Method and device for detecting an arc between an overhead line and a rail traction unit

Abstract

A method for detecting carried DC voltage (V) line The overhead contact wire (12) of the track and the current (I) collected by the track traction unit (11) are connected. p The electric arc (A, V) occurring between the pantograph (11a) of the track traction unit (11) and the track traction unit (11) arc The method, wherein the pantograph (11a) includes an input low-pass filter, the input low-pass filter: operates at a given natural frequency (f N ); receives the voltage (V) between the pantograph (11a) and the reference node, particularly the voltage between the pantograph shoe and the reference node, at its input. p ), and the current (I) absorbed or injected by the track traction unit (11). p ); and at its output, a filtered voltage (V) is supplied to the track traction unit (11). dsf The method includes measuring (110) the voltage (V) between the pantograph (11a) and the reference node. p ) and the current (I) absorbed or injected by the track traction unit (11). p ), thereby obtaining the measured voltage (V) respectively. p,out ) and measuring current (I p,out ), from the measured voltage (V p,out Extracting (120; 220; 320) with values ​​around a given detection frequency (f) det Extracting the voltage signal (V) from the defined frequency spectrum portion bp V filt ;VT), from the measured current (I) absorbed or injected by the locomotive p,out Extracting (130; 230; 330) has a frequency around the given natural frequency (f) N Extracting the current signal (I) from the defined frequency spectrum portion bp ;I filt ;IT), will extract the voltage signal (V) having a defined spectral portion. bp V filt The amplitude of VT and the extracted current signal (I) having a defined spectral portion bp ;I filt The magnitude of IT and the corresponding threshold (t) hv , t hi The comparison operation (140) is compared and verified (150; 250) to determine whether the extracted voltage signal (V) has a defined spectral portion. bp V filt The amplitude of VT and the extracted current signal (I) having a defined spectral portion bp ;I filt; IT) are all higher than the respective threshold (t hv , t hi ), and a positive signal is sent (160) of the detection (AD) of the electric arc (A).

Description

Technical Field

[0001] This description relates to a method for detecting an electric arc occurring between a track overhead contact wire carrying a DC voltage and the pantograph of a track traction unit that collects current absorbed or injected by the track traction unit, and to a corresponding detection device.

[0002] One or more embodiments may be suitable for the following applications: collecting data related to energy consumption and transmitting them to an on-ground data collection system. Background Technology

[0003] In most electric rail systems, power is transferred from the supply unit to the traction unit (locomotive or electric train) via a sliding contact between the overhead contact line (OHL) and the pantograph. The latter is a servo-actuated current collector mounted on top of the train, which applies and controls the force exerted by the contact bar against the contact line. The large power (up to approximately 8 MW) to be transferred from the OHL to the carbon blades of the pantograph via a contact section of only a few square millimeters makes current collection one of the most critical elements of the electric rail power chain.

[0004] Precise analysis of the electrical quantity, voltage, and current detected at the pantograph (which collects current absorbed by track traction units such as locomotives or electric trains) can provide valuable information relating to the functional status of both the supply system and the rail vehicle. Tools for detecting electrical events occurring at the pantograph and methods for reliably cataloging them can be used for predictive maintenance. One such event is arcing, which can occur at the pantograph collecting current absorbed / injected by the locomotive due to separation from the overhead contact line (OHCL). The causes leading to separation between the two electrodes of the sliding contact can be summarized as follows: track irregularities, catenary irregularities, high speeds, and weather conditions (snow, ice, frost). A sustained number of arcing events can result in: rapid degradation of the collector bar, an increase in arcing events, a decrease in power quality, and accidents.

[0005] Therefore, it is desirable to count arcing events to monitor the condition of both the pantograph and the overhead contact line. Widespread deployment of such tools on every train associated with the data collection system could make a valuable contribution to predictive maintenance of the devices involved in the sliding contact.

[0006] In particular, in a future scenario where all trains in service are equipped with devices capable of detecting arcing events and transmitting the number of such events to a ground data collection system, predictive maintenance of the quality of the contact between the pantograph and the OHL will be possible. Furthermore, in the next future, all trains in service across Europe must collect data related to energy consumption and transmit it to a ground data collection system. This obligation is enforced by the Interoperability Technical Specification (TSI).

[0007] The current system monitors the condition of the pantograph (the element in contact with the OHCL) by registering a video system, which requires the installation of a video capture device and the difficult identification of arc events from the acquired images. Summary of the Invention

[0008] Based on the preceding description, the need arises for one or more solutions to overcome the shortcomings outlined earlier.

[0009] According to one or more embodiments, this objective is achieved by a method having the features specifically set forth in this invention disclosure. Furthermore, the embodiments relate to related detection devices.

[0010] The disclosure provided herein includes components of the technical teachings of this invention.

[0011] As described above, this disclosure provides a solution relating to a method for detecting an electric arc occurring between a track overhead contact wire carrying a DC voltage and the pantograph of a track traction unit that collects current absorbed or injected by the track traction unit.

[0012] The pantograph includes an input low-pass filter, wherein the input low-pass filter:

[0013] Operation at a given natural frequency;

[0014] It receives at its input the voltage between the pantograph (particularly the pantograph shoe) and the reference node, as well as the current absorbed or injected by the track traction unit; and

[0015] A filtered voltage is supplied to the track traction unit at its output.

[0016] The method includes:

[0017] The voltage between the pantograph and the reference node and the current absorbed or injected by the track traction unit are measured to obtain the measured voltage and measured current, respectively.

[0018] Extract a voltage signal having a defined spectral portion around a given detection frequency from the measured voltage.

[0019] Extraction current signal with a defined spectral portion around a given natural frequency is extracted from the measured current absorbed or injected by the locomotive.

[0020] The amplitudes of the extracted voltage signal having a defined spectral portion and the amplitudes of the extracted current signal having a defined spectral portion are compared with corresponding thresholds.

[0021] Verify whether the comparison operation indicates that the amplitude of the extracted voltage signal with a defined spectral portion and the amplitude of the extracted current signal with a defined spectral portion are both higher than the corresponding threshold, and if affirmative, signal the detection of the arc.

[0022] In a variant embodiment, the extraction of an extracted voltage signal from the measured voltage, having a defined spectral portion around a given detection frequency, includes performing an analog Butterworth filter or a special resonant filter around the given detection frequency, and

[0023] The extraction of an extraction current signal from the measured current absorbed or injected by the locomotive, having a defined spectral portion around a given natural frequency, includes performing a particularly second-order analog passband Butterworth filter centered on the natural frequency of the input low-pass filter.

[0024] The comparison operation includes comparing the extracted voltage and extracted current using a corresponding threshold comparator.

[0025] In a variant embodiment, the detection frequency is in the range of 1 kHz to 3 kHz, and the bandwidth of the analog Butterworth filter is specifically 143 Hz.

[0026] In a variant embodiment, the natural frequency is in the range of 15 Hz to 30 Hz, and the bandwidth of the analog passband Butterworth filter is specifically 11.2 Hz.

[0027] In a variant embodiment, the comparison operation includes delaying the output of the comparison of the extracted voltage portion.

[0028] In a variant embodiment, the voltage measurement includes analog pre-filtering the measured voltage by an analog filter having a resonant frequency at the detection frequency to obtain an analog filtered voltage, and then digitally acquiring the analog filtered voltage.

[0029] The measurement of the current includes digitally acquiring the measured current in sync with the acquisition of the analog filter voltage.

[0030] The extraction of an extraction voltage signal from the measured voltage, having a defined spectral portion around a given detection frequency, includes performing a fast Fourier transform on the measured voltage (particularly an analog filtered voltage) to extract the tone corresponding to the detection frequency.

[0031] The extraction of a current signal having a defined spectral portion around a given natural frequency from the measured current absorbed or injected by the locomotive includes performing a fast Fourier transform on the measured current to extract the harmonics corresponding to the natural frequency.

[0032] The voltage harmonic and the current harmonic are compared with their respective individual thresholds.

[0033] In a variant embodiment, the detection frequency of the simulated pre-filter is in the range of 1 kHz to 2 kHz.

[0034] In a variant embodiment, the Fast Fourier Transform of the measured voltage is performed with an analysis time in the range of 4 to 10 ms, and the Fast Fourier Transform of the measured current is performed with an analysis time in the range of 100 to 300 ms.

[0035] This disclosure also provides a solution relating to an apparatus for detecting an electric arc occurring between a track overhead contact line carrying a DC voltage and a pantograph of a track traction unit that collects current absorbed or injected by the track traction unit, the pantograph comprising an input low-pass filter that: operates at a given natural frequency; receives at its input the voltage between the pantograph (particularly the pantograph shoe) and a reference node, and the current absorbed or injected by the track traction unit; and supplies a filtered voltage to the track traction unit at its output.

[0036] Its features

[0037] The device includes a sensor module configured to measure the voltage between the pantograph and a reference node, and the current absorbed or injected by the track traction unit, thereby obtaining the measured voltage and measured current, respectively.

[0038] The device is configured to perform the steps of the method according to any of the embodiments described above.

[0039] This document provides components of the technical teachings of the present invention with reference to embodiments. Attached Figure Description

[0040] One or more embodiments will now be described by way of non-limiting example only, with reference to the accompanying drawings, in which:

[0041] Figure 1It is a schematic diagram that provides a circuit description for an electric arc event;

[0042] Figure 2A It is a time diagram of the voltage and current behavior at the pantograph in the presence of an arcing event;

[0043] Figure 2B yes Figure 2A A simplified time-lapse diagram.

[0044] Figure 3 This is a flowchart illustrating a general embodiment of the method described herein;

[0045] Figure 4 This is a schematic diagram of an apparatus for implementing the first embodiment of the method described herein;

[0046] Figure 5 yes Figure 4 A time diagram of voltage quantities in an embodiment;

[0047] Figure 6 yes Figure 4 A time-varying diagram of the current in an embodiment;

[0048] Figure 7 yes Figure 4 A time diagram of voltage and current quantities in an embodiment;

[0049] Figure 8 This is a schematic diagram of an apparatus for implementing the second embodiment of the method described herein.

[0050] Figure 9 yes Figure 8 A time diagram of voltage quantities in an embodiment;

[0051] Figure 10 yes Figure 8 A time-varying diagram of the current in an embodiment;

[0052] Figure 11 yes Figure 8 The voltage and current time diagram of the embodiment. Detailed Implementation

[0053] In the following description, one or more specific details are illustrated to provide a thorough understanding of examples of embodiments described herein. Embodiments may be implemented without one or more specific details or using other methods, components, materials, etc. In other instances, known structures, materials, or operations are not illustrated or described in detail so that certain aspects of the embodiments will not be obscured.

[0054] References to “embodiment” or “one embodiment” within the framework of this description are intended to indicate that a particular configuration, structure, or feature described with respect to the embodiment is included in at least one embodiment. Therefore, phrases such as “in an embodiment” or “in one embodiment” that may appear at one or more points in this description do not necessarily refer to the same embodiment.

[0055] Furthermore, specific constructions, structures, or characteristics can be combined in one or more embodiments in any suitable manner.

[0056] References used herein are provided for convenience only and therefore do not limit the scope or extent of protection of the embodiments.

[0057] Throughout the figures attached to this article, similar references / numbers are used to indicate similar parts or elements, and the corresponding descriptions will not be repeated for the sake of brevity.

[0058] The accompanying drawings are simplified rather than to scale.

[0059] When separation between the pantograph and the overhead contact line occurs in the presence of current flux, an electric arc is generated between the two electrodes of the sliding contact. Despite the complexity in the physical description of the arc, for our purposes, such an event can be readily described in a circuit model as an arbitrary voltage generator that applies an arbitrary pulsating voltage waveform between the pantograph and the OHCL. A more detailed description can be found in G. Crotti et al.'s publication "Pantograph-to-OHL Arc: Conducted Effects in DC Railway Supply System" (in IEEE Transactions on Instrumentation and Measurement, vol. 68, no. 10, pp. 3861-3870, October 2019).

[0060] Figure 1 A schematic diagram of a simplified circuit depicting an arcing event during the absorption (positive) of current in the traction unit or the generation (negative) of current by the traction unit, the latter possibly occurring during the braking phase.

[0061] therefore, Figure 1 The diagram shows a traction unit 11 (e.g., a locomotive) coupled to an overhead line 12, which carries a DC supply voltage V supplied by a power supply system 13 via a pantograph 11a. line .

[0062] The pantograph 11a is essentially connected to the receiving DC supply voltage V. lineThe elevated line has 12 phase contacts, but the voltage generator indicates that it has an arc voltage V. arc Arc A occurred simultaneously between overhead line 12 and pantograph 14 due to one of the reasons summarized above. p The indicator current is formed when the overhead line 12 flows between the pantograph 11a.

[0063] exist Figure 1 This is also represented by the equivalent circuit of the coupling between the overhead line 12 and the pantograph 11a, where the input filter 15 represents the input stage of the pantograph 14. As shown, the DC supply voltage V line By representing the arc voltage V arc The equivalent voltage generator is coupled to terminals separated by the input terminals of input filter 15. Therefore, the input voltage of input filter 15 (pantograph voltage V) p ) is V line -V arc This corresponds to the DC supply voltage V when there is no electric arc. line The pantograph current Ip at the input node of filter 15 is the current absorbed or injected relative to overhead line 12.

[0064] like Figure 1 As shown, the pantograph voltage V P It is formed between the pantograph 11a and a reference node (e.g., a ground reference). Typically, the reference node is at zero voltage or at a voltage relative to the pantograph voltage V. p Or DC supply voltage V line A lower potential. In an embodiment, the reference node can be represented by a rail.

[0065] Input filter 15 is a low-pass input stage filter for traction unit 11 (i.e., the locomotive), a type of low-pass input stage filter typically found in DC locomotives. This filter plays a crucial role in understanding the conductivity effects triggered by the electric arc. Figure 1 In this system, it is schematically represented as having parallel output capacitors C. if and series inductor L if An LC filter. At the output capacitor C if The terminals (they are the series inductors L) if At the reference node, a filtered DC voltage V is formed to supply the electric motor of the traction unit 12. dsf .like Figure 1 As shown in the figure, therefore, the filtered DC voltage V dsf Also known as a reference node (e.g., ground reference), it serves as the reference for the pantograph voltage V. p More generally, this includes the input node (on which the pantograph voltage V is formed). pAll potentials of the input filter 15 are referred to as such a reference node, which can be a ground reference as described, or, in the embodiment, represented by a rail. The rail may not necessarily be at zero voltage, but only at a relative voltage of V. line V p V dsf The node has a lower potential.

[0066] Figure 2A The voltage V at the pantograph is the voltage V when an arc event A is detected while train 11 is absorbing current. p The time plot of the behavior of current Ip.

[0067] Figure 2B yes Figure 2A The simplified diagram is a zoom in on the time region of arc A, thus showing the same amount of electricity.

[0068] If the traction unit 11 is absorbing current, then the arc A will induce a pantograph voltage V. p The voltage drop, and if the traction unit 11 injects current positively into the overhead line 12, triggers a swell. This rapid change causes oscillations in the second-order low-pass filter 15, which are reflected in the pantograph current I. p superior.

[0069] For example, in Proceedings of the 2019 IEEE 10th International Workshop on Applied Measurements for PowerSystems, Crotti, G., Giordano, D., Signorino, D., Femine, A. Delle, Gallo, D., Landi, C., Luiso, M., Biancucci, A., Donadio, L. (AMPS), Aachen (Germany), September 25-27, 2019) describes such Figure 2A The waveform shown is similar to the waveform in the image.

[0070] The solution described here is achieved through, for example Figure 3 The method shown in the flowchart utilizes the electrical conductivity generated by the electric arc. Figure 3 An embodiment 100 of the method is shown, the method comprising: step 110, measuring the pantograph voltage V between the pantograph 11a and a reference node. p and the current I absorbed or injected by the track traction unit 11p Thus, the measured voltage V is obtained respectively. p,out and measuring current I p,out Then in step 120, from such a measured voltage V p,out Extracting those with values ​​around a given detection frequency f det Extracting the voltage signal V from the defined spectral portion bp That is, for example, having a spectrum within a finite frequency range after bandpass filtering or around a given detection frequency f. det The frequency band of the signal,

[0071] The measured current I absorbed or injected by the locomotive p,out Extract 130 with a given natural frequency f around the input filter. N Extracting the current signal I from the defined frequency spectrum bp ,

[0072] The extracted voltage signal V having a defined spectral portion bp The amplitude and the extracted current signal I having a defined spectral portion bp The amplitude and the corresponding threshold (voltage threshold t) hv Or current threshold t hv Compare 140,

[0073] In step 150, it is verified whether the comparison operation 140 indicates an extracted voltage signal V with a defined spectral portion. bp The amplitude and extracted current signal I with a defined spectral portion bp The amplitudes are all higher than the corresponding threshold t hv t hv ,

[0074] In affirmation, in step 160, a signal is sent to notify the detection AD of arc A.

[0075] Reference Figure 4 The image shows a detection device 200, which represents a first embodiment of the more analogous orientation method described herein.

[0076] like Figure 4 As shown in the diagram, the pantograph voltage V between pantograph 11a and the reference node is measured. p and the current I absorbed or injected by the track traction unit 11 p Thus, the measured voltage V is obtained respectively. p,out and measuring current I p,out Step 110 is performed by the combined current-voltage transducer 11b. Preferably, such a combined current-voltage transducer 11b operates in a frequency range that is described below with reference to... Figure 4The downstream filters (e.g., filters 220, 230) in the illustrated measurement chain have compatible bandwidths, such as wider or equal bandwidth. The sensor module corresponding to transducer 11b can also be represented by separate voltage and current sensors.

[0077] From such a measured voltage V p,out Extract 120 with a given detection frequency f det The defined spectrum portion V filt Extracted voltage signal V bp The steps involve employing a passband second-order Butterworth filter 220 at an arbitrary (i.e., given) detection frequency f. det This is reflected by filtering around the center. The detection frequency f in the embodiment... det The value can be selected in the range of 1 kHz to 3 kHz, while the bandwidth can be, for example, 143 Hz. These are example values; different values ​​of bandwidth may be possible, chosen to balance the need for sufficiently narrow bandwidth to enhance the peak, and the cost of the circuit increases as such bandwidth narrows.

[0078] This embodiment includes an extracted voltage signal V that defines the spectral portion. bp The filtered analog voltage V filt To express.

[0079] The measured current I absorbed or injected by the locomotive p,out Extract 130 with a given natural frequency f around the input filter. N Extracting the current signal I from the defined frequency spectrum bp The steps involve employing a second-order passband Butterworth filter 230 with the natural frequency f of the low-pass filter 15 at the input stage of locomotive 11. N This is reflected through filtering centered on the frequency f. N The value depends on the resonant frequency of the locomotive's input filter stage 15, such as the resonant frequency of the LC resonant circuit forming the passband second-order Butterworth filter 230. The natural frequency f in the embodiment... N The value can be selected from 15 Hz to 30 Hz, while the bandwidth can be, for example, 11.2 Hz. The same considerations apply here to the bandwidth value of filter 220. The extracted current signal I has a defined spectral portion. bp In this case, the filter current I is used. filt It is manifested.

[0080] In order to perform the extraction of such a voltage signal V with a defined spectral portion filt The amplitude and the extracted current signal I having a defined spectral portion filt The amplitude and the corresponding threshold thv t hi Compare 140, each filtered signal V filt I filt Then, especially at positive and negative thresholds (+t respectively) hv -t hv and +t hi -t hi The corresponding threshold comparators 240v and 240i, which operate between the filtered signal V, are used for processing. filt I filt Above the threshold (for voltage t) hv and for current t hi Then the output signal t of the corresponding threshold comparators 240v and 240i hv_out t hi_out Logical 1 if true, otherwise logical 0. Used for threshold t. hv t hi The range of variation is summarized in Table 1 below.

[0081]

[0082] The output signal t of the voltage comparator is 240V. hv_out The time-delayed output signal t is delayed by a delay D (in the example shown, delay D is 5 ms) in delay block 245, thereby supplying the delayed output signal t. hv_out_D The value of delay D is chosen in order to compensate for the different time delays introduced by filters 220 and 230.

[0083] The output signal t from comparators 240V and 240I hv_out_D t hi_out The signal is sent to AND gate 250, which embodies the verification 150 comparison operation 140 to determine whether the extracted voltage signal V has a defined spectral portion. filt and the extracted current signal V with a defined spectral portion filt The amplitudes are all higher than the corresponding threshold t hv t hi .

[0084] Only when the output signal t hv_out t hi_out All are one (i.e., above the corresponding threshold t) hv t hi When the output signal of AND gate 250 is equal to 1, it indicates a positive or affirmative response to verification step 150, thus signaling the detection of the arc in step 160. Otherwise, if the output signal t hv_out t hi_outOne of them is zero (i.e., below the corresponding threshold t). hv t hi If AD is zero, it means that no electric arc has occurred.

[0085] Figure 5 The figure shown is the measured voltage V as a function of time t. p,out Filter voltage V filt and delayed output signal t hv_out_D The indicator arc event A and the measured voltage V p,out The spike correlation. It also refers to previous oscillations above a threshold to indicate the delayed output signal t. hv_out_D The delay D in the equation. Such a delay D naturally exists in the following oscillation determined by the electric arc A.

[0086] Figure 6 The figure shown is the measured current I as a function of time t. p,out Filter current I filt and current output signal t hi_out Indicating arc event A and measuring current I p,out The peak correlation.

[0087] Figure 7 The figure shown is a measured voltage V as a function of time t, superimposed on the same graph. p,out and measuring current I p,out And the generated flag AD. When the flag AD reaches 1, an electric arc is detected.

[0088] Reference Figure 8 This illustrates a second embodiment of the more digitally oriented approach described herein.

[0089] like Figure 8 As shown in the diagram, the pantograph voltage V between pantograph 11a and the reference node is measured. p The measured voltage V is obtained by absorbing or injecting the current Ip from the track traction unit 11. p,out and measuring current I p,out Step 110 is performed by the combined current-voltage transducer 11b.

[0090] But regarding what about measuring voltage V p,out Before step 120, pre-filtering is also performed by analog filter 312, which is essentially a low-passband filter. The frequency response is flat at low frequencies and at a given detection frequency f. det Having resonance, the given detection frequency in this embodiment is preferably in the range of [1 ÷ 2] kHz, such that only fast transients utilize the filter. Figure 9The voltage of the reporting filter 312 is used to describe the filter's response to an actual arc event. Figure 9 In addition to the comparator 340V output t described below (which is better understood below), hv_out In addition, the measured voltage V is also shown. p,out And the analog filtered output V output by analog filter 312 pf Detection frequency f det amplitude The timeline is as follows. Therefore, the voltage measurement step 110 is essentially followed by analog pre-filtering of the measured voltage by an analog filter 312 having a resonant frequency at the detection frequency, and then digital acquisition of the analog-filtered voltage V is performed by the analog-to-digital voltage conversion module 314v. pf This generates a digital measurement voltage V. p,d .

[0091] The measured current I is acquired synchronously with the voltage measurement signal in the corresponding analog-to-digital current conversion module 314i. p,out This generates a digital measurement current I. p,d .

[0092] Then, the digital measurement voltage V p,d After adjusting the resonant frequency f of the upstream special filter 312 in FFT block 320 det The detection application uses Fast Fourier Transform (FFT) to obtain the voltage V from such a digital measurement. p,d Extracting those with values ​​around a given detection frequency f det Extracted voltage signal V from the defined spectral portion (in this case, the harmonic frequency VT) bp The steps.

[0093] In the same way, digital measurement of current I p,d After the natural frequency f of the low-pass filter 15 at the input stage of locomotive 11 in FFT block 330 is... N The FFT of the detection, such as Figure 11 As shown, the current harmonic frequency IT is thus extracted as the extraction part. t .

[0094] The harmonic frequencies VT and IT are then compared with the corresponding threshold t in the corresponding threshold comparators 340v and 340i. hv t hi Compare them. If the amplitudes of the harmonic frequencies VT and IT are higher than the threshold (for voltage t),... hv and for current signal t hi Then the output signals t of the corresponding comparators 340V and 340I are... hv_out t hi_out It is 1 if it is true, otherwise it is 0. Figure 10The measured current as a function of time and the output t of the current comparator 340i at the 15Hz harmonic frequency IT are shown. hi_out .

[0095] Moreover, in this case, the output signal t from comparators 340V and 340I hv_out t hi_out The signal is sent to AND gate 250, which embodies verification 150 and comparison operation 140 to determine whether the amplitudes of the extracted voltage spectrum portion (in this case, voltage harmonic VT) and the extracted current spectrum portion (in this case, current harmonic IT) are both higher than the corresponding threshold t. hv ,t hi .

[0096] Only when the output signal t hv_out t hi_out All are one (i.e., above the corresponding threshold t) hv t hi When the output signal of AND gate 250 is equal to 1, it indicates a positive or affirmative response to verification step 150, thus signaling the detection of the arc in step 160. Otherwise, if the output signal t hv_out t hi_out If any one of them is zero, that is, below the corresponding threshold t hv t hi If AD is zero, it means that no electric arc has occurred. Figure 11 As shown in the simplified diagram, Figure 11 The measured voltage V as a function of time t is shown superimposed on the same graph. p,out and measuring current I p,out And the generated flag AD. When the flag AD reaches 1, an electric arc is detected.

[0097] For this digital approach, the time interval selected for calculating the FFT transform in blocks 340v and 340i can be related to the detection of the searched harmonics. Operating conditions are typically far from stable, therefore, the time interval used for the FFT operation should be chosen to be as small as possible to achieve a good approximation of stable conditions. In addition, good spectral resolution is required, and therefore a sufficiently long analysis time is needed for harmonic detection. For these reasons, it is preferable to obtain the detection of the resonant frequency of the upstream special filter with an analysis time of [4 ÷ 10] ms, while the detection of the natural frequency of the low-pass filter in the locomotive's input stage is within the range of [100 ÷ 300] ms.

[0098] The selection of the thresholds to be applied to the filtered voltage and current signals is clearly linked to the type of track system on which the arc detection device is operating. The values ​​are summarized in Table 2 below:

[0099]

[0100] Table 2

[0101] The proposed solution allows for the counting of arcing events to monitor the condition of the pantograph and overhead contact line without requiring any additional devices installed on the train roof that are separate from the already installed voltage and current transducers.

[0102] This allows for the widespread distribution of devices implementing the solution on every train associated with the data collection system, which in turn enables a valuable contribution to the predictive maintenance of devices involved in the sliding contact (particularly for the predictive maintenance of the quality of the contact between the pantograph and the OHL).

[0103] The solution described here also allows for the collection of energy consumption-related data and its transmission to ground-based data collection systems, such as those implemented by the Interoperability Technology Specification (TSI). Communication systems deployed for energy billing from both the train and the ground can be used to collect arcing events for each train. Appropriate algorithms for managing this bug data can be used to determine whether the problem is with the pantograph or the OHCL (Overhead Electro-Conductor Closure). In fact, if for a given segment, all trains operating on that segment detect an unusual number of arcing events, the problem is most likely attributable to the OHCL. Conversely, if a train only records an unusual number of events for a few segments, it implies that the problem is related to the pantograph.

[0104] Otherwise it will be understood that the various individual implementation options illustrated throughout the accompanying drawings are not necessarily intended to be used in the same combinations illustrated in the drawings. Therefore, one or more embodiments may employ these (otherwise non-mandatory) options relative to the individual combinations illustrated in the drawings and / or in different combinations.

[0105] Without prejudice to the fundamental principles and without departing from the level of protection, the details and embodiments may be changed, even significantly, relative to what has been described as an example only.

Claims

1. A device for detecting carried DC voltage (V) line The overhead contact wire (12) of the track and the current (I) collected by the track traction unit (11) are connected. p The electric arc (A, V) occurring between the pantograph (11a) of the track traction unit (11) and the track traction unit (11) arc ) method, The pantograph (11a) includes an input low-pass filter, the input low-pass filter being: Operation at a given natural frequency (f N ); Receive at its input The voltage (V) between the pantograph (11a) and the reference node p ),as well as The current (I) absorbed or injected by the track traction unit (11) p );as well as At its output, a filtered voltage (V) is supplied to the track traction unit (11). dsf ), The method includes Measure (110) the voltage (V) between the pantograph (11a) and the reference node. p ) and the current (I) absorbed or injected by the track traction unit (11). p ), thereby obtaining the measured voltage (V) respectively. p,out ) and measuring current (I p,out ), From the measured voltage (V) p,out Extracting (120; 220; 320) with values ​​around a given detection frequency (f) det Extracting the voltage signal (V) from the defined frequency spectrum portion bp V filt ;VT), The measured current (I) absorbed or injected by the locomotive p,out Extracting (130; 230; 330) with frequencies around the given natural frequency (f) N Extracting the current signal from the defined frequency spectrum (I) bp ;I filt IT). The extracted voltage signal (V) having a defined spectral portion bp V filt The amplitude of VT and the extracted current signal (I) having a defined spectral portion bp ;I filt The magnitude of IT and the corresponding threshold (t) hv , t hi Compare (140), Verification (150; 250) indicates whether the comparison (140) indicates the extracted voltage signal (V) having a defined spectral portion. bp V filt The amplitude of VT and the extracted current signal (I) having a defined spectral portion bp ;I filt The magnitudes of (IT) are all higher than the corresponding thresholds (t). hv , t hi ), and in affirmation, signal (160) the detection (AD) of the arc (A).

2. The method as described in claim 1, wherein, The voltage (V) between the pantograph (11a) and the reference node p ) represents the voltage between the power receiving shoe and the reference node.

3. The method of claim 1, wherein From the measured voltage (V) p,out ) for those with a given detection frequency (f) det Extracting the voltage signal (V) from the defined frequency spectrum portion bp V filt The extraction (120; 220; 320) of VT includes performing operations around the given detection frequency (f det Analog Butterworth filtering or special resonant filtering, and The measured current (I) absorbed or injected by the locomotive p,out In ) for those having around the given natural frequency (f N Extracting the current signal from the defined frequency spectrum (I) bp ;I filt The extraction (130; 230; 330) of the input low-pass filter (15) includes performing (320) at the natural frequency (f) of the input low-pass filter (15). N Analog passband Butterworth filter centered on ) The comparison (140) includes comparing the extracted voltage signal and the extracted current signal by a corresponding threshold comparator.

4. The method of claim 3, wherein, The analog passband Butterworth filter is a second-order analog passband Butterworth filter.

5. The method of claim 3, wherein, The detection frequency (f) det It falls within the range of 1 kHz to 3 kHz.

6. The method of claim 5, wherein, The bandwidth of the simulated Butterworth filter is 143 Hz.

7. The method of claim 3, wherein, The natural frequency (f) N It falls within the range of 15 Hz to 30 Hz.

8. The method of claim 7, wherein, The bandwidth of the analog passband Butterworth filter is 11.2 Hz.

9. The method of claim 3, wherein, The comparison (140) includes a delay (245) of the output of the comparison of the extracted voltage signal.

10. The method of claim 1, wherein The measurement of voltage (110) includes measurement at the detection frequency (f det An analog filter with a resonant frequency is used for the measured voltage (V). p,out Simulation pre-filtering (312) is performed to obtain the analog filter voltage (V). pf Then, the analog filter voltage (V) of 314V is obtained digitally. pf ), The measurement of the current (110) includes the measurement of the analog filter voltage (V). pf The measured current (I) is acquired synchronously in a digital manner (314i). p,out ), From the measured voltage (V) p,out ) for those with a given detection frequency (f) det Extracting the voltage signal (V) from the defined frequency spectrum portion bp V filt The extraction (120; 220; 320) of the measured voltage (V) includes performing (320) on the measured voltage (V) p,out The fast Fourier transform of the detection frequency (f) is used to extract the information related to the detection frequency (f). det The corresponding harmonic frequency (VT) The measured current (I) absorbed or injected by the locomotive p,out In ) for those having around the given natural frequency (f N Extracting the current signal from the defined frequency spectrum (I) bp ;I filt The extraction (130; 230; 330) of the measured current (I) includes performing (330) on the measured current (I) p,out The fast Fourier transform of the natural frequency (f) is used to extract the frequency. N The corresponding harmonic frequency (IT) The voltage harmonic (VT) and the current harmonic (IT) are compared with the corresponding single threshold (t). hv , t hi (Compare) 11. The method of claim 10, wherein, The extraction (120; 220; 320) includes performing (320) on the analog filtered voltage (V pf Fast Fourier Transform (FFT) of .

12. The method of claim 10, wherein, The detection frequency (f) of the analog pre-filter det It falls within the range of 1 kHz to 2 kHz.

13. The method of claim 10, wherein, The fast Fourier transform of the measured voltage is performed with an analysis time in the range of 4 to 10 ms, and the fast Fourier transform of the measured current (324i) is performed with an analysis time in the range of 100 to 300 ms.

14. A device for detecting DC voltage (V) carried by a carrier. line The overhead contact wire (12) of the track and the current (I) collected by the track traction unit (11) are connected. p The electric arc (A, V) occurring between the pantograph (11a) of the track traction unit (11) and the track traction unit (11) arc The device (200, 300), the pantograph (11a) includes an input low-pass filter, the input low-pass filter: operates at a given natural frequency (f N ); receives the voltage (V) between the pantograph (11a) and the reference node at its input. p ), and the current (I) absorbed or injected by the track traction unit (11). p ); and supplying a filtered voltage (V) to the track traction unit (11) at its output. dsf ), Its features The device (200, 300) includes a sensor module (11b) configured to measure (110) the voltage (V) between the pantograph (11a) and the reference node. p ) and the current (I) absorbed or injected by the track traction unit (11). p ), thereby obtaining the measured voltage (V) respectively. p,out ) and measuring current (I p,out ), The apparatus (200, 300) is configured to perform the steps of the method as described in any one of claims 1 to 8.

15. The apparatus (200, 300) as claimed in claim 14, wherein, The voltage (V) between the pantograph (11a) and the reference node p ) represents the voltage between the power receiving shoe and the reference node.

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