The small current grounding line selection device provides efficient and accurate fault handling capabilities for power systems through multi-circuit synchronous monitoring and rapid fault location. Its core approach lies in the coordinated application of synchronous data acquisition, multi-criteria fusion, a distributed architecture, and high-speed signal processing. Synchronous data acquisition is the foundation of the small current grounding line selection device's multi-circuit monitoring capabilities. Using high-precision zero-sequence current transformers and zero-sequence voltage sensors, the device performs real-time, synchronous sampling of zero-sequence current and busbar zero-sequence voltage across each circuit. This ensures consistent data acquisition timestamps across all monitored circuits, eliminates phase deviations caused by sampling time differences, and provides a reliable data foundation for subsequent algorithm analysis. This synchronization is particularly important during transient fault conditions. For example, during an arc grounding event, the zero-sequence current and zero-sequence voltage of the faulted line exhibit a specific phase relationship. Synchronous sampling accurately captures this characteristic, avoiding misjudgments caused by timing deviations.
The multi-criteria fusion algorithm is key to the small current grounding line selection device's improved fault location accuracy. Traditional devices rely solely on a single criterion (such as zero-sequence current amplitude comparison) and are susceptible to interference from factors such as system operating mode and transition resistance. Modern devices integrate multiple algorithms, including group amplitude and phase comparison, harmonic analysis, wavelet transform, and transient energy methods, to form a multi-criteria system. For example, the group amplitude and phase comparison method compares the amplitude and phase of the zero-sequence current in each circuit to preliminarily identify suspected faulty circuits. Harmonic analysis utilizes the distribution characteristics of high-frequency harmonic components during fault transients to further narrow the fault scope. Wavelet transform extracts the transient waveform characteristics of the zero-sequence current to identify complex fault types such as intermittent arc grounding. Cross-validation of multiple criteria significantly reduces the probability of false positives and missed detections.
A distributed monitoring architecture expands the monitoring capacity and flexibility of small current grounding line selection devices. For multi-circuit systems, the device adopts a modular design, supporting multiple monitoring boards operating in parallel. Each board monitors multiple circuits, and data is aggregated via bus communication. For example, one model can be expanded to monitor multiple outgoing lines, meeting the access requirements of large substations. The distributed architecture also supports cascading expansion, connecting multiple devices via a master-slave communication protocol to form a monitoring network covering the entire distribution network. In addition, some devices utilize wireless sensing technology, deploying low-power current sensors on branch lines and transmitting data to the main device via wireless communication, further reducing wiring costs.
High-speed signal processing and decision-making mechanisms are the core of the small current grounding line selection device's rapid fault location. The device incorporates a high-speed DSP or ARM chip, which performs real-time filtering, sorting, and feature extraction on collected data. For example, when the zero-sequence voltage exceeds the trigger threshold, the device immediately initiates the fault analysis process, quickly completing the zero-sequence current comparison of all circuits and identifying the faulty circuit using a decision tree algorithm. For faults with distinct transient characteristics (such as arc grounding), the device utilizes wavelet analysis to locate the fault in a fraction of the time, significantly improving response speed compared to traditional devices.
Anti-interference design is crucial for ensuring the reliability of the small current grounding line selection device. To combat complex operating conditions such as electromagnetic interference and harmonic pollution, the device utilizes a triple layer of protection: shielded cables, filtering circuits, and software anti-interference algorithms. At the hardware level, conducted interference is suppressed through optimized PCB layout and the addition of magnetic ring filters. At the software level, algorithms such as sliding average filtering and wavelet denoising are used to eliminate random noise. The device also features a self-test function that monitors sensor status, communication links, and algorithm performance in real time, ensuring stable operation in harsh environments.
Communication and data management capabilities extend the fault handling capabilities of the small current grounding line selection device. Equipped with multiple communication interfaces and supporting standard protocols, the device can upload fault information to the dispatching master station or distribution automation system in real time. Furthermore, the device's built-in large-capacity memory records fault waveforms and operation logs, providing detailed data for incident analysis. Some high-end models also support remote retrieval of fault recordings, enabling maintenance personnel to quickly locate the cause of faults.
The small current grounding line selection device utilizes synchronous data acquisition technology, multi-criteria fusion algorithms, a distributed monitoring architecture, and high-speed signal processing mechanisms to enable real-time monitoring and rapid fault location in multi-circuit systems. Its technological evolution includes higher-precision sensors, more intelligent algorithm models, and more open communication protocols to meet the higher requirements for ground fault handling in modern power systems.
