Track loop device and online train determination method

Abstract

To provide a technology of a track circuit device with a principle completely different from those of conventional track circuit devices.SOLUTION: A track circuit device 1 measures a transmission voltage and a transmission current of an alternating signal transmitted to a rail, calculates an impedance equivalent value based on an amplitude and a phase difference of the measured transmission voltage and transmission current, and determines whether a train exists on a rail based on values of a real component and an imaginary component of the calculated impedance equivalent value.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a track circuit device and the like.

Background Art

[0002] A conventional track circuit device determines the presence of a train by connecting a transmitter that transmits a train detection signal to one end of the rail of the track circuit and detecting a decrease in the reception level at a receiver connected to the other end (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In a conventional track circuit device, a train detection signal is transmitted to one end of the rail of the track circuit, and the reception level is monitored at the other end located at a predetermined distance. Therefore, a transmission power of a certain level or higher is required. As a result, it has been difficult to save energy. In addition, a conventional track circuit device requires a transmitter and a receiver in principle.

[0005] The problem to be solved by the present invention is to provide a technology for a track circuit device whose principle is completely different from that of a conventional track circuit device.

Means for Solving the Problems

[0006] A first invention for solving the above problems is calculating means (for example, the impedance equivalent value calculation unit 34 in FIG. 1) that calculates an impedance equivalent value based on the amplitude and phase difference of the transmission voltage and transmission current of an AC signal transmitted to the rail by transmission means (for example, the transmitter 10 in FIG. 1), and Based on the real and imaginary components of the impedance equivalent value, a determination means (for example, the determination unit 35 in Figure 1) determines the presence of a train. This is a track circuit device equipped with [a specific feature / feature].

[0007] Other inventions include, To measure the transmission voltage and transmission current of the AC signal transmitted to the rail by the transmitting means, To calculate an impedance equivalent value based on the amplitude and phase difference of the transmitted voltage and transmitted current, Based on the real and imaginary components of the impedance equivalent value, the presence of a train is determined. A train presence determination method may be configured that includes this.

[0008] The first invention provides a track circuit device technology that operates on a completely different principle from conventional track circuit devices. The first invention focuses on the fact that the impedance of the track circuit as seen from the AC signal transmission point changes depending on whether a train is present or not, and that this change in impedance causes changes in the amplitude and phase difference of the transmission voltage and transmission current. According to the first invention, the equivalent impedance value of the track circuit is determined from the amplitude and phase difference of the transmission voltage and transmission current, and the presence of a train is determined based on the real component (resistance component) and imaginary component (reactance component) when this equivalent impedance value is expressed as a complex number. Since the presence of a train can be determined based on the transmission voltage and transmission current of the AC signal transmitted to the rail, a receiver is not required, and there is no need to transmit a signal that maintains a constant signal level at the receiving point, thus reducing transmission power. As a result, an energy-saving track circuit device can be realized. Furthermore, the elimination of the receiver provides additional benefits, such as reducing the number of components in the track circuit device.

[0009] The second invention relates to the above invention, The determination means determines the location of the train based on the transmission point of the AC signal by the transmission means. It is a track circuit device.

[0010] According to the second invention, the position of a train on the track can be determined with respect to the AC signal transmission point. This is because the impedance of the track circuit as seen from the AC signal transmission point changes according to the position of the short circuit in the rails caused by the train's axles.

[0011] The third invention is, in the above invention, The determination means determines the location of the train relative to the transmission point based on the plotted points of the impedance equivalent values ​​in a coordinate system with the real and imaginary components as axes. It is a track circuit device.

[0012] According to the third invention, the location of a train can be determined based on plotted points of impedance equivalent values ​​in a coordinate system (complex plane) with real and imaginary components as axes. This is because the impedance of the track circuit is determined according to the short-circuit position of the rails caused by the train's axles. Therefore, by pre-associating the location of the train with the location of the plotted points of impedance equivalent values ​​in the coordinate system, the location of the train can be determined.

[0013] The fourth invention is, in the invention described above, The determination means determines the location of the train based on the position of the plotted points along a predetermined reference trajectory in the coordinate system. It is a track circuit device.

[0014] The impedance of a track circuit is determined by the position of the train within that track circuit, that is, the position of the rail short-circuit caused by the train's axles. Therefore, as in the fourth invention, by pre-defining the change in the position of plotted points representing the impedance equivalent value in a coordinate system corresponding to the train's position as a reference trajectory, the train's position can be determined based on the position of the plotted points along this reference trajectory.

[0015] The fifth invention is, in the invention described above, The determination means determines the state of the rail based on the real component and the imaginary component values of the impedance equivalent value. It is a track circuit device.

[0016] When the state of the rail changes, the impedance of the track circuit changes. Therefore, as in the fifth invention, for example, by comparing the real component and the imaginary component values of the current impedance equivalent value with the real component and the imaginary component of the impedance equivalent value when the rail is in a normal state, the state of the rail such as whether it is in a normal state can be determined.

[0017] The sixth invention is in the above-described invention, The determination means determines an abnormal portion of the rail based on the transmission point of the AC signal by the transmission means. It is a track circuit device.

[0018] According to the sixth invention, as the state of the rail, an abnormal portion of the rail based on the transmission point of the AC signal can be determined.

[0019] The seventh invention is in the above-described invention, When the plot point deviates from the reference locus, the determination means has means for determining an abnormal portion of the rail related to leakage conductance and / or rail breakage based on the position of the deviation. It is a track circuit device.

[0020] According to the seventh invention, as the state of the rail, it is possible to determine an abnormal portion of the rail related to leakage conductance and / or rail breakage. For example, when an abnormality related to leakage conductance occurs in the rail, such as an increase in leakage conductance due to the immersion of the rail, the amount of change in the impedance of the track circuit changes depending on the in-line position of the train before and after the train passes through the abnormal portion. Therefore, when the plotted point deviates from the reference locus, the position where it returns to the reference locus can be determined as the abnormal portion of the rail related to leakage conductance. More specifically, when the train passes before and after the abnormal portion related to leakage conductance, it deviates from the starting point of the reference locus (moves to the transmission point side) before the abnormal portion, and becomes a locus along the reference locus after passing through the abnormal portion. Also, when a rail breakage occurs, the amount of change in the impedance of the track circuit changes before and after the train passes through the abnormal portion. Therefore, when the plotted point deviates from the reference locus, the position where it returns to the reference locus can be determined as the rail breakage location. More specifically, when the train passes before and after the rail breakage location, although the portion other than the abnormal portion is normal, the portion farther than the abnormal portion deviates from the reference locus, so the plotted point will be displaced between the position along the reference locus and the position deviating from the reference locus.

[0021] The eighth invention is the invention described above, where the determination means has a rail breakage determination means for determining the presence or absence of rail breakage based on the sign of the value of the imaginary component. It is a track circuit device.

[0022] According to the eighth invention, it is possible to determine the presence or absence of rail breakage based on the sign of the value of the imaginary component of the impedance equivalent value. This is because when a rail breakage occurs, the imaginary component of the impedance equivalent value becomes a negative value.

[0023] The ninth invention is the invention described above, where the rail breakage determination means determines the position of the rail breakage based on the values of the real component and the imaginary component of the impedance equivalent value, with reference to the transmission point of the AC signal by the transmission means. It is a track circuit device.

[0024] According to the ninth invention, the location of a rail fracture can be determined relative to the transmission point of the AC signal based on the real and imaginary components of the impedance equivalent value. This is because, when a rail fracture occurs, the imaginary component of the impedance equivalent value becomes negative, and both the real and imaginary components change to values ​​corresponding to the distance from the transmission point of the AC signal to the location of the rail fracture.

[0025] The tenth invention is, in the above invention, The determination means determines whether there is an abnormality or sign of an abnormality in the rail based on whether the plotted points of the impedance equivalent values ​​in a coordinate system with the real and imaginary components as axes are outside the allowable variation range of the impedance equivalent values ​​determined according to the distance from the transmission point of the AC signal by the transmission means. It is a track circuit device.

[0026] If any abnormality or signs of abnormality occur in the rails, the impedance of the track circuit changes. Also, since rails are usually installed outdoors, the impedance of the track circuit can fluctuate depending on the surrounding environment such as temperature, humidity, rainfall, and snowfall. For this reason, as in the tenth invention, for example, by defining an allowable fluctuation range that can be considered the normal state of the rails, based on the position of the plotted point of the impedance equivalent value when the rails are in a predetermined normal state, it is possible to determine whether there is an abnormality or signs of abnormality in the rails based on whether the plotted point of the impedance equivalent value is outside the allowable fluctuation range. [Brief explanation of the drawing]

[0027] [Figure 1] Examples of track circuit device applications. [Figure 2] An example of an equivalent circuit for an orbital circuit. [Figure 3] An example of the transmission voltage waveform and transmission current waveform of an AC signal. [Figure 4] An example of how the plotted points of the impedance equivalent value change. [Figure 5]An example of how the plotted points of the impedance equivalent value change when a rail break occurs. [Figure 6] An example of how the plotted points of the impedance equivalent value change when a rail break occurs. [Figure 7] An example of how the plotted impedance equivalent value changes when an anomaly related to leakage conductance occurs. [Figure 8] An example of track circuit equipment installation. [Figure 9] Example of setting the allowable variation range. [Figure 10] Other examples of track circuit device configurations. [Figure 11] An example of how the plotted points of the impedance equivalent value change in the case of an isolated track circuit. [Modes for carrying out the invention]

[0028] Preferred embodiments of the present invention will be described below with reference to the drawings. However, the applicable forms of the present invention are not limited to the following embodiments. Furthermore, in the drawings, the same elements are denoted by the same reference numerals.

[0029] [composition] Figure 1 shows an example of the application of the track circuit device 1 in this embodiment. The track circuit device 1 is a device that transmits an AC signal to the rails and determines the presence of a train and the condition of the rails based on the transmitted voltage and current of the AC signal. The track circuit device 1 comprises a transmitter 10, a current sensor 20, and a processing device 30. If the track circuit device 1 is installed in one central location, a long cable will be required, in which case a matching transformer will also be provided to match the impedance of the cable and the track to some extent.

[0030] The transmitter 10 transmits a constant level of AC signal via a transmission cable to a transmission point in a detection section T1 that divides the rails of the track circuit, in accordance with the control of the processing unit 30. The transmission point is located at the outward end of the detection section T1. The track circuit may be either an insulated or uninsulated track circuit, but in this embodiment, it will be described as an uninsulated track circuit. Therefore, the AC signal transmitted from the transmission point to the rails of the detection section T1 also propagates to other sections adjacent to the detection section T1. The current sensor 20 is located in the transmission cable between the transmitter 10 and the rails and measures the current (AC current) of the AC signal transmitted to the rails.

[0031] The processing unit 30 includes a transmit voltage waveform acquisition unit 31, a transmit current waveform acquisition unit 32, a quadrature detection circuit unit 33, an impedance equivalent value calculation unit 34, a determination unit 35, a transmit voltage output unit 36, a transmit voltage / frequency setting unit 37, a set frequency / transmission level determination unit 38, and a noise measurement unit 39. Each functional unit of the processing unit 30 can also be configured using a circuit unit that performs signal processing to realize the function, or an arithmetic processing unit that realizes the function in software.

[0032] The transmission voltage waveform acquisition unit 31 acquires the waveform of the transmission voltage (transmission voltage waveform) of the AC signal transmitted to the rail in the detection section T1 via the transmission cable. The transmission current waveform acquisition unit 32 acquires the waveform of the transmission current (transmission current waveform) measured by the current sensor 20. The quadrature detection circuit unit 33 quadrature detects the transmission voltage waveform and the transmission current waveform and outputs the amplitude of the transmission voltage and the transmission current, and the phase difference of the transmission current with respect to the transmission voltage. The impedance equivalent value calculation unit 34 calculates the real and imaginary components of the impedance equivalent value of the track circuit, expressed as a complex number, based on the amplitude and phase difference of the transmission voltage and transmission current output from the quadrature detection circuit unit 33. Details of this impedance equivalent value of the track circuit will be described later.

[0033] The determination unit 35 determines the presence of a train and the condition of the rails based on the real and imaginary components of the impedance equivalent value calculated by the impedance equivalent value calculation unit 34. Details of this determination of train presence and rail condition will be described later.

[0034] The transmission voltage output unit 36 ​​outputs the transmission voltage set by the transmission voltage / frequency setting unit 37 to the transmitter 10. The transmission voltage / frequency setting unit 37 controls the transmission voltage of the transmission voltage output unit 36 ​​so that it becomes an AC signal with the transmission level determined by the set frequency / transmission level determination unit 38. It also controls the transmission switch of the transmitter 10 to turn on and off so that it becomes an AC signal with the set frequency set by the set frequency / transmission level determination unit 38. The set frequency / transmission level determination unit 38 determines the frequency and transmission level of the AC signal to be transmitted to the rails based on the noise (retard noise) measured by the noise measurement unit 39. The noise measurement unit 39 measures the noise (retard noise) generated on the rails of the track circuit. Details on the measurement of these noises and the setting of the frequency and level of the AC signal will be described later.

[0035] [Train presence determination] The determination of train presence by the determination unit 35 will now be explained. Figure 2 is a diagram showing the equivalent circuit when the detection section T1 is considered as a track circuit. Figure 2 shows the equivalent circuit according to the presence or absence of a train and its position. In Figure 2, the upper part shows the equivalent circuit when there is no train, the middle part shows the equivalent circuit immediately after the train enters the detection section T1 (position L2 in Figure 1), and the lower part shows the equivalent circuit when the train enters (arrives at) the transmission point (position L3 in Figure 1). It is assumed that the rail condition is normal (no abnormalities have occurred). The combined impedance of this equivalent circuit is the impedance of the track circuit as seen from the AC signal transmission point.

[0036] As shown in the upper part of Figure 2, the equivalent circuit of the track circuit when no train is present is composed of the rail inductance component La, the series resistance component Ra, the capacitance component C between the rails, and the leakage conductance component G = 1 / Rb. Also, as shown in the center of Figure 2, the equivalent circuit of the track circuit immediately after a train enters the detection section T1 is composed of the rail inductance component La, the series resistance component Ra, the capacitance component C between the rails, the leakage conductance component G = 1 / Rb, and the impedance Rv due to the axle short circuit in the detection section T1.

[0037] In this embodiment, since the track circuit is an unisolated track circuit, the AC signal transmitted from the transmission point to the rails propagates to adjacent sections of the detection section T1. Therefore, even if the train has not yet reached the detection section T1, if it is approaching within a certain distance, the axle short-circuit impedance Rv will have an effect. Furthermore, even after the train has moved out of the detection section T1, the axle short-circuit impedance Rv will have an effect until it moves away to a certain distance. The range affected by this axle short-circuit impedance Rv (the range to which the AC signal reaches) is called the detectable range. In other words, the detectable range is the range obtained by extending the detection section T1 in the longitudinal direction along the rails. In addition, each circuit element of the track circuit (rail inductance component La, series resistance component Ra, capacitance component C between rails, and leakage conductance component G=1 / Rb) is determined according to the distance from the AC signal transmission point to the axle short-circuit position (train's position on the track), so it is largest when the train is not present and gradually decreases as the train approaches the AC signal transmission point.

[0038] Therefore, as shown in the lower part of Figure 2, the equivalent circuit of the track circuit when the train enters the transmission point consists only of the axle short-circuit impedance Rv, because the distance from the transmission point to the axle short-circuit position is very short, the rail inductance component La, the series resistance component Ra, and the capacitance component C between rails become very small, and the leakage conductance component G = 1 / Rb becomes very large. In this way, the equivalent circuit of the track circuit changes as the train moves through the detection section T1. In other words, the impedance of the track circuit changes.

[0039] Figure 3 shows an overview of the transmission voltage and transmission current waveforms of the AC signal transmitted to the rails. In Figure 3, the horizontal axis represents time and the vertical axis represents level, showing the transmission voltage and transmission current waveforms. Furthermore, assuming that the transmission voltage waveform is constant, the transmission current waveform is shown when the train is not present and when the train approaches the transmission point (position L3).

[0040] As shown in Figure 2, the equivalent circuit of the track circuit in detection section T1 changes as the train moves from entering to exiting detection section T1. In other words, the impedance of the track circuit as seen from the AC signal transmission point changes, and therefore the transmitted current waveform changes relative to the transmitted voltage waveform. Specifically, as the train enters detection section T1 and approaches the transmission point, the phase of the transmitted current waveform shifts in the opposite direction relative to the transmitted voltage waveform, and the level (amplitude) of the transmitted current waveform increases. The amplitude (level) and phase of the transmitted current waveform change in accordance with the change in the impedance of the track circuit. From this, the amplitude of the transmitted voltage waveform and the transmitted current waveform, and the phase difference of the transmitted current waveform relative to the transmitted voltage waveform can be considered as values ​​corresponding to the impedance of the track circuit (impedance equivalent values).

[0041] In this embodiment, the quadrature detection circuit unit 33 quadrature detects the transmitted voltage waveform and the transmitted current waveform and outputs the amplitude and phase difference of the transmitted voltage waveform and the transmitted current waveform. Then, the impedance equivalent value calculation unit 34 calculates the real and imaginary components of the impedance equivalent value of the track circuit, expressed as complex numbers, based on the amplitude and phase difference.

[0042] Figure 4 shows the change in the impedance equivalent value of the track circuit when a train travels through detection section T1. In Figure 4, the impedance equivalent value is plotted in a Cartesian coordinate system (complex plane) with the real and imaginary components as axes. It also shows the change (trajectory) of the plotted points of the impedance equivalent value of the track circuit from when the train is not present until it enters and exits detection section T1.

[0043] As shown in the equivalent circuit of the track circuit in Figure 2, the impedance equivalent value of the track circuit changes analogously with changes in the train's position (i.e., the short-circuit position of the rail axles). Therefore, the change in the position of the plotted point of the impedance equivalent value also follows a continuous trajectory. Specifically, when the train is not present, both the real and imaginary components of the impedance equivalent value of the track circuit are positive, and the position P1 of the plotted point is in the first quadrant. This position P1 of the plotted point is almost fixed if the rail condition is normal.

[0044] Then, when the train enters the detection range, the impedance of the track circuit changes as the train's position on the track (i.e., the position of the axle short circuit) changes, causing the position of the plotted point for the impedance equivalent value to gradually change from position P1. In other words, as the distance from the AC signal transmission point to the axle short circuit position gradually decreases, the real and imaginary components of the impedance equivalent value gradually decrease and change in the direction toward the origin O of the Cartesian coordinate system (approaching it). Position P2 is the position of the plotted point for the impedance equivalent value immediately after the train enters the detection section T1 (position L2 on the track in Figure 1).

[0045] Next, when the train approaches the transmission point (location L3 in Figure 1), the plotted point for the impedance equivalent value is located at position P3, near the origin O. After the train moves past the transmission point, the plotted point for the impedance equivalent value changes in the reverse order, gradually returning to position P1. Therefore, by detecting that the plotted point has recently come into contact with the origin O (or a position very close to the origin O) and has begun to displace towards position P1, the track circuit device 1 can determine that the train has moved past the transmission point. In other words, the track circuit device 1 can determine the direction of the train's movement relative to the transmission point by whether the plotted point is displaced and moving towards or away from the origin O.

[0046] In this way, the presence or absence of a train in the detection section T1 can be determined from the change in the plotted value of the impedance equivalent of the track circuit in a Cartesian coordinate system (complex plane) with the real and imaginary components as axes. When the plotted point is at position P1, there is no train present (not present), and when the plotted point begins to move from position P1 toward the origin O, it is determined that a train is approaching the detection section T1. Next, when the plotted point becomes position P2, it is determined that a train has entered the detection section T1, i.e., there is a train present. Subsequently, when the plotted point displaces from position P2 to position P3 (origin O) and then returns to position P2, it is determined that a train has left the detection section T1, i.e., there is no train present. After that, when the plotted point changes back toward position P1, it is determined that the train that left the detection section T1 is moving away. If another train approaches, the presence or absence of a train can be similarly determined by the change in the position of the plotted value of the impedance equivalent from position P1.

[0047] As described above, since the track circuit in this embodiment is an uninsulated track circuit, the AC signal transmitted from the transmission point to the rail also propagates to the adjacent section on the advance end side (forward in the direction of travel) of the detection section T1. For this reason, the presence or absence of a train may be determined by including the adjacent section on the advance side in the detection section T1. In this case, after the plotted point of the impedance equivalent value is displaced to position P3 (origin O), it is further displaced to a position corresponding to the distance of the adjacent section, thereby determining whether a train is advancing from the detection section T1 (no train present).

[0048] Furthermore, the position of the plotted points for impedance equivalent values ​​in the Cartesian coordinate system (complex plane) is determined according to the impedance of the track circuit, that is, the short-circuit position of the rails (the position of the train). Therefore, by determining the correspondence between the position of the train (short-circuit position of the rails) and the position of the plotted points for impedance equivalent values ​​in advance through measurements, the position of the train can be determined based on the position of the plotted points, with respect to the AC signal transmission point.

[0049] Furthermore, the trajectory, which is the change in the plotted points of the impedance equivalent value in this Cartesian coordinate system (complex plane), has a unique shape determined according to the detection interval. For this reason, it is possible to determine in advance the trajectory of the impedance equivalent value associated with the movement (passage) of a train when the rails are in a normal (no abnormality) state. The trajectory of the plotted points of the impedance equivalent value when the rails are in a normal state is called the reference trajectory.

[0050] [Checking the condition of the rails] Next, the determination of the rail condition by the determination unit 35 will be explained. The rail condition is determined by comparing the plotted impedance equivalent values ​​with the reference trajectory. The determination of the rail condition is whether the rail condition is normal or abnormal, and abnormal rail conditions include rail fracture and abnormalities related to leakage conductance.

[0051] (A) Rail fracture Figure 5 shows an example of a plotted point for the impedance equivalent value when a rail break occurs. In Figure 5, the plotted points for the impedance equivalent value are shown in a Cartesian coordinate system (complex plane) with the real and imaginary components as axes, and the reference trajectory is also shown. As shown in Figure 5, the position of the plotted point when the rail is not present under normal conditions is position P1. When a rail break occurs, the position of the plotted point changes significantly from position P1. Specifically, the real component of the impedance equivalent value remains positive, but the imaginary component changes to a negative value. Therefore, the position of the plotted point transitions from the first quadrant to the fourth quadrant. Also, the closer the rail break position is to the AC signal transmission point, the larger both the real and imaginary components of the impedance equivalent value become, so it transitions to position P4, which is further from the origin O. In Figure 5, the positions of the plotted points for the impedance equivalent value are P4-1 and P4-2 for different rail break positions. When the plotted point is at position P4-1, it indicates that the rail break position is closer to the transmission point than when it is at position P4-2.

[0052] Furthermore, the position P4 of the plotted point for the impedance equivalent value in the Cartesian coordinate system (complex plane) when a rail break occurs is determined according to the location of the break. Therefore, by determining the correspondence between the rail break location and the position P4 of the plotted point for the impedance equivalent value in advance through measurement or calculation, the rail break location can be determined from the position P4 of the plotted point.

[0053] Thus, when a rail break occurs, the plotted point for the impedance equivalent value is located at position P4, which is off the reference trajectory. However, as shown in Figure 6, after the train passes this rail break location, the rails are short-circuited by the train's axle at a position closer to the transmission point than the rail break location, causing the position of the plotted point for the impedance equivalent value to change along the reference trajectory. Therefore, if the plotted point is off the reference trajectory, and then changes along the reference trajectory after returning to it, the position where the plotted point returns to the reference trajectory can be determined as the rail break location.

[0054] (B) Abnormalities related to leakage conductance Figure 7 shows an example of plotted points for impedance equivalent values ​​when an anomaly related to leakage conductance occurs. For clarity, the change (trajectory) of the plotted points for impedance equivalent values ​​when an anomaly related to leakage conductance occurs is shown with a thick line across the entire rail. An anomaly related to leakage conductance is the change in the leakage conductance component G=1 / Rb in the equivalent circuit of the track circuit shown in Figure 2. This is mainly an increase in leakage conductance caused by poor insulation between the rail and the ground due to moisture such as rain and snow.

[0055] When an anomaly related to leakage conductance occurs, the impedance of the track circuit changes when the train travels through (passes through) the detection section T1, causing the plotted point of the impedance equivalent value in the Cartesian coordinate system (complex plane) to deviate from the reference trajectory. For example, if the leakage conductance component G=1 / Rb increases, the impedance of the track circuit decreases, and the impedance equivalent value decreases, causing the plotted point in the Cartesian coordinate system (complex plane) to deviate from the reference trajectory. The trajectory It becomes shorter than the reference trajectory. (See diagram) 7 Therefore, since leakage conductance is increasing across the entire rail, the change in the position of the plotted impedance equivalent value accompanying the passage of a train will result in a shorter trajectory relative to the reference trajectory, as shown by the thick line. However, even if an abnormality occurs in leakage conductance, the position of the plotted point changes toward the origin O of the Cartesian coordinate system as the train moves, which is almost the same as in a normal state.

[0056] In other words, the greater the leakage conductance, the shorter the trajectory of the plotted point relative to the reference trajectory, and the position P1 of the plotted point when the train is not present (no trains within the detectable range) and the position P2 of the plotted point when the train enters the detection section T1 become closer together. Therefore, when the position of the plotted point is near position P2 on the reference trajectory, it becomes difficult to distinguish whether it is position P1, which is close to position P2 due to increased leakage conductance despite the train not being present, or whether there is no abnormality related to leakage conductance and the train is entering the detection section T1. In other words, it becomes difficult to determine whether the train is present or not. In particular, it is difficult to distinguish the change in the plotted point from the position P1, which is an unpresented position, to the position P2, which is when the train enters the detection section T1.

[0057] Here, the leakage conductance of the track circuit is merely a circuit element within the track circuit, and when a train is present at the transmission point, as shown in Figure 2, the impedance viewed from the transmission point consists only of the axle short-circuit impedance Rv, so the impedance at this time is almost constant. For this reason, the track circuit device 1 can distinguish, based on the presence or absence determination result of another track circuit device whose detection section is adjacent to the detection section T1, whether the position of the plot point is near position P2 on the reference track, and whether it is a position P1 that is approaching position P2 due to an increase in leakage conductance even though the train is not present, or whether there is no abnormality related to leakage conductance and the train is entering the detection section T1. In other words, it can determine whether or not an abnormality related to leakage conductance has occurred.

[0058] In other words, as shown in Figure 8, another track circuit device 1B is provided, which has the adjacent section on the entry end side (rear in the direction of travel) of detection section T1 as detection section T2. ​​As described above, the track circuit in this embodiment is an uninsulated track circuit, so the AC signal transmitted from the transmission point to the rail also propagates to the adjacent section on the exit end side (forward in the direction of travel) of the detection section. For this reason, in Figure 8, the detection section of the track circuit device is set to two consecutive sections before and after the transmission point. That is, track circuit device 1 has the two detection sections T1a and T1b before and after the transmission point (position L3) as detection section T1, and track circuit device 1B has the two detection sections T2a and T2b before and after the transmission point (position L1) as detection section T2. ​​Furthermore, the level of the AC signal transmitted by track circuit device 1 to the transmission point (position L3) is designed so that the transmission point (position L1) of track circuit device 1B is included in its detectable range.

[0059] In such a case, when a train is present at the transmission point (position L1) of the track circuit device 1B, the track circuit device 1B can determine whether a train is present at the transmission point (position L1) by the magnitude of the impedance seen from the transmission point (position L1). Then, the track circuit device 1 can determine whether or not an abnormality related to leakage conductance has occurred by comparing the magnitude of the impedance seen from the transmission point (position L3) at that time with the magnitude under normal conditions (when no abnormality related to leakage conductance has occurred). In other words, if the leakage conductance is increasing, the magnitude of the impedance will decrease.

[0060] Furthermore, if an anomaly related to leakage conductance occurs in only a portion of the rail rather than the entire rail, the location of the leakage conductance anomaly can be determined from the change in the position of the plotted impedance equivalent value as the train passes. In other words, similar to the case of a rail fracture, when an anomaly related to leakage conductance occurs, the plotted impedance equivalent value is located at a position outside the reference trajectory. However, after the train passes over the location of the leakage conductance anomaly, the rails are short-circuited by the train's axle at a position closer to the transmission point than the anomaly location, causing the position of the plotted impedance equivalent value to change along the reference trajectory. Therefore, if a plotted point is outside the reference trajectory, and then changes along the reference trajectory after returning to it, the position where the plotted point returned to the reference trajectory can be determined as the location of the leakage conductance anomaly.

[0061] (C) Permissible range of variation The determination unit 35 determines the condition of the rail (whether it is normal or not) by comparing the position of the plotted point of the impedance equivalent value in the Cartesian coordinate system (complex plane) with the reference trajectory. However, in reality, even if the condition of the rail is normal, the position of the plotted point of the impedance equivalent value does not necessarily perfectly coincide with the reference trajectory. This is mainly due to the fact that the rail is installed outdoors, causing slight fluctuations in leakage conductance and capacitance components between the rails due to the effects of temperature, humidity, rainfall, snowfall, etc. For this reason, as shown in Figure 9, an allowable fluctuation range is defined, which is the range in which fluctuations in the impedance equivalent value at position P1 on the reference trajectory are permitted. In Figure 9, the allowable fluctuation range for position P1 is shown, and the dashed line surrounding position P1 is the allowable fluctuation range for position P1. If the position of the plotted point of the impedance equivalent value falls outside this allowable range, it is determined to be some kind of abnormality or sign of abnormality. This abnormality or sign of abnormality may include the rail fracture and leakage conductance abnormalities mentioned above.

[0062] [Transmission of AC signals] Next, the transmission of AC signals will be described. In this embodiment, the processing unit 30 transmits AC signals intermittently. The intermittent transmission of AC signals is achieved by controlling the transmission voltage by the transmission voltage output unit 36.

[0063] Furthermore, during periods when AC signals are not being transmitted, the transmission voltage / frequency setting unit 37 turns off the transmission switch of the transmitter 10 or cuts off the output, and the noise measurement unit 39 measures rail noise (return noise). Next, the set frequency / transmission level determination unit 38 performs frequency analysis processing such as FFT (Fast Fourier Transformation) on the noise (return noise) measured by the noise measurement unit 39 to determine the level and frequency of the noise (return noise). Then, it determines the frequency and level that do not interfere with the noise (return noise) as the set frequency and transmission level for the AC signal.

[0064] By transmitting AC signals intermittently, the transmission power can be reduced, further energy savings can be achieved for the track circuit device 1. Furthermore, since an AC signal with an optimal transmission level corresponding to the level of rail noise (return noise) is transmitted, further energy savings can be achieved for the track circuit device 1. In addition, since an AC signal of an optimal frequency that does not interfere with frequencies other than the rail return noise is transmitted to the rail, it does not affect other signals flowing through the rail.

[0065] [Effects and Effects] According to this embodiment, a track circuit device 1 can be realized that operates on a completely different principle from conventional track circuit devices. In other words, the impedance of the track circuit as seen from the AC signal transmission point changes depending on whether a train is present or not, and this change in impedance changes the amplitude and phase difference of the transmission voltage and transmission current. Therefore, the impedance equivalent value of the track circuit can be determined from the amplitude and phase difference of the transmission voltage and transmission current, and the presence of a train can be determined based on the real component (resistance component) and imaginary component (reactance component) when this impedance equivalent value is expressed as a complex number. Since the presence of a train can be determined based on the transmission voltage and transmission current of the AC signal transmitted to the rail, a receiver is not required, and there is no need to transmit a signal that maintains a constant signal level at the receiving point, thus reducing the transmission power. As a result, an energy-saving track circuit device 1 can be realized. Furthermore, since a receiver is not required, further benefits can be obtained, such as reducing the number of components compared to conventional track circuit devices.

[0066] [Differentiation] It should be noted that the applicable embodiments of the present invention are not limited to those described above, and can be modified as appropriate without departing from the spirit of the invention.

[0067] (A) Scanning method In the embodiment described above, the track circuit device 1 transmits an AC signal to one detection section T1, but a so-called scanning method may also be used, in which AC signals are transmitted sequentially to multiple detection sections by switching between them.

[0068] Figure 10 shows an example of a scanning-type track circuit device. As shown in Figure 10, the scanning-type track circuit device 1A further includes a group of selector switches 18, which is a collection of selector switches that transmit AC signals to each of the transmission points of multiple detection sections T1, T2, ... The processing unit 30A outputs a switching signal to the group of selector switches 18 that selects and controls to turn on the selector switch corresponding to one detection section (one of the detection sections T1, T2, ...) to which an AC signal is transmitted. Then, it transmits an AC signal to the selected detection section. In Figure 10, the two sections before and after the transmission point, which is the boundary of the track circuit, are considered as one detection section. The level of the AC signal transmitted to the transmission point is designed so that the transmittable range for one detection section includes the transmission point of the adjacent detection section. This makes it possible to switch and select the detection section to which an AC signal is transmitted while tracking a train, except for the entry-side detection section of the track circuit device 1A. In this case, the frequency of the transmitted AC signal may also be switched according to the detection section T1, T2, ...

[0069] (B) Insulated track circuit In the above embodiment, the track circuit was described as an uninsulated track circuit, but it may also be an insulated track circuit. Figure 11 is a diagram showing an example of the trajectory of the plotted points of the impedance equivalent values ​​of the track circuit in a Cartesian coordinate system (complex plane) when the detection section T1 shown in Figure 1 is an insulated track circuit, and corresponds to Figure 4. In the case of an insulated track circuit, the AC signal flows only in the detection section T1 and not in adjacent sections. Therefore, as shown in Figure 11, the position of the plotted point is position P1 until the train enters the detection section T1. Then, immediately after the train enters the detection section T1 (location L2), the position of the plotted point transitions to position P2. After that, as in the case of an uninsulated track circuit, the position of the plotted point changes analogously from position P2 to position P3 (origin O) as the train moves. When the train enters (arrives at) the transmission point, its position becomes P3 (origin O). As it moves past the transmission point and enters the detection section T1, the position of the plotted point immediately transitions to position P1.

[0070] The detection section T1 may also be defined as two consecutive sections before and after the transmission point. In this case, the position of the plotted impedance equivalent value changes in the reverse order of before, gradually returning from position P3 (origin O) to position P2 after the train has advanced (passed) the transmission point. Then, as the train advances through the detection section T1, the position of the plotted point immediately transitions to position P1.

[0071] (C) Insulation failure at the boundary of an insulated track circuit If the track circuit is an insulated track circuit, the condition of the rails can be further assessed to determine if there is insulation failure at the track circuit boundary. Insulation failure at the track circuit boundary can occur due to the accumulation of foreign matter on the insulator or deterioration of the insulator.

[0072] (D) Tracks of multiple trains passing by Alternatively, rail abnormalities or signs of abnormalities may be determined by acquiring and collecting the trajectories of impedance equivalent values ​​associated with the passage of multiple trains and comparing these trajectories for each passage. Or, rail abnormalities or signs of abnormalities may be determined by comparing the trajectory associated with the passage of a single train with a reference trajectory. This comparison of trajectories for each passage or comparison with the reference trajectory can be performed, for example, by determining whether the similarity calculated by pattern matching treating the trajectory as an image, or the error rate calculated by the least squares method, satisfies predetermined threshold conditions. Furthermore, the reference trajectory data stored in the determination unit 35 may be updated based on the change in the position of the plotted points when the rail condition is determined to be normal. [Explanation of symbols]

[0073] 1...Track circuit device 10…Transmitter 20...Current sensor 30… Processing equipment 31...Transmission voltage waveform acquisition unit 32...Transmission current waveform acquisition unit 33…Corner-law detection circuit section 34...Impedance equivalent value calculation unit 35…Judgment section 36...Transmit voltage output section 37…Transmission voltage / frequency setting section 38…Set frequency / transmission level determination unit 39... Noise measurement section

Claims

1. A calculation means for calculating an impedance equivalent value based on the amplitude and phase difference of the transmission voltage and transmission current of an AC signal transmitted to a rail by a transmitting means, A determination means for determining the presence of a train based on the real and imaginary components of the impedance equivalent value, A track circuit device equipped with the following features.

2. The determination means determines the location of the train based on the transmission point of the AC signal by the transmission means. The track circuit device according to claim 1.

3. The determination means determines the location of the train relative to the transmission point based on the plotted points of the impedance equivalent values ​​in a coordinate system with the real and imaginary components as axes. The track circuit device according to claim 2.

4. The determination means determines the location of the train based on the position of the plotted points along a predetermined reference trajectory in the coordinate system. The track circuit device according to claim 3.

5. The determination means determines the state of the rail based on the real and imaginary components of the impedance equivalent value. A track circuit device according to any one of claims 1 to 4.

6. The determination means determines the location of an abnormality in the rail, with reference to the transmission point of the AC signal by the transmission means. The track circuit device according to claim 5.

7. The determination means includes, when the plotted point deviates from the reference trajectory, means for determining the location of the abnormality in the rail related to leakage conductance and / or rail fracture based on the position of the deviation. The track circuit device according to claim 4.

8. The determination means includes a rail fracture determination means that determines whether or not a rail fracture has occurred based on the sign of the imaginary component value. A track circuit device according to any one of claims 1 to 4.

9. The rail fracture determination means determines the location of the rail fracture with respect to the transmission point of the AC signal by the transmission means, based on the real and imaginary component values ​​of the impedance equivalent value. The track circuit device according to claim 8.

10. The determination means determines whether there is an abnormality or sign of an abnormality in the rail based on whether the plotted points of the impedance equivalent values ​​in a coordinate system with the real and imaginary components as axes are outside the allowable variation range of the impedance equivalent values ​​determined according to the distance from the transmission point of the AC signal by the transmission means. A track circuit device according to any one of claims 1 to 4.

11. To measure the transmission voltage and transmission current of the AC signal transmitted to the rail by the transmitting means, To calculate an impedance equivalent value based on the amplitude and phase difference of the transmitted voltage and transmitted current, Based on the real and imaginary components of the impedance equivalent value, the presence of a train is determined. A method for determining the presence of a train, including the method described above.

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