ComAp MainsPro G99TT - 3.3.2 Delta connection; 3.3.3 Connection with voltage transformers

MainsPro G99TT 1.0.0 Global Guide
13
3.3.2 "Delta" connection
In this arrangement, MainsPro G99TT is rated for 400 VAC ph-ph with over-range to 130% = 520 VAC with no
change of measurement accuracy. Setpoint Uin (page 54) is to be set to 400 V, no additional setting is
necessary for indication of "Delta" connection. MainsPro G99TT provides automatic detection of phase-
phase voltage measurement.
3.3.3 Connection with voltage transformers
MainsPro G99TT allows connecting HV or other measurement transformers with secondary rated voltage
100V. Provide the "Star" or "Delta" arrangement on the primary windings of the transformers and connect the
secondary 100 V to the MainsPro G99TT measurement inputs. Setpoint Uin (page 54) is to be set to 120V.
This setting provides the guaranteed measurement accuracy for the 100V inputs with overrange to 120V *
130% = 156 VAC.
Note: It is recommended to use "Delta" arrangement on the HV side to avoid nuisance tripping caused by
phase voltage unbalance.