KR100193060B1 - Automatic analyzing apparatus of insulation resistance for communication cable - Google Patents

Abstract

The present invention is a high speed, automatic measurement of the insulation resistance between the core wire and the core wire or the core wire and the ground in the inter-station relay or subscriber line of the telecommunication line, automatic analysis for quickly checking the state of the communication line by analyzing the results Relates to a device. More specifically, the present invention relates to an automatic insulation resistance analysis device for communication lines that can automatically analyze the state of insulation resistance between measured lines, store the result, and output the result to a monitor and a printer.

The automatic insulation resistance analysis device for communication lines of the present invention includes a line switching means for sequentially switching a plurality of measured lines and a line for removing unnecessary noise connected to the line switching means and induced on a signal transmission line. Insulation resistance measuring means for measuring the insulation resistance of the noise removing means and the line from which the noise is removed, Balanced amplification means for amplifying the signal output from the insulation resistance measuring means to the required level, and output from the balanced amplification means. A low pass filter for removing unnecessary noise from the received signal, a buffer amplifier means for amplifying the signal output from the low pass filter to a predetermined size, and a digital signal for inputting the signal output from the buffer amplifier means to a computer. A / D conversion means for converting the It is characterized in that it comprises a digital input / output means for output to the line loss means and a measuring power supply means for supplying a predetermined power to the insulation resistance measuring means.

Description

Automatic Insulation Resistance Analysis Device for Communication Line

1 is a block diagram schematically showing the configuration of the automatic insulation resistance analysis device for communication lines according to the present invention.

2 is a detailed circuit diagram of an embodiment of an automatic insulation state analysis device for communication lines according to the present invention.

3 is a schematic circuit diagram illustrating the insulation resistance measuring principle of the present invention.

4 is a graph showing an A / D conversion value.

5 is a flowchart for explaining the computer control operation of the present invention.

* Explanation of symbols for main parts of the drawings

11: line switching unit 12: line noise removing unit

13 insulation resistance measuring unit 14 balance amplifier

15 low pass filter 16 buffer amplifier

17: A / D Converter 18: Computer

19: digital input, output 20: measuring power supply

R: Resistor C: Capacitor

L: Coil RLY: Relay

U1, U2, U3, U4, U5, U6, U7-A, U7-B: Integrated Circuit

[Field of Invention]

The present invention is an automatic analysis device for quickly checking the state of a communication line by measuring the insulation resistance between the core line and the core line or the core line and the ground at high speed and automatically in the relay or subscriber line of the telecommunication line. It is about. More specifically, the present invention relates to an automatic insulation resistance analysis device for communication lines that can automatically analyze the state of insulation resistance between measured lines, store the result, and output the result to a monitor and a printer.

[Background of invention]

Significant developments in electrical and electronic communication means have led to an exponential increase in the number of subscribers that can be accommodated at individual telephone office levels. Accordingly, the relay service between the telephone stations of each unit is also increasing. Each telephone company is putting a lot of manpower and equipment for large subscriber management, but it is not keeping up with the surge in the number of congested lines.

Moreover, the rate of increase of technical manpower, which judges the goodness of the communication line condition and is in charge of maintenance of the line, is very low, and it is not able to fully digest the advanced communication technology.

Therefore, there is an increasing need for an automatic insulation resistance analyzer for communication lines that is easy to use, can be operated without a skilled on-site technician, can be measured quickly, and can be purchased at low cost.

This can be clarified by the fact that 90% of the causes of total line failure and crosstalk are caused by poor insulation resistance. Neglecting poor insulation resistance affects the line as well as other lines, which significantly reduces the quality of most lines.

Conventionally known methods for determining a state of a communication line include 1) a method of measuring near-end crosstalk, 2) a method of detecting disconnection, and 3) a method of measuring insulation resistance. 1) Near-end crosstalk measurement method is to measure the state of the line by measuring the leakage magnetic field. It is very bulky and heavy to grasp the overall characteristics of the line, it is very expensive, and it has a very high technology for measurement operation and analysis. It has not been widely put to practical use. 2) In the disconnection detection method, since the tester must be located at both ends of the track to be measured, it is inconvenient to measure the measurement, and it is difficult to accurately identify the location of the disconnection even in the repair work of the disconnected track. 3) The method of measuring insulation resistance is the most widely used method, but the insulation resistance measuring device used in the past has been used for the purpose of power facilities, etc., which causes unexpected problems in subtle devices such as communication lines.

In other words, high voltages are induced during measurement, causing a breakdown in the communication line, and even in the measurement range, most of the products of several tens of megaohms or more exceeding several hundred kiloohms should be used for the communication line. This was a difficult situation. In addition, since the measurement results are simply displayed as electrical resistance values, it is difficult to make accurate judgments, thereby exposing limitations in practical applications.

However, the results of the investigation by KICT, which indicates that the main cause of line breakdown and crosstalk are due to moisture invasion, are the evaluation of standardized line quality requiring the establishment of an appropriate insulation resistance measuring device and accurate judgment criteria. The need for methods is gradually increasing.

[Purpose of invention]

The present invention has been made to solve the above problems, and an object of the present invention is to measure the insulation resistance between core and core wires or core and ground in high speed relay and subscriber lines, and to analyze the results automatically. It is to provide automatic insulation resistance analysis device for communication line that can check the condition of line quickly.

Another object of the present invention is to provide an automatic insulation resistance analysis device for communication lines that can easily analyze data because the measured results can be automatically analyzed.

[Summary of invention]

Insulation resistance automatic analysis device for a communication line of the present invention for achieving the above object is connected to the line switching means and the line switching means for sequentially switching a plurality of lines to be measured and unnecessary noise induced on a signal transmission line A line noise removing means for removing the noise, an insulation resistance measuring means for measuring the insulation resistance of the line from which the noise is removed, and a balanced amplification means for amplifying the signal output from the insulation resistance measuring means to a level of a required size; A low pass filter for removing unnecessary noise from the signal output from the balanced amplification means, buffer amplification means for amplifying the signal output from the low pass filter to a predetermined size, and a signal output from the buffer amplification means to a computer. A / D conversion means for converting into a digital signal for input, and the computer That is configured for digital signal processing by the line switching means and the digital output means, and power supply means for measuring the power supply for measuring the line resistance for outputting the features.

[Description of Specific Example of the Invention]

Hereinafter, the automatic insulation resistance analysis device for communication lines of the present invention will be described in detail with reference to FIGS. 1 to 4 as follows.

Shown in FIG. 1 is a schematic block diagram of an automatic insulation resistance analysis apparatus for a communication line according to the present invention. As shown, a line switching unit 11 sequentially connecting a plurality of measurement lines (typically 50 or 25 lines) connected to a coal base according to a program embedded in the computer 18. The line switching unit 11 The line noise removing unit 12 for removing the noise signal induced on the line among the signals input from the line 12), and the voltage applied to measure the line insulation resistance of each line connected by the switching unit 11 to the insulation resistance. The conversion into a proportional voltage signal amplifies the insulation resistance measurement unit 13 and the voltage signal measured by the insulation resistance measurement unit 13 to a level capable of signal processing, and a balanced amplifier 14 having an excellent in-phase signal removal ratio (CMRR). ), A low pass filter 15 for filtering low-frequency signals among the amplified and noise-removed signals output from the balanced amplifier 14, and a scene output from the low pass filter 15. A buffer amplifier 16 for amplifying the signal to a predetermined size, an A / D converter 17 for converting a signal from the buffer amplifier 16 into a digital signal, and a digital signal from the A / D converter 17 Measurement for supplying predetermined power to the digital input / output unit 19 and the insulation resistance measuring unit 13 for processing by the 18 and outputting the line loss switching unit 11 and the insulation resistance measuring unit 13. The power supply 20 is comprised.

The line switching unit 11 serves to sequentially connect or short-circuit a line to be measured by a program embedded in the computer 18. The number of lines to be measured is usually 25 or 50 lines connected simultaneously to the coal base. First, one of them is selected, and then the line is connected by appropriate means (usually a relay) to make three measurements per line. Enforce. The three measurements are made of item-specific insulation resistance in the order of tip-ring, tip-ground, and ring-ground to measure between core and core or core and ground. The measurement is connected to perform.

After completion of the measurement, measure the insulation resistance of each of the above 3 items across all the lines by sequentially changing and connecting the next line to be measured. The insulation resistance value data for each line item measured together with each line number (for example, 50 × 3 = 150 data lines for 50 lines) is stored in the internal memory of the computer 18, and then a display device such as a monitor. And through a printer.

The present invention can be connected to the computer 18 to input a command using a dedicated keyboard of the computer, it can be easily implemented by a control program.

The line noise removing unit 12 removes noise of various components induced on the line. The noise induced on the line generates a wide range of noise such as a 60 kHz signal caused by electromagnetic induction of general zergol power lines, broadcast wave by wireless signal, induced noise caused by surrounding electronic equipment, or impact noise including lightning. do. These noises are easily induced through the tracks, and the tracks are very vulnerable to these noises due to their structure. In the apparatus of the present invention, in particular, the line noise canceller 12 is first used to remove noise of a high frequency component above a specific frequency band from the composite noise.

The insulation resistance measuring unit 13 measures the line resistance and measures the voltage according to the insulation resistance of the line under measurement. The principle of the insulation resistance measurement is described in detail with reference to FIG. 3. It will be described later.

The resistance value measured by the insulation resistance measuring unit 13 is input to the balance amplifier 14. The balance amplifier 14 amplifies the input signal voltage to a level capable of signal processing. At the same time, it has a high in-phase signal rejection ratio (CMRR) to effectively remove in-phase noise (noise at both ends of the line, commonly known as having a form of a phase). Therefore, even if the intensity of the noise is strong, it is possible to effectively remove the in-phase noise in the balance amplifier 14.

The amplified and noise-reduced signal output from the balance amplifier 14 passes through the low pass filter 15 and the noise of the low frequency band is again removed. In the low pass filter 15, the frequency is designed to be 10 Hz in particular. In this way, the high-frequency noise signal is removed from the line noise removing unit 12 so that most of the noise existing on the line is effectively blocked.

The slow amplifier 16 has an interface function for connecting the signal passing through the low pass filter 15 to the computer 18 and prevents the load from being changed for the filter and can be generated by a digital circuit. Minimize the impact. It also includes an equalization function to match the level with the A / D converter inside the computer 18.

The supply of predetermined power to the insulation resistance measuring unit 13 is the measurement power supply means 20. The measuring power supply 20 is DC 80V-160V, 0-20Hz, preferably DC. Supply 100V / 2, 5㎃ power.

2 is a detailed circuit diagram as an embodiment of an automatic insulation resistance analyzing apparatus for a communication line of the present invention having the above configuration. In general, communication cables measure 25 lines and 50 lines as one unit and measure the insulation resistance of each line. In the present invention, the (2-to-4) line decoder (U1) as a component of the switching means for selecting the measurement line, the 74ALS139 is a relay short circuit specified by the latch element and (2-to-4) line decoder (U1). The signal is divided into signals of different lines by 74LS154, which is a (4-to-16) line decoder (U2, U3, U4, U5). The signals of the separated lines are sequentially connected by a plurality of relays RLY to measure the insulation resistance of the tip ring, the tip ground, and the ring ground.

The line connected by the line switching unit 11 removes noise by the line noise removing unit 12 including the coils L1 and L2. In the present invention, the line noise removing unit 12 removes high frequency components such as broadcasting frequencies among the noise components, and low frequency components such as power supply noise are removed by the low pass filter 15 of the rear stage.

When a specific line is connected by the line switching unit 11, a process of measuring insulation resistance of the line is performed, which is performed by the insulation resistance measurement unit 13. A predetermined voltage (DC100V / 2.5 mA) is applied to the insulation resistance measuring boom 13, and the insulation resistance of a specific line is measured by this voltage. 3 shows a simplified circuit for explaining the principle of insulation resistance measurement. The voltage across the line (+) (-),

Becomes Therefore, the line insulation resistance can be obtained by knowing the applied voltage and the output voltage (E).

In the present invention, by using the relay (RLY54, RLY55) is divided into two ranges of 0.1 to 2.0 kHz and 2.0 to 10.0 kHz or more, the measurement formula is as follows.

1) 0.1 to 2.0 kHz range (first range)

The transplant can be written as (40 + Rx ') * (5ADval) = 4095000, so

1) 2.0 to 10.0 ms range (second range)

Referring to FIG. 4, ADval, which is an A / D conversion coefficient according to the first range and the second range, is illustrated. According to FIG. 4, in the first range, when an insulation resistance of 2 kΩ or more is measured, it is out of the range of accuracy considered in the design of the system, and is automatically switched to the second range by an internal circuit to perform the measurement operation.

The voltage applied to the insulation resistance measuring unit 13 is supplied from the measuring power supply device 20. The measuring power supply 20 supplies DC100V / 2.5 kW power to the transmission line. It also has a built-in protection circuit against opening or shorting depending on the condition of the line and consists of a constant voltage device against fluctuations in input power. The measured power supply directly affects the line insulation resistance measurement, so the voltage must be maintained very accurately.

In the present invention, a three-terminal regulator (LM317T) is used as the constant voltage device, and it will be apparent to those skilled in the art that many other conventional techniques for stably supplying power can be used.

The voltage signal measured by the insulation resistance measuring unit 13 is input to the balance amplifier 14 and then amplified to a signal processable level. For this purpose, the present invention used an OP amplifier, and commercially available IC (AD524) was used.

The signal output from the balance amplifier 14 passes through the low pass filter 15 again to remove noise of low frequency signal components. The signal passing through the low pass filter 15 is amplified by the buffer amplifier 16 and then converted into a digital signal by the A / D converter 17 to be input to the computer 18 and processed. In addition, a control signal by a program embedded in the computer 18 is input through a digital input / output circuit 19, a signal for selecting a measurement line is input to the line switching unit 11, and a signal for selecting a measurement range is input to an insulation resistance measurement unit. do.

The buffer amplifier 16 has an interface function and includes a function for preventing a load variation on the filter, minimizing the influence of the digital circuit, and level matching with the A / D converter 17. do. In the present invention, for this purpose, the low pass filter 15 and the buffer amplifier 16 use an op amp (U7 = A, U7-B), and a commercial IC LF353H (1/2) is used. .

5 is a flowchart for explaining the control operation of the computer 18 of the present invention.

First, enter the measurement date and time (S10), select the measurement function or diagnostic function (S11), select the measurement function, enter the data related to insulation resistance measurement (S12), and if the diagnostic function is selected, the system diagnosis itself While the relevant data is automatically set (S13).

When the start button on the keyboard of the dedicated computer 18 is pressed (S14), the measurement operation of the line insulation resistance is performed (S15). At this time, when the measured value is out of the initially set range, the measurement range is automatically converted and measured (S16), and the measurement result is displayed on the monitor (S17).

Next, the measurement lines are switched (S18) to continuously measure in units of 25 or 50 lines. When the continuous measurement ends, the measurement results are printed by the command (S19).

As described above, according to the present invention, it is possible to check the state of the line quickly by measuring the insulation resistance between the core wire and the core wire or the core wire and the ground at high speed in the national relay and subscriber lines, and analyzing the results. It can easily analyze the data and output the result, so it is easy to manage the data.

Claims (2)

A line switching means 11 for sequentially connecting a plurality of measured lines connected to the bullet base according to a program embedded in the computer 18, and a signal input from the line switching means 11, Line noise removing means 12 for removing the high frequency noise signal, and insulation resistance measuring means 13 for converting a voltage applied as a voltage signal proportional to the insulation resistance to measure the insulation resistance Rx 'of the line; Balanced amplification means 14 amplifies the voltage signal measured by the insulation resistance measuring means 13 to a level capable of signal processing, and has an in-phase signal removal ratio CMRR, amplification output from the balanced amplification means 14 and Low pass filter 15 for filtering out low frequency noise signals among the noise-removed signals, and buffer amplification means for amplifying the signal output from the low pass filter 15 into a predetermined size signal. (16), A / D conversion means (17) for converting the signal output from the buffer amplifying means (16) into a digital signal for input into the computer (18), and a digital signal processed from the computer (18). Characterized in that it comprises a digital input and output means 19 for outputting the power to the line switching means 11, and a measuring power supply means 20 for supplying a predetermined power to the insulation resistance measuring means (13). Automatic insulation resistance analysis device for communication line. 2. The line switching means (11) according to claim 1, wherein the line switching means (11) connects a plurality of communication lines in sequence, and for each communication line a tip-ring, a tip-ground, and a ring-ground. Automatic insulation device for communication lines, characterized in that the line is switched so that the insulation resistance can be measured in the order of (Ring-GND).