on the thyristor failure probability. Based on the thyristor junction temperature and node-to-ground potential of the risk valve group, determine whether to trigger the redundancy switching strategy and switch the risk valve group accordingly. In response to the triggering of the redundancy switching strategy, several backup valve groups are selected as the first backup valve group according to the priority of each backup valve group of the DC ice melting device, and the load allocation ratio of the first backup valve group is calculated according to the load current of the risk valve group. The risk valve group is replaced by the first backup valve group, and the load of the first backup valve group is controlled according to the load distribution ratio. The failure probability of the thyristor is calculated using the following formula: In the formula, P represents the thyristor failure probability, a, b, and c are all model coefficients, ΔL represents the rate of change of ice thickness, I represents the valve group load current, and T represents the ambient temperature.

2. The fault detection and handling method for the DC de-icing device according to claim 1, characterized in that, Before the step of determining whether to trigger a redundancy switching strategy based on the thyristor junction temperature and node-to-ground potential of the risk valve group, the method further includes: Calculate the current balance coefficient based on the standard deviation of the current values ​​of each thyristor in the risk valve group; Determine whether the current equalization coefficient is greater than the coefficient threshold. If so, calculate the difference between the real-time current value of each thyristor and the average thyristor current. Based on the difference, select the thyristor to be adjusted from each thyristor and adjust the conduction angle of the thyristor to be adjusted. The current equalization coefficient is expressed by the following formula: In the formula, N represents the total number of thyristors, and I j denoted by , where represents the real-time current value of the j-th thyristor, and μ represents the average thyristor current.

3. The fault detection and handling method for the DC de-icing device according to claim 1, characterized in that, The step of determining whether to trigger the redundancy switching strategy based on the thyristor junction temperature and node-to-ground potential of the risk valve group includes: Based on the junction temperature, real-time current value and conduction time of each thyristor in the risk valve group, calculate the local overheat index of each thyristor. Determine whether the local overheating index is greater than the index threshold. If it is greater than the index threshold, trigger the redundancy switching strategy. If it is not greater than the index threshold, the potential difference of the valve group is calculated based on the ground potential of each node of the risk valve group; the ground potential of each node of the risk valve group refers to the ground voltage of the key electrical connection points in the valve group, including the anode and cathode of the thyristor and the auxiliary circuit nodes in the valve group. Determine whether the potential difference of the valve group is greater than the potential difference threshold. If it is greater than the potential difference threshold, trigger the redundancy switching strategy.

4. The fault detection and handling method for the DC de-icing device according to claim 3, characterized in that, The local overheating index is expressed by the following formula: In the formula, Q j T represents the local overheat index of the j-th thyristor. j β represents the junction temperature of the j-th thyristor, β represents the thermal resistance coefficient, and t j I represents the cumulative on-time of the j-th thyristor. j This represents the real-time current value of the j-th thyristor; The potential difference of the valve group is expressed by the following formula: In the formula, V max V represents the maximum potential of a node relative to ground. min This represents the minimum potential of a node relative to ground.

5. The fault detection and handling method for the DC de-icing device according to claim 1, characterized in that, The step of selecting several backup valve groups as the first backup valve group based on the priority of each backup valve group of the DC ice melting device includes: Based on the load current of the risk valve group and the rated current of each standby valve group, calculate the load adaptability of each standby valve group, and determine the weighting coefficient based on the current de-icing progress of the transmission line. Based on the weighting coefficients, the load adaptability and the current ice melting progress are weighted and summed to obtain the priority of each standby valve group; The number of valve groups to be selected is determined based on the average load current of the risk valve group and the rated current of the standby valve group. Based on the priority and the number of valve groups selected, a first standby valve group is selected from each standby valve group; The priority is represented by the following formula: In the formula, ρ s Let α represent the priority of the s-th standby valve group, α represent the weighting coefficient, R represent the current ice melting progress, and I represent the current ice melting progress. load Indicates the load current of the risk valve assembly. This represents the rated current of the i-th standby valve group.

6. The fault detection and handling method for the DC de-icing device according to claim 3, characterized in that, The step of calculating the load allocation ratio of the first standby valve group based on the load current of the risk valve group includes: A load allocation ratio model is established with the objective function being to minimize the difference between the allocated current value of each first backup valve group and the target balanced current value, and with the constraint that the sum of the allocated current values ​​of each first backup valve group does not exceed the load current of the risk valve group. The load distribution ratio model is solved using a linear programming algorithm to obtain the distribution current value of each of the first standby valve groups.

7. The fault detection and handling method for the DC de-icing device according to claim 6, characterized in that, The objective function is expressed by the following formula: In the formula, I represents the maximum parameter function. i I represents the allocated current value of the i-th first standby valve group, M represents the total number of first standby valve groups, and I represents the allocated current value of the i-th first standby valve group. t Indicates the target equalization current value; The constraint conditions are expressed by the following formula: In the formula, I load This indicates the load current of the risk valve group.

8. The fault detection and handling method for the DC de-icing device according to claim 1, characterized in that, After the step of load control of the first standby valve group according to the load distribution ratio, the method further includes: Based on the current fluctuation value of the working valve group and the thyristor junction temperature of the DC ice melting device, the stability index is calculated. Determine whether the stability index is less than the stability index threshold. If so, select the working valve group with the largest current fluctuation value from all working valve groups as the valve group to be optimized. Reduce the load current of the valve group to be optimized, select the second backup valve group based on the reduced load current and the priority of each backup valve group, and connect the second backup valve group to the DC de-icing device. The stability index is represented by the following formula: In the formula, ΔI represents the current fluctuation value, I n The rated total current is represented by ΔT, which represents the maximum difference between the thyristor junction temperature and the ambient temperature. max λ1 represents the maximum allowable junction temperature of the thyristor, λ2 represents the current weight, and λ3 represents the temperature weight.

9. A fault detection and handling system for a DC ice-melting device, characterized in that, include: The ice layer prediction module is used to collect ice layer data, valve group load data and meteorological data of transmission lines in real time, and input them into a preset ice layer prediction model to obtain the ice layer thickness change rate. The ice layer prediction model is constructed based on support vector machine, and the meteorological data includes ambient temperature. The fault detection module is used to calculate the thyristor failure probability of each working valve group of the DC ice melting device based on the ice thickness change rate, the valve group load data and the meteorological data, using a logistic regression algorithm, and to select the risk valve group from each working valve group based on the thyristor failure probability. The failure probability of the thyristor is calculated using the following formula: In the formula, P represents the thyristor failure probability, a, b and c are all model coefficients, ΔL represents the rate of change of ice thickness, I represents the valve group load current, and T represents the ambient temperature. The switching judgment module is used to determine whether to trigger the redundancy switching strategy based on the thyristor junction temperature and node-to-ground potential of the risk valve group, and to switch the risk valve group accordingly. The redundancy switching module is used to respond to the triggering of the redundancy switching strategy, select several backup valve groups as the first backup valve group according to the priority of each backup valve group of the DC ice melting device, and calculate the load distribution ratio of the first backup valve group according to the load current of the risk valve group. The risk valve group is replaced by the first backup valve group, and the load of the first backup valve group is controlled according to the load distribution ratio.

10. A DC ice-melting device, characterized in that, The DC ice-melting device uses the method described in any one of claims 1 to 8 for fault detection and processing.

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