Figure 140: Sensitive Power Input Vectors - GE MiCOM P40 Agile Technical Manual

Chapter 12 - Power Protection Functions
V V jV
= +
A Ar Ai
I I jI
= +
AS ASr ASi
V00903

Figure 140: Sensitive Power input vectors

CT Compensation
The CT correction rotates the I
calculation and can be achieved with the use of a rotation matrix:
θ − θ
 
cos sin
C C
 
θ θ
 sin cos 
C C
The corrected phase-A sensitive current I
 
I
=  = =
ASCr
I  I
ASC AS
 
I
ASCi
therefore:
= θ −
I I cos I
ASCr ASr C
and
θ
= +
I I sin I
ASCi ASr C ASi
Active Power Calculation
The compensated A-phase sensitive current vector is used to calculate the sensitive A-Phase active power P
Using the equation:
*
P = Re V I
AS A ASC
we can derive:
P Re V jV
( )
= +
AS Ar Ai
( ) (
= +
Re V jV I
Ar Ai ASCr
268
V
A
q
c
Φ
vector by the correction angle. This correction is performed before the power
AS
is therefore:
ASC
θ
−
  
I cos sin
ASr C
  
θ θ
  
I sin co s s
ASi C
θ
sin
ASi C
θ
cos
C
I jI
( )
+
ASCr ASCi
) (
− =
jI Re V I
ASCi Ar ASCr
V = A-phase-N volts
A
I = A-phase sensitive current
AS
I = compensated a phase sensitive current
ASC
Φ = angle of I with respect to V
AS
q
= CT correction angle
c
I
ASC
I
AS
θ θ
−
 
I cos I
 =
C ASr C ASi

θ
+
 
I sin I
C ASr C ASi
) (
+ +
V I j V I
Ai ASCi Ai ASCr r
A
θ

sin
C

θ

cos
C
)
−
V I
Ar ASCi
P14xEd1-TM-EN-1
P14x
.
AS