592 / 2017-05-15 09:23:17

Mechanical Condition Assessment of High Voltage Circuit Breaker Based on Vibration Signal Analysis

HVCB, mechanical condition assessment, vibration signal, Teager energy operator, k-means

High Voltage Circuit Breaker (HVCB) is the key apparatus in power system, which plays a control and protection role. To further improve the reliability of HVCB operation, vibration signals are analyzed to detect HVCB mechanical state and identify potential faults in OLTC. In consideration of nonlinear and non-stationary of HVCB vibration signals, a novel method based on the combination of local extremum points distribution and optimized k-means clustering algorithm is proposed to describe the HVCB vibration signal during opening/closing process.
The proposed method is as follows: First, the Teager energy operator (TEO) is applied to determine the start and end point of measured vibration signal. Then, local extremum points are extracted as the characteristic points of vibration signal and every two adjacent characteristic points are connected in vector form. Next, these vectors are illustrated in a log-polar coordinate diagram and the optimized k-means clustering algorithm is applied to find the centroids of the characteristic vectors distribution diagram. Finally, the lengths and angles of centroid vectors are regarded as the judgment criterion to identify HVCB mechanical condition.
An ABB OHB HVCB has been chosen as the experiment subject. Seven acceleration sensors are attached on the surface of HVCB to acquisite vibration signals in different states including normal state and some typical mechanical fault states. The calculate results have shown that the vibration signals have good repeatability. The differences of centroids distributions agreed well with the different mechanical conditions and the centroid vectors can be regarded as the feature of vibration signal. Thus the proposed vibration signal analysis method can provide the reliable indications of the mechanical condition assessment of HVCB.