ABB Relion 670 Series Applications Manual page 160

Section 8
Current protection
ResetTypeCrvx : The reset of the delay timer can be made in different ways. The possibilities are
described in the technical reference manual.
tResetx : Constant reset time delay in s for step x.
HarmBlockx : This is used to enable block of step x from 2
tPCrvx, tACrvx, tBCrvx, tCCrvx : Parameters for user programmable of inverse time characteristic
curve. The time characteristic equation is according to equation 41:
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EQUATION1722 V1 EN-US
Further description can be found in the technical reference manual.
tPRCrvx, tTRCrvx, tCRCrvx : Parameters for user programmable of inverse reset time characteristic
curve. Further description can be found in the technical reference manual.
8.4.3.6 Line application example
Four step residual overcurrent protection can be used in different ways. Below is described one
application possibility to be used in meshed and effectively grounded systems.
The protection measures the residual current out on the protected line. The protection function
has a directional function where the polarizing voltage (zero-sequence voltage) is the polarizing
quantity.
The polarizing voltage and current can be internally generated when a three-phase set of voltage
transformers and current transformers are used.
154
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nd
harmonic restrain function.
1MRK 511 401-UUS F
(Equation 41)
M15282-184 v8
Bay control REC670
Application manual