b) Figure Q4 shows a three-line network. The load currents and the fault levels at various locations are indicated in the figure. The operation time of both the CBS 0.4 s. The IDMT relay characteristic in terms of PSM is shown in Table Q4. Assume the pickup current of relay is set to 1.5 A, the TMS for Relay 1 is 0.1 an the ratio of current transformer as below CT ratio for relay R₁ = A₁= 100/1; CT ratio for relay R₂ = A2-200/1 Determine, (1) the TMS value for Relay 2 if fault of 3000A detected at Bus C, and (ii) the actual operating time of Relay 2 if fault of 4800A found at Bus B. Bus A Over current Relay 2 PSM T (sec) Bus B 20 2.2 Transmission line: IL = 200A Max: IF = 4800 A = CB Figure Q4 Table Q4 18 16 2.6 2.8 (Relay operating time 0.7 S fuse = Over current Relay 1 14 3.0 TX TMS) Transmission Bus line: IL = 100A D Transmission line: I₁ = 100A 12 3.2 10 3.5 Bus C Max: IF - 3000 A =
Protection System
A system that protects electrical systems from faults by isolating the problematic part from the remainder of the system, preventing power from being cut from healthy elements, improving system dependability and efficiency is the protection system. Protection devices are the equipment that are utilized to implement the protection system.
Predictive Maintenance System
Predictive maintenance technologies are designed to assist in determining the state of in-service equipment so that maintenance can be scheduled. Predictive maintenance is the application of information; proactive maintenance approaches examine the condition of equipment and anticipate when it should maintain. The purpose of predictive maintenance is to forecast when equipment will fail (depending on a variety of parameters), then prevent the failure through routine and corrective maintenance.Condition monitoring is the continual monitoring of machines during process conditions to maintain optimal machine use, which is necessary for predictive maintenance. There are three types of condition monitoring: online, periodic, and remote. Finally, remote condition monitoring allows the equipment observed from a small place and data supplied for analysis.
Preventive Maintenance System
To maintain the equipment and materials on a regular basis in order to maintain those running conditions and reduce unnecessary shutdowns due to unexpected equipment failure is called Preventive Maintenance (PM).
![(b) Figure Q4 shows a three-line network. The load currents and the fault levels at
various locations are indicated in the figure. The operation time of both the CBs is
0.4 s. The IDMT relay characteristic in terms of PSM is shown in Table Q4.
Assume the pickup current of relay is set to 1.5 A, the TMS for Relay 1 is 0.1 and
the ratio of current transformer as below
CT ratio for relay R₁ = A₁= 100/1; CT ratio for relay R₂ = A₂=200/1
Determine,
(i)
the TMS value for Relay 2 if fault of 3000A detected at Bus C, and
(ii)
the actual operating time of Relay 2 if fault of 4800A found at Bus B.
Bus
A
PSM
T (sec)
Over
current
Relay 2
Bus
B
Transmission
line: I₁= 200A]
Max: IF
= 4800 A
CB
0.7 S
fuse
Over
current
Relay 1
Figure Q4
Table Q4
20
18
16
2.2
2.6
2.8
(Relay operating time = Tx TMS)
14
3.0
Transmission
line: I₁= 100A
Transmission
line: IL = 100A|
12
3.2
10
3.5
Bus
Bus
Max: IF
= 3000 A](/v2/_next/image?url=https%3A%2F%2Fcontent.bartleby.com%2Fqna-images%2Fquestion%2F4000e28a-5cf8-47ab-bb9c-d9b564c038d2%2Fac14565a-c8f8-422c-b1f7-dc5499f31056%2Fxvxhaf9_processed.jpeg&w=3840&q=75)
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