Thankyou from WB,india please keep it up it is so useful for new site engineer like us.May God give you strength and happiness so that you can continue with this noble job of teaching.
I want to know about the wiring for phase overcurrent and earth fault current , three CTs are used for three phase , how are they connected for phase overcurrent and earth fault current detection.
Great video sir... But one question... Jodi fault current above 3.3In hoi, tahole ki idmt r delay time, second stage delay time er cheye always beshi hbe? Oi reference point ta kivabe pabo?
Hi Sir, may I know the rating of the variac you used? If we use 300Va step down transformer 220v / 12v, from your video I understand that 46V and primary side of step down transformer is equal to 25A at secondary side. Base on the calculations, the ampere of primary side of the step down transformer is 300Va/46v = 6.52A. it mean the rating of the variac must be bigger that 6.52A to generate 25A at step down transformer secondary side it is? If convert to Va, it mean we need to choose 1.5kva variac?
Hello there, the secondary current which is 25A in this case is being drawn in short circuit condition(Low voltage side). Since the %Z of this transformer is about 21% thus in short circuit condition if you apply 21% x 220 = 46 volt at Primary it will cause to draw rated current at every side. Now what is the rated current of a 220/12V, 300 VA transformer? It's 300/220 = 1.36 A at primary and 300/12=25A at secondary. Thus in short circuit condition (at Low voltage side) applying 46 volt in primary will cause to draw that rated 1.36A through primary. If the %Z for example is 50% for a typical Transformer then 50% x 220 = 110 V will cause to flow that 1.36 A on that typical transformer. Thus primary voltage is dependent on %Z for Low voltage short circuit condition. Thus you need 1.36Ax220V=300 VA Variac. So you need at least same size of Variac as Transformer. However, I am using 300 VA transformer with 500 VA Variac. Hope you will understand. For any further quary Please. let me know
1. Can u please explain about the connection between transformer and relay. Which relay terminals to use. 2. What will be the VA of th autotransformer , equal to VA of 230/12V transformer?
Hello Mr. Singhal, Here is what you have asked for: 1. Connection between Transformer and Relay is as "series Load" where the load resistance is the contact/coil (Analog Input contact/coil i.e. Current, Voltage etc. of the relay) resistance of the relay which is actually Zero. Thus transformer experience Zero impedance at secondary and thus Short Circuit operation is occurred. This transformer is doing the same job as secondary of any high voltage CT does for the relay. 2. Transformer VA depends upon the output Current (Current Injection) limit that you desire. For example as i have used here 300 VA with 12 Volt Secondary thus i can draw 300/12=25 Ampere at the short circuit condition. If still you have any confusion or further query feel free to comment. ---bdprofessionals
@@bdprofessionals-8474 Thank you for the detailed reply. I want to know about the VA of the auto transformer also, is it same as step down transformer? Thanks in advance.
Need 1 Variac (0-250 volt) and a transformer. If you buy 300 VA with secondary 12 Volt XF then you can draw 300/12= 25 Amp Current. Thus for 5 A CT secondary you can test upto 5*In Protection settings. And these all are available at Nababpur, Dhaka.
@@bdprofessionals-8474 transformer secondary 12v and ov short kore... Oi duto terminal teke 2 to wire relay protection ct terminal a dite hobe to sir??
Regardless of voltage level you can check any CT. You only need to ensure the supply of primary current of the CT. With this kit you can test but need a large VA transformer
Thankyou from WB,india please keep it up it is so useful for new site engineer like us.May God give you strength and happiness so that you can continue with this noble job of teaching.
You are most welcome and thanks for your Compliment.
Very helpful video
I want to know about the wiring for phase overcurrent and earth fault current , three CTs are used for three phase , how are they connected for phase overcurrent and earth fault current detection.
Great video sir... But one question... Jodi fault current above 3.3In hoi, tahole ki idmt r delay time, second stage delay time er cheye always beshi hbe? Oi reference point ta kivabe pabo?
idmt will switch to dmt
Good.go ahead
Outstanding sir !!!
Thanks.
❤❤❤
Hi Sir, may I know the rating of the variac you used? If we use 300Va step down transformer 220v / 12v, from your video I understand that 46V and primary side of step down transformer is equal to 25A at secondary side. Base on the calculations, the ampere of primary side of the step down transformer is 300Va/46v = 6.52A. it mean the rating of the variac must be bigger that 6.52A to generate 25A at step down transformer secondary side it is? If convert to Va, it mean we need to choose 1.5kva variac?
Hello there, the secondary current which is 25A in this case is being drawn in short circuit condition(Low voltage side). Since the %Z of this transformer is about 21% thus in short circuit condition if you apply 21% x 220 = 46 volt at Primary it will cause to draw rated current at every side. Now what is the rated current of a 220/12V, 300 VA transformer? It's 300/220 = 1.36 A at primary and 300/12=25A at secondary. Thus in short circuit condition (at Low voltage side) applying 46 volt in primary will cause to draw that rated 1.36A through primary. If the %Z for example is 50% for a typical Transformer then 50% x 220 = 110 V will cause to flow that 1.36 A on that typical transformer. Thus primary voltage is dependent on %Z for Low voltage short circuit condition. Thus you need 1.36Ax220V=300 VA Variac. So you need at least same size of Variac as Transformer. However, I am using 300 VA transformer with 500 VA Variac. Hope you will understand. For any further quary Please. let me know
@@bdprofessionals-8474 Thank a lot. Now I understand already. Really thank for your great explanation.
1. Can u please explain about the connection between transformer and relay. Which relay terminals to use.
2. What will be the VA of th autotransformer , equal to VA of 230/12V transformer?
Hello Mr. Singhal, Here is what you have asked for:
1. Connection between Transformer and Relay is as "series Load" where the load resistance is the contact/coil (Analog Input contact/coil i.e. Current, Voltage etc. of the relay) resistance of the relay which is actually Zero. Thus transformer experience Zero impedance at secondary and thus Short Circuit operation is occurred. This transformer is doing the same job as secondary of any high voltage CT does for the relay.
2. Transformer VA depends upon the output Current (Current Injection) limit that you desire. For example as i have used here 300 VA with 12 Volt Secondary thus i can draw 300/12=25 Ampere at the short circuit condition.
If still you have any confusion or further query feel free to comment.
---bdprofessionals
@@bdprofessionals-8474 Thank you for the detailed reply. I want to know about the VA of the auto transformer also, is it same as step down transformer? Thanks in advance.
Very nice sir.... Plz upload p141 realy testing...
Plz explain about the transformer used here...
300 VA, 220/12 volt transformer
@@bdprofessionals-8474 got it sir.. but how to get 25amp... Thats little confusing...
Kindly explain me sir..
Short secondary side. At this situation you need to supply impedance voltage at primary (220 volt side) which is here near 50 volt
Please upload 7SR relay
Please upload 850 and 845 relay setting accordingly kindly sir !!!
Pls make video in hindi or English
LED kivabe settings dibo setao dekhayen
ua-cam.com/video/S6FWRi9Mq00/v-deo.html
Kmn kore oi secondary onjection kit ta banabo r koto va rating r.. Pls jodi ktu bolen
Need 1 Variac (0-250 volt) and a transformer. If you buy 300 VA with secondary 12 Volt XF then you can draw 300/12= 25 Amp Current. Thus for 5 A CT secondary you can test upto 5*In Protection settings. And these all are available at Nababpur, Dhaka.
@@bdprofessionals-8474 transformer secondary 12v and ov short kore... Oi duto terminal teke 2 to wire relay protection ct terminal a dite hobe to sir??
Protection terminal coil has almost zero ohm. Thus if you connect xf secondary to the 41&42 (for micom) xf secondary will be short circuited
@@bdprofessionals-8474 thanx a lot sir
Very nice
Thanks
Can I test 33kv CT like Current Injector?
Regardless of voltage level you can check any CT. You only need to ensure the supply of primary current of the CT. With this kit you can test but need a large VA transformer
@@bdprofessionals-8474 Sir কত VA হলে ভাল হবে? ৩৩কেভি সিটির প্রাইমারী তে কি ট্রান্সফারের output Voltage দিবো? Diagram দিলে খুশি হতাম
If you want to test a 400/5 ampere CT then to have 400 amp at 12 volt need 400×12=4800 VA
Thank you sir, can you make video about trouble shooting of PFI?
Please upload 7SR relay
7SR : ua-cam.com/video/DkawOwnXDhk/v-deo.html