power transformers Flashcards
A substation transformer used to control the flow of power between different transmission lines and systems is a ? type transformer.
phase shifting
Some substations have a separate voltage regulator to automatically boost or buck the voltage of the outgoing lines under energized conditions.
true
Single-phase substation transformers are found in older substations and used in high voltage substations such as ?
500 kv
The type of transformer located just outside the generating station that changes the voltage for transmission to distant locations is the ? transformer.
step up
If the substation power transformer is to be equipped with fans, the fans are to be positioned to blow with the prevailing wind.
true
Connections made from primary to secondary, primary to ground, and secondary to ground are procedures needed to perform ? tests.
megohmmeter
A ? test is a check to see if arcing, corona, or overheating of connections have occurred.
dissolved gas analysis
The condition of a power transformer lightning arrester is checked with a ? test while the arrester is disconnected from the top conductor and the ground.
dga
A substation transformer cooled by forced oil circulation is of the ? type.
o.f.n
The presence of contaminants such as water or particulates in transformer oil can be discovered by performing a ? test.
dielectric
The condition of not only the transformer oil, but also the insulation papers, is determined with a ? test.
gas chromatography
Substation power transformers can only be equipped with no-load tap changers.
false
The use of cooling fans can raise a substation power transformer’s capability by approximately ?
30%
No-load tap changers make it possible to adapt a transformer to a range of supply voltages. The range is usually ?
5% above and 5% below normal 2.5 steps
If a substation transformer is energized but not carrying any load, the no-load tap changer can be safely operated.
false
