14
Requirements
&KDSWHU
*HQHUDO
istic of the non remanence type CT (TPZ) is not well defined as far as the phase angle
error is concerned, and we therefore recommend contacting ABB Automation Products
AB to confirm that the type in question can be used.
The current transformers must have a rated equivalent secondary e.m.f. E
al
that is larger
than the maximum of the required secondary e.m.f. E
alreq
below:
(Equation 1)
(Equation 2)
where
I
kmax
Maximum primary fundamental frequency current for close-in forward and reverse
faults (A)
I
kzone1
Maximum primary fundamental frequency current for faults at the end of zone 1
reach (A)
I
pn
The rated primary CT current (A)
I
sn
The rated secondary CT current (A)
I
R
The protection terminal rated current (A)
R
CT
The secondary resistance of the CT (
Ω
)
R
L
The resistance of the secondary cable and additional load (
Ω)
. The loop resistance
should be used for phase-to-earth faults and the phase resistance for three-phase
faults.
a
This factor is a function of the network frequency and the primary time constant for
the dc component in the fault current, see figure 1.
k
A factor of the network frequency and the primary time constant for the dc compo-
nent in the fault current for a three-phase fault at the set reach of zone 1, see figure2.
The time constant is normally less than 50 ms.
E
al
E
alreq
>
I
kmax
I
sn
⋅
I
pn
------------------------
a
R
CT
R
L
0.25
I
2
R
-----------
+
+
⋅ ⋅
=
E
al
E
alreq
>
I
kzone1
I
sn
⋅
I
pn
----------------------------
k
R
CT
R
L
0.25
I
2
R
-----------
+
+
⋅ ⋅
=
Содержание REO 517
Страница 10: ... RQWHQWV ...
Страница 16: ...6 Introduction to the application manual KDSWHU QWURGXFWLRQ ...
Страница 64: ...54 Blocking of signals during test KDSWHU RPPRQ IXQFWLRQV ...
Страница 88: ...78 Scheme communication logic ZCOM KDSWHU LQH LPSHGDQFH ...
Страница 100: ...90 Time delayed phase and residual overcurrent protection TOC1 KDSWHU XUUHQW Equation 36 Iset IsSEC I1b 100 ...
Страница 146: ...136 Unbalance protection for capacitor banks TOCC KDSWHU XUUHQW ...
Страница 166: ...156 Dead line detection DLD KDSWHU 3RZHU V VWHP VXSHUYLVLRQ ...
Страница 171: ...161 About this chapter KDSWHU RQWURO KDSWHU RQWURO ERXW WKLV FKDSWHU This chapter describes the control functions ...
Страница 293: ...283 About this chapter KDSWHU RJLF KDSWHU RJLF ERXW WKLV FKDSWHU This chapter describes the logic functions ...
Страница 378: ...368 Monitoring of DC analog measurements KDSWHU 0RQLWRULQJ ...
Страница 379: ...369 About this chapter KDSWHU 0HWHULQJ KDSWHU 0HWHULQJ ERXW WKLV FKDSWHU This chapter describes the metering functions ...
Страница 384: ...374 Pulse counter logic PC KDSWHU 0HWHULQJ ...
Страница 412: ...402 Serial communication modules SCM KDSWHU DWD FRPPXQLFDWLRQ ...
Страница 440: ...430 LED indication module KDSWHU DUGZDUH PRGXOHV ...