A method for determining the state of at least one sensor, the method using a first electromechanical transducer and a second electromechanical transducer that are coupled to a substrate, and a non-linear electrical circuit connected between the second electromechanical transducer and the sensor, the method comprising the steps of: applying an electrical signal at a first amplitude to the terminals of the first electromechanical transducer, and determining a first set of values of a parameter characteristic of the electrical impedance of the first electromechanical transducer in response to the application of the electrical signal; applying the electrical signal at a second amplitude to the terminals of the first electromechanical transducer, and determining a second set of values of the parameter characteristic of the impedance; measuring a difference between the first set of values and the second set of values; determining a state of the sensor on the basis of the difference between the first set of values and the second set of values.

There are provided a device for removing partial discharge noise and a method of diagnosing the same. The device includes a noise removing device configured to remove noise of a partial discharge signal using a reaction rate difference of signals when the partial discharge signal is generated, and output a signal in which noise is removed, a laser module configured to output a laser beam to a surface of a power device when the partial discharge signal is generated and extract sound wave and vibration data from a reflection signal of the laser beam, a correlation analyzing unit configured to compare the partial discharge signal in which noise is removed input through a sensor connecting unit and the sound wave and vibration data extracted through the laser module, and analyze a correlation, and a partial discharge diagnostic unit configured to perform partial discharge diagnosis on a signal that matches the partial discharge signal in which noise is removed with at least one of a generation cycle, a time, and a phase of the sound wave and vibration data based on a result of correlation analysis of the correlation analyzing unit.

There are provided a device for removing partial discharge noise and a method of diagnosing the same. The device includes a noise removing device configured to remove noise of a partial discharge signal using a reaction rate difference of signals when the partial discharge signal is generated, and output a signal in which noise is removed, a laser module configured to output a laser beam to a surface of a power device when the partial discharge signal is generated and extract sound wave and vibration data from a reflection signal of the laser beam, a correlation analyzing unit configured to compare the partial discharge signal in which noise is removed input through a sensor connecting unit and the sound wave and vibration data extracted through the laser module, and analyze a correlation, and a partial discharge diagnostic unit configured to perform partial discharge diagnosis on a signal that matches the partial discharge signal in which noise is removed with at least one of a generation cycle, a time, and a phase of the sound wave and vibration data based on a result of correlation analysis of the correlation analyzing unit.

An apparatus for inspecting a well having nested multi-tubular structure, includes: an acoustic transducer conveyed in an inner-most tubular in the structure and configured to receive a return acoustic signal having a plurality of resonances due to the structure; an acoustic impedance matching material disposed on a sensing face of the acoustic transducer; a signal generator that generates a signal having a plurality of frequencies to drive the acoustic transducer; a signal shaper that modifies the signal to provide a drive signal to the acoustic transducer; and a processor configured to determine an annulus distance of any tubular in the structure with respect to an adjacent tubular using a time of flight of a transmitted acoustic signal, an acoustic speed in a component in the nested multi-tubular structure using the annulus distance and the plurality of resonances, and a characteristic of the component that corresponds with the acoustic speed.

A “periodic signal parameter” (PSP) indicates periodic patterns in an autocorrelated vibration waveform and potential faults in a monitored machine. The PSP is calculated based on statistical measures derived from an autocorrelation waveform and characteristics of an associated vibration waveform. The PSP provides an indication of periodicity and a generalization of potential fault, whereas characteristics of the associated waveform indicate severity. A “periodic information plot” (PIP) is derived from a vibration signal processed using two analysis techniques to produce two X-Y graphs of the signal data that share a common X-axis. The PIP is created by correlating the Y-values on the two graphs based on the corresponding X-value. The amplitudes of Y-values in the PIP is derived from the two source graphs by multiplication, taking a ratio, averaging, or keeping the maximum value.

A “periodic signal parameter” (PSP) indicates periodic patterns in an autocorrelated vibration waveform and potential faults in a monitored machine. The PSP is calculated based on statistical measures derived from an autocorrelation waveform and characteristics of an associated vibration waveform. The PSP provides an indication of periodicity and a generalization of potential fault, whereas characteristics of the associated waveform indicate severity. A “periodic information plot” (PIP) is derived from a vibration signal processed using two analysis techniques to produce two X-Y graphs of the signal data that share a common X-axis. The PIP is created by correlating the Y-values on the two graphs based on the corresponding X-value. The amplitudes of Y-values in the PIP is derived from the two source graphs by multiplication, taking a ratio, averaging, or keeping the maximum value.

The invention comprises a device (10) for testing a test object (40), comprising an excitation system (13) for generating broadband ultrasound pulses (12′) in the test object, a detection system (20) for detecting ultrasound waves (21), which are generated through the broadband ultrasound pulses (12′) in the test object (40) and emitted by the test object (40). The device (10) comprises a processing unit (30) for processing the detected ultrasound waves (21), while the excitation system (13) being one of a thermoacoustic emitter or a pulsed laser and the detection system (20) is a broadband detection system. The excitation system (13) comprises a modulator (11) for modulating the broadband ultrasound pulses (12′). Furthermore, the invention comprises a method for testing a test object.

The invention comprises a device (10) for testing a test object (40), comprising an excitation system (13) for generating broadband ultrasound pulses (12′) in the test object, a detection system (20) for detecting ultrasound waves (21), which are generated through the broadband ultrasound pulses (12′) in the test object (40) and emitted by the test object (40). The device (10) comprises a processing unit (30) for processing the detected ultrasound waves (21), while the excitation system (13) being one of a thermoacoustic emitter or a pulsed laser and the detection system (20) is a broadband detection system. The excitation system (13) comprises a modulator (11) for modulating the broadband ultrasound pulses (12′). Furthermore, the invention comprises a method for testing a test object.

The present invention relates to a piezoelectric sensor (1,100) comprising a piezoelectric material (10) interposed between a first (11) and a second (12) electric contact element. The first electric contact element (11) comprises at least two sensing areas (110, 111) spatially separated along a sensing direction. It also describes a sensor node that includes the piezoelectric sensor, a system and a method for monitoring the integrity of a structure using said piezoelectric sensor.

The present invention relates to a piezoelectric sensor (1,100) comprising a piezoelectric material (10) interposed between a first (11) and a second (12) electric contact element. The first electric contact element (11) comprises at least two sensing areas (110, 111) spatially separated along a sensing direction. It also describes a sensor node that includes the piezoelectric sensor, a system and a method for monitoring the integrity of a structure using said piezoelectric sensor.