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Substation Practice

The document discusses substation practice, including: 1. The functions of substations include transforming voltages from high to low levels for distribution and classifying substations based on operating voltage. 2. Factors considered for site selection include space requirements, proximity to load centers, and environmental conditions. 3. Main equipment includes transformers, circuit breakers, switches, protective relays, and metering equipment which transform and distribute power and protect equipment.

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Yuvraj Gogoi
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156 views7 pages

Substation Practice

The document discusses substation practice, including: 1. The functions of substations include transforming voltages from high to low levels for distribution and classifying substations based on operating voltage. 2. Factors considered for site selection include space requirements, proximity to load centers, and environmental conditions. 3. Main equipment includes transformers, circuit breakers, switches, protective relays, and metering equipment which transform and distribute power and protect equipment.

Uploaded by

Yuvraj Gogoi
Copyright
© © All Rights Reserved
We take content rights seriously. If you suspect this is your content, claim it here.
Available Formats
Download as DOCX, PDF, TXT or read online on Scribd
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Substation Practice

1. What are the functions of a substation? Classify substations on the basis


of operating voltage.
2. What are the factors considered while selecting the site for a substation?

3. What are the main equipment in a substation? Mention the functions of


these equipment.
4. Write down the purposes for which substation earthing system is
provided.

5. Draw the single line diagram of a 33 kv , 66 kv and 220 kv substation


showing different incoming and outgoing feeders and other equipments.

6. What are the different switchgear used in a substation? Discuss briefly


about them.
7. What do you mean by grounded neutral system? What are the different
classifications of neutral grounding? Explain briefly.

Grounded System
In neutral grounding system, the neutral of the system is connected to the
ground. Because of the problems associated with ungrounded neutral
systems, the neutrals are grounded in most of the high-voltage systems.

Classification of neutral grounding are:

 Solidly Neutral Grounded Systems


Solidly grounded systems are usually used in low voltage applications at 600 volts or less. In solidly grounded
system, the neutral point is connected to earth.
 Resistance earthed systems: Grounding Resistors are generally connected
between ground and neutral of transformers, generators and grounding transformers to limit
maximum fault current as per Ohms Law to a value which will not damage the equipment in the
power system and allow sufficient flow of fault current to detect and operate Earth protective relays to
clear the fault.
 Resonant earthed system: The current generated by the reactance
during an earth fault approximately compensates the capacitive
component of the single phase earth fault current, is called a resonant
earthed system.

 Petersen Coils: A Petersen Coil is connected between the neutral point of the system and
earth, and is rated so that the capacitive current in the earth fault is compensated by an inductive
current passed by the Petersen Coil. 

Earthing Transformers:

For cases where there is no neutral point available for Neutral Earthing (e.g. for a delta winding), an earthing
transformer may be used to provide a return path for single phase fault currents
8. Write down the procedures in designing a substation.

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