7SR11 & 7SR12 Description Of Operation
©2012 Siemens Protection Devices Limited Chapter 1 Page 29 of 76
A minimum operate time for the characteristic can be set using 51-n Min. Operate Time setting.
A fixed additional operate time can be added to the characteristic using 51-n Follower DTL setting.
Where directional elements are present the direction of operation can be set using 51-n Dir. Control setting.
Directional logic is provided independently for each 51-n element
Operation of the time delayed overcurrent elements can be inhibited from e.g. giving the option of using two
elements set to forward and two to reverse.
Inhibit 51-n A binary or virtual input.
79 P/F Inst Trips: 51-n When ‘delayed’ trips only are allowed in the auto-reclose sequence
(79 P/F Prot’n Trip n = Delayed).
51c Activation of the cold load settings.
50-n Inrush Action: Block Operation of the inrush current detector function.
51-n VTSAction: Inhibit Operation of the VT Supervision function (7SR1205 & 7SR1206).
Figure 1-26 Logic Diagram: Time Delayed Overcurrent Element
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