THR, current threshold (pu sbase)

asked 2024-11-11 06:55:43 -0500

Anonymous

This is the CONS model of TIOCR1 line relay, can anyone show the exact calculation for this threshold value? And what is the difference between THR, current threshold (pu sbase) and lowest operating current (multiple of pickup.)

answered 2024-11-11 11:47:12 -0500

perolofl

3312 ●1 ●8 ●18

See Program Application Guide, Volume II, Chapter Model TIOCR1.

THR is given in pu current. Inverse time current points (five points) are given in pu of THR, i.e. current values shall be increasing and > 1. Corresponding time values shall be decreasing.

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I have already seen the chapter but could not find the exact calculation. In my .dyr file the current threshold is given as 6.7. I am just curious how this value is being calculated?

junaid2657@gmail.com ( 2024-11-12 01:35:54 -0500 )edit

Current base, Ibase, is Sbase/Vbase/sqrt(3) kA. Ipu = IkA/Ibase. With 100 MVA base and 230 kV the current base is 0.251 kA. 2.5 kA = 2.5/0.251 = 9.96 pu.