Basler BE1-CDS240, Инструкция по эксплуатации

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has
c a high peak that is non-sinusoidal. The relay extracts the fundamental component of the operate
urrent for use by the unrestrained element to greatly reduce its sensitivity to this non-sinusoidal inrush
current. In addition, the high initial peak generally decays quickly to a lower value. The slight inverseness
f the unrestraint tripping char cteristic (refer to Section 1, General Inform tion ) provides additional
ecurity from unrestrained trippin on inrush with a sensitive setting.
o a a
s g
Since the tap values are based upon the forced cooled rating and adjusted if necessary by the factor
X calculated in Calculate Minpu, Step 1, Equation D-8, the pickup can be calculated:
D-8 BE1-CDS240 Settings Calculations 9365200990 Rev F
cooled forced MVA
X URO * * 6

cooled self MVA
2 . 3
280
150
* 1 * 6
 
URO
6 . 3

URO
This (3.2 is rounded up to 4.0; rounding down should not be done in this application) is the
URO
value
inrush. The next step will determine the value required to avoid
ipping for the maximum external ult under worst case CT saturation.
tep 1. Calculate the maximum external fault (IE) in multiples of tap. Use these two equations:
For wye connected CT’s For delta connected CT’s (See Setting Note 2)
minimum setting to avoid tripping during
tr
fa
Check Maximum External Fault Saturation Effects
S
Tap
Fault Maximum
IE

Tap
phase Fault Maximum
IE
3 * 3

HIGH LOW TERTIARY
8 . 9
39 . 4
160
16900






 
IE
3 . 6
69 . 4
300
8900








1 . 2
64 . 14
800
24600




IE

 

IE
Step 2. The transient monitor function provides security from tripping for external through faults by
doubling the u s detected. Calculate the
unrestrained pic
greater than 70% of the
nrestrained unit pickup setting when saturation i
kup such that
2 times the unrestrained pickup is
maximum external through fault in times tap. This calculation assumes that the CTs carrying
the maximum fault saturate severely, yielding only 30% of the expected ratio current. This leaves
70% of the fault current as false differential current.
43 . 3
2
8 . 9 * 7 . 0
 
URO 21 . 2
2
3 . 6 * 7 . 0
 
URO 74 . 0
2
1 . 2 * 7 . 0
 
URO
As previously noted when examining the CT performance and Saturation Factor SF , a more complete
analysis of the unrestrained pickup setting would include applying these calculations to every CT that
sees current during the external fault. For brevity, this check is not done in these calculations.
Step 3. Select the unrestrained pickup setting. Choose the larger of the unrestrained pickup values
calculated in the above equations on this page and round it up to the next integ is
results in a setting of URO = 4 times tap for this example.
Step 4. Convert pickup setting to primary amperes.
, convert the unrestrained pickup sensitivity to high side and low side primary amperes.
er value. Th
As a reality check
The equation to do so is similar to the last equation on page D-7. Ignore energization from the tertiary as
it will never be done in actual practice.
A Ipri 810 , 2
160 * 39 . 4 * 4
 
@ 230 kV A Ipri
69 . 5 * 4

628 , 5
1
300 *

@ 115 kV
1