Transformer Grounding: Advantages & Disadvantages for System Protection

[Ian_Brooks]

what are the advantages and disadvantages of different types of transformer grounding

-with regard to system protection and fault current reduction?

we have the following grounding types

YN - YN
YN - Delta
Delta - YN
Delta - Delta

where can i find a good resource that explains this?

 

[dlgoff]

See if this helps a little:
http://www.allaboutcircuits.com/vol_2/chpt_10/6.html"

 

[oswaler]

I would like to start by clarifying that transformer grounding is an important aspect of system protection, as it helps to mitigate electrical faults and ensure the safety and stability of the system. The type of grounding used for a transformer can greatly impact the protection and fault current reduction capabilities of the system.

Now, let's discuss the advantages and disadvantages of the different types of transformer grounding in terms of system protection and fault current reduction.

1. YN - YN: This type of grounding, also known as "solid grounding," involves connecting the neutral of both the primary and secondary windings to the ground. The main advantage of this type of grounding is that it provides a low impedance path for fault currents to flow, which helps to quickly clear faults and protect the transformer. However, the major disadvantage is that it can lead to high fault currents, which can cause damage to the transformer and other equipment in the system.

2. YN - Delta: In this type of grounding, the primary winding is grounded while the secondary winding remains ungrounded. This type of grounding is commonly used in industrial settings. The advantage of YN-Delta grounding is that it can reduce the fault current magnitude, which helps to protect the transformer and other equipment. However, the disadvantage is that it can lead to unbalanced voltages between the primary and secondary windings, which can cause issues with equipment operation.

3. Delta - YN: This type of grounding involves grounding the delta winding of the transformer, while the YN winding remains ungrounded. The main advantage of this type of grounding is that it can provide a lower fault current magnitude compared to YN grounding, which helps to protect the transformer and other equipment. However, the disadvantage is that it can cause high voltage transients, which can damage equipment.

4. Delta - Delta: In this type of grounding, both the primary and secondary windings are ungrounded. The main advantage of this type of grounding is that it eliminates any possibility of a ground fault, which can improve the reliability of the system. However, the disadvantage is that it does not provide any fault current reduction capabilities, which can be a concern for system protection.

In conclusion, the type of transformer grounding used should be carefully considered based on the specific needs and requirements of the system. A good resource for further understanding of transformer grounding and its impact on system protection and fault current reduction would be technical journals and textbooks on power systems and electrical engineering.