ABB RELION REX640 Technical Manual page 604

Protection and control

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Protection functions

Figure 343: Operation timer characteristic of IFPTOC function when Operation

principle = "EF-current based" and Operating curve type = "Inverse time EN50522".

Setting UTp multiplier is 1.0, Maximum earthing Ris = 10ohms, EF current Str Val =

0.02*In (2A), IDMT stage Min Op Tm = 100 ms and IDMT stage Max Op Tm = 5000

ms. Reduction factor = 1.0. Characteristics are according to standard EN50522.

Example 2b. Inverse time operation of IFPTOC, when

current based" and

minimum operate time 100 ms and maximum operate time of 5000 ms. Setting

multiplier is 2.0 and setting Maximum earthing Ris is 10 ohms. Reduction factor =

1.0. For illustrating the operating speed requirement of protection, limits of earth

potential rise durations defined in standard EN50522 scaled into corresponding

earth-fault current requirements using the maximum earthing resistance R

Operating curve type = "Inverse time EN50522" is illustrated in

. Start value for operation is set to be 0.04*In (4 A). IFPTOC is set to have

Maximum earthing Ris ) encountered in protected feeder are shown for

1MRS759142 F

Operation principle = "EF-

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