GE Industrial Solutions Entellisys System User Manual - Manual (Page 15)

System components 15
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1.3.3 Potential transformers
Potential or voltage transformers (PTs) are sensors that measure voltage. Unlike traditional
switchgear, only the main (or source) circuit breakers in the system require PTs. This hardware
and wiring reduction is possible because of the central processor architecture and the sampling
synchronization maintained by the system.
Three PTs, one for each phase, are required on the main circuit breakers in the system. The
remaining circuit breakers reference one circuit breaker with physical PTs and use that source's
voltage readings for metering calculations. This source reference may change as the system
topology changes.
The PTs are located outside the circuit breaker compartments in auxiliary compartments.
Figure 1-5 Entellisys PT