4.1 By considering a radial power system shown below, overcurrent IDMT protection relays are to be installed as shown in the Figure. Assume that the fault current of 7.69kA is taking place and the relay time-setting multiplier ranges from 0.1 to 1 in steps of 0.02 and the relay plug setting ranges from 25% to 250% in steps of 15%. Plug setting multipliers for Relay 1 and Relay 2 are 7 and 15, respectively. For a given fault current, Relay 2 must trip within 0.3 seconds and a grading margin of 0.6 seconds should be allowed between the relays. Correct to two decimal places 41.Determine the plug setting current for relay 2 (A). (2) 42.Determine the plug setting current for relay 1 (A). (2) 43.Determine the plug setting percentage for relay 1 (%).
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).
4.1 By considering a radial power system shown below, overcurrent IDMT protection
relays are to be installed as shown in the Figure. Assume that the fault current of 7.69kA is taking place and the relay time-setting multiplier ranges from 0.1 to 1 in steps of
0.02 and the relay plug setting ranges from 25% to 250% in steps of 15%. Plug setting
multipliers for Relay 1 and Relay 2 are 7 and 15, respectively. For a given fault current,
Relay 2 must trip within 0.3 seconds and a grading margin of 0.6 seconds should be
allowed between the relays.
Correct to two decimal places
41.Determine the plug setting current for relay 2 (A). (2)
42.Determine the plug setting current for relay 1 (A). (2)
43.Determine the plug setting percentage for relay 1 (%).
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