Page 6 - PDTrac II - Use data effectively
P. 6

ON-LINE MONITORING THE EFFICIENT WAY

     The What?




           The What … Partial Discharge
           … because the PD monitoring system uses VHF and time-of-flight to automatically filter out noise and classify
           disturbances, then the output of the PDTrac monitor is only the PD detected by each sensor.  As such, the DCS can be
           configured to trend (doubling over a twelve-month interval) and when compared to the Iris database issue alerts,
           warnings, and notifications.  Additionally, the polarity of the PD pulses is tracked individually, so whether the source
           is polarity predominant and/or correlates with load or temperature can be determined.  This makes it possible to




                                                         400
                                                           High 217-360mV
                                                         350
                                                         300
                                                        Peak Magnitude (mV)  200                            C1 Qm+
                                                         250
                                                                                                            C1 Qm-
                                                         150
                                                                                                            Linear (C1 Qm+)
                                                         100
                                                           Moderate 62-316mV                                Linear (C1 Qm-)
                                                         50
                                                           Typical <62mV
                                                         0
                                                          9/15  10/15  11/15 12/15  1/16  2/16  3/16  4/16  5/16  6/16  7/16  8/16  9/16  10/16
                                                                               Month/Year













             Iris Power provides a solution that separates electrical noise like
             partial discharge and other disturbances in the power system
             from the asset partial discharges. In cases where there is 30 m or
             more of power cable to the generator, high frequency system
             noises that resemble machine partial discharges are attenuated
             by the power cable.

             The remaining low frequency disturbances from the power system
             are eliminated using the Iris Power 80 pF capacitive sensors. The
             sensors attenuate all low frequency electrical noises below 40MHz
             leaving only the machine partial discharges to be analyzed. Pulse
             shape is then automatically analyzed to ensure only machine
             partial discharges are presented in the data output. Low
             frequency solutions like those using 1000 pF couplers do not block
             these frequency ranges.
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