ASCO 5010 Remote Display Unit
29
Figure 15: Current trasformer conductor inserted correctly through
the ASCO 5400 Series Power Quality Meter
Nominal values:
This page allows the user to input the nominal values necessary for internal calculations and for
comparison purposes in calculating power quality compliance to the EN50160 standard. Nominal values are to be input
only after configuring PT/CT ratios. The nominal values to be input are:
√
Frequency- 50 or 60 Hz
√
Voltage- Phase to phase value
√
Current- Phase to neutral
PT/CT Configuration:
This page accepts the required transformation values for measuring the electrical system. The
ASCO 5400 Series Power Quality Meter can monitor all AC voltages and all currents. This is achieved by using
measuring transformers. The CT or Current Transformer is comprised of a coil fitted around the current carrying
conductor with the secondary conductors designed to carry no more than 5 amperes (in some cases 1 ampere secondary
conductors are used). A CT designed for a 500A load with a 5A secondary will have a CT ratio of 500:5. The PT or
Potential Transformer operates under a parallel methodology; a voltage transformer is designed to transform the rated
network voltage to a secondary output with a typical value of 110V. For example, a PT for a 22000V network will have
a PT ratio of 22000:110.
Figure 15 illustrates the interface. Each value has a separate page. PT phase primary is input on its own page, as is the
PT phase secondary. The ASCO 5400 Series supports different inputs for the phase and for the neutral lines.
Figure 16:PT/CT Settings- inputting the Primary PT Value
NOTE: When the PT/CT ratio is modified, the ASCO 5400 Series automatically recalculates the nominal values for
voltage and current and replaces the existing values. Therefore, nominal values must be input only after PT/CT
values.
