A sensor system comprising: a sensor network comprising at least one optical fiber that includes one or more optical sensors (141, 145) including at least one vibration sensor, the vibration sensor configured to be disposed within a power grid electrical device and configured to sense vibration of the power grid electrical device; at least one detector configured to generate an electrical time domain signal in response to a time variation in light output from the vibration sensor; characterized in that it further comprises an analyzer configured to: acquire a first snapshot frequency component signal and a second snapshot frequency component signal using a wavelet transformation or a Fourier transformation on the time domain signal, the first snapshot frequency component signal comprising a time varying signal of frequency components of the time domain signal over a first data acquisition time period and the second snapshot frequency component signal comprising a time varying signal of frequency components of the time domain signal over a second data acquisition time period, the first and second data acquisition periods for each of the first and second snapshot frequency component signals being different from each other, the second data acquisition period being shorter than the first data acquisition period; and detect a change in a first parameter based on the first snapshot frequency component signal and a change in a second parameter based on the second snapshot frequency component signal. a sensor network comprising at least one optical fiber that includes one or more optical sensors (141, 145) including at least one vibration sensor, the vibration sensor configured to be disposed within a power grid electrical device and configured to sense vibration of the power grid electrical device; at least one detector configured to generate an electrical time domain signal in response to a time variation in light output from the vibration sensor; characterized in that it further comprises an analyzer configured to: acquire a first snapshot frequency component signal and a second snapshot frequency component signal using a wavelet transformation or a Fourier transformation on the time domain signal, the first snapshot frequency component signal comprising a time varying signal of frequency components of the time domain signal over a first data acquisition time period and the second snapshot frequency component signal comprising a time varying signal of frequency components of the time domain signal over a second data acquisition time period, the first and second data acquisition periods for each of the first and second snapshot frequency component signals being different from each other, the second data acquisition period being shorter than the first data acquisition period; and detect a change in a first parameter based on the first snapshot frequency component signal and a change in a second parameter based on the second snapshot frequency component signal. acquire a first snapshot frequency component signal and a second snapshot frequency component signal using a wavelet transformation or a Fourier transformation on the time domain signal, the first snapshot frequency component signal comprising a time varying signal of frequency components of the time domain signal over a first data acquisition time period and the second snapshot frequency component signal comprising a time varying signal of frequency components of the time domain signal over a second data acquisition time period, the first and second data acquisition periods for each of the first and second snapshot frequency component signals being different from each other, the second data acquisition period being shorter than the first data acquisition period; and detect a change in a first parameter based on the first snapshot frequency component signal and a change in a second parameter based on the second snapshot frequency component signal.