Ground resistance deterioration location estimation device and method

Abstract

To reduce a maintenance load of ground resistance maintenance by estimating a deterioration position of ground resistance.SOLUTION: A ground resistance deterioration position estimation device for estimating a ground resistance deterioration position in a target route comprises: a ground resistance deterioration-time rail ground voltage calculation unit which calculates a rail ground voltage candidate value based on a predicted position where there is a possibility of ground resistance deterioration for each of plural positions and stores the value in a manner of being able to output the value; a rail ground voltage acquisition unit which acquires rail ground voltage measurement values at the plural positions in a target route; and a ground resistance deterioration position collation unit which selects the predicted position where the approximate tendency is found as the ground resistance deterioration position on the basis of the result of comparing and collating the rail ground voltage measurement values with the rail ground voltage candidate value. The ground resistance deterioration position collation unit, when there is the tendency of approximating the rail ground voltage candidate value at each of the plural position, sets the ground resistance deterioration position with the approximation obtained by dividing the predicted positions across the plural positions according to the degree of approximation.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a ground resistance degradation location estimation device and method for estimating the location of degradation (decrease) of ground resistance in a return track formed by rails of an electric railway. [Background technology]

[0002] To prevent electrolytic corrosion caused by stray (leakage) current from the return tracks of electric railways, the international standard IEC62128 specifies the annual allowable amount of stray current.

[0003] Furthermore, a method is known for clarifying the actual state of stray current from the return line from the electric vehicle to the substation using a simulation model formed by an equivalent circuit and a calculation formula (for example, Patent Document 1).

[0004] Also known is a method of monitoring rail-to-ground voltages measured at multiple positions and determining that stray current is abnormal if the rail-to-ground voltages deviate from a reference range (for example, Patent Document 2). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 7-128374 [Patent Document 2] EP1391741A1 publication Summary of the Invention [Problem to be solved by the invention]

[0006] When deterioration of the ground resistance is detected, maintenance such as part replacement and cleaning must be carried out. However, because the inspection range is wide, frequent inspections impose a heavy maintenance burden.

[0007] The technology in Patent Document 1 can clarify the rail-to-ground voltage and rail leakage current of a DC electric railway through simulation, but this technology cannot estimate the location of deterioration of the ground resistance in the return track formed by the rails extending along the target line as a proactive measure to prevent electrolytic corrosion.

[0008] Furthermore, by using the technology of Patent Document 2, it is possible to detect the occurrence of abnormal stray currents and carry out inspections at the time of detection. Therefore, this technology makes it possible to reduce the frequency of inspections, contributing to a reduction in the maintenance burden. However, the technology of Patent Document 2 cannot estimate the location of deterioration in the ground resistance, which is the cause of stray currents.

[0009] Therefore, in order to find the location where the deterioration of the ground resistance has occurred, it is necessary to inspect a wide area, which requires manpower and time for maintenance. The present invention has been made in consideration of the above-mentioned problems, and its purpose is to provide a ground resistance deterioration location estimation device that can reduce the maintenance burden for maintaining the ground resistance by estimating the location of deterioration of the ground resistance. [Means for solving the problem]

[0010] The present invention, which solves the above-mentioned problems, is a ground resistance degradation location estimation device that estimates the location of ground resistance degradation within a target railway line, and includes: a rail-to-ground voltage calculation unit in the event of ground resistance degradation that calculates rail-to-ground voltage candidate values ​​for each of a plurality of locations based on predicted locations where ground resistance degradation is possible and stores the values ​​so that they can be output; a rail-to-ground voltage acquisition unit that acquires actual rail-to-ground voltage values ​​at a plurality of locations within the target railway line; and a ground resistance degradation location comparison unit that, based on the results of comparing and collating the actual rail-to-ground voltage values ​​and the rail-to-ground voltage candidate values, selects predicted locations where a similar trend is found and sets them as locations of ground resistance degradation. [Effects of the Invention]

[0011] According to the present invention, it is possible to provide a ground resistance deterioration location estimation device that reduces the maintenance burden for maintaining ground resistance by estimating the location of deterioration of ground resistance. [Brief explanation of the drawings]

[0012] [Figure 1] 1 shows an example of the configuration of a ground resistance deterioration location estimation device (hereinafter also referred to as "the device") according to a first embodiment of the present invention. [Figure 2] 2 is a flowchart showing an operation procedure in a rail-to-ground voltage calculation unit in FIG. 1; [Figure 3] 2 is an example of a simulation pattern in the device of FIG. 1. [Figure 4] This is an example of a return resistance model that assumes a single layer of ground resistance and is used to calculate rail-to-ground voltage in the device shown in Figure 1. [Figure 5] This is an example of a return resistance model that assumes two layers of ground resistance and is used to calculate rail-to-ground voltage in the device shown in Figure 1. [Figure 6] 2 is an example of an equivalent circuit diagram for explaining a method for calculating rail-to-ground voltage in the device of FIG. 1. [Figure 7] 2 is a flowchart showing an operation procedure of the ground resistance deterioration position comparison unit of FIG. 1; [Figure 8] 8 is a graph for explaining the process of comparing rail voltages to ground in step S702 of FIG. 7. [Figure 9] 10 shows an example of the configuration of a ground resistance deterioration location estimation device (also referred to as "the device") according to a second embodiment of the present invention. [Figure 10] 10 is an example of processing in a rail-to-ground voltage calculation unit in FIG. 9. [Figure 11] 11 is a histogram for explaining the process of step S1002 in FIG. 10. DETAILED DESCRIPTION OF THE INVENTION

[0013] Hereinafter, the device according to Example 1 will be described using Figures 1 to 8, and the device according to Example 2 will be described using Figures 9 to 11. Most of the units and processes shown here are realized by a computer constituting the device executing a program stored in its memory. Units formed by software are not necessarily visibly distinguishable components like hardware, and their shapes, affiliations, and installation locations can be modified in any way. Furthermore, the names of the units and processes are merely examples, and other synonyms are also included in the present invention. [Example]

[0014] [composition] The configuration of this device will be described using Figure 1. The device illustrated in Figure 1 is composed of a rail-to-ground voltage acquisition unit 101, a position current acquisition unit 102, a rail-to-ground voltage calculation unit when ground resistance has deteriorated (also simply referred to as the "rail-to-ground voltage calculation unit") 103, a ground resistance deterioration position comparison unit 104, a ground resistance deterioration position notification unit 105, and a date and time designation unit 106.

[0015] The rail-to-ground voltage acquisition unit 101 measures the voltages of the rail and the ground electrode at multiple positions on the track and records them in a form that can be searched for by a specified date and time. Then, when the specified date and time 190 is received, the rail-to-ground voltage at the specified date and time is output to the ground resistance deterioration position comparison unit 104 as the rail-to-ground voltage measurement result 111.

[0016] The position current acquisition unit 102 acquires the running positions and currents of all electric vehicles running on the target line, the positions of substations on the target line and the currents thereat, and records them in a form that can be searched for by a specified date and time. Then, when a specified date and time 190 is received, the unit outputs the current and position information at the specified date and time to the rail-to-ground voltage calculation unit 103 as position current information 112.

[0017] The rail-to-ground voltage calculation unit 103 inputs the specified date and time 190 and the position current information 112, calculates the rail-to-ground voltage at the specified date and time, and outputs the rail-to-ground voltage calculation result 113 at the time of ground resistance degradation to the ground resistance degradation position comparison unit 104. The rail-to-ground voltage calculation unit 103 will be described in detail later.

[0018] The ground resistance degradation position comparison unit 104 inputs the specified date and time 190, the rail-to-ground voltage measurement result 111, and the rail-to-ground voltage calculation result 113 when the ground resistance is deteriorated, compares the position where the ground resistance is deteriorated, and outputs the ground resistance degradation position estimation result 114 to the ground resistance degradation position notification unit 105. The details of the ground resistance degradation position comparison unit 104 will be described later.

[0019] The ground resistance degradation location notification unit 105 inputs the ground resistance degradation location matching result 114 and notifies the system user of the location of the ground resistance degradation. The notification method may be at least one of a panel display, a screen display, a voice message, a printout on paper or the like, or a similar display. In this way, the notification method may be of any type as long as it allows the system user to grasp the estimated location of the ground resistance degradation.

[0020] The date and time designation unit 106 is triggered by the operator's date and time designation operation and outputs the date and time designated by the operator's operation as the designated date and time 190.

[0021] [Rail-to-ground voltage calculation section] Fig. 2 is a flowchart showing the operation procedure of the rail-to-ground voltage calculation unit 103. As shown in Fig. 2, the rail-to-ground voltage calculation unit 103 executes the processing of steps S201 to S205. As mentioned above, the execution entities shown in Fig. 1 are formed by software and therefore cannot be visually distinguished, but for the sake of convenience, roles are divided among them. Furthermore, in explanations without a particular subject, the execution entity is this device.

[0022] In step S201, a return resistance model is created, and the process proceeds to step S202. Details of the return resistance model created in step S201 will be described later with reference to FIGS.

[0023] In step S202, the position current acquisition unit 102 acquires the positions of the train and the substation and the currents therein at the specified date and time, and the process proceeds to step S203.

[0024] Step S203 is a loop process, in which the process of step S204 is repeated the number of times equal to the number of simulation patterns, and when the repetition is completed, the process proceeds to step S205. The simulation patterns will be described later.

[0025] In step S204, the rail-to-ground voltage calculation unit 103 connects the low resistance 611 to the return resistance and calculates the rail-to-ground voltage. The method for calculating the rail-to-ground voltage in step S204 will be described later.

[0026] In step S205, all rail-to-ground voltages calculated by repeating step S204 are output as rail-to-ground voltage calculation results 113 when the ground resistance has deteriorated, and the process ends.

[0027] [Simulation pattern] The device stores rail-to-ground voltage values ​​when the ground resistance is deteriorated at multiple locations on the target track, and outputs the values ​​as deterioration samples based on at least one of information on values ​​calculated by simulation calculations and acquired past values. Meanwhile, the device acquires actual measured rail-to-ground voltage values ​​at observation points corresponding to the multiple locations.

[0028] The device also compares the stored degradation samples with the measured rail-to-ground voltage values ​​for the patterns, i.e., waveform trends, associated with each of the multiple locations. If the comparison results in a match, the device determines that the degradation location set for the degradation sample is the location of the earth resistance degradation. Such simulation patterns are explained using Figure 3.

[0029] As shown in Figure 3, a simulation pattern is composed of a low resistance pattern number, an installation wire where the low resistance 611 is installed, the position where the low resistance 611 is installed, and the resistance value of the low resistance 611. Multiple low resistance installation positions may be set in one simulation pattern. In that case, although not shown in Figure 3, two or more ground wires, low resistance installation positions, and resistance values ​​are set with the same low resistance pattern number.

[0030] Simulation patterns are set manually through an interface, etc. The longer the route, the greater the variation in low-resistance installation positions. Therefore, if all ground contact positions are set comprehensively, it takes a long time to calculate all patterns.

[0031] Therefore, it is desirable to estimate the locations where ground resistance degradation is likely to occur and narrow down the target locations to set. For example, locations where ground resistance degradation is likely to occur can be considered as locations where it has been confirmed that ground resistance degradation has actually occurred in the past.

[0032] On electric railway rails, near stations where electric trains depart and stop frequently, iron powder and other particles are scattered when the electric trains slow down using the air brakes, which can easily cause deterioration of the ground resistance.

[0033] Another reason is that powering and regeneration are performed near stations, creating conditions where rail-to-ground voltages tend to be relatively high in both the positive and negative directions. Insulating materials such as rail pads installed in these locations are thought to be prone to insulation deterioration.

[0034] In addition, tunnel sections with high humidity are considered to be environmental conditions where moisture adheres to the dust and dirt that has accumulated between the rail and the roadbed, making them more conductive, so it is possible to estimate locations where earth resistance degradation is likely to occur.In this way, it is desirable to set up a simulation pattern in which low resistance 611 that simulates that degradation is installed in locations where earth resistance is relatively likely to deteriorate.

[0035] [Return resistance model created in step S201] Figure 4 shows an example of a return resistance model in which the earth resistance is assumed to be one layer, used to calculate the rail-to-ground voltage in the device of Figure 1. As shown in Figure 4, when there is an up line 401, a down line 402, and a crossover line 403 connecting the up and down lines, the return resistance is made up of rail resistance 410a, rail resistance 410b, rail resistance 410c, earth resistance 420a, and earth resistance 420b.

[0036] The parameter of the rail resistance 410 is defined in Ω / km, and the parameter of the ground resistance 420 is defined in S / km, and the resistance value is determined according to the length of the track. The intervals between the ground resistances 420 can be set arbitrarily, and are generally set every few hundred meters.

[0037] 4, the crossover 403 is simulated by rail resistance, but this is not limiting. Since the crossover 403 is short and may not affect the calculation accuracy, it may be simulated by connecting the crossover positions of the up and down lines at the same node, rather than simulating it by rail resistance.

[0038] 4, the electrical connection between the up and down lines is only via the crossover wire 403, but this is not limiting. Even when a cable such as a rail tie is used for connection instead of the crossover wire 403, it is desirable to connect and simulate the rail resistance nodes of the up and down lines in the same way as with a connection using a crossover wire.

[0039] Also, while Figure 4 illustrates an example in which the earth resistance is one layer, this is not limiting. As shown in Figure 5, rail direction resistance 501 and depth direction resistance 502 may be added to configure the return resistance with a grid-like resistor in multiple layers. Figure 5 shows an example of a return resistance model in which the earth resistance is assumed to be two layers, used to calculate the rail-to-ground voltage in the device shown in Figure 1. In this way, the calculation accuracy of the return resistance model can be further improved.

[0040] It is desirable to set an appropriate resistance value for each position of the ground resistor 420. For example, the ground resistance differs between an above-ground section where rails are laid on gravel laid on normal ground, an elevated section where rails are laid on a concrete viaduct, and a tunnel section where rails are laid in an underground tunnel, so it is desirable to set the resistance value of the ground resistor taking this into consideration.

[0041] Furthermore, even in ground sections or elevated sections, the overall ground resistance decreases due to moisture during rainy weather, so it is desirable to change and set the ground resistance according to the weather.

[0042] [Calculation method of rail-to-ground voltage in step S204] Figure 6 is an example of an equivalent circuit diagram for explaining a method for calculating rail-to-ground voltage in the device of Figure 1. First, in the return resistance model created in step S201, a low resistance 611 is added to the position associated with the simulation pattern number currently being referenced.

[0043] Next, the train currents (a) and (b) and the substation current are input to the nodes corresponding to the train position and the substation position included in the position current information 112, and the voltage at each node is calculated. The potential at the nodes at both ends of each rail resistance is output as the rail-to-ground voltage.

[0044] [Ground resistance deterioration location verification section] Fig. 7 is a flowchart showing the operation procedure of the ground resistance degradation position comparison unit 104 in Fig. 1. In Fig. 7, step S701 is a loop process, in which the process of step S702 is repeated the number of times equal to the number of patterns of the rail-to-ground voltage calculation result 113 when the ground resistance is deteriorated, and when the repetition is completed, the process proceeds to step S703.

[0045] In step S702, the rail-to-ground voltage measurement result 111 is compared with the rail-to-ground voltage calculation result 113 of the rail-to-ground voltage when the ground resistance has deteriorated, and the rail-to-ground voltage when the ground resistance has deteriorated, which has the closest rail-to-ground voltage value at each position, is updated as a ground resistance deterioration pattern candidate. The processing of step S702 will be described in detail later.

[0046] In step S703, the ground resistance deterioration position of the ground resistance deterioration pattern candidate at the stage when the loop processing S701 is completed is output as the ground resistance deterioration position matching result 114.

[0047] [Processing of step S702] Fig. 8 is a graph for explaining the rail-to-ground voltage comparison process in step S702 of Fig. 7. In Fig. 8, the vertical axis represents rail-to-ground voltage 801, and the horizontal axis represents position, and the graph shows actual rail-to-ground voltage measurement results 111 and calculation results 113 of rail-to-ground voltage when ground resistance has deteriorated, divided into cases A and B.

[0048] The rail-to-ground voltage calculation result A when the ground resistance is deteriorated (also simply referred to as "calculation result A") and the rail-to-ground voltage calculation result B when the ground resistance is deteriorated (also simply referred to as "calculation result B") are distinguished as follows: Calculation results A and B are rail-to-ground voltage calculation results when the ground resistance is deteriorated at different locations, i.e., when the low-resistance installation locations are different, and are included in the rail-to-ground voltage calculation result 113.

[0049] The positions where plots are generated in the graph are the positions where the actual rail-to-ground voltage was measured. The simplest comparison method is to compare the actual measured and calculated voltages at the same positions, and select the one with the smallest total difference between the two as the candidate for the earth resistance deterioration pattern.

[0050] In rail-to-ground voltage 801 in Figure 8, the actual measurement results shown by the solid line are plotted closer to the actual measurement values ​​than the calculation result B shown by the dashed line, and therefore the calculation result A shown by the dashed line is selected as a candidate for the ground resistance deterioration pattern.

[0051] In the example shown in Figure 8, the best results were obtained by selecting the ground resistance deterioration pattern candidate with the smallest difference between the actual measurement result and the calculation result A or B. However, if no limit is placed on the difference between the actual measurement result and the calculation result, there is a possibility of misjudgment as follows.

[0052] For example, in Figure 8, depending on how the simulation parameters are set, even if the difference between the calculated results A and B and the actual measurement results is large overall, if it is relatively small, it may be erroneously determined that the ground resistance has deteriorated, even if it is at a location other than the actual one.

[0053] Therefore, a threshold is set for the sum of the differences between the two, and if the sum is not below the threshold, a review of the simulation parameters is required to identify the location of the ground resistance degradation. In such cases, adding a function to the device that notifies the user that a review is necessary makes it possible to more appropriately narrow down the location of the ground resistance degradation. As a result, the device can efficiently estimate the location of the ground resistance degradation.

[0054] The device according to the first embodiment calculates the rail-to-ground voltage calculation result 113 when the ground resistance is deteriorated under all conditions set as a simulation pattern. After this calculation, the device also executes a process of comparing the rail-to-ground voltage actual measurement result 111 with the result 113 to check the location of the deteriorated ground resistance.

[0055] In this first embodiment, the calculation of the rail-to-ground voltage calculation result may be simplified to only one condition in the simulation pattern, and a method may be applied in which the process of comparing the calculation result when the ground resistance is deteriorated under such a limited one condition with the rail-to-ground voltage measurement result 111 is repeated the number of times equal to the number of all conditions set in the simulation pattern.

[0056] In this case, it is advisable to perform calculations and comparisons under conditions where the low-resistance installation location is shifted by several kilometers, and then perform calculations and comparisons under conditions where the location is shifted by several hundred meters around the nearest low-resistance installation location.By configuring this device with a processing function that searches for detailed low-resistance installation locations, it is possible to estimate the location of degraded ground resistance while achieving both comprehensiveness and short calculation times.

[0057] The device of the first embodiment compares and collates actual rail-to-ground voltage measurements acquired at multiple positions on the target track with rail-to-ground voltage values ​​(degraded samples) acquired in the past or calculated by simulation when the grounding resistance is degraded. Specifically, the device compares and collates trends (patterns) of waveforms plotted on a graph in which the horizontal axis indicates position and the vertical axis indicates rail-to-ground voltage 801, as shown in Fig. 8.

[0058] This device estimates the location of the ground resistance degradation as the location indicated by the degradation sample with a matching waveform trend (pattern).With this device, it is sufficient to take measures against degradation only in the narrow range limited to the vicinity of the estimated location of the ground resistance degradation, thereby reducing the maintenance burden for maintaining the ground resistance. [Example]

[0059] [composition] The configuration of the present device according to the second embodiment will be described with reference to Fig. 9. The present device according to the second embodiment shown in Fig. 9 includes a rail-to-ground voltage acquisition unit 901, a position current acquisition unit 902, a rail-to-ground voltage calculation unit during ground resistance degradation (also referred to as "rail-to-ground voltage calculation unit" for short) 903, a ground resistance degradation position comparison unit 904, a ground resistance degradation position notification unit 105, and a ground resistance degradation position estimation start determination unit 990.

[0060] The rail-to-ground voltage acquisition unit 901 measures the voltages of the rail and the ground electrode at multiple positions within the track, and outputs the time-series data of the rail-to-ground voltage as rail-to-ground voltage measurement results 911 to the rail-to-ground voltage memory unit 903, the ground resistance degradation location estimation start determination unit 990, and the ground resistance degradation location comparison unit 904.

[0061] The position current acquisition unit 902 acquires the running positions and currents of all electric vehicles running on the target line, and the positions and currents of substations on the target line, and outputs the time series data of current and position as position current information 912 to the rail-to-ground voltage memory unit 903 and the ground resistance deterioration position estimation start determination unit 990.

[0062] The rail-to-ground voltage storage unit 903 records the rail-to-ground voltage, the positions of the train and the substation, and the time-series changes in the current based on the rail-to-ground voltage measurement result 911 and the position current information 912 .

[0063] If earth resistance degradation is confirmed through inspection, etc., the location of the earth resistance degradation is linked to the rail-to-ground voltage and position current information for a certain period of time, and this is stored as the rail-to-ground voltage at the time of earth resistance degradation, and output as the rail-to-ground voltage measurement result 913 at the time of earth resistance degradation.

[0064] In addition, rail voltage to ground and position current information when no deterioration of the ground resistance is confirmed by inspection or the like is stored as reference rail voltage to ground related information and output as reference rail voltage to ground related information 923.

[0065] The ground resistance degradation position comparison unit 904 inputs the rail to ground voltage measurement result 911, the rail to ground voltage measurement result 913 when the ground resistance is degraded, and the ground resistance degradation position estimation start flag 991, and executes the following process.

[0066] The ground resistance degradation position matching unit 904 matches the position where the ground resistance is degraded, and outputs the ground resistance degradation position matching result 114 to the ground resistance degradation position notification unit 105. Details of this process will be described later.

[0067] The ground resistance degradation location estimation start determination unit 990 inputs the rail voltage to ground measurement result 911, the position current information 912, and the reference rail voltage to ground related information 923, and executes the following process.

[0068] The ground resistance degradation location estimation start determination unit 990 searches for the reference rail-to-ground voltage when the positions and currents of the train and substation included in the reference rail-to-ground voltage related information 923 match within a predetermined range, and compares it with the value of the rail-to-ground voltage actual measurement result 911.

[0069] Furthermore, if a predetermined deviation occurs in the rail-to-ground voltage at each position, the ground resistance degradation location estimation start determination unit 990 determines that there is a possibility that ground resistance degradation has occurred somewhere, and outputs a ground resistance degradation location estimation start flag 991.

[0070] In the second embodiment, an example was described in which the deterioration of the grounding resistance was determined based on the deviation of the rail-to-ground voltage at each position. However, in reality, deviations may occur due to non-essential causes such as environmental conditions.

[0071] In contrast, as a method for eliminating transient or sudden and trivial phenomena, it is preferable for the present device to use a method in which statistics such as the standard deviation and average value of the rail-to-ground voltage for a specified period at each position are calculated, and a judgment is made if the statistics are found to be deviated.

[0072] This allows the device to make appropriate judgments even when the positions and currents of the train and substation do not completely match those recorded when the rail-to-ground voltage was recorded during the time of ground resistance degradation. Note that the configuration of the ground resistance degradation position notification unit 105 is the same as that of the first embodiment, and therefore a detailed description thereof will be omitted.

[0073] [Ground resistance deterioration location verification section] The processing of the ground resistance degradation determination unit 904 in Fig. 10 will be described with reference to Fig. 10. Fig. 10 illustrates an example of processing of the rail-to-ground voltage calculation unit 903 according to the second embodiment.

[0074] Steps S701 and S703 are the same as the ground resistance deterioration position checking unit 104 in the first embodiment, that is, steps S701 and S703 in FIG. 7, and therefore redundant explanations will be omitted.

[0075] In step S1002, the actual measured rail-to-ground voltage value is compared with the rail-to-ground voltage statistics, and if the closest value is found, the ground resistance deterioration pattern candidate is updated. The processing of step S1002 will be described in detail with reference to Fig. 11. Fig. 11 is a histogram for explaining the processing of step S1002 in Fig. 10.

[0076] In step S1002, the average rail-to-ground voltage and standard deviation for a predetermined period at each position are calculated based on the time-series data of rail-to-ground voltage measurement result 911 and rail-to-ground voltage measurement result when ground resistance has deteriorated 913. Then, the rail-to-ground voltage measurement result when ground resistance has deteriorated that has the closest average value and standard deviation at each position is determined as a ground resistance deterioration pattern candidate.

[0077] Actual measurement result A of rail voltage to ground when earth resistance has deteriorated (hereinafter also referred to as "actual measurement result A") and actual measurement result B of rail voltage to ground when earth resistance has deteriorated (hereinafter also referred to as "actual measurement result B") refer to the following results. Actual measurement results A and B are actual measurement results of rail voltage to ground when the ground resistance has deteriorated in different locations, i.e., when the low resistance installation locations are different, and are included in actual measurement result 913 of rail voltage to ground when earth resistance has deteriorated.

[0078] As shown in Fig. 11, in this device, actual measurement result B has closer average values ​​and standard deviations than actual measurement result A, and therefore actual measurement result B, which has a stronger tendency to be similar, becomes a candidate for the ground resistance deterioration pattern. Based on the above principle, the device according to Example 2 in Figs. 9 to 11 can estimate the position of the rail-to-ground voltage using only actual measurement values, without having to perform simulation calculation processing as in Example 1.

[0079] In Figure 11, electrical circuit calculations can explain that the smaller the fluctuation in rail-to-ground voltage, the more likely it is that the location is one where the ground resistance has deteriorated. This is because if the ground resistance is 0 Ω, the rail-to-ground voltage will also be 0 V regardless of the direction or magnitude of the stray current.

[0080] [supplement] In Example 1, the rail-to-ground voltage when the ground resistance is deteriorated is calculated by simulation. On the other hand, in Example 2, the actual measured value of the rail-to-ground voltage is compared with the statistical amount of the rail-to-ground voltage when the ground resistance is deteriorated to calculate the candidate ground resistance deterioration pattern. This device can also be realized with a configuration and method that combines the characteristic techniques of Examples 1 and 2.

[0081] In addition, in Example 1, actual measured rail-to-ground voltage values ​​and rail-to-ground voltage values ​​at each position when ground resistance has deteriorated, as well as the magnitude relationship between these values, were compared to calculate potential ground resistance deterioration patterns. Meanwhile, in Example 2, rail-to-ground voltages when ground resistance has deteriorated were output based on records of rail-to-ground voltages. This device can also be realized with a configuration and method that combines the characteristic techniques of Examples 1 and 2.

[0082] In this case, by adding to the conditions for calculating candidate ground resistance deterioration patterns that the position currents of the electric vehicle and the substation match within a specified range, it is possible to estimate the location of ground resistance deterioration with greater accuracy.

[0083] In addition, the present invention is not limited to the above-described examples, and includes various modifications within the scope of the gist of the present invention. For example, the present invention is not limited to those having all of the configurations described in the above-described examples, and includes those in which some of the configurations are omitted. Furthermore, some of the configurations according to one embodiment can be added to or replaced with configurations according to another embodiment.

[0084] [Stray current] In electric railways, the substation (power source) and the vehicle (load) are connected with the overhead wire (positive pole) and the rail (negative pole), respectively, to form an electrical circuit that supplies the power needed for the vehicle to run. When the vehicle is running, current flows from the substation to the vehicle through the overhead wire (positive pole), and current flows from the vehicle to the substation through the rail (negative pole) (return current). At this time, part of the return current leaks from the rail into the ground, passing through the ground as stray current and returning to the substation.

[0085] It is known that when stray current flows into underground pipes or reinforcing bars in structures around railway facilities, it promotes embrittlement through electrolytic corrosion. In response to this, the international standard IEC62128 specifies the annual allowable amount of stray current.

[0086] This device can be summarized as follows. [1] As shown in Figures 1 and 9, this device is a ground resistance degradation location estimation device that estimates the location of ground resistance degradation within a target track in an electric railway. This device has a rail-to-ground voltage calculation unit 103, 903 when ground resistance is degraded, a rail-to-ground voltage acquisition unit 101, 901, and a ground resistance degradation location comparison unit 104.

[0087] In electric railways, when deterioration of ground resistance is detected, maintenance such as part replacement and cleaning must be carried out. However, because the inspection range is wide, conducting inspections too frequently increases the maintenance burden. Based on the operating status of the electric railway, it is possible to narrow down the wide inspection range to a few predicted locations.

[0088] The rail-to-ground voltage candidate values ​​based on the plurality of predicted positions narrowed down and stored in this way are output by the rail-to-ground voltage calculation units 103, 903. In other words, the rail-to-ground voltage calculation units 103, 903 calculate rail-to-ground voltage candidate values, which serve as comparison standards or degradation samples, for each of the plurality of positions based on the predicted positions where there is a possibility of grounding resistance degradation, and store them in an outputtable manner.

[0089] The rail-to-ground voltage candidate value based on the predicted position means the rail-to-ground voltage at each node point obtained from an equivalent circuit that simulates the electric railway return line and a calculation formula. Meanwhile, the rail-to-ground voltage acquisition unit 101, 901 acquires actual rail-to-ground voltage values ​​at multiple positions, including at least the predicted position.

[0090] The ground resistance degradation location comparison unit 104, 904 compares the actual rail-to-ground voltage value with the rail-to-ground voltage candidate value, and selects a predicted location where a similar trend (pattern) is found, as the ground resistance degradation location. Depending on the approximation of the trend, it is possible to estimate the degree of degradation.

[0091] In this way, the locations of ground resistance deterioration estimated by this device are sorted from the predicted locations in order of the probability of accuracy. Therefore, maintenance workers can prioritize locations estimated to be severely deteriorated and then carry out maintenance. This device can reduce the maintenance burden of maintaining ground resistance during electric railway track maintenance work.

[0092] [2] As shown in Figures 1 and 8, the location of the ground resistance deterioration is estimated to be closer to the predicted location indicated by calculation result A by the amount that calculation result A is closer than calculation result B. In other words, in the above [1], if there is a tendency for each of the multiple locations to be similar to the rail-to-ground voltage candidate value, the ground resistance deterioration location comparison unit 104, 904 determines the location of the ground resistance deterioration to be close by dividing the predicted locations of the multiple locations proportionally according to the degree of similarity of the tendency. This allows the device to more accurately estimate the location of the ground resistance deterioration.

[0093] [3] As shown in Figures 1 and 9, the above [2] further includes a position current acquisition unit 102, 902 that acquires the positions of electric vehicles and power supply equipment on the target line, as well as their currents, at the same time as the acquisition of the actual rail-to-ground voltage measurement value.

[0094] The position current acquisition unit 102, 902 acquires the running positions and currents of all electric vehicles running on the target line, and the positions and currents of substations on the target line, and records them in a form that can be searched for by a specified date and time. Then, when the specified date and time 190 is received, the position current acquisition unit 102, 902 outputs the current and position information at the specified date and time to the rail-to-ground voltage calculation unit 103 as position current information 112.

[0095] For electric railways, several locations of ground resistance degradation are generally predicted based on the train schedule. Therefore, this device can estimate the locations of ground resistance degradation more precisely based on records that can be searched for by specified date and time related to the schedule.

[0096] [4] As shown in Figures 1, 6 and 9, in the above [2], the rail voltage to ground calculation unit 103, 903 when ground resistance is degraded has the function of operating as follows: First, as shown in Figures 4 to 6, a ground resistance degradation return resistance model is created by connecting a low resistance 611 that simulates ground resistance degradation to a return resistance model simulated by rail resistance 410 and ground resistance 420.

[0097] Next, the positions of the electric vehicle and substation at the time of the actual rail-to-ground voltage measurement, as well as their currents, are input into the earth resistance degradation return resistance model to calculate the voltage to ground across the rail resistance. This voltage to ground is then output as a candidate value for the rail-to-ground voltage when earth resistance is degraded. This allows the device to more accurately estimate the location of ground resistance degradation, taking into account the actual equipment layout and its positional relationship with the electric vehicle.

[0098] [5] As shown in Figures 1, 6, and 9, in [1] or [4] above, the rail-to-ground voltage calculation unit 103, 903 in the event of ground resistance degradation stores the location of ground resistance degradation when ground resistance degradation occurred on the target track in the past, in association with the actual measured rail-to-ground voltage values ​​at multiple locations at that time. The device outputs the stored information as candidate rail-to-ground voltage values ​​in the event of ground resistance degradation. This allows the device to more accurately estimate the location of ground resistance degradation by utilizing past experience.

[0099] [6] As shown in Figures 1 and 9, in [2] above, the ground resistance degradation location comparison unit 104, 904 has the following functions. First, it compares the actual rail-to-ground voltage value at each location with the candidate rail-to-ground voltage value when ground resistance is degraded. Next, it searches for the rail-to-ground voltage value when ground resistance is degraded that is closest to the rail-to-ground voltage value at each location.

[0100] The location of the ground resistance degradation when the rail-to-ground voltage during ground resistance degradation is recorded or generated is determined to be the location of the ground resistance degradation.In this way, this device makes use of past empirical rules to actively search for the rail-to-ground voltage during ground resistance degradation that has the closest rail-to-ground voltage value at each location, and finds the correct answer, allowing for more accurate estimation of the location of ground resistance degradation.

[0101] [7] As shown in Figures 1 and 9, in the above [5], the rail-to-ground voltage calculation unit 103, 903 when ground resistance is degraded selects and outputs the rail-to-ground voltage when ground resistance is degraded that is recorded in a state where ground resistance is degraded, under the condition that the positions of the electric vehicle and power supply equipment when the actual measured value of the rail-to-ground voltage is acquired and their currents match within a specified range.

[0102] The current is acquired by the position current acquisition unit 102, 902 and is given to the rail-to-ground voltage calculation unit 103, 903 when the ground resistance is deteriorated. This allows the device to estimate the location of the deteriorated ground resistance more precisely, taking into account the actual equipment layout and the positional relationship with the electric car, and making use of not only the current value acquired by the position current acquisition unit 102, 902 but also past empirical rules.

[0103] [8] As shown in Figures 1 and 9, in the above [1], the ground resistance degradation position matching unit 104, 904 has the following functions: First, it calculates the statistics of the rail-to-ground voltage value at each position for a predetermined period and the statistics of the rail-to-ground voltage value at the time of ground resistance degradation for a predetermined period.

[0104] Next, the rail-to-ground voltage when the ground resistance is degraded is searched for, and the rail-to-ground voltage when the ground resistance is degraded, which has the closest statistical value at each location, is estimated as the location of the degraded ground resistance when that rail-to-ground voltage when the ground resistance is degraded is recorded or generated. This device is simple to calculate and can easily obtain highly reliable results. For example, the location of the degraded ground resistance can be estimated with practical accuracy by calculation processing using a simple computer such as a one-chip microcomputer.

[0105] [9] In the above [8], it is preferable that the statistical quantity is at least one of the mean value and the standard deviation. The actual measured value of the rail-to-ground voltage used by this device may be subject to deviations due to non-essential causes. In response to this, it is preferable that this device calculates statistical quantities such as the standard deviation and mean value of the rail-to-ground voltage at each position over a predetermined period of time as a method of eliminating transient or sudden, trivial phenomena.

[0106]

[10] As shown in Figures 1, 8, 9, and 11, in the device described in [4] above, the rail-to-ground voltage calculation unit 103, 903 first outputs the reference rail-to-ground voltage when no ground resistance degradation occurs. The device then compares the reference rail-to-ground voltage with the measured rail-to-ground voltage. Based on the comparison results, the device may further have a function to trigger the estimation of the location of ground resistance degradation when the rail-to-ground voltage value or statistical quantity at each location deviates by more than a predetermined value.

[0107] This device can determine the degree of deviation in the statistics using a threshold and output an appropriate judgment result. For example, in Figure 11, the smaller the fluctuation in the rail-to-ground voltage, the more likely it is that the location is one where the ground resistance has deteriorated. This allows the device to make an appropriate judgment even if the positions and currents of the train and substation do not completely match those recorded when the rail-to-ground voltage was recorded during the time of ground resistance deterioration.

[0108] In other words, if the device obtains a reasonably close match, it simply outputs that as the estimated location. As a result, the device can avoid the waste of continuing the search process until it finds one that perfectly matches the actual measurement value from among many deterioration samples. Therefore, the device can eliminate the burden of repeating unnecessary calculations on a simple computer with a program that is launched as needed, and still estimate the location of ground resistance deterioration with practical accuracy.

[0109] The main components of this system can be configured as a single computer, but it can also be realized by sharing the same computer with other systems. For example, it can be fully put to practical use by sharing part of the computer used for the train traffic control system. Therefore, this system requires less equipment burden. [Explanation of symbols]

[0110] 101···Rail-to-ground voltage acquisition unit, 102···Position current acquisition unit, 103, 903··Rail-to-ground voltage calculation unit, 104, 904···Ground resistance deterioration position collation unit, 105···Ground resistance deterioration position notification, 106···Date and time designation part, 401···Up line, 402···Down line, 403···Crossing line, 410, 410a, 410b, 410c··Rail resistance, 420a, 420b··Ground resistance, 501···Rail direction resistance resistance), 502···Depth resistance, 611···Low resistance, 801 Rail-to-ground voltage, 901···Rail-to-ground voltage acquisition unit, 902···Position current acquisition unit, 990···Grounding resistance deterioration position estimation start judgment unit, 1101···Rail-to-ground voltage measurement results, 1102,1103 Rail-to-ground voltage measurement results when ground resistance deteriorates B

Claims

1. A ground resistance deterioration position estimation device that estimates a ground resistance deterioration position within a target route, a rail-to-ground voltage calculation unit in the event of ground resistance degradation that calculates rail-to-ground voltage candidate values ​​for each of a plurality of positions based on predicted positions where there is a possibility of ground resistance degradation and stores the calculated rail-to-ground voltage candidate values ​​in an outputtable manner; a rail-to-ground voltage acquisition unit that acquires actual rail-to-ground voltage measurements at a plurality of positions within the target track; a ground resistance degradation position collation unit that selects, based on a result of comparing and collating the actual rail-to-ground voltage value and the candidate rail-to-ground voltage value, the predicted position at which a waveform pattern showing a relationship between position and voltage is similar for the actual rail-to-ground voltage value and the candidate rail-to-ground voltage value, and determines the predicted position as a ground resistance degradation position; A ground resistance deterioration location estimation device having the above-mentioned.

2. The ground resistance deterioration position matching unit If the waveform pattern is similar to the rail-to-ground voltage candidate value at each of the plurality of positions, the predicted positions across the plurality of positions are determined to be close to each other by dividing the predicted positions proportionally according to the degree of similarity of the waveform patterns. The ground resistance deterioration location estimation device according to claim 1 .

3. a position current acquisition unit that acquires the positions of electric vehicles and power supply equipment on the target line, and the currents thereof, at the same time as the acquisition of the measured rail-to-ground voltage value; The ground resistance deterioration location estimation device according to claim 2.

4. The rail-to-ground voltage calculation unit when the ground resistance is deteriorated is A ground resistance degradation return resistance model was created by connecting a low resistance that simulates ground resistance degradation to a return resistance model that simulates rail resistance and ground resistance. The positions of the electric vehicle and substation at the time of acquiring the actual rail-to-ground voltage measurement and their currents are input into the earth resistance degradation return resistance model to calculate the ground voltage at both ends of the rail resistance. The voltage to ground is output as a candidate value of the rail voltage to ground when the ground resistance is deteriorated. The ground resistance deterioration location estimation device according to claim 2.

5. The rail-to-ground voltage calculation unit when the ground resistance is deteriorated is The location of ground resistance deterioration when it occurred on the target line in the past, and The actual rail-to-ground voltage measurements at multiple locations at that time are linked and stored. Output as a rail-to-ground voltage candidate value when ground resistance deteriorates. The ground resistance deterioration location estimation device according to claim 1 or 4.

6. The ground resistance deterioration position matching unit The actual rail-to-ground voltage measurement values ​​at each position are compared with the rail-to-ground voltage candidate values ​​when the ground resistance is deteriorated. The rail-to-ground voltage value at each position is searched for when the ground resistance is deteriorated, and the rail-to-ground voltage value at each position is searched for. The location of the ground resistance degradation when the rail-to-ground voltage is recorded or generated during the ground resistance degradation is determined as the location of the ground resistance degradation. The ground resistance deterioration location estimation device according to claim 2.

7. The rail-to-ground voltage calculation unit when the ground resistance is deteriorated is Under the condition that the positions of the electric vehicle and power supply equipment when the actual rail-to-ground voltage measurement value is acquired and their currents match within a specified range, Select and output rail-to-ground voltage when ground resistance is deteriorated, recorded when ground resistance is deteriorated. The ground resistance deterioration location estimation device according to claim 5.

8. The ground resistance deterioration location matching unit is Statistics of rail-to-ground voltage values ​​at each position over a predetermined period; Statistics of rail-to-ground voltage during a predetermined period when ground resistance is deteriorated; Calculate The statistical value at each position is searched for the rail-to-ground voltage when the earth resistance is deteriorated, The location of the ground resistance degradation when the rail-to-ground voltage is recorded or generated during the ground resistance degradation. It is estimated that this is the location of the ground resistance deterioration. The ground resistance deterioration location estimation device according to claim 1 .

9. The statistic is at least one of the mean and standard deviation. The ground resistance deterioration location estimation device according to claim 8.

10. A reference rail-to-ground voltage calculation unit is provided that outputs a rail-to-ground voltage when no earth resistance degradation occurs, By comparing the actual rail-to-ground voltage with the reference rail-to-ground voltage, When the rail-to-ground voltage value or statistical quantity at each position deviates by more than a predetermined value, Start estimating the location of ground resistance deterioration, The ground resistance deterioration location estimation device according to claim 4.

11. A method for estimating a ground resistance deterioration position in a target line, comprising: storing a plurality of predicted positions where there is a possibility of ground resistance degradation and rail-to-ground voltage candidate values ​​corresponding to the predicted positions for each of the plurality of positions; acquiring actual rail-to-ground voltage measurements at the plurality of positions over a predetermined period of time; comparing the actual rail-to-ground voltage value with the rail-to-ground voltage candidate value based on the trend over the predetermined period; Based on the comparison result, the predicted position where the waveform pattern showing the relationship between position and voltage is similar for the actual rail-to-ground voltage value and the candidate rail-to-ground voltage value is determined as the ground resistance degradation position. Method for estimating the position of ground resistance deterioration.

12. If the waveform pattern is similar to the rail-to-ground voltage candidate value at each of the plurality of positions, the predicted positions across the plurality of positions are determined to be close to each other by dividing the predicted positions proportionally according to the degree of similarity of the waveform patterns. The method for estimating the location of deterioration in ground resistance according to claim 11.

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