Vacuum Circuit Breaker Closing Time Key Moments Detection via Vibration Monitoring: A Run-to-Failure Study

Abstract

Circuit breakers (CBs) play an important role in modern society because they make the power transmission and distribution systems reliable and resilient. Therefore, it is important to maintain their reliability and to monitor their operation. A key to ensure a reliable operation of CBs is to monitor their condition. In this work, we performed an accelerated life testing for mechanical failures of a vacuum circuit breaker (VCB) by performing close-open operations continuously until failure. We recorded data for each operation and made the collected run-to-failure dataset publicly available. In our experiments, the VCB operated more than 26000 closeopen operations without current load with the time span of five months. The run-to-failure long-term monitoring enables us to monitor the evolution of the VCB condition and the degradation over time. To monitor CB condition, closing time is one of the indicators, which is usually measured when the CB is taken out of operation and is completely disconnected from the network. We propose an algorithm that enables to infer the same information on the closing time from a nonintrusive sensor. By utilizing the short-time energy (STE) of the vibration signal, it is possible to identify the key moments when specific events happen including the time when the latch starts to move, and the closing time. The effectiveness of the proposed algorithm is evaluated on the VCB dataset and is also compared to the binary segmentation (BS) change point detection algorithm. This research highlights the potential for continuous online condition monitoring, which is the basis for applying future predictive maintenance strategies.

Design of Bypass Switches for HV/MV Hybrid Transformer Auxiliary Converters

“…In the hybrid Aux Bypass the bypass currents i a bp,a ,..,i c bp,a are taken over by a MS after an assumed closing time of t on = 140ms. The closing time t on includes a safety margin so that the number n p of thyristors in parallel is sufficient in case closing the contacts of the MS takes longer than the closing time for a vacuum circuit breaker determined in [18]. Therefore, the closing time is set to t on = 140ms, which is twice the closing time for a vacuum circuit breaker in [18].…”

“…The allowed mean on state current and surge on state current is significantly lower for pulse power thyristors than for phase controlled thyristors [24] and therefore phase controlled thyristors are chosen for the Aux Bypass and the Sec Bypass. Due to the MV level and the current rating of the Aux Bypass the turn on time t on for the MS is assumed as turn on time of a MV vacuum circuit breaker [18]. The turn on time t on of the MS is one important design criterion for the number n p of parallel thyristors needed in the Aux Bypass.…”

“…A critical HT auxiliary converter current is reached within microseconds in case of a SI in the HV grid. A mechanical switch MS with a turn on time in the milliseconds range [18] is too slow to bypass the HT auxiliary converter in case of a critical fault. As a consequence, a bypass switch with solid state switches, as for example thyristors, is required to bypass the HT auxiliary converter within a few microseconds.…”

An online detection method for the mechanical fault of circuit breakers of rural distribution lines based on continuous wavelet transform and vibration signal characteristics

“…We take the transformation decomposition process of a group of vibration signals as an example [6] as follows:…”

Design of fault degree diagnosis algorithm for circuit breaker spring based on fuzzy clustering

“…It can detect and disconnect situations where the current exceeds the rated value or malfunctions in the circuit to prevent damage to the circuit and equipment. When the current exceeds the rated value or a fault occurs, the protection unit will detect an abnormal situation and send a signal to the triggering mechanism [2]. The triggering mechanism transmits the triggering signal to the main body of the circuit breaker, enabling it to quickly disconnect the circuit to protect electrical equipment and systems from overload, short circuits, and other faults [3].…”