System Composition

System Architecture

2 System Instructions

The comprehensive monitoring system for cable tunnels consists of a front-end online monitoring system, a communication network, and a comprehensive monitoring platform.

Ø Application layer: Summarize real-time data information of the entire station, evaluate the operation status of the entire station, and schedule and control the monitoring layer based on relevant data information.

Data layer: The process of storing, parsing, distributing, and applying collected data through a unified database read-write interface.

Ø Access layer: The equipment responsible for data communication transmission, including network switches, servers, communication fibers or cables, in order to transmit data collected by monitoring layer devices to servers.

Ø Monitoring layer: Directly perform online detection and statistics of the status parameters of each monitoring point, including various sensors, signal acquisition integration units, professional data processing devices, and other equipment.

Technical Solution

● Project Introduction

The total length of this project is XXX meters. A comprehensive monitoring system for cable tunnels is designed, including cable body status monitoring, online monitoring of cable tunnel environment, etc. A comprehensive monitoring platform is set up at the nearest substation or user designated location to be responsible for the daily management, equipment monitoring, and safety prevention of cable tunnels. The design is as follows:

1Distributed Fiber Optic Temperature Measurement System

Advanced distributed fiber optic temperature measurement technology is used for online monitoring of cable temperature. By laying a temperature measuring optical cable on the surface of the cable, the temperature of the cable is monitored to ensure the safety of the entire cable line operation. Real time temperature measurement, alarm, and early prediction are achieved to prevent problems before they occur.

Configuration Description:It is estimated that X groups of 3 cables will need to be monitored in this phase of the project, with a total of X sets of 10km temperature measurement hosts for X channels. The temperature measurement hosts will be installed in the substation or at a nearby installation location. The temperature measuring optical cable is laid on the surface of the cable, and appropriate allowance is considered.

Fiber optic host temperature sensing fiber

1.1 System Features

1）Continuous distributed measurement
Distributed fiber optic sensors are truly distributed measurements that can continuously obtain measurement information along several tens of kilometers of temperature sensing fibers, greatly reducing false alarm and missed alarm rates. Simultaneously achieve real-time monitoring.

2）Anti electromagnetic interference, can work normally in high electromagnetic environment

The optical fiber itself is composed of quartz material, which is completely electrically insulated; At the same time, the signal of the fiber optic sensor is carried by fiber optic, which is inherently safe and not affected by any external electromagnetic environment interference.

3）Intrinsic lightning protection

Lightning often damages a large number of electrical sensors. Fiber optic sensors, due to their complete electrical insulation, can resist the impact of high voltage and high current.

4）Long measurement distance, suitable for remote monitoring

The two prominent advantages of optical fiber are the large amount of transmitted data and low loss, which can achieve remote monitoring for tens of kilometers without the need for relays.

5）High sensitivity and measurement accuracy

In theory, the sensitivity and measurement accuracy of most fiber optic sensors are superior to general sensors, and this has been proven by mature products in practice.

6）Long lifespan, low cost, and simple system

The material of optical fiber is quartz glass, which has the characteristics of non corrosion, fire resistance, water resistance, and long service life, and can usually serve for 30 years. Taking into account the cost of the sensor itself and future maintenance expenses, using fiber optic sensors can greatly reduce the final operating cost of the entire project.

1.2 Technical Parameters

2. Cable sheath current monitoring system

This system monitors the grounding current in real time by installing a protective layer current monitoring device. When the grounding current of the metal protective layer is abnormal, the system will automatically alarm and the signal will be transmitted to the monitoring platform, which can real-time grasp the operation status of the cable metal protective layer grounding system.

Configuration Description:The protective layer grounding current monitoring device is installed at the position where the cable metal sheath is grounded. Each protective layer current monitoring device includes one protective layer current collector and three clamp current transformers.

Data acquisition host current transformer

2.1 System Functions

1) Protective layer current monitoring function: Real time monitoring of the grounding current of power cables, which can detect abnormal grounding current of cables early and take measures to deal with cable faults;

2) Expandable collection of cable line current, sheath voltage, cable joint temperature, environmental temperature and humidity, etc;

3) The front-end equipment adopts low-power design, with a power not exceeding 3W; except for the current transformer, it is installed as a whole in the collection device inside the tunnel, with a high protection level (IP68), suitable for the humid environment inside the tunnel;

4) Multiple levels of alarms are available, including normal, prompt, warning, alarm, and fault;

5) Implement grounding current change rate alarm, which includes 1-minute, 15 minute, and 1-hour monitoring of grounding current changes;

6) Real time storage of information, capable of querying historical data, printing alarm information, etc; Publish relevant data such as cable sheath current through WEB;

7) Self checking function: The system has a self checking function, which can conduct regular or real-time inspections of lower level machines, on-site equipment, etc., and detect communication or device abnormalities in the first time.

2.2 Technical Parameters