43
Matrix
Protection and Control Units
2
.
I
N
T
E
R
N
A
L
O
V
E
R
V
O
L
T
A
G
E
S
:
Caused due to changes in the operating condition of the network. Can be further classified in two groups:
a
.
S
w
i
t
c
h
i
n
g
o
r
t
r
a
n
s
i
e
n
t
o
v
e
r
v
o
l
t
a
g
e
s
These over voltages are generally of oscillatory nature caused by the transient phenomena which appears
when the state of the network is changed by switching operation or a fault condition.
The frequency of the oscillations is governed by the inherent inductance and capacitance of the system & may
vary from few hundred Hz to few kHz
For e.g.
i. Switching On & OFF of equipment, like switching of high voltage reactors or switching of
transformer on no load
ii. If fault occurs in any one phase the voltage of other phases with respect to the ground increases
until the faults get cleared
iii. Because of the re-striking voltage across the contacts of the breaker, when breaker has tripped
on fault, voltage of amplitude nearly twice the system voltage and relatively high frequency gets
generated
b
.
S
t
e
a
d
y
-
s
t
a
t
e
o
r
t
e
m
p
o
r
a
r
y
o
v
e
r
v
o
l
t
a
g
e
s
These are over voltages developed due to the disconnection of loads at power frequency.
Summary of Contents for OMEGA
Page 2: ...Stabilise systems with technology ...
Page 4: ...Change course quickly ...
Page 6: ...Match performance with prudence ...
Page 8: ...Adopt technological brilliance ...
Page 10: ...Keep an eye on upkeep ...
Page 26: ...Matrix Protection Control Units T UW M X4 5 ...
Page 70: ...Accessories ...
Page 84: ...Control Circuit Wiring ...
Page 92: ...Mounting Termination ...
Page 135: ...SP 50567 R5 ...
