Instantaneous Derived Earth Fault Protection (50N); Figure 4.2-1 Logic Diagram: Derived Directional Earth Fault Element - Siemens Solkor 7PG2113 Technical Manual

Minimum Polarising Voltage
The 67N Minimum Voltage setting defines the minimum polarising voltage level. Where the measured polarising
voltage is below this level no directional output is given and operation of protection elements set as directional will
be inhibited. This prevents mal-operation under fuse failure/MCB tripped conditions where noise voltages can be
present.

Figure 4.2-1 Logic Diagram: Derived Directional Earth Fault Element

4.2.2 Instantaneous Derived Earth Fault Protection (50N)

Two instantaneous derived earth fault elements are provided in the 7PG2113/5 relay and four elements are
provided in the 7PG2114/6 relay.
Each instantaneous element has independent settings for pick-up current 50N-n Setting and a follower time
delay 50N-n Delay. The instantaneous elements have transient free operation.
Where directional elements are present the direction of operation can be set using 50N-n Dir. Control setting.
Directional logic is provided independently for each 50-n element.
Operation of the instantaneous earth fault elements can be inhibited from:
Inhibit 50N-n
79 E/F Inst Trips: 50N-n
50-n Inrush Action: Block
50N-n VTSAction: Inhibit
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50N-1, 50N-2, (50N-3 & 50N-4 – 7PG2114/6)
A binary or virtual input.
When 'delayed' trips only are allowed in the auto-reclose sequence
(79 E/F Prot'n Trip n = Delayed).
Operation of the inrush current detector function.
Operation of the VT Supervision function (7PG2114/6).
7PG2113/4/5/6 Solkor Description of Operation
Chapter 1 Page 42 of 80