Measurement Computing WavePort 312P rev.1.0 - Manual (Page 43)

PowerVista/312 User’s Manual Device Configuration 4-9
Items in the System Configuration Dialog include:
• Voltage Range (V1,2,3): is the voltage input range for three phase voltages. This setting allows the user to
maximize accuracy of measurement by utilizing programmable gain within the hardware.
• Ext. PT Ratio (V1,2,3): is the external Potential Transformer (PT) ratio for three phase voltages. For example, if
the instrument is connected to PT secondaries to measure a 13.8 kV bus voltage, where line-to-ground PTs are
used, the ratio could be 8400:120 or 70:1. Attenuation of voltages from sheathed banana inputs to
instrumentation signal levels is already included in software as a 1250:5 ratio.
• PT Connection (V1,2,3): is the external system connection arrangement for three phase voltages. Proper
selection is defined in the section on External Connections for the following system arrangements.
• Three Phase Grounded Wye Wye
• Three Phase UnGrounded Wye Wye or Delta
• Three Phase Delta Delta
• Three Phase Open Delta Open Delta
• Single Phase Wye
• 120/240 Service Wye
• Current Range (I1,2,3): is the current input range for three phase currents. This setting allows the user to
maximize accuracy of measurement by utilizing programmable gain within the hardware.
• Ext CT Ratio (I1,2,3): is the external Current Transformer (CT) ratio for three phase currents. For example, if
the instrument is connected to CT secondaries to measure a primary current on a 2000 A bus, the ratio could be
2000:5 or 400:1. Clamp on turns ratios are not included here, but are built into the software as defined below.
• Current Probe Manufacturer: is the manufacturer of clamp-on current transducers being used to measure
currents.
• Current Probe Model: is the model of clamp-on current transducers being used to measure currents.
• Current Probe Range Select: for clamp-on current transducers with switch selectable input ranges, matches the
setting on the probe so that current measurements are scaled appropriately.
• Voltage Phasing/Invert: is used to select a phase rotation via the drop down list box and invert voltages via each
of the check boxes. If checked, voltage is inverted. All possible phasing combinations are supplied in the drop
down list. See the Phasing Application for more details.
• Current Phasing/Invert: is used to select a phase rotation via the drop down list box and invert currents via each
of the check boxes. If checked, current is inverted. All possible phasing combinations are supplied in the drop
down list. See the Phasing Application for more details.
• Follow Frequency: when selected tells the Phasor Diagram, Cycle-by-Cycle and Event/Demand Capture
acquisition functions to follow input frequency. See the Frequency Following section for details.
• Base Frequency: should be set to the system base frequency of the measured system. For 60 Hz systems, set
Base Frequency at 60 Hz. For 400 Hz systems, set Base Frequency at 400 Hz for fully detailed 1 st to 50 th
harmonic measurements within Detailed Harmonics. However, as of the writing of this manual, notebook PCs do
not have the processing speed to perform Phasor Diagram, Cycle-by-Cycle and Event/Demand Capture at this rate.
A Base Frequency of 200 Hz has been well tested for this application and is recommended.
Note: For 400 Hz systems, set Base Frequency to 200 Hz to perform Phasor Diagram, Cycle-by-Cycle and
Event/Demand Capture since PC processing speed is not presently adequate.