Using The 2-Watt Element (2 Ct) Method On A 3-Wire Delta Service - Dent ELITEpro XC Operator's Manual

**Since the 2 ½ Element method is often used on high voltage metering, a PT ratio other than one is
typical and should be set to whatever the actual PT ratio is.
***Set the CT value that is true for the CT connected to the ELITEpro XC. Again, because the 2 ½
element method is most often used in high voltage applications, there will be high voltage CTs present.
Use the high-accuracy 5A CT from DENT Instruments on the existing high voltage CT secondary. The CT
value used in the Setup Table should be the primary rating of the high voltage CT (assuming the
secondary output is 5A).
U T 2-W E
SING HE ATT LEMENT
Blondel's Theorem states that the number of watt elements (CTs) needed to monitor a system is one
less than the number of wires in the system. This means that a 3-Wire Delta service, even though three
phase, requires only two CTs to meter it as there are only three current carrying conductors. The
ELITEpro XC uses the 3 CT method for monitoring Delta services as a default because the data is easier
to interpret. However, if it is required to use only 2 CTs on a Delta such as when it is desirable to use one
ELITEpro XC to monitor two Delta connect loads simultaneously (such as two motors), connect the
meter as shown below.
DENT Instruments
ELITEpro
(2 C ) M O A 3-W
T ETHOD N
2 CT, 3-Wire Delta
Appendices
D S
IRE ELTA ERVICE
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