RU2331080C1 - Method of wired telecommunication network equipment monitoring and associated device - Google Patents

Abstract

FIELD: electricity.

SUBSTANCE: invention is referred to electric engineering and designed for emergency surveillance of wired telecommunication network equipment. The essence of invention: sensors and connection lines status is monitored in time but no less than three times in second for each line. Four status categories are monitored such as normal, sensor accident, short circuit or line break before sensor by current measuring in line. Line is charged no less than three times to define line break. Length of cable before broken point is calculated based on charge characteristics. Device includes input signal normalising and multiplexing unit and voltage control unit. Both units are connected with supply unit and microprocessor. Input signal normalising and multiplexing unit can define current in each line and protect inputs from high voltages. Voltage control unit is in the form of two opto-keys which can be simultaneously switched over. Each line is provided with two resistances on their ends. One of resistance is by-passed with sensor contacts.

EFFECT: improvement of monitoring device reliability and accuracy in wired telecommunication network equipment.

2 cl, 2 dwg

Description

The invention relates to electrical engineering and is intended for emergency surveillance of equipment of wired telecommunication networks.

The closest in technical essence to the proposed method is a method for monitoring the equipment of wired telecommunication networks, which consists in the operational monitoring of the state of sensors and connecting lines (see patent RU 2269789).

Its disadvantage is low reliability, insufficient speed and accuracy of determining the location of damage, as well as a small number of controlled objects.

The present invention solves the problem of improving the reliability, accuracy of determining the location of damage, speed and increase the number of controlled objects.

To solve the technical problem, they monitor the equipment of wired telecommunication networks, which consists in monitoring the state of the sensors and connecting lines with the device, and monitoring the status of sensors and connecting lines is carried out cyclically in time with a cycle of at least three times per second on each line in four states - the norm, sensor failure, short circuit or open circuit to the sensor by determining the current in the line and comparing with the current determined by the formula

where U _in - voltage at the input to the line;

R _I - the value of the input resistance of the device;

R ₁ is the resistance value at the end of the line connected in series with the sensor;

R ₂ is the resistance value at the end of the line connected in parallel with the sensor;

moreover, if the current in the line is within

then the state of the line with the sensor is defined as the norm;

if the current in the line is within

then the state of the sensor is defined as an accident;

if the current in the line is greater than or equal to

this condition is defined as a short circuit in the line;

if the current in the line is less

that state is defined as a line break,

in this case, when determining a line break, the line is charged at least three times, and the time constant is determined by the charge characteristic, and averaged by the formula

L = C / C _km

where C is the measured line capacity;

C _km - line capacity per kilometer,

C = τ / R _in

where τ is the time constant;

R _I - the input impedance of the device through which the charge of the line passes, calculate the line length to break.

A distinctive feature of the proposed method is that the monitoring of the state of the sensors and connecting lines is carried out cyclically in time with a cycle of at least three times per second on each line in four states - normal, sensor failure, short circuit or open circuit to the sensor by determining the current in the line and comparison with the current determined by the formula

where U _in - voltage at the input to the line;

R _I - the value of the input resistance of the device;

R ₁ is the resistance value at the end of the line connected in series with the sensor;

R ₂ is the resistance value at the end of the line connected in parallel with the sensor;

moreover, if the current in the line is within

then the state of the line with the sensor is defined as the norm;

if the current in the line is within

then the state of the sensor is defined as an accident;

if the current in the line is greater than or equal to

this condition is defined as a short circuit in the line;

if the current in the line is less

that state is defined as a line break,

in this case, after determining the line break, the line is charged at least three times, and the time constant is determined by the charge characteristic, and averaged by the formula

L = C / C _km

where C is the measured line capacity;

C _km - line capacity per kilometer,

C = τ / R _in

where τ is the time constant;

R _I - the input impedance of the device through which the charge of the line passes, calculate the line length to break.

The closest in technical essence to the proposed device for monitoring equipment of wired telecommunication networks is a device for monitoring equipment of wired telecommunication networks, including connecting lines, containing a microprocessor, a power supply (see patent RU 2125239).

Its disadvantage is low reliability, insufficient speed and accuracy of determining the location of damage, as well as a small number of controlled objects.

The present invention solves the problem of improving the reliability, accuracy of determining the location of damage, speed and increase the number of controlled objects.

To solve the technical problem, a device for monitoring equipment of wired telecommunication networks, including connecting lines, contains a microprocessor, a power supply, the device additionally contains a block for normalizing input signals and multiplexing, as well as a block for switching the supply voltage, and these blocks are connected to the block power supply and microprocessor, while the normalization block of input signals and multiplexing is configured to determine the current in each line and the ability to protect the device inputs are from high voltage, and the power supply switching unit is made in the form of two optical keys with the ability to simultaneously switch these optical keys, in addition, each line is equipped with two resistances installed at its end, one of which is shunted by the sensor contacts.

A distinctive feature of the proposed device is that the device further comprises a unit for normalizing the input signals and multiplexing, as well as a unit for switching the supply voltage, and these units are connected to the power unit and the microprocessor, while the unit for normalizing the input signals and multiplexing is configured to determine the current in each lines and the ability to protect the inputs of the device from high voltage, and the power supply switching unit is made in the form of two optical keys with possible Stu simultaneous switching of optoklyuchey addition, each line has two resistances mounted at its end, one of which is shunted by the sensor contacts.

The essence of the device is illustrated by drawings, where figure 1 shows a block diagram of the proposed device, figure 2 is a graph of the change in the line current when it is charged.

A device for monitoring equipment of wired telecommunication networks, including connecting lines, contains a microprocessor 1, a power supply 2. The device further comprises a normalization unit for input signals and multiplexing 3, as well as a power supply switching unit 4, and these blocks 3, 4 are connected to the unit power supply 2 and microprocessor 1. The input signal normalization and multiplexing unit 3 is configured to determine the current in each line and to protect the inputs of the device from high voltage I reached through the use of Zener diodes. The normalization block contains the input resistance of the device R _in equal to 54.9 kΩ ± 5%.

The input signal normalization and multiplexing unit consists of input resistors and sets of resistors, the voltage drop on which is proportional to the line current, protective zener diodes and multiplexers that allow switching one of the device inputs to the input of the analog-to-digital microprocessor converter. The microprocessor, measuring the voltage drop at each input, determines its state: normal, sensor failure, open or short circuit to the sensor.

The power supply switching unit 4 is made in the form of two optical keys with the ability to simultaneously switch these optical keys. Each line 5 is equipped with a board 6 installed at its end as close as possible to the sensor 7. The board 6 contains two resistances R ₁ 8 and R ₂ 9, one of which 9 is bridged by the contacts of the sensor 7. The resistance R _{1 is} set to 27 kOhm ± 5% and the resistance R _{2 is} set equal to 68 kΩ ± 5%. Resistance values are selected for reasons of reducing power consumption and obtaining distinguishable and reliably detectable signals for assessing the states of lines and sensors.

A device for monitoring the equipment of wired telecommunication networks, including connecting lines, operates as part of a hardware-software complex as an object device and is designed to monitor the operation and protection of various equipment of wired telecommunication networks.

Power supply 2 provides power to all nodes of the device. The microprocessor 1 is connected to the switching unit of the supply voltage 4, with the normalization and multiplexing unit of the input signals 3 and controls them during operation of the device. Due to the use of multiplexers in the normalization and multiplexing unit of input signals, the number of monitored lines increases. The device provides an automatic interrogation of sensors or alarm devices, and the transmission of their status during the exchange of information with central devices or a computer. The device allows you to monitor the status of the sensors type "dry contact". The main difference between dry contact sensors is the presence of two separate contacts that do not have any power connection. An example of dry contact sensors are reed switches for opening control cabinets, controlled for open and short circuits in the cable. Board 6 is used to monitor the four states. It changes its output resistance depending on the state of the contacts of the connected sensor.

Thus, at each input, relative to the ground of the power supply station (+60 V), a current flows, depending on the state of the connecting line and sensor 7. By measuring this current, microprocessor 1 determines the state of the input.

The device, cyclically polling each input, detects four discrete states: “the sensor is closed”, “the sensor is open”, “short circuit in the line”, “line break” and additionally measures the length of the line from the device to the place of its break.

The device measures the current in the line and compares with the current determined by the formula:

where U _in - voltage at the input to the line;

R _I - the value of the input resistance of the device;

R ₁ is the resistance value at the end of the line connected in series with the sensor;

R ₂ is the resistance value at the end of the line connected in parallel with the sensor,

moreover, if the current in the line is within

then the state of the line with the sensor is defined as the norm;

if the current in the line is within

then the state of the sensor is defined as an accident;

if the current in the line is greater than or equal to

this condition is defined as a short circuit in the line;

if the current in the line is less

that state is defined as a line break,

Length measurement occurs when any of the conditions at the input (“sensor closed”, “sensor open”, “short circuit in the line”) goes into the “line break” state. The device, having detected such a transition, measures the length of the remaining line and passes it to the center as additional information about the cliff. The algorithm for measuring the line length is based on determining the line capacitance from the time constant of the line capacitance, by charging it. Microprocessor 1, analyzing the charge characteristic of the line, calculates the time constant τ and, knowing the resistance through which the charge occurred (R _in = 54.9 kOhm, the input resistance of the device located in the input signal normalization and multiplexing unit), calculates the capacitance of line C. And knowing the line capacity per kilometer (C _km = 0.047 μF / km), and calculates the line length

The resistance of the line itself (90-180 Ohm / km) is not taken into account, because it is much less than the input impedance of the device. The measurement error is not more than 5%. The maximum length of the line measured by the device reaches 12 km.

When the line is charged, the current in it changes exponentially (figure 2).

The time constant T can be determined at the level of 0.368 · I ₀ , where I ₀ is the current value at the initial moment of charge of the line.

Example

The proposed device was mounted in the city of Ocher of the Perm Territory at the ATS-3 wired telecommunication networks facility for organizing integrity control of trunk cables and access to distribution cabinets.

Device parameter values:

- the number of controlled lines 60 pcs .;

- length of lines up to 2000 m;

- power supply voltage 60 V;

- the value of the input resistance of the device R _I = 54.9 kOhm;

- the resistance value at the end of the line connected in series with the sensor R ₁ = 27 kOhm;

- the resistance value at the end of the line connected in parallel to the sensor R ₂ = 68 kOhm;

- current consumption 60 mA.

The power supply unit is a DA1 36-75V / 5V voltage converter with a protective diode against reverse voltage with an input filter and output filtering capacitors. A microprocessor clocked from a quartz resonator with capacitors ensures the operation of the device by controlling its nodes. The input signal normalization and multiplexing unit consists of input resistors and sets of resistors, the voltage drop on which is proportional to the line current, protective zener diodes and multiplexers that allow switching one of the 60 device inputs to the input of the analog-to-digital microprocessor converter. The microprocessor, measuring the voltage drop at each input, determines the current and decides on the state of the input, its state: normal, sensor failure, open or short circuit to the sensor. Optical switches with limit resistors form a switching unit for the supply voltage. These optical keys are turned on in parallel and controlled from a single microprocessor output. This ensures their simultaneous switching. The power node generates a voltage from which the entire circuit of the device is powered.

The operation of the proposed device showed reliability, ensuring high accuracy in determining the location of damage, speed and the ability to control a large number of objects.

Claims (2)

1. A method for monitoring the equipment of wired telecommunication networks, which consists in monitoring the state of the sensors and connecting lines by a device, characterized in that monitoring the status of sensors and connecting lines is carried out cyclically in time with a cycle of at least three times per second on each line in four states - the norm, sensor failure, short circuit or open circuit to the sensor by determining the current in the line and comparing with the current determined by the formula

where U _ВХ - supply voltage at the input to the line; R _IN - the value of the input resistance of the device; R ₁ is the resistance value at the end of the line connected in series with the sensor; R ₂ is the resistance value at the end of the line connected in parallel with the sensor, moreover, if the current in the line is within

then the state of the line with the sensor is defined as the norm, if the current in the line is within

then the state of the sensor is defined as an accident; if the current in the line is greater than or equal to

this condition is defined as a short circuit in the line if the current in the line is less

that state is defined as a line break, at the same time, when determining a line break, the line is charged at least three times, and the time constant is determined by the charge characteristic, and averaged by the formula L = C / C _km where C is the measured line capacity; C _km - line capacity per kilometer, C = τ / R _BX where τ is the time constant; R _BX - input resistance of the device through which the charge of the line passes, calculate the line length to break. 2. A device for monitoring equipment of wired telecommunication networks, including connecting lines and sensors, containing a microprocessor, a power supply, characterized in that the device further comprises a unit for normalizing input signals and multiplexing, as well as a switching unit for supply voltage, these blocks being connected to a power supply unit and a microprocessor, while the normalization of input signals and multiplexing unit is configured to determine the voltage in each line and the ability to protect inputs devices from high voltage, and the power supply switching unit is made in the form of two optical keys with the ability to simultaneously switch these optical keys, in addition, each line is equipped with two resistors installed at its end, one of which is shunted by the sensor contacts.

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