Hitachi RED670 Commissioning Manual page 182

Section 11
Testing functionality by secondary injection
The set operate value in secondary amperes is calculated according to the following equations:
First part of the characteristic (Restrain voltage ≤ 25% of UBase):
StartCurr
IECEQUATION2432 V1 EN-US
Second part of the characteristic (25% of UBase ≤ Restrain voltage ≤ UHighLimit/100*UBase),
valid when setting parameter VDepMode = Slope:







 

IECEQUATION2433 V1 EN-US
Third part of the characteristic (UHighLimit/100*UBase ≤ Restrain voltage):
StartCurr
IECEQUATION2434 V1 EN-US
Example (rated secondary current = 1A):
CT ratio
VT ratio
StartCurr
VDepFact
UHighLimit
IBase
A test for each section of the characteristic of the function VRPVOC may be performed; that
may be achieved by applying the following voltages:
First section of the characteristic:
If VDepMode = Slope, the minimum measured phase-to-phase voltage is lower than
0,25*UBase; if VDepMode = Step, the minimum measured phase-to-phase voltage is lower
than UHighLimit/100*UBase:
•
•
•
Second section of the characteristic only:
If VDepMode = Slope, the minimum measured phase-to-phase voltage is between 0,25*UBase
and UHighLimit/100*UBase:
•
•
•
Last section of the characteristic:
If VDepMode = either Slope or Step, the minimum measured phase-to-phase voltage is higher
than UHighLimit/100*UBase:
176
In the following equations, restrain voltage is the magnitude of the minimum phase-
to-phase voltage in secondary volts.
CT sec
IBase
× × ×
100
CTprim


StartCurr CT sec VDepFact
× ×  × −
IBase  1

100 CTprim  100
( )
−
UH i i ghLimit 25
VT sec
× ×
UBase
100 VTprim
CT sec
IBase
× ×
100
CTprim
UL1: Ampl = 10 / √3; Angle = 0°
UL2: Ampl = 10 / √3; Angle = 240°
UL3: Ampl = 100 / √3; Angle = 120°
UL1: Ampl = 50 / √3; Angle = 0°
UL2: Ampl = 50 / √3; Angle = 240°
UL3: Ampl = 100 / √3; Angle = 120°
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VDepFact
100




25
× − ×

Re strainVoltage U U Base

100
10 000/1A
10 kV/100 V
100%
25%
100%
10 000 A
10 kV
1MRK 505 378-UEN Rev. K


 
VT sec  StartCurr C C T sec
× + × ×
 
IBase

 
VTprim 100 CTprim
 

Line differential protection RED670
Commissioning manual
(Equation 92)

VDepFact
×


100
(Equation 93)
(Equation 94)