Distributed Optical Fiber Sensing: Full-Chain Empowerment for Power Safety Monitoring

In the "frontline" of power safety assurance, distributed optical fiber sensing technology serves as a reliable "intelligent guardian" with numerous critical applications. For transmission lines, leveraging the principles of Brillouin and Raman scattering, it monitors strain and temperature during icing events, accurately determining ice thickness and weight to prevent line breaks and tower collapses. It captures details of gentle wind vibrations and oscillations, protecting lines from long-term damage. In power cable monitoring, temperature is measured using Raman scattering to prevent overheating and aging, vibration sensing detects external force damage, and acoustic wave sensing locates partial discharges. Within substations, it conducts "body temperature" checks and "health examinations" on equipment, controlling temperatures and monitoring vibrations to identify faults. In the surrounding environment, it provides fire warnings and intrusion monitoring, comprehensively fortifying the power safety "protective net."

Transmission Line Condition Monitoring

• Icing Monitoring: When transmission lines are iced over, their weight increases and sag heightens, which can lead to line breaks and tower collapses. Distributed optical fiber sensing technology utilizes the principles of Brillouin scattering and Raman scattering to monitor strain and temperature changes in the lines. By installing optical fiber sensors along the transmission lines, the strain on the fibers is monitored in real-time, enabling the determination of whether icing has occurred, as well as the thickness and weight of the ice. This allows for timely de-icing measures to ensure the safe operation of transmission lines.
• Gentle Wind Vibration Monitoring: Transmission lines experience vibrations under gentle wind conditions, and prolonged vibrations can cause fatigue damage to the lines. Distributed optical fiber vibration sensing technology can monitor parameters such as vibration frequency and amplitude in real-time. By analyzing the vibration signals, the vibration state of the lines is assessed, enabling the early detection of abnormal vibrations and providing a basis for implementing vibration reduction measures, thereby extending the service life of the transmission lines.
• Oscillation Monitoring: In severe weather conditions like strong winds, transmission lines may experience oscillations, which can cause significant damage. Distributed optical fiber sensing systems can monitor dynamic strain and displacement changes during oscillations, accurately capturing the amplitude, frequency, and trajectory of the oscillations. This helps power departments issue early warnings and take effective anti-oscillation measures, such as installing anti-oscillation devices, to ensure the safe and stable operation of transmission lines.

Power Cable Monitoring

• Temperature Monitoring: During operation, power cables generate heat due to the passage of electrical current. Poor heat dissipation or overloaded operation can cause the cable temperature to rise, accelerating insulation aging and potentially causing fires. Distributed optical fiber temperature sensing technology utilizes the Raman or Brillouin scattering effects of optical fibers to measure the temperature distribution along the cable in real-time. This allows for the timely identification of overheating areas, providing essential information for assessing cable current capacity, fault warning, and operational maintenance, thereby ensuring the safe and reliable operation of power cables.
• External Force Damage Monitoring: Distributed optical fiber vibration sensing technology can monitor vibrations around power cables. When external forces act on the vicinity of the cables, such as excavation, drilling, or vehicle traffic, the sensors can capture vibration signals. By analyzing and processing these signals, the type, location, and intensity of the external force can be determined, allowing for timely alarms to prevent cable damage caused by external forces and avoid power outages.
• Partial Discharge Monitoring: Partial discharge is an important early indicator of insulation aging and faults in power cables. Distributed Optical Fiber Acoustic Sensing (DAS) technology can detect ultrasonic signals generated by partial discharges in cables, enabling online monitoring and localization of partial discharges. By monitoring and analyzing partial discharge signals, insulation defects and potential faults in cables can be promptly identified, providing scientific basis for cable maintenance and replacement, thereby enhancing the operational reliability of cables.

Substation Equipment Monitoring

• Equipment Temperature Monitoring: Equipment within substations, such as transformers, switch cabinets, and busbars, generate heat during operation. Excessive temperatures can affect the performance and lifespan of the equipment, potentially causing faults. Distributed optical fiber temperature sensing systems can be installed on these devices to monitor temperature changes in real-time, providing overheat protection for the equipment. When the equipment temperature exceeds a set threshold, the system promptly issues an alarm signal to notify maintenance personnel for timely intervention, ensuring the safe and stable operation of substation equipment.
• Mechanical Vibration Monitoring: Certain equipment within substations, such as transformers and reactors, generate mechanical vibrations during operation. Distributed optical fiber vibration sensors can monitor the vibration conditions of the equipment. By analyzing vibration signals, the presence of faults or abnormalities can be determined. For example, when a transformer experiences winding looseness or core displacement, it causes changes in vibration signals. The sensors can promptly capture these changes, providing reference information for fault diagnosis and maintenance of the equipment.

Surrounding Environment Monitoring of Power Facilities

• Fire Warning: Distributed optical fiber temperature sensing technology can monitor the ambient temperature around power facilities. In the event of a fire, the sensors can quickly detect a sudden rise in temperature and issue fire alarm signals in a timely manner. This provides early warnings for fire prevention and extinguishing measures, reducing the damage caused by fires to power facilities.
• Intrusion Monitoring: By laying distributed optical fiber sensors around power facilities and utilizing their vibration sensing capabilities, personnel activities and object intrusions in the vicinity can be monitored in real-time. When individuals or objects approach the power facilities, the sensors detect vibration signals and transmit them to a monitoring center, enabling perimeter security surveillance of the power facilities. This prevents unauthorized intrusions and destructive activities.

Distributed optical fiber sensing technology comprehensively empowers the entire chain of power safety monitoring, enhancing the ability to ensure the safe, reliable, and efficient operation of power systems. By providing real-time, accurate, and extensive monitoring across various components and environments, it plays a pivotal role in safeguarding power infrastructure against a wide range of risks and ensuring the stability of energy supply.