Condition monitoring is an extension of the predictive maintenance or proactive maintenance process for detecting faults in a machine component with the help of pre identified measuring parameters to identify a significant change which is indicative of a developing fault. The fault developed due to various factors in the hydropower plants can damage or halt the operation of power plants. The literatures on the measurement process for condition monitoring of power plants has been reviewed and discussed. Since condition monitoring is a newer and a broader topic, few literatures were available and they were review on the basis of measurement and faults detection processes.