Installation method of power cable temperature monitoring optical cable: for temperature monitoring of 10KV or lower cables, an S-shaped laid temperature-sensing optical cable can be used. Generally, cables on the same layer can be covered with one optical cable. The S-shaped laying can save the amount of optical cable while ensuring an effective protection area.
The calculation method of the number of clamps fixing the temperature-sensing optical cable is as follows: number of fixing clamps = number of sine half-waves × 2 + 1. The length of the temperature-sensing optical cable is calculated by the following formula: length of temperature-sensing optical cable = bracket length × multiplication coefficient. The multiplication coefficient is selected according to the table below:
When a fire or high-temperature hazard occurs at the cable, the distributed fiber optic linear heat detector can provide an alarm in time, thereby preventing or reducing the damage caused by fire accidents. The system can also upload alarm and temperature information to the fire alarm host for comprehensive management. For the joints of power cables, the optical cable needs to be wound to provide better monitoring and protection, as shown in the figure below.
Through equipment linkage, status information can be used to control the operation of other equipment, thereby completing automatic control and unattended operation. For 110KV and above power cables, temperature monitoring should be performed for each cable. In application, the temperature-sensing optical cable (about 3mm in diameter) is generally laid closely above the cable, as shown in the figure below.
For power cables, the distributed fiber optic temperature measurement system can detect the surface temperature of the cable, thereby monitoring the operating condition of the cable. Abnormal cable temperature will trigger a system alarm. Installation method of ambient temperature monitoring optical cable: the sensing optical cable is suspended and fixed above the tunnel. The schematic diagram of the optical cable suspension method is as follows:
During installation, the cable is fixed on the bracket with wire clips every 1.5m. After the temperature-sensing optical cable is installed, the cable markers corresponding to the head and tail ends of each zone should be recorded. Schematic diagram of the sensing optical cable installation in the tunnel:
The fiber optic temperature measurement fire detection system is composed of the fiber optic temperature measurement host and the sensing optical cable. The system monitors the ambient temperature of the integrated pipe corridor in real time, and the host displays the current temperature distribution curve of the corridor, which is quite intuitive. When the corridor temperature reaches the preset threshold, the system automatically gives a sound and light alarm and sends an alarm contact closing signal to the monitoring center.
3.6 System communication: the use of PC-to-PC communication technology means that on-site information can be reproduced at a remote control center, which is of great help for unmanned control rooms. In this project, data exchange can be performed by connecting the control room computer with the control center computer. The specific connections of this project are as follows: ① The VGA interface of the measurement host is connected to one LCD display (in the monitoring room) to display the temperature information (text and graphics) collected by the system. ② The RJ45 interface of the measurement host can connect the host to the enterprise LAN via a Modem, enabling users' computers to remotely view temperature and alarm information. ③ The LED indicators of the measurement host display the operating status, system faults (fiber fault, hardware fault, etc.) and fire alarm information, and provide sound signals (continuous sound for faults, intermittent sound for fire). ④ The RS232 interface of the measurement host can connect external devices, such as the fire alarm controller, to achieve fire linkage control.
