Figure. 5.3.1 - 28. Inverse operating time formulas for IEC and IEEE standards.
Non-standard delay characteristics
In addition to the previously mentioned delay characteristics, some functions also have delay
characteristics that deviate from the IEC or IEEE standards. These functions are the following:
• overcurrent stages
• residual overcurrent stages
• directional overcurrent stages
• directional residual overcurrent stages.
The setting parameters and their ranges are documented in the chapters of the respective function
blocks.
Table. 5.3.1 - 45. Inverse operating time formulas for nonstandard characteristics.
RI-type
RD-type
Used to get time grading with
mechanical relays
Mostly used in earth fault protection which grants selective tripping even in non-
directional protection
t = Operating delay (s)
k = Time dial setting
I
m
= Measured maximum current
I
set
= Pick-up setting
t = Operating delay (s)
k = Time dial setting
I
m
= Measured maximum current
I
set
= Pick-up setting
A
AQ
Q-M255
-M255
Instruction manual
Version: 2.06
© Arcteq Relays Ltd
IM00020
57
Содержание AQ-M255
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Страница 384: ...Figure 7 4 189 Example block scheme A AQ Q M255 M255 Instruction manual Version 2 06 382 Arcteq Relays Ltd IM00020...
Страница 405: ...Figure 8 14 211 Device installation A AQ Q M255 M255 Instruction manual Version 2 06 Arcteq Relays Ltd IM00020 403...