Z-OVR Cable Impedance Test Set
The Z-OVR is a cable impedance test system for the measurement of impedance of overhead lines and underground cables. The system consists of a separate control unit containing all metering and control functions and an output transformer that provides isolation of the output current and feedback voltage.
A current is injected into the line under test and the resultant magnitude and phase angle of the voltage across the line is measured. The current, voltage, phase angle and impedance of the line (Z & X) under test are displayed. In addition, the harmonic content of the voltage and current can be displayed.
The unit has data logging facilities using a standard USB memory key. Date, time, current, voltage, phase angle, and frequency are stored to a CSV file on the memory key along with a comment entered using the supplied USB keyboard. Pressing the “store” pushbutton causes a new set of values to be written to the CSV file.
The output has three taps (75V, 150V & 300V), allowing the measurement of impedance of a wide range of lines and cables. All metering is true rms. Four current ranges (2.000, 10.00, 20.00 and 100.0A) and three voltage ranges (10.00V, 30.00V and 300.0V) are provided.
The output transformer unit uses 6mm safety connectors for all outputs and 4mm safety connectors for inputs. A block of connectors is provided adjacent to the output to allow easy parallel connection of cables for parallel measurements on all three phases.
The unit is provided with a set of four 10m 12mm2 duplex measurement cables. These provide a 12mm2 conductor for current injection and a 6mm2 conductor for voltage feedback in each cable.