This PPT contains electrical switch yard protective relay basics. switch yard-relay basic working-SOTF protection-50LBB protection-PT fuse failure protection-vector surge protection-distance protection-TCS relay protection-electrical safety-basic electrical equipment workings

1. CIRCUITS, PRINCIPLE AND OPERATION OF
PROTECTION RELAYS-SWITCHYARD-PART2
&
BASICS OF ELECTRICAL

2. Relay basic working

3. Switch yard basic video

4. Switch yard

5. SOTF(Switch On To Fault)
• While maintenance if we close
the CB when Earth rod or switch
is present at the time SOTF
comes to picture very fast
• Voltage 50 to 60% low
• I increase to maximum while
fault

6. 50LBB(Local Breaker Backup protection or Breaker
failure protection)
• If a Generator CB fails to trip,
50LBB trips the Grid CB
• 50LBB sense the setting current
because of Gen CB not trip while
the fault

8. PT fuse failure relay - To avoid unwanted tripping of P.relays due to PT fuse failure & Works by sensing
potential across the fuse

9. Vector surge relay

10. • Vector surge relay used to de-
couple the generator from the
grid as the grid supply fails in
parallel operation
• Fast acting relay – 300ms
• Surges leads to wrong
synchronization and prime
mover damage

11. Distance protection
• Z=V/I
• Used to L-L and L-G faults
• If fault is occur in line, I inc. & V
dec. so Z value of the line dec.
• Z directly prop. To line length of
line
• Type
1.Definite DR-If Z value is dec.
less then set point relay trips
2.Time DR-Time prop. To Z or
distance

13. 1st zone – very fast & 80% of total Z or line length(20% margin for acc. Of
measurement and infeed&outfeed effect )
2nd zone - time delay given comp. to Z1 & due to over lap 20% extra setting

14. Trip Circuit Supervision relay (TCS)
• To ensure healthiness of
protection system
• 95HV – Trip circuit
• 95/86HV – Trip coil
• Pre & Post close
supervision
• C- for DC supply extension
due to R

15. TCS

16. Electrical basic Safety videos

20. Basic working of Transformer

21. Basic working of Alternator

22. Numerical relays

23. Thank you

24. TCS

27. Relay