JP3660577B2 - Method and apparatus for measuring resistance between rail joints - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method and an apparatus for measuring resistance between rail joints. More specifically, the present invention relates to resistance existing between joints of railroad rails that are electrically connected by a joint plate having a function equivalent to rail bond. It relates to the technology to measure.
[0002]
[Prior art]
Railroad rails are also used as electric circuits for track currents and return currents. When these currents are interrupted, troubles occur in traffic light systems and the like. Therefore, the electrical connection between the rail joints is achieved by rail bonds (soft copper strands).
[0003]
In the case of rail bond, since the weld terminal and the rail attached to both ends of the annealed copper wire are completely welded, the calculated sufficiently small value can be secured, so that there is no need to particularly manage resistance. On the other hand, since the attachment to the rail is performed by welding, there is a possibility that the welded portion may be suddenly peeled off due to the passing vibration of the vehicle.
[0004]
Therefore, instead of rail bonding, a method of connecting rails with a joint plate having the same function as rail bonding has already been adopted in some sections. In the case of a joint plate having a function equivalent to rail bond, since electrical continuity is obtained by mechanical contact, the resistance value is equal to or less than a predetermined reference value for judging the quality after construction. It is necessary to confirm that.
[0005]
[Problems to be solved by the invention]
However, since orbital current and retrace current normally flow through the rail, the orbital current becomes noise to the measuring instrument. In order to reduce this noise, it is necessary to apply a large direct current to the rail from the direct current generator and to average the measured values, so that the apparatus becomes large.
[0006]
[Means for Solving the Problems]
According to the measuring method of the present invention, it is possible to accurately measure the resistance between the rail joints by the joint plate having the same function as the rail bond without being affected by the track current and the return current flowing in the rail. In addition, it is possible to automatically make a pass / fail judgment.
[0007]
Therefore, when measuring the resistance existing between the joints of the railroad rails that are electrically connected by the joint plate having the same function as the rail bond, the present invention uses the AC four-terminal method to connect the rail joints. After detecting the effective resistance value (ACR) in the AC impedance, the ACR is calculated as DCR = (ACR−β) / α (where α is a conversion coefficient inherent to the rail, β is a correction value (Ω) of the joint plate, DCR; DC resistance value] is converted to DCR by the following formula.
[0008]
When AC measurement is performed, noise can be removed by a filter circuit, a synchronous detection circuit, or the like. Therefore, stable resistance measurement can be performed with a relatively small measurement current as compared with the DC measurement method. Actually, since the orbital current is large, the DC measurement method was able to perform stable measurement only when no orbital current was flowing, but according to the present invention, the influence is reduced even when the orbital current is flowing. Stable measurement is possible.
[0009]
According to the normal railway structure rule, in the DC electrification section, the upper limit of the resistance value connecting the rails is defined by the DC resistance. However, according to the present invention, the ACR is DCR based on the above conversion formula. Since it is automatically converted to, there is no problem even if it is measured by alternating current.
[0010]
By the way, the alternating current generally has a skin effect, and the current does not penetrate into the rail. For example, when measured at a measurement current of 1 kHz, the current flows from the rail surface to a depth of about 0.7 mm. Further, since the joint plate portion having the same function as the rail bond has a contact resistance between the joint plate and the rail, the portion is not a simple skin effect but a contact resistance.
[0011]
In general, the AC resistance becomes larger than the DC resistance due to the skin effect, but the conversion from the AC resistance to the DC resistance including the skin effect and the contact resistance can be approximated to a linear function. This linear function is the above-described conversion formula, which differs for each rail type.
[0012]
In addition, the measuring apparatus of the present invention includes a resistance detecting means for detecting an ACR between rail joints by an AC four-terminal method, a rail selecting means for selecting the type of rail to be measured, and a unique conversion for each rail type. Including the storage means in which the correction value β (Ω) of the joint plate having the function equivalent to the coefficient α and the rail bond is written, the arithmetic control means for converting the ACR into DCR, and the display means. The means reads the inherent conversion coefficient α and the seam plate correction value β from the storage means in accordance with the rail type selected by the rail selection means, and calculates DCR = (ACR−β) / α. The ACR detected by the resistance detecting means is converted to DCR and displayed on the display means.
[0013]
In the present invention, a comparison reference value for pass / fail judgment is further written in the storage means for each rail type, and the arithmetic control means compares the DCR with the reference value and displays the comparison judgment result on the display. The mode displayed on the means is included.
[0014]
In this comparison determination, a first threshold value on the low resistance side (upper limit value during construction) and a second threshold value on the high resistance side (upper limit value during maintenance) are set as the comparison reference value, and the above-mentioned DCR <first threshold value is satisfied. It is preferable to display these comparison determination results on the display means as a good determination in the case, the first threshold ≦ the DCR <the second threshold, the attention determination, and the second threshold ≦ the DCR as the failure determination. .
[0015]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 shows a joint portion in which two rails R1 and R2 are connected by a joint plate J having the same function as a rail bond. According to the present invention, the resistance between the seams is detected by the AC four-terminal method.
[0016]
That is, the resistance detecting means 10 includes an alternating current generator 11 and an alternating voltage measuring device 12, and a predetermined alternating current measurement is performed between the alternating current generator 11 and the rails R1 and R2 via the pair of current probes 11a and 11b. A current I is supplied, and a voltage drop V generated between the rails R1 and R2 at that time is measured by the AC voltage measuring instrument 12 via the pair of voltage probes 12a and 12b.
[0017]
The AC measurement current I and the measurement voltage V are digitally converted by the A / D converter 20 shown in FIG. A CPU (central processing unit), a microcomputer, or the like is used as the arithmetic control unit 30, and the arithmetic control unit 30 calculates an ACR from the AC measurement current I and the measurement voltage V.
[0018]
There are various types of rails defined by JIS, such as 40 kg rails, 50 kg rails, and 60 kg rails, each having a specific coefficient. In order to be able to select the rail to be measured, rail selection means 40 is connected to the arithmetic control means 30. The rail selection means 40 may be a selection key method, for example.
[0019]
In addition, two storage units, a first storage unit 51 and a second storage unit 52, are connected to the arithmetic control unit 30. The first storage means 51 stores comparison reference values for pass / fail determination for each rail type. According to this embodiment, the comparison reference value includes a first threshold value (upper limit value during construction) RL on the low resistance side and a second threshold value (upper limit value during maintenance) RH on the high resistance side.
[0020]
The second storage means 52 stores the inherent conversion coefficient α for each rail type and the correction value β (Ω) of the joint plate J having the same function as the rail bond. In FIG. 2, for convenience of explanation, the first storage means 51 and the second storage means 52 are shown separately, but each memory area may be set in one storage means.
[0021]
The conversion coefficient α and the correction value β are obtained by changing the resistance between the rails R1 and R2 connected by the joint plate J having the same function as the rail bond as shown in FIG. It is obtained by measuring each by the terminal method and the direct current four terminal method and correlating the measured data.
[0022]
As a reference, FIG. 3 shows a data plot in which the correlation between the DCR and ACR of the 50 kg rail is taken. The correlation data between DCR and ACR in FIG. 3 shows that the measurement current in the AC four-terminal method is fixed at an effective value of 50 mA, the measurement current in the DC four-terminal method is fixed at 2 A, and is equivalent to the rail bond. This is data when the bolt of the joint plate J having a function is slightly loosened and gradually tightened with a torque wrench, and the final tightening force is 2000 kgcm.
[0023]
As can be seen from the data plot of FIG. 3, DCR and ACR are
ACR = α ・ DCR + β
Can be approximated by the linear function In this case, α is a conversion coefficient unique to each rail due to the skin effect, and β is a correction value (Ω) of the joint plate J having the same function as the rail bond.
[0024]
Therefore, the ACR can be converted to DCR by the calculation formula (ACR−β) / α. Such conversion coefficient α and correction value β are stored in the second storage means 52.
[0025]
Next, an example of the measurement operation will be described. First, when the type of rail to be measured is selected by the rail selection means 40 and a measurement start instruction signal is given to the arithmetic control means 30, resistance detection by the AC four-terminal method is performed by the resistance detection means 10.
[0026]
The arithmetic control unit 30 calculates an ACR from the AC measurement signal I and the measurement voltage V from the resistance detection unit 10. Then, the conversion coefficient α and the correction value β are read from the second storage means 52, and the ACR is converted into DCR by the calculation formula (ACR−β) / α.
[0027]
Next, the arithmetic control means 30 makes a pass / fail determination for this DCR. That is, the first threshold value (upper limit value during construction) RL and the second threshold value (upper limit value during maintenance) RH (RL <RH) are read from the first storage means 51 and compared with the DCR.
(1) If DCR <the first threshold value, good judgment,
(2) If first threshold value ≦ DCR <second threshold value,
(3) If the second threshold ≤ DCR,
These comparison determination results are displayed on the display means 60 together with the DCR. For reference, FIG. 4 shows an operation flowchart of the present invention, and FIG. 5 shows a display example of the display means 60 when a 50 kg rail is selected.
[0028]
In the above embodiment, two threshold values are set as the comparison reference value, but one comparison reference value may be used. In that case, the upper limit defined in the Ordinary Railway Structure Rules may be adopted. The “=” (equal sign) setting at the time of comparison determination is not limited to the above-described embodiment. It is included in the present invention as equivalent means even if an equal sign is attached in the opposite direction to the above embodiment. Further, although the arithmetic control means 30 is provided with both an effective resistance calculation function and a determination function, the arithmetic control means 30 may be divided into a processor dedicated to calculation and a comparator dedicated to determination.
[0029]
【The invention's effect】
As described above, according to the measurement method of the present invention, by adopting the AC four-terminal method, even when the orbital current and the return current flow, the same as the rail bond is hardly affected. It is possible to accurately measure the resistance between the rail joints connected by the joint plate having the function of, and the ACR is automatically converted to DCR. This is convenient for comparison with the resistance value.
[0030]
In addition, according to the measuring apparatus of the present invention, conversion from ACR to DCR and comparison with a comparison reference value are automatically performed only by selecting the type of rail to be measured. Can be performed easily and quickly. Further, since the apparatus can be miniaturized, it is convenient to carry and the workability outdoors is greatly improved.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram showing a state in which resistance between rail joints connected by a joint plate having a function equivalent to rail bond is detected by an AC four-terminal method in the present invention.
FIG. 2 is a block diagram showing each component of the present invention.
FIG. 3 is a data plot reference diagram showing a correlation between DCR and ACR of a 50 kg rail.
FIG. 4 is a schematic operation flowchart of the present invention.
FIG. 5 is a display screen diagram showing a display example of measurement results according to the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Resistance detection means 11 AC current generator 12 AC voltage measuring device 20 A / D converter 30 Arithmetic control means 40 Rail selection means 51, 52 Storage means 60 Display means R1, R2 Rail J It had a function equivalent to a rail bond Seam plate

Claims (4)

In the resistance measurement method between the rail joints, which measures the resistance existing between the rail rail joints that are electrically connected by the joint plate having the same function as the rail bond,
After detecting the effective resistance value (hereinafter referred to as ACR) in the AC impedance between the rail joints by the AC four-terminal method, the ACR is
DCR = (ACR−β) / α
[However, α: Conversion coefficient specific to rail, β: Correction value of the seam plate (Ω), DCR; DC resistance value (hereinafter referred to as DCR)]
A resistance measurement method between rail joints, which is converted into DCR by the following formula. In a resistance measuring device between rail joints that measures resistance existing between joints of railroad rails that are electrically connected by a joint plate having the same function as rail bonds,
Resistance detection means for detecting ACR between rail joints by the AC four-terminal method, rail selection means for selecting the type of rail to be measured, its inherent conversion coefficient α for each rail type, and correction values for the joint plate storage means in which β (Ω) is written, arithmetic control means for converting the ACR into DCR, and display means,
The arithmetic control unit reads the inherent conversion coefficient α and the correction value β of the joint plate from the storage unit according to the type of rail selected by the rail selection unit, and DCR = (ACR−β) / A resistance measuring device between rail joints, which performs an operation of α, converts the ACR detected by the resistance detecting means into DCR, and displays it on the display means. A comparison reference value for pass / fail judgment is further written in the storage means for each rail type, and the arithmetic control means compares the DCR with the reference value and displays the comparison judgment result on the display means. The resistance measuring device between rail joints according to claim 2. The comparison reference value includes a first threshold value on the low resistance side (upper limit value during construction) and a second threshold value on the high resistance side (upper limit value during maintenance) for pass / fail judgment. When DCR <the first threshold value, a good judgment is made. When the first threshold value ≦ the DCR <the second threshold value, a caution judgment is made. The resistance measuring device between rail joints according to claim 3, which is displayed on the means.

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