# Fault Diagnosis of Universal Circuit Breakers Based on Variational Mode Decomposition and WOA-DBN
## 2 Experiment Setup and Data Acquisition
### Experimental Dataset  
Figure 1 illustrates the experimental setup for collecting vibration signals under operating conditions. This paper used the universal circuit breaker model HSW1-2000, manufactured by Hangzhou Zhijiang Switchgear Stock Co., Ltd., Hangzhou, China, which  
is operated in Figure 1a. The sensor that acquires the vibration signal was mounted on the universal circuit breaker's top beam, which satisfied the installation location and detection direction specifications while enabling non-invasive detection. The data acquisition system in Figure 1b consisted of a vibration sensor, constant current adapter, and oscilloscope. Vibration sensors converted mechanical vibrations into electrical signals that could be easily transmitted, transformed, processed, and stored. Constant current adapters provided vibration sensors with their appropriate voltage, and the oscilloscope was connected to the vibration sensor to collect the current signal from it. Under various operating conditions, the experimental platform gathered vibration signals from the universal circuit breaker. Six distinct operating conditions were simulated during the universal circuit breaker closing process, including normal conditions, mechanical structure stuck, insufficient core travel, core stuck, high operating voltage, and low operating voltage. The vibration acceleration sensor was YK-YD500, with a maximum measurable impact acceleration of 500 g. The vibration signals were analyzed, the sampling frequency was 500 kHz, and the sampling duration was 20 ms.  
Table 1 shows the configuration of the data collection system for universal circuit breakers. The signal was sampled at 500 kHz and stored on a USB flash disk using an oscilloscope. Subsequently, the data were transmitted to the upper computer for further analysis. \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Name of Device** & **Producer** & **Type** & \multicolumn{2}{c}{**The Configuration**} \\ \hline  & & & Parameter & Value \\ Vibration sensor & YANKOON & YK-YD500 & Range & 500 g \\  & & & Sensitivity & 10 mV/g \\ Oscilloscopes & SIGLENT & SDS3000 & Sampling frequency & 500 kHz \\ Power supply & YANKOON & YK5201 & Output voltage & +24 V \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Configuring the data collecting system for universal circuit breakers. Figure 1: Universal circuit breaker experimental device. (**a**) Universal circuit breaker; (**b**) data acquisition systems. In this paper, five different fault conditions were simulated in the laboratory using specific methods, as described below:  
1. Mechanical structure stuck fault: A 5 mm-thick copper sheet was wrapped twice around the bottom collision mechanism to simulate this fault. This created resistance during switching and closing impacts, as Figure 2a depicts. 2. Insufficient core travel fault: A 10 mm \(\times\) 10 mm \(\times\) 0.5 mm wooden block was fixed to the core travel terminals to simulate this fault. This prevented them from fully resetting during the switching operation, thus simulating insufficient core travel fault. Refer to Figure 2b for the fault simulation method. 3. Core stuck fault: The fault simulation method for this type of fault involved inserting a cylindrical copper sheet with a thickness of 1 mm around the iron core of the opening and closing tripper. This generated resistance during the opening and closing operation, as shown in Figure 2c. 4. High operating voltage fault: In this case, the operating voltage was artificially set to 110% of rated voltage to simulate the fault. For the fault simulation method, refer to Figure 2d. 5. Low operating voltage fault: In this case, the operating voltage was artificially set to 90% of rated voltage to simulate the fault. For the fault simulation method, refer to Figure 2e. Figure 2: Universal circuit breaker fault emulation methods. (**a**) Mechanical structure stuck. (**b**) Insufficient core travel. (**c**) Core stuck. (**d**) High operating voltage. (**e**) Low operating voltage.