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<< Click to Display Table of Contents >> Protection Modelling |
  
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<< Click to Display Table of Contents >> Protection Modelling |
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The protection device is utilised for providing the breaker with a trip signal initiating the opening of the breaker poles and hence clearing the fault.
PowaMaster provides the modelling of IDMT relays and user-definable protection devices (e.g. fuses).
With the mouse click on the Protection Button on the Toolbar or use the Protection command from the Network main menu. A Protection data dialog box will appear. Enter all the relevant information and Click on a Branch in the project at the point at which the devices is to be located.
1.Name,Number,Description,
2.Curve Type,
3.Settings (See Protection Details),
Typically the grading time between relays, in a grading study, is determined by the following:
•Breaker tripping time (time to clear the fault from the moment of having recieved the trip signal)
•Relay error
•Current transformer error
In order to determine the operating time of a relay for a fault in the network perform the following:
•Right click a busbar and select fault
•Perform a fault calculation
•Protection relays that operate, as a result of the fault, will have changed colour
•Obtain the relay operating time by displaying the operating time as a text result or by right-clicking the protection device and selecting results
To view the relays on a common graph perform the following:
All relays that are in the path of the fault are displayed on a common graph. The User can select to alter the protection settings of each relay to obtain correct discrimination. The Update Button must be clicked to reflect the changes made.
Relays with a discrimination time of greater than 400ms are flagged with a (*) as a suffix to the relay’s name.
If the User selects Tools\Protection Groups and no relays are detailed, then the User has not performed a fault calculation or no relay is in the path of the fault.