Research and Practice of Intelligent Monitoring System for Generator Circuit Breaker
The generator circuit breaker is a critical component in power systems, and its reliability directly affects the stable operation of the entire power system. Through research and practical application of intelligent monitoring systems, the real-time operational status of circuit breakers can be monitored, enabling early detection of potential faults and risks, thereby enhancing the overall reliability of the power system.
Traditional circuit breaker maintenance primarily relies on periodic inspections and experience-based judgment, which is not only time-consuming and labor-intensive but may also miss latent issues due to inadequate inspection coverage. Intelligent monitoring systems provide real-time monitoring, data analysis, and fault early-warning capabilities, reducing unnecessary maintenance and repairs, thus lowering operation and maintenance (O&M) costs.
They also enable more accurate assessment of equipment health, allowing for rational scheduling of maintenance activities to avoid both overuse and excessive maintenance, effectively extending equipment service life. The development and application of intelligent monitoring systems have advanced monitoring technologies for power equipment, including infrared thermal imaging and big data analytics. These technological advancements not only improve the monitoring efficiency of generator circuit breakers but also lay a technical foundation for intelligent management of other power system equipment.
1.Methods and Practices
1.1 Architecture of the Intelligent Monitoring System
The intelligent monitoring system consists primarily of sensors, an intelligent online monitoring device (IED), and a back-end monitoring system. Mechanical displacement sensors, low-current mechanical characteristic sensors, thermal imaging video sensors, and SF6 gas sensors are installed directly on the main equipment. These sensors collect real-time operating parameters of the generator circuit breaker and transmit signals via cables to the intelligent online monitoring device. An on-site monitoring cabinet houses the IED and a network switch, which acquire sensor signals, process them, and then transmit the data via fiber optic cable to the back-end monitoring system for storage and evaluation.
1.2 Circuit Breaker Mechanical Characteristic Monitoring System
The mechanical characteristic monitoring system comprises displacement sensors, low-current sensors, an intelligent online monitoring device, and a back-end system. By monitoring the operating displacement of the circuit breaker, the current values in the opening/closing control circuits, and the current in the energy-storage motor circuit, key mechanical parameters of the circuit breaker are obtained. Mechanical characteristic curves are plotted and compared against standard and historical travel curves to assess the breaker’s operational condition.
The monitoring system enables the following functions:
Plot waveforms of opening/closing coil current, energy-storage motor current, and mechanism travel curves;
Obtain data such as opening/closing time, speed, travel distance, peak coil current, characteristic coil parameters, peak energy-storage motor current, and energy-storage duration;
Compare measured travel curves with standard curves for analysis;
Query historical data and generate reports;
Monitor system faults and communication interruptions, with automatic alarm triggering.
This project installs three displacement sensors—one at the bottom of each phase’s opening/closing drive shaft on the generator outlet circuit breaker. The sensors convert angular displacement (caused by the linkage rod driving the crank arm) into digital TTL signals and transmit them to the intelligent online monitoring device. With independent displacement sensors per phase, the system can precisely identify the faulty phase and detect issues such as loose locking nuts on the linkage rod or loose/detached crank arms that cause incomplete opening or closing operations.
Low-current sensors are installed in the local control cabinet of the circuit breaker and include four measurement channels. Based on the Hall effect principle, they convert measured current signals into low-current analog signals and transmit them to the intelligent online monitoring device.
1.3 SF6 Gas Condition Monitoring System
The SF6 gas condition monitoring system consists of an SF6 gas sensor, an intelligent online monitoring device, and a back-end monitoring system. In this project, the intelligent monitoring device is shared with the mechanical characteristic monitoring system. This system provides operators with real-time data on SF6 gas density, pressure, and temperature inside the gas compartment, enabling long-term tracking and analytical evaluation of historical trends.
The SF6 gas sensor features an integrated design measuring density, pressure, and temperature simultaneously. It is mounted at the circuit breaker’s gas filling port and connected to the intelligent monitoring device via an RS485 communication interface.
The monitoring system provides the following capabilities:
Continuously monitor SF6 gas conditions in the generator circuit breaker compartment using the IEC61850 communication protocol;
Generate trend curves based on simulated data algorithms for predictive analysis;
Trigger alarms and provide recommended actions.
Traditional maintenance methods rely heavily on scheduled inspections and empirical judgment—time-consuming, labor-intensive, and prone to missing early fault indicators. In contrast, the SF6 gas monitoring system delivers continuous, real-time data, enabling predictive maintenance and timely intervention to prevent major failures. With the advancement of IoT and big data technologies, such condition monitoring systems can be integrated into broader equipment health monitoring networks, improving data accuracy, analytical depth, and fostering innovation in new solutions.
1.4 Infrared Thermal Imaging Video Monitoring System
The infrared thermal imaging video monitoring system comprises an infrared thermal imaging video sensor, a network switch, and a back-end system. It monitors the temperature of internal conductors in the generator circuit breaker by combining infrared thermal imaging with visible-light video. This dual-mode approach enhances measurement accuracy and allows monitoring of the disconnector contact gaps at the generator outlet circuit breaker.
In this project, the infrared thermal imaging video sensor is mounted externally on the circuit breaker enclosure, with its field of view covering the disconnector contact gaps and portions of the conductor. Image signals are transmitted via the sensor’s tail cable to the intelligent online monitoring device.
The system provides the following functions:
Display real-time conductor temperatures using color gradients and highlight regions with maximum/minimum temperatures along with numerical values;
Plot and store time-temperature curves;
Perform trend analysis based on historical data to evaluate operational status and issue anomaly warnings.
Infrared thermal imaging is a non-contact monitoring tool that allows technicians to remotely monitor equipment thermal conditions without interrupting operations, thereby reducing operational risk. It can instantly identify overheating, insulation degradation, or load imbalance—common early signs of failure—enabling preventive action to avoid large-scale outages and costly repairs. Combining infrared and visible-light video enables comprehensive equipment assessment, detailed analysis, and precise maintenance decisions. Additionally, the system records historical data for long-term trend analysis and performance evaluation, supporting predictive maintenance and forecasting future maintenance needs.
2.Conclusion
The developed intelligent monitoring system has not only established an accurate fault early-warning model but also optimized equipment maintenance strategies. These achievements effectively reduce the failure rate and maintenance costs of generator circuit breakers and significantly extend their service life. The innovation of this project lies in realizing multi-dimensional data analysis and highly automated monitoring of generator circuit breakers. It introduces big data analytics into generator circuit breaker monitoring and leverages cloud-based data storage and analysis to enhance data accessibility and analytical efficiency. These innovations not only improve the overall operational efficiency and safety of power systems but also provide new ideas and directions for technological advancement and development in the power industry.
