5.4.3. ASA 10/50
ASA 10/50 The point in the square log-log graph where increasing the voltage by 10 % leads to an
increase of the current by 50 %.
The ASA 10/50 was first described in 5.6.1). ASA stands for the
American Standards Association
which is now the
American National Standards Institute (ANSI). The ASA 10/50 voltage is easily
determined by applying the measurement method from Section 5.3.2 and finding the voltage at
which its increase leads to a current increase of 50%.
If the first voltage
U
0
is normalized to 1 a 10% increase leads to U1 = 1.1 and respectively for the
current
I
1
= 1.5.
Using Equation 5.2.a) and 5.2.c) leads to the slope
m
ASA 10/50
and angle
α
ASA 10/50
.
5.4.3.a) Equation:
s
ASA 10
/50
=
log
U
1
U
0
log
I
1
I
0
=
log 1.1
log 1.5
5.4.3.b) Equation:
s
ASA 10
/ 50
≈ 0.235
5.4.3.c) Equation:
σ
ASA 10
/50
= arctan
log
U
1
U
0
log
I
1
I
0
= arctan
log 1.1
log 1.5
5.4.3.d) Equation:
σ
ASA 10
/50
≈ 13.2
°
5.5 VT Turns Ratio
The turns ratio of a voltage transformer is generally given as the ratio of the rated high voltage side
value V
H
versus the rated low voltage side value V
L
(See Equation 5.5c)). In the following
equations (Equations 5.5a), 5.5b) and 5.5c)), V
H
and V
L
are the voltages at high voltage and low
voltage side terminals of voltage transformer respectively and U
x
and U
H
are the voltage values
measured by CT-T1. Note that H clamps of CT-T1 must be connected to LV side of VT and X
clamps must be connected to HV side of VT (See Equation 5.5a) and 5.5b))
Chia sẻ với bạn bè của bạn: 
