EKSTRAKSI PARAMETER STATISTIK PADA DOMAIN WAKTU DAN DOMAIN FREKUENSI UNTUK MENDETEKSI KAVITASI PADA POMPA SENTRIFUGAL BERBASIS PRINCIPAL COMPONENT ANALYSIS (PCA)
Abstract
Cavitation is the phenomenon which often happened on sentrifugal pump. The impact of
cavitation can cause decreasing of pump activities. It might cause the damage if it left
unchecked too long. Recently, the popular method used to detect cavitation is vibration signal
analysis method. The extraction of statistical parameters using the time domain and frequency
domain are the two general basiss in vibration signal analysis. Previous research usually tends
to use the statistical parameter feature in time domain or the frequency domain only, so there
is still research gap that can be done by combining the time domain and frequency domain. To
get more accurate results, further optimization is done using Principal Component Analysis
(PCA). PCA can transform vibration signal data linearly and then classify the data, so that it
can distinguish normal operating condition and cavitation.
The acquisition of vibration signal data was carried out using the Test-rig cavitation scheme by
varying the valve cover on the suction side of the pump. Vibration signal data was taken under
normal condition with valve fully open condition, level 1 cavitation on valve cover by 25%,
level 2 cavitation at 50%, and level 3 cavitation at 75%. Then the data was extracted into 7
features statistical parameter in time domain and 5 statistical parameters of the frequency
domain. From 500 data recorded using accelerometer , the data were divided into 400 data
training - 100 testing data. Data training was normalized with PCA and produced matrix
loading data. Then, the data loading matrix was multiplied by testing data so that the score
result was used to classify each test condition.
The test results showed, PCA which use combination of features in time domain and frequency
domain statistical parameters is not the most optimal method. The most optimal result in
detecting cavitation was shown by PCA which used frequency parameters.