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What primary conductor can be use for 45 kva continuous loaded in 3 phase transformer 480 V where OCPD protection used is 70A?
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Why differential relay is not used for 11kv transformers?
It depends what you mean by an '11-kV transformer'; do you mean a primary transformer (33/11-kV transformer) or a distribution transformer (11-kV/400-230-V transformer). Differential protection IS offered on primary transformers.
How emf induce while apply in primary side of the transformer?
when an alternating current apply on primary side of transformer then magnetic flux produced in the iron core of transformer.Then flux link with secondary winding of transformer so that an emf produced in a transformer.
What is differential transformer protection?
The current input (primary) to a transformer is proportional to the output (secondary) current. Differential protection relays monitor these via current transformers (CT). The percentage of difference between primary and secondary can be adjusted. If it is over the seting the relay will trip the primaryand secondary feeder breakers. Thus indicating an inbalance between internal phasewindings and or shorts to earth.
Why does the primary side of a step down transformer burn out and not the secondary of a 480V to 240V transformer?
Sounds like the wrong size fuse protection was used. The transformer should be protected to its kva capacity.
What is the differences between current and potential transformer?
Current Transformer- Instrument transformer used for measure high current. it hasless and thin turns in primary and more and thick turns in secondary.Potential transformer- Instrument transformer used for measure high voltage. it has more and thin turns in primary and less and thick turns in secondary.CommentUnfortunately, the original answer has got things the wrong way around for the CT! A current transformer's primary has a thicker conductor than its secondary.
What size maximum level of primary-only overcurrent protection is required for a 600-volt transformer with a primary current rating of 54 amperes?
100
Are the primary and secondary of a transformer having same thickness.why?
Unless the transformer is an isolation transformer, whose primary and secondary voltages are the same, the cross-sectional area of the primary and secondary winding conductors are normally different. The higher-voltage winding has a smaller current flowing through it than the lower-voltage winding when the transformer is loaded. So the higher-voltage winding is manufactured using a conductor with a smaller cross-sectional area, therefore a smaller diameter.
How does the standby earth fault scheme work?
Restricted earth fault protection is used to protect a specific zone, and should not trip for a fault outside of that zone (usually limited to a transformer, and possibly extending to lowside, highside, and tertiary breakers). Stand by earth fault protection is a term I am not very familiar with, but I believe this would be protection that is meant for a specific zone as backup, and can operate for faults outside of this zone. An example might be a highside time overcurrent relay set looking into a transformer, where the transformer is protected by a differential (primary protection), and there is a lowside feeder with relays (primary protection). The highside overcurrent acts as a backup (secondary protection) for the transformer and the feeder, and is delayed due to the nature of a time overcurrent relay.
How does a ct work?
As current flows through a conductor (wire) an electromagnetic field is produced. A CT is just a coil of wire that surrounds the conductor with the current flow. The EMF produced induces a voltage in the CT and that is sensed by some type of device to determine the amount of current in the primary conductor. Usually used when a large current is fed through the primary and you want to know what that is without measuring it directly. ADDITIONAL: THE MOST NEGLECTED ANSWER SPECIALLY IN DEFINING THE PURPOSE AND USE OF INSTRUMENT TRANSFORMERS (CURRENT AND POTENTIAL OR VOLTAGE TRANSFORMER) IS PROTECTION.
Does the secondary feeder of a transformer need to be rated at less than the main breaker of the feeder supply panel?
It depends on the situation and how you are utilizing the transformer. Under certain conditions the secondary does not need to be protected. The protection on the primary is enough to protect the secondary side of the transformer.
When would you use current transformer?
A 'current transformer' (CT) is classified as an instrument transformer, which means it is used to provide a small secondary current that is in proportion to its large primary current, for purposes of metering or protection. At the same time, it electrically-isolates the secondary (metering) circuits from the primary circuits (which are often high-voltage circuits) for the purpose of safety.
Why you uluminium on primary side of transformer?
This isn't the case. You can have aluminium or copper on primary or secondary side of a transformer.
