INTRODUCTION TO SUBSTATIONS - PRACTICE
QUESTIONS AND CERTIFIED SOLUTIONS.
what are the main functions of a substation? correct answers 1. change voltage from one level to
another
2. connect or disconnect lines or equipment from each other
3. control the flow of power
4. record the flow of power and related data
what are the four main types of substations? correct answers 1. generation
2. subtransmission
3. transmission
4. distribution
what is the advantage of having two subtransmission circuits feed a substation? correct answers
if one circuit fails or is taken off line, power is still supplied with no interruption
what is the function of the potential transformers? correct answers monitor voltage levels that
enter substation
what is the function of the current transformers? correct answers monitor current for relay and
metering purposes
what is the function of the circuit switcher? correct answers protects transformer and distribution
bus from fault
what purposes do disconnects serve in a substation? correct answers isolation points
what is the difference between an ltc and a station transformer? correct answers ltc automatically
changes secondary voltage to maintain desired limits
what is the purpose of the transfer bus? correct answers allows circuit breaker to be removed
from service for maintenance without disrupting power flows
what is the purpose of the station ground grid? correct answers ensures all ground connections
are same potential
what can be found inside the control house? correct answers batteries, meters and relays
when should a single-line diagram be referenced? correct answers before maintenance operation
or construction
why are substation inspections conducted? correct answers reliability and safety
what are the two main duties of a circuit breaker? correct answers 1. protect electrical equipment
and lines from abnormal conditions
QUESTIONS AND CERTIFIED SOLUTIONS.
what are the main functions of a substation? correct answers 1. change voltage from one level to
another
2. connect or disconnect lines or equipment from each other
3. control the flow of power
4. record the flow of power and related data
what are the four main types of substations? correct answers 1. generation
2. subtransmission
3. transmission
4. distribution
what is the advantage of having two subtransmission circuits feed a substation? correct answers
if one circuit fails or is taken off line, power is still supplied with no interruption
what is the function of the potential transformers? correct answers monitor voltage levels that
enter substation
what is the function of the current transformers? correct answers monitor current for relay and
metering purposes
what is the function of the circuit switcher? correct answers protects transformer and distribution
bus from fault
what purposes do disconnects serve in a substation? correct answers isolation points
what is the difference between an ltc and a station transformer? correct answers ltc automatically
changes secondary voltage to maintain desired limits
what is the purpose of the transfer bus? correct answers allows circuit breaker to be removed
from service for maintenance without disrupting power flows
what is the purpose of the station ground grid? correct answers ensures all ground connections
are same potential
what can be found inside the control house? correct answers batteries, meters and relays
when should a single-line diagram be referenced? correct answers before maintenance operation
or construction
why are substation inspections conducted? correct answers reliability and safety
what are the two main duties of a circuit breaker? correct answers 1. protect electrical equipment
and lines from abnormal conditions
