RF4:- Settings for Transformer Over Current Relay

     As shown in the figure consider a  ?? transformers;  Transformer capacity is ?? MVA.  HV CTR is ??/1 Amp  and it's LV CTR is ??/1 Amp.  132kV Bus Three Phase short circuit MVA is ?? MVA  and transformer percentage reactance is ?? %.  Transformer has 17 taps and normal tap is ??

     Information of provision of alarm and Load Trimming Scheme is as below 
     ALARM =  ??
     LTS =  ??

     Calculate HV Side and LV Side Over Current relay settings for the transformer.

(NOTE: While calculating HV side O/C PSM for under loaded T/F it is not necessary to consider T/F HV side current on extreme tap. For fully loaded T/F HV side PSM shall be as per current on extreme tap; it shall be 5% more along with Alarm scheme and 10% along with LTS)

Section-A: Calculations for Fault Current and PSM.

1) Source reactance at 100 MVA base =    %

2) T/F % impedance at 100 MVA base =    %

3) LV Bus Source reactance at base 100 MVA =    %

4) LV Bus Short Circuit MVA =    MVA

5) T/F LV Short Circuit Current =    Amp.

6) T/F HV Short Circuit Current =    Amp.

7) Transformer LV side O/C Relay PSM =    %.

8) Transformer HV Side O/C Relay PSM =    %.

9a) T/F LV O/C Relay Current for LV Bus Fault =    Amp.

9b) T/F HV O/C Relay Current for LV Bus Fault =    Amp.

10a) T/F LV Side O/C Relay Current as Multiple of PSM =   

10b) T/F HV Side O/C Relay Current as Multiple of PSM =   

11a) T/F LV Side O/C Relay Operation Time with TMS=1 =    Sec.

11b) T/F LV Side O/C Relay Operation Time with TMS=1 =    Sec.

12a) T/F LV Side O/C Relay TMS =    

12b) T/F HV Side O/C Relay TMS =    

13a) T/F LV Side O/C Highset Current Setting =    Amp.

13b) T/F LV Side O/C Highset Delay Setting in miliseconds =    ms

14a) T/F HV Side O/C Highset Current Setting =    Amp.

14b T/F HV Side O/C Highset Delay Setting in miliseconds =    ms

Topic SETOCTF Ex-4 Your score is:

000

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Code Number:

ABD AMT NSK PUN NGP KRD VSH

ABD1 ABD2 JALN PRBN NND1 NND2 LTR1 LTR2 BEED PRLI EKTN GRWL WALJ TPTN KMBH