Preventive maintenance of spring applying vibration diagnostic tool- a Malaysian experience
Broad ranges of spring switchgears have been extensively used in most of Malaysian substations. Condition monitoring of hydraulic and spring switchgears have been a critical problem since the conventional methods applied failed to alert prior occurrence of faults. Recent routine reports of TNB Malaysia highlight an occurrence of 20% failures over a period of 5 year. This has lead to greater loss and high expenditure in replacing these switchgears. One of the major contributing factors in failure of hydraulic switchgears is occurrence of mechanical faults, which the conventional method of monitoring failed to detect and locate. However the recent vibration testing prevents and minimizes the breakdowns due to mechanical faults. This current vibration analysis is a noninvasive diagnostic tool applied in comprehensive monitoring of HV switchgears. This method of investigation is well ventured in many countries in Europe and USA but not yet in Malaysia. TNB Malaysia is taking the stepping stone is venturing this technology in line with our objective of seeking predictive maintenance, cost effective and reliable diagnostic tool. This paper will explore in depth the possible mechanical faults that contribute to spring switchgears failures applying vibration analysis. This paper will further interpret the results of vibration testing on 118 spring switchgears 132 kV. This, preliminary study involves interpreting the vibration signal during the event of close and open only to better understand the movement of the mechanical component during operation time enabling us to distinguish which component contributes to the fault of the switchgear.
Vibration Analysis for Diagnostic Testing of Circuit Breakers
In order to assess the feasibility of vibration analysis for the diagnostic testing of high-voltage circuit breakers, a comprehensive field test program has been carried out. Vibration patterns from 31 breakers (93 identical single-phase units) have been acquired, compared and analyzed. The breakers were assumed to be in good condition with no known irregularities at the time of testing. However, several serious faults, including an incipient rupture of the contact plug shaft, an incorrectly assembled crank, and major lubrication problems were disclosed. Thus, this "blind test" performed under realistic conditions on circuit breakers in normal service demonstrates that vibration analysis can be a reliable and suitable tool for noninvasive diagnostic testing.
Acoustic diagnosis of high voltage circuit-breakers
A noninvasive technique for assessing the condition of circuit breakers by considering the acoustic signals generated during nonenergized switching is described. Mechanical malfunction, wear, and other types of abnormal behavior can be detected as changes in this acoustic signature. Digital signal processing techniques known from speech recognition were successfully applied to extract, compare, and present the information from the breaker signatures. A fault in the release mechanism which developed over time and eventually rendered one pole of a circuit-breaker inoperative was detected in an early stage, demonstrating the efficiency of this diagnostic technique. >