KR20120124597A - Track circuit test device and method for testing track circuit - Google Patents

Abstract

PURPOSE: A track circuit measurement device and a method thereof are provided to obtain frequency displacement which is a frequency diagnosing function of an AF track circuit. CONSTITUTION: A TU(Tuning Unit)(10) and an input transformer(20) receive a transmitting track circuit signal of an FSK(Frequency Shift Keying) waveform generated in a transmitting unit. A band pass filter(30) removes noises coming from surrounding tracks from a track circuit signal of an FSK waveform. An amplifier(40) amplifies the signal of the FSK waveform. A low band pass filter(50) removes a signal noise from an amplification process. A digital signal processing unit(60) displays an analysis result on a display unit(70) through a DSP(Digital Signal Processor) circuit for analyzing a signal error of a USB(Upper Signal Band) and an LSB(Lower Signal Band) and a signal size of each band. The digital signal processing unit detects a modulation frequency and a frequency contrast size element by using an IIR(Infinite Impulse Response) filter and an FIR(Finite Impulse Response) filter. [Reference numerals] (100) ±17Hz demodulation unit with the nominal frequency; (20) Input transformer; (40) Amplifier; (70) Display unit; (AA) FSK wave form(oscillating in ±17Hz of the nominal frequency in the period of 4.8Hz)

Description

TRACK CIRCUIT TEST DEVICE AND METHOD FOR TESTING TRACK CIRCUIT}

The present invention relates to a track circuit measuring apparatus and method capable of measuring a signal of the track circuit.

The track circuit uses the rail as a part of the circuit for the signal current to determine whether the train is present as the rail is shorted by the axle of the train, so that it can directly or indirectly control the signal, track switch, interlock, and other signaling devices. An electric circuit using a track installed for the purpose.

As a typical track circuit, oil-insulated high voltage impulse ("HVI") track circuits are widely used in trunk railway and station premises. HVI track circuit is a facility to detect the presence or absence of train at a certain section using special waveforms of impulse voltage 400 ~ 600 [V], 3 [Hz].

The HVI track circuit is equipped with a voltage stabilizer, transmitter, receiver and track relay in the machine room. It also consists of transmit and receive impedance bonds in the field. The return current flowing through the tramline is composed of a circuit up to the substation, and the signal current flows through only one track circuit. The tramline return current flows in the opposite direction of the coil halfway so that the core is not magnetized. to be. Long term high voltage impulse (HVI) track circuits, such as voltage, current and impedance can be measured with a multitester attached to an integrator. However, measuring the frequency 3 [Hz] is difficult. Until now, it is impossible to measure frequency and measure voltage directly, and only measure the magnitude of the voltage impulse peak value with an integrator.

In general, multitesters measure the sine wave's effective value, which is impossible without an integrator. In addition, the principle of the integrator is applied to the charging principle of the capacitor, so the numerical value is not accurate and only an approximate value can be known. In addition, there is a disadvantage in that the service life is short due to repeated charge and discharge of high pressure. If it is necessary to make a measurement, it can only be done with a low pressure oscilloscope on the control panel of the machine room.

The transmitter of the HVI track circuit impedance-bonds an asymmetric waveform impulse in which the ratio of positive and negative pulses is 3: 1 or more at regular intervals (180 pulses / minute 5 [%]) by the operation of the R OC charging and discharging circuit. Transmit to orbit through. The signal current (3 [Hz]) is a method of forming an independent track circuit by cutting off the impedance bond, and using a high voltage impulse, so that the voltage drop is small and the power consumption of one track circuit is about 50 to 60 [VA]. 1 shows a configuration of an HVI track circuit. As shown in FIG. 1, the HVI track circuit includes a transmitter, a receiver, an impedance bond (transmitter, a receiver), and a track relay.

As another track circuit, there is a non-isolated audio frequency ("AF") track circuit, which has recently been increasingly used. The AF track circuit modulates and transmits an audible frequency to a signal current through a modulator, and amplifies the corresponding frequency with a select amplifier among the modulated frequencies at the receiving side, and rectifies and operates the track relay. This AF track circuit is very advantageous in terms of installation or function.

The AF track circuit constitutes a track circuit by flowing an audible frequency railway signal current of 16 to 20,000 [Hz] on a rail, and is most suitable for use for onboard signals. 2 shows the configuration of the AF track circuit. As shown in FIG. 2, the AF track circuit device includes a power supply unit, a transmission unit, a tuning unit, a receiving unit, and a monitoring unit. In Fig. 2, AT represents an A track circuit, BT represents a B track circuit, MT represents a matching transformer, and TR represents an orbital relay.

Most AF track circuits are non-isolated, and the transmitter's operation oscillates a square wave of 4.8 [Hz] in a multivibrator. The oscillator oscillates at a nominal frequency of 17 [Hz] and modulates frequency shift keying through the modulator. Frequency Shift Keying (FSK) modulation waveforms are transmitted via amplifiers to orbits through matching transformers, filters, and TUs. The receiver transmits the signal transmitted through the track circuit through the TU and through the input transformer, and the frequency of the nominal frequency ㅁ 17 [Hz] through the filter, the amplifier and the filter through demodulation through the AND gate, respectively. Operate to deliver to the orbital relay. The track relay operates when the operating current is above the target value.

The importance of testing and measuring instruments for HVI track circuits and AF track circuits is becoming increasingly important. Currently, the HVI track circuit has an integrator attached to a multitester, and the AF track circuit has a TTM (TI21 Test Meter).

However, the test and measuring device of the AF track circuit and the HVI track circuit has the following problems.

3 is a representation of an A-type TI21 alternating frequency waveform and shows that it is alternated at 4.8 [Hz]. At the receiver, when the USB and LSB frequencies are demodulated and passed through the AND gate, the orbital relay operates. However, if only one of the LSB or USB is transmitted due to a failure of the transmitter side, a problem occurs that the track relay is not excited and the train is occupied. In current TTM, the signal output of LSB and USB cannot be separated to measure voltage and signal current clearly. Therefore, even if a failure occurs on the transmitter side, it is measured as a normal operation and it is difficult to determine whether there is a failure.

The field engineer must predict the measurement, select the range, and measure it. However, engineers who are familiar with the auto-adjustment method can make the wrong choice of range and damage expensive TTM equipment or inaccurate measurements.

In addition, in the conventional AF track measuring device (TTM), when measuring the frequency in the receiver-side measurement section, there is no method for confirming the maximum transmitter value received. The receiver operates by the reception value of the frequency, and is operated to the safety side due to the characteristics of the railway signal. If a problem such as interference occurs, it is designed to operate in a normal state only when it is solved. Therefore, there is a need for a method to solve the abnormality caused by the frequency interference of the transmitter and the adjacent line.

Figure 4 shows the interference by the adjacent track circuit transmitter and noise.

The factors of frequency interference are as follows. First, as shown in FIG. 4, the values of the transmitter and the transmitter of the front end enter the receiver, and if the second vehicle passes by, the intermittent case may generate an abnormal noise and cause a problem. This is the case when the transmitter waveform of the next stage is inputted beyond the fourth impedance bond. When such cases occur, a function that can solve the problem through the measurement is required, and current equipment has no way of measuring the abnormal state of the impedance bond and the correct operation.

The problem of the conventional HVI track circuit measurer is as follows.

In the HVI track circuit, a voltage stabilizer, a transmitter, a receiver, and a track relay are installed in the machine room, and a transmission / reception impedance bond is installed in the field. The return current flowing in the tramline is composed of a circuit up to the substation, and the signal current flows only in one track circuit. The tramline return current flows in the opposite direction of the coil halfway so that the core of the impedance bonder is not magnetized. The voltage, current, and impedance of a high voltage HVI track circuit can be measured with a multitester with an integrator. However, frequency measurement at frequency 3 [Hz] is difficult. In general, multitesters measure the effective value of sinusoidal wave, so it is impossible to measure it unless the integrator is attached. In addition, since the integrator uses the charging principle of the capacitor, the numerical value is not accurate and only an approximate value can be known. In addition, since the charge and discharge of a high pressure is repeated, there is a disadvantage that its life is short. If it is necessary to make a measurement, there is a problem in that it is necessary to measure with a low-pressure oscilloscope in the control room of the machine room.

SUMMARY OF THE INVENTION An object of the present invention is to provide a track circuit measuring apparatus and a method which can solve the problems of the above-described conventional AF track circuit and HVI track circuit test and measuring device.

An orbital circuit measuring apparatus according to an embodiment of the present invention comprises: receiving means for receiving a modulated transmission signal of an orbital circuit; Detects and analyzes the upper signal band ("USB") frequency and the lower signal band ("LSB") frequency of the track circuit signal received through the receiving means, and analyzes each of the USB and LSB frequencies. Analysis means for analyzing the size of the; And output means for outputting a result analyzed by the analyzing means.

In the track circuit measuring apparatus according to an embodiment of the present invention, the track circuit signal received through the receiving means may be a frequency shift keying (FSK) signal, and the analyzing means may include: The AC voltage of the received track circuit signal is calculated as a root mean square (RMS) value, and then positive-to-negative and negative-negative based on zero-crossing. A frequency can be calculated by averaging interval values between to-positive).

In the track circuit measuring apparatus according to an embodiment of the present invention, the analyzing means measures the modulation frequency magnitude through the change and the changed time of the zero-crossing frequency, and the USB frequency through the zero-crossing time. And LSB frequency can be measured.

In the track circuit measuring apparatus according to the embodiment of the present invention, the analyzing means may measure the signal source cumulatively by a set period to analyze the measurement frequency error relative to the reference frequency.

In the track circuit measuring apparatus according to an embodiment of the present invention, the receiving means includes a band pass filter and an infinite impulse response (IIR) for removing noise introduced from a peripheral line. ) Or a finite impulse response (FIR) filter.

In the track circuit measuring apparatus according to an embodiment of the present invention, the analyzing means uses a blackman window, which is a type of the FIR filter, and a USB frequency and LSB of the received track signal. The magnitude of each frequency of the frequency may be detected, and the presence or absence of a train on the track may be determined based on the detection result.

A track circuit measuring method according to another embodiment of the present invention includes a receiving step of receiving a modulated transmission signal of a track circuit; An analysis step of detecting and analyzing the USB frequency and the LSB frequency of the track circuit signal received through the receiving means, and analyzing the magnitudes of the USB and LSB frequencies, respectively; And an output step of outputting the result analyzed by the analyzing step.

In the track circuit measuring method according to another embodiment of the present invention, the track circuit signal received in the receiving step may be an FSK signal, and in the analyzing step, the AC voltage of the received track circuit signal is measured. After calculating the RMS value, the frequency can be calculated by averaging the interval value between positive and negative and negative and positive based on the zero-crossing method.

Further, in the track circuit measuring method according to another embodiment of the present invention, in the analyzing step, the modulation frequency magnitude is measured by the change and the time of the zero-crossing frequency, and the USB frequency through the zero-crossing time And LSB frequency can be measured.

Further, in the track circuit measuring method according to another embodiment of the present invention, in the analyzing step, by measuring the signal source cumulatively by a set period, it is also possible to analyze the measurement frequency error relative to the reference frequency.

In the track circuit measuring method according to another embodiment of the present invention, in the analyzing step, each frequency of the USB frequency and the LSB frequency of the received track signal using a blackman window, which is a type of FIR filter, may be used. Star size can be detected.

In the track circuit measuring method according to another embodiment of the present invention, in the analyzing step, it is possible to determine whether or not the train on the track based on the size of each frequency of the detected USB frequency and LSB frequency.

The present invention can separately measure the USB frequency, which is the frequency of +17 [Hz] of the nominal frequency of the AF track circuit, and the LSB, which is the frequency of -17 [Hz] of the nominal frequency, respectively. In addition, the present invention can find a frequency shift which is a frequency diagnosis function of the AF track circuit.

In addition, the present invention can implement a scan function that can measure the frequency having the largest input value at the measurement point. In addition, since a high impulse voltage is applied, it can be designed to increase the durability against impact on the impulse waveform instead of lowering the accuracy.

In addition, the Auto-Range feature can be implemented to solve the problem of engineers incorrectly selecting a manual range to read inaccurate readings or damage the instrument.

In addition, the present invention can be implemented as a portable, multi-functional, which can be used in both the HVI track circuit and the AF track circuit.

1 is a schematic block diagram showing the configuration of an HVI track circuit.
2 is a schematic block diagram showing the configuration of the AF track circuit device.
3 is a diagram showing waveforms of the A-type frequency of TI21.
4 is a diagram illustrating interference by an adjacent track circuit transmitter and noise.
5 is a schematic block diagram of a track circuit measuring apparatus according to a preferred embodiment of the present invention.
6 is a schematic block diagram of a track circuit measuring method according to a preferred embodiment of the present invention.

5 is a schematic block diagram of a track circuit measuring apparatus according to a preferred embodiment of the present invention. As shown in FIG. 5, a track circuit measuring apparatus according to a preferred embodiment of the present invention includes a tuning unit (TU) 10, an input transformer 20, a band pass filter 30, an amplifier 40, and a low pass. The filter 50 includes a digital signal processor 60, an output unit 70, and a demodulator 100.

The TU 10 and the input transformer 20 receive a transmission trajectory circuit signal of an FSK waveform generated by a transmitter, and the band pass filter 30 (BPF) is the TU 10. And noise introduced from the peripheral line from the track circuit signal of the FSK waveform received through the input transformer 20.

The amplifier 40 amplifies the attenuated FSK waveform of the track circuit signal for signal processing, and includes a low pass filter 50; "LPF" removes signal noise during signal amplification by the amplifier 40.

The digital signal processor 60 (DSP) outputs an analysis result through the output unit 70 through a DSP circuit for analyzing a single signal error of USB or LSB and a signal size for each frequency band. .

In this case, the digital signal processor 60 includes an Infinite Impulse Response (IIR) filter and a Finite Impulse Response (FIR) filter.

The digital signal processor 60 uses an IIR filter and an FIR filter to detect the modulation frequency and the magnitude component of the frequency. For accurate frequency detection, frequency analysis through zero-crossing detection of the modulated FSK signal is performed to detect frequency and modulation frequency for each signal source.

(Features and Algorithms of Applied IIR Filters)

Frequency measurement using the applied IIR filter is mainly performed at the frequency transmitter to determine whether there is a problem with the transmitter. In this case, the output is relatively clean, with some waveform distortion, but with less noise. Therefore, the present invention is advantageously applied to high-speed calculations with fewer orders than the FIR filter. The filter was designed using "eziir32.m", a Matlab program included in the C28X Filter Library (SPRC082). Table 1 shows the characteristics of the filter.

[Table 1]

In Table 1, if the sampling frequency is excessively applied to the signal processing processor too much burden. In addition, the timeout during continuous calculations causes data loss.

In a preferred embodiment of the present invention, since the frequency to be measured is up to 2600 [Hz], 20 [kHz] corresponding to 8 times the maximum frequency is applied. The reason for applying the proper sampling frequency also includes the reason for reducing the calculation time consumed in the digital signal processor 60.

The demodulator 100 demodulates the trajectory circuit signal of the FSK waveform of? 17 [Hz] of the nominal frequency modulated at the transmitting side into its original signal.

6 is a schematic block diagram of a track circuit measuring method according to a preferred embodiment of the present invention.

Referring to Fig. 6, in the present invention, the TU 10 and the input transformer 20 receive a transmission trajectory circuit signal of an FSK waveform generated at the transmitting side (S10).

Then, the band pass filter 30 removes the noise flowing from the peripheral line from the track circuit signal of the FSK waveform received through the TU 10 and the input transformer 20, and the amplifier 40 the track circuit The attenuated FSK waveform of the signal is amplified for signal processing, and the low pass filter 50 removes signal noise in the signal amplification process by the amplifier 40 (S20).

The noise-removed and amplified track circuit signal is subjected to an analog-to-digital (A / D) conversion process (S30), and through the digital signal processor 60, error measurement of frequency (S40) and FSK. Measurement of the modulation frequency (S50) and train occupancy determination (S60) is passed.

Specifically, in the error measuring step (S40) of the frequency, only a band signal from which noise is removed is measured using a narrow band pass filter on the FSK waveform. Calculate the AC voltage as the RMS value, and then use the zero-crossing method to determine the interval between positive-to-negative ("PtoN") and negative-to-positive ("NtoP"). Calculate the frequency by averaging the values.

Through this process it is possible to measure the frequency analysis and voltage size for the single signal through the orbital signal measuring apparatus and method of the present invention.

In addition, it is possible to detect the measurement frequency error compared to the reference frequency. When detecting the FSK waveform, a simple zero-crossing method measures the reference frequency error up to 2600 [Hz] at the frequency 20 [kHz] sampled during the analog-digital conversion process. It is impossible to do. An example of this is as follows.

Pt = time in Pt section

Nt = time of Nt section

Frequency = 1 / Pt + 1 / Nt

Minimum detection sampling time according to sampling frequency = 1/20 [kHz] = 50 [μs]

If the reference frequency section is 2600 [Hz] as shown below, the time for one cycle is 384.62 [μs]. The sampling time is 384.47 [μs] when the signal reference according to the measurement is 2601 [Hz]. To detect the reference error, the sampling time should be shorter than 384.62 [μs]-384.47 [μs] = 0.15 [μs] between 2600 [Hz]-2601 [Hz]. However, in the embodiment of the present invention, since the sampling time is 50 [μs], it is impossible to measure the error by measuring the signal source one by one.

To solve this problem, the measured signal sources were accumulated in 5000 cycles. When the reference of the measured signal source is 2601 [Hz], the reference reference 2600 [Hz] and the sampling time error become 750 [μs]. In this case, the error can be measured because it is larger than the set sampling time.

In the measuring step of the FSK modulation frequency (S50), the FSK track signal of the AF track circuit is modulated at 4.8 [Hz] by low frequency -17 [Hz] and high frequency +17 [Hz] at the reference frequency.

The proposed algorithm to detect abnormality of modulation frequency detects zero-crossing point within one period and enables frequency analysis and modulation frequency analysis of USB and LSB signals. An example of this is as follows.

The maximum modulation width of the AF track circuit in the railway is 1 to 10 [Hz]. Accordingly, it can be seen that 50 ms is a time when there is no frequency variation based on the modulation of 10 [Hz], which is the harshest condition. In other words, one period of modulation is composed of low frequency and high frequency waveforms, and the time for one period is 100 [ms]. As a result, there is no variation in frequency for 50 [ms].

With this in mind, it is possible to detect a section in which the number of zero-crossings is changed, and then analyze a single signal frequency of the USB signal and the LSB signal. It is also possible to analyze the modulation frequency within one period. An example of this is as follows.

Maximum No Modulation Interval: 100 [ms] / 2 = 50 [ms]

When measured at 50 [ms] intervals, one or more unmodulated intervals, which must be in the low or high frequency state, can be obtained.

That is, the USB frequency and the LSB frequency can be analyzed by detecting the zero-crossing count and time as follows. By measuring the zero-crossing point of change, the modulation frequency can also be analyzed.

Number of zero-crossings and times within 50 [ms]:

USB Frequency: 1549 [Hz] + 17 [Hz] = 1566 [Hz]

LSB Frequency: 1549 [Hz]-17 [Hz] = 1532 [Hz]

One cycle time of USB section: 638.6 [μs]

Total number of USB zero-crossing detections: 1566 [Hz] * 50 [ms] = 78.3 times

One cycle time for LSB section: 652.7 [μs]

LSB zero-crossing total detections: 1532 [Hz] * 50 [ms] = 76.6 times

It is possible to measure the modulation frequency magnitude through the change and the time of the zero-crossing times illustrated above, and the frequency of the USB and LSB signals through the zero-crossing time.

 As described above, the present invention proposes an algorithm for measuring the frequency and modulation frequency of the LSB and USB signals through the IIR filter.

In the train occupancy determination step (S60), it is possible to determine whether or not the occupancy of the train on the track using the FIR filter FSK track signal of the AF track circuit. The Blackman Window, a type of FIR filter, can detect the magnitude of each frequency of the USB and LSB of the modulated signal. Through this, it is possible to determine whether the train occupies the track.

The result of the error measurement (S40) of the frequency, the measurement of the FSK modulation frequency (S50), and the train occupancy determination (S60) performed by the digital signal processor 60 are output through the output unit 70.

As described above, according to the present invention, when only one of the LSB or the USB signal is transmitted due to a failure of the transmitter side, in order to solve the problem that the track relay is not excited and the train is occupied, frequency is measured. (AF) to check the modulation state numerically.

In addition, according to the present invention, it is designed to measure the maximum value (frequency) of the measurement site. The tuning unit must separate the track circuit by the electric tuning zone, and if it is an error, it may not be able to cancel the frequency of the front end, and when the frequency of the side line comes in, it can diagnose the problem due to the interference. In addition, if the frequency is measured when the power of the peripheral transmitter is removed, it can be diagnosed as a problem due to noise.

In addition, according to the present invention, by adding a function of the Auto-Range can be designed so that inaccurate measurement and the device is not damaged due to the convenience and the user's mistake.

In addition, the conduction test may be performed so that it may be displayed when it is less than 20 [Ω].

Thus, the present invention can have the following improved functionality over conventional TTM. First, the modulation frequency can be measured so that the modulation state can be identified numerically. Second, it can be convenient to use by adding the function of Auto-Range, and can protect the device from user's range selection mistake. Third, the conduction test can be performed so that it can be displayed if it is less than 20 [Ω].

The present invention provides an improved track circuit signal measuring device capable of measuring the signals of the conventional track circuit, especially the HVI track circuit and the AF track circuit, without affecting the peripheral lines, and the single signal of the USB and LSB due to the failure of the transmitting side. And methods.

10: Tuning Unit (TU)
20: input transformer
30: Bandpass Filter
40: amplifier
50: low pass filter
60: digital signal processor
70: output unit
100: demodulator

Claims (14)

Receiving means for receiving a modulated transmit signal of the track circuit;
Detects and analyzes the upper signal band ("USB") frequency and the lower signal band ("LSB") frequency of the track circuit signal received through the receiving means, and analyzes each of the USB and LSB frequencies. Analysis means for analyzing the size of the; And
And an output means for outputting a result analyzed by said analysis means. The method according to claim 1,
The track circuit signal received through the receiving means is a frequency shift keying (FSK) signal,
The analyzing means calculates an AC voltage of the received track circuit signal as a root mean square (RMS) value and then uses positive-to-negative and negative signals based on a zero-crossing scheme. A track circuit measuring device that calculates a frequency by averaging interval values between negative-to-positive. The method according to claim 2,
And the analyzing means measures the modulation frequency magnitude through the change and the changed time of the zero-crossing times, and the USB frequency and LSB frequency through the zero-crossing time. The method according to claim 1,
And the analyzing means accumulates and measures the signal source by a set period to further analyze the measurement frequency error relative to the reference frequency. 5. The method according to any one of claims 1 to 4,
The receiving means includes a track circuit measuring device including a band pass filter for removing the noise flowing from the peripheral line 5. The method according to any one of claims 1 to 4,
And the analyzing means includes an infinite impulse response (IIR) filter. 5. The method according to any one of claims 1 to 4,
The analyzing means comprises a finite impulse response (FIR) filter. The method of claim 7,
The analyzing means detects the size of each frequency of the USB frequency and the LSB frequency of the received orbital signal using a Blackman Window, which is one type of the FIR filter, and trains on the orbit based on the detection result. Track circuit measuring device to determine the presence or absence. Receiving a modulated transmit signal of the track circuit;
An analysis step of detecting and analyzing the USB frequency and the LSB frequency of the track circuit signal received through the receiving means, and analyzing the magnitudes of the USB and LSB frequencies, respectively; And
And an output step of outputting a result analyzed by the analyzing step. The method according to claim 9,
The track circuit signal received in the receiving step is a signal of the FSK method,
And in the analyzing step, calculating an AC voltage of the received track circuit signal as an RMS value and calculating a frequency by averaging interval values between positive to negative and negative to positive based on a zero-crossing scheme. The method according to claim 9,
In the analyzing step, the modulation frequency magnitude is measured through the change and the changed time of the zero-crossing time, and the orbital circuit measuring method for measuring the USB frequency and LSB frequency through the zero-crossing time. The method according to claim 9,
And in the analyzing step, accumulating the signal source by a set period to further analyze the measurement frequency error relative to the reference frequency. The method according to claim 9,
And in the analyzing step, detecting a magnitude for each frequency of the USB frequency and LSB frequency of the received orbital signal using a blackman window, which is a type of FIR filter. The method according to claim 13,
In the analyzing step, the track circuit measuring method for determining whether or not the train on the track based on the size of each frequency of the detected USB frequency and LSB frequency.

Images