Hitachi Relion 650 Series Technical Manual page 68

Section 7
Controlled Switching and Monitoring
time t ) for the reactive load. Now the controller delays the command by T
osi
time delay) and releases it to circuit breaker at t
instant t
IEC17000164 V2 EN-US
Figure 29:
Where
t = instant of random switching command
rsc
t = instant of delayed (point-on-wave controlled) switching command
osc
t = instant of random switching instant without point-on-wave control
rsi
t = instant of optimal switching instant
osi
T = circuit breaker operating time
CB
T = controller time delay
CTD
D = point on wave for random switching
rsi
D = optimal (target) point on wave
osi
After releasing the switching command, the controller monitors the switching operation to evaluate
various electrical and mechanical parameters of CB, like electrical operating time, mechanical
operating time etc. These monitored parameters are used for assessing the success of the
performed operation and the health of the circuit breaker, as well as for adapting the operating
parameters for subsequent operations so as to achieve optimal point-on-wave performance. Key
parameters will also be logged for future analysis.
62
considering the circuit breaker closing time of T
osi
t t
rsc osc
T
T
T
Principle of controlled switching (single phase)
© 2021 Hitachi Energy. All rights reserved.
. This will result into making of the current at
osc
CB
t t
rsi osi
D
osi
D
rsi
CB
CTD
CB
1MRK 511 557-UEN Rev. A
= t – t
CTD osi
.
Time(t)
IEC17000164‐1‐en.vsdx
(controller
rsi
Technical Manual