JPH0325187Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a device for detecting insulation breakdown between adjacent sections of an insulated track circuit provided for detection of railway vehicles.

To detect the position of a railway vehicle on a track, the rails are insulated at predetermined distances, a track circuit with multiple sections is formed, and an AC signal is transmitted between the tracks of the track circuit for each section. is received as a signal voltage between the rails, and when a vehicle enters this section, the axle of the vehicle short-circuits the rails and the signal voltage between the rails disappears, so as the reception output disappears accordingly. , detecting the presence of a vehicle in a specific section.

FIG. 1 is a block diagram showing an example of such a conventional vehicle detection device using AC signals.
is divided into track circuits such as sections 1T to 3T by rail insulation, and transmitters TX ₁ and TX ₂ consisting of modulators, amplifiers, etc. are installed at the back of each section 1T and 2T with respect to the traveling direction of the vehicle TR. is provided,
The respective outputs of carrier wave oscillators COS ₁ and COS ₂ that generate carrier waves F ₁ and F ₂ of different frequencies are connected to modulated wave oscillators MOS ₁ and MOS that generate modulated waves fm of the same frequency, respectively.
After amplitude modulation by each output of MOS ₂ , each section 1
It is designed to transmit to the track circuit from the back side of T and 2T.

In addition, each section 2 in the direction of travel of the vehicle TR
Receivers RX ₂ and RX ₃ are provided on the front side of T and 3T, each of which is composed of a transducer FL or a rectifier circuit RECr. The transmission is received, relays 2TR and 3TR are activated, and the vehicle
Relays 2TR and 3TR are restored by the disappearance of the reception input in response to the entry of the TR, thereby providing vehicle TR detection information to a signal circuit composed of relays and the like.

In other words, if we take the section 2T as an example, the transmitter
The transmitted carrier wave of TX ₂ is extracted by wave generator FL, the output of this is demodulated by demodulator DEMr, only the modulated wave is separated by selection amplifier SA, and from this output, the level of Schmitt trigger circuit etc. After components above a predetermined level are extracted by the discriminator SCHr, they are amplified by the AC amplifier AAr, and the output thereof is converted to DC by the rectifier circuit RECr to drive the relay 2TR.

However, in the case of the configuration shown in Figure 1, the vehicle
Even if TR can be detected well, if the insulation between the rails in each section 1T to 3T etc. breaks down or deteriorates, no measures have been taken to detect this. If the signal current from the transmitter flows to the adjacent section due to breakdown or deterioration of the insulation, the signal voltage between the rails will decrease due to the reduction in load impedance, and relays 2TR, 3TR, etc. will be restored due to the decrease in input to the receiver. However, it was not possible to distinguish between normal detection of the vehicle TR, and the signal circuit unnecessarily blocked the section in order to provide the detection information of the vehicle TR to the signal circuit despite the absence of the vehicle TR. However, it creates disadvantages that are left unaddressed.

The purpose of the present invention is to eliminate such drawbacks of the conventional technology at once, by individually transmitting carrier waves of different frequencies modulated by modulated waves of the same frequency whose phases differ by 180 degrees to adjacent sections, and , by installing a fault detector in one of the adjacent sections to detect that these are simultaneously given as reception inputs, it is possible to reliably and quickly detect dielectric breakdown of the track circuit.This is an extremely effective method.
A track circuit dielectric breakdown detection device is provided.

The details of the present invention will be explained below with reference to FIG. 2 showing an embodiment.

FIG. 2 is a block diagram similar to FIG. 1, and FIGS. 3 and 4 are diagrams showing waveforms of each part in FIG. 2. In _FIG. , TX ₂ and receivers RX ₂ and RX ₃ , etc., but each transmitter in the adjacent sections 1T and 2T
Carrier waves F ₁ and F ₂ with different frequencies to TX ₁ and TX ₂ , respectively
are given by the carrier wave oscillators COS ₁ and COS ₂ , and the modulated wave oscillators MOS ₁ and MOS ₂ , which operate synchronously with the modulated wave oscillator MOS ₁ as a reference, generate signals of the same frequency with a phase difference of 180° from each other. Modulated wave f
m(φ) and fm(-φ) are transmitter TX ₁ ,
Each section is given to TX ₂ , and both sections 1T, 2
If the insulation between T is normal, there is a carrier wave in section 1T.
A signal obtained by amplitude modulating F ₁ with modulating wave fm (φ) is transmitted, and in section 2T, carrier wave F ₂ is modulated with modulating wave f
A signal whose amplitude is modulated by m(-φ) is being transmitted.

Therefore, under normal conditions, the input of the fault detector ED provided to the section 2T corresponding to the transmitter TX ₂ is as follows:
A signal modulated by the square wave modulation wave fm(-φ) in _FIG .
If the signal is extracted through the bandpass filter BPF ₁ , the signal shown in FIG. 2B is obtained.

The output b of the bandpass filter BPF ₁ is demodulated by the demodulator DEMd to become the demodulated output c, and a level discriminator SCHd such as a Schmitt trigger circuit detects components above this level by setting the threshold level Vt to a predetermined level. is extracted, AC component d
Then, after being amplified by the AC amplifier AAd, it is converted to DC by the rectifier circuit RECd,
Drive relay DR.

Therefore, if the insulation between sections 1T and 2T is normal, relay DR always maintains its operating state.

On the other hand, if the insulation between sections 1T and 2T is poor, transmitters TX ₁ and
A signal in which the transmitted signals from TX ₂ are mixed and the carrier wave F ₁ is modulated by a square wave modulation wave fm (φ),
A signal modulated by a similar modulated wave fm(-φ) is superimposed on the carrier wave _F2 , and the modulated wave fm
Since the phases of (φ) and fm(-φ) are 180° different from each other, the signal shown in FIG. 4a is given as an input to the fault detector ED.

Then, the carrier wave F ₁ passes through the bandpass filter BPF ₂ which uses this as the passing frequency, so each waveform
The outputs of BPF ₁ and BPF ₂ are those shown in FIG. 4b, and when these are demodulated by the demodulator DEMd, most of the AC energy is lost as shown in FIG. 4c.

Therefore, when extracted by the level discriminator SCHd above the threshold level Vt, only the DC component is obtained as shown in FIG. 4d, and accordingly, the output of the AC amplifier AAd disappears, and the relay DR is restored.

Therefore, due to the restoration of relay DR, section 1
Dielectric breakdown between T and 2T can be detected.

However, the same structure may be used for each section 1T to 3T or the sections after this, and the same is true even if the fault detector ED is provided on the section 1T side. It's fine if you can.

Furthermore, it is clear that the bandpass filters BPF ₁ and BPF ₂ may be integrated, and various modifications are possible, such as the AC amplifier AAd may be omitted depending on the conditions.

In addition, each carrier wave F ₁ , F ₂ and modulator fm
The amplitudes of (φ) and fm(-φ) are determined on each transmitting side according to the electrical distance between the transmitting point and the receiving point, or are determined by a bandpass wave device so that the amplitudes are almost the same when both are mixed. It is necessary to perform level adjustment on the output side of BPF ₁ and BPF ₂ .

As is clear from the above explanation, according to the present invention, dielectric breakdown between sections of insulated track circuits can be detected reliably and quickly, so fault countermeasures can be taken quickly, and this has great effects on insulated track circuits of various railways. is obtained.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a conventional example, FIG. 2 is a block diagram showing an embodiment of the present invention, and FIGS. 3 and 4 are diagrams showing waveforms of various parts in FIG. PW...Trajectory, 1T~3T...Section, TX ₁ ,
TX ₂ ... transmitter, F ₁ , F ₂ ... carrier wave, fm
(φ), fm(-φ)...Modulated wave, ED...Fault detector, BPF ₁ , BPF ₂ ...Band wave detector, DEMd...
Demodulator, SCHd...level discriminator, RECd...rectifier circuit.

Claims (1)

[Scope of utility model registration request] A transmitter is provided in each adjacent section of the track circuit for transmitting carrier waves of different frequencies modulated by modulated waves of the same frequency whose phases differ by 180 degrees from each other to the insulated track circuit, and a wave device that passes each carrier wave, a demodulator that demodulates the output of the wave device, a level discriminator that extracts a level higher than a predetermined level from the output of the demodulator, and a rectifier that rectifies the output of the level discriminator. A track circuit dielectric breakdown detection device characterized in that a fault detector including a rectifier circuit is provided in a section corresponding to one of the transmitters.