JPH04303723A - Abnormality monitoring system in tunnel - Google Patents

Abstract

PURPOSE:To obtain an abnormality monitoring system in a tunnel whose maintenance is easy at a low cost by utilizing a temperature measuring system wherein an optical fiber itself is a sensor. CONSTITUTION:An abnormality monitoring system in a tunnel is a system utilizing a temperature measuring system wherein an optical fiber itself is a sensor. One or two optical cables are laid for the respective monitoring item in the tunnel for electric power cable. The data of all monitoring items are operated and processed with one central processing unit 5 by controlling a switch 4 under the control of a computer 6.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a system for monitoring abnormalities in power cable tunnels.

0002

2. Description of the Related Art Conventionally, the following systems have been used as abnormality monitoring systems in power cable tunnels. Abnormalities in equipment: Consisting of a central device and slave stations installed in the tunnel, the slave stations collect information on abnormalities of various equipment in the tunnel and transmit this to the central device. Cable fault location: Current detection sensors are installed in the insulated junction box and terminal section of the power cable line, and the fault location is located based on the time difference between the surge current reaching two adjacent current detection sensors. Fire detection: Using spot-type fire detection sensors such as smoke sensors and heat detection sensors, or heat detection lines, the slave stations collect this information and transmit it to the central device. Cable surface temperature: A thermocouple or a platinum resistance thermometer is attached to the cable surface, and the output is amplified, collected by the slave station, and transmitted to the central device. Recently, there are also examples of using distributed optical fiber sensors.

0003

[Problems to be Solved by the Invention] In the conventional monitoring system described above, different systems are used for each monitoring item, and the equipment is large and expensive, and maintenance requires a lot of cost and effort. There was a problem that it was necessary.

0004

[Means for Solving the Problems] The present invention solves the above-mentioned problems and provides an inexpensive and easy-to-maintain intra-sinus abnormality monitoring system, which is characterized by using the optical fiber itself as a sensor to measure A system that uses a temperature measurement system that measures the temperature distribution of the object by installing a sensor along the object, injecting a light pulse into the sensor, and detecting the intensity of the Raman scattered light included in the backscattered light. There it is,
By laying one or two optical fibers for each monitoring item in the power cable tunnel and controlling the changeover switch using computer control, one central processing unit can calculate information on all monitoring items. It's about processing.

[0005]

[Embodiment] The present invention uses an optical fiber itself as a sensor and utilizes one of the techniques that can continuously measure physical quantities along the sensor. A light pulse is input from a laser light source connected to one end of the light, and the delay time of the backscattered light is measured to find the generation position of the backscattered light, and the intensity of the Raman scattered light included in the backscattered light is detected. This is a temperature measurement system that calculates the temperature at each location.

FIG. 1 is a circuit diagram of a specific example of the intra-sinus abnormality monitoring system of the present invention. In the drawings, reference numerals 1 to 3 indicate optical fibers as sensors installed in the tunnel. 1 is an optical fiber for detecting temperature in the cave and fire, which is laid along the ceiling, side walls, etc. of the cave. 2A, 2B, and 2C are all optical fibers for cable surface temperature and accident point location, and are laid along the surface of each cable laid in the tunnel. 3
is an optical fiber for collecting equipment abnormalities, which is installed along the side walls of the tunnel. When equipment breaks down, that information is sent to contact input 3.
2, the heater 31 is turned on for a certain period of time, and the heating device 33 heats the coiled optical fiber. 4 indicates optical fibers 1 to 3 for each item installed in the tunnel above.
and a changeover switch for connection to the central processing unit 5, and the computer 6 controls which optical fiber is connected to the central processing unit 5.

Reference numeral 5 denotes a central processing unit that sends optical pulses to the optical fibers 1 to 3, processes the Raman scattered light returning from each optical fiber, calculates the temperature of each part, and transmits it to the computer 6. 6 is a computer which displays the processing results of the central processing unit 5 on the CRT 7, determines whether or not there is an abnormality by comparing it with a standard value, and outputs an output to an alarm contact in the case of an abnormality. It also takes in the circuit breaker operation relay contact output from the substation and controls the changeover switch 4 according to that information.

The monitoring system of the present invention is equipped with the above-mentioned components, and the information on the optical fibers connected by the changeover switch is processed by the central processing unit 5, and the results are displayed on the CRT via the computer 6. . The computer 6 not only outputs processing information from the central processing unit 5 to the CRT, but also has the function of selecting a changeover switch based on relay information. One central processing unit 5 and one computer 6 monitor information on a plurality of optical fibers while switching them with a changeover switch. At this time, the most important fire detection is subject to constant monitoring, and since there is no sudden change in cable surface temperature and equipment failure detection is not urgent, for example, 1
The changeover switch 4 may be controlled by software that monitors the monitor once per hour.

[0009]

[Effects of the Invention] As explained above, the intra-sinus abnormality monitoring system of the present invention provides the following effects. ■ By switching the information of multiple optical fibers with a changeover switch, it is possible to monitor multiple monitoring items with one central processing unit, which is inexpensive. ■The only system equipment inside the tunnel is an optical fiber heating device, and when the equipment is operating normally, power consumption inside the tunnel is zero, and running costs are low. ■There is no need for maintenance as there are no expensive electronic devices inside the tunnel. Additionally, optical fibers are constantly monitored for abnormalities.
Since maintenance personnel only need to repair the optical fiber when there is an abnormality, the labor of the maintenance personnel is reduced.

[Brief explanation of drawings]

FIG. 1 is a circuit configuration diagram of a specific example of the intra-sinus abnormality monitoring system of the present invention.

[Explanation of symbols]

1 Optical fibers for tunnel temperature and fire detection 2A, 2B, 2
C Optical fiber for cable surface temperature and accident point location 3 Optical fiber for equipment abnormality collection 31 Heater 32 Contact input 33 Optical fiber heating device 4 Changeover switch 5 Central processing unit

Claims (3)

[Claims] Claim 1: An optical fiber itself is used as a sensor and is laid along the object to be measured, and a light pulse is incident on the sensor and the intensity of the Raman scattered light included in the backscattered light is detected. A system that uses a temperature measurement system to measure temperature distribution, in which one or two optical fibers are laid for each monitoring item in the power cable tunnel, and the changeover switch is controlled by computer control. An abnormality monitoring system in a sinus is characterized in that information on all monitoring items is processed by one central processing unit. [Claim 2] Claim 1, characterized in that a changeover switch is controlled so that fire detection is always monitored, and other monitoring items are monitored spot-on.
The sinus tract abnormality monitoring system described. 3. The tunnel anomaly monitoring system according to claim 1, further comprising a function of receiving a circuit breaker operation relay contact output from a substation and controlling a changeover switch according to the information.