ABB RELION 620 Series Technical Manual page 515

1MRS757644 F
620 series
Technical Manual
The operation of TR2PTDF can be described by using a module diagram. All the
modules in the diagram are explained in the next sections.
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Figure 257: Functional module diagram
Differential calculation
TR2PTDF operates phase-wise on a difference of incoming and outgoing currents.
The positive direction of the currents is towards the protected object.
I
W 1
Winding 1
(usually HV)
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Figure 258: Positive direction of the currents
Protection functions
I
W 2
Winding 2
(usually LV)
Section 4
509