What is a tap changer in a transformer?
What is a tap changer in a transformer?
The purpose of a tap changer is to regulate the output voltage of a transformer. It does this by altering the number of turns in one winding and thereby changing the turns ratio of the transformer. There are two types of transformer tap changers: an on-load tap changer (OLTC) and a deenergised tap changer (DETC).
How does a transformer load tap changer work?
This is accomplished by installing a load tap changer onto the transformer. The LTC actually changes the transformer turns ratio by moving among a number of access points or “taps” on one of the two windings, thus either raising or lowering the voltage supplied to the customer.
How do you calculate tap changes?
Transformer Tap Calculation
- Normal tap (100% tap) primary voltage [V]* Rated primary voltage from name plate.
- Normal tap (100% tap) secondary voltage [V]*
- Actual primary voltage [V]*
- Nominal tap-internal.
- +7.5% tap-Secondary voltage.
- +7.5% tap-internal.
- +5% tap-internal.
- +5% tap-Secondary voltage.
Where are tap changing transformer used?
No-load tap changer This type of transformer is frequently employed in low power, low voltage transformers in which the tap point often may take the form of a transformer connection terminal, requiring the input line to be disconnected by hand and connected to the new terminal.
What are the advantages of tap changing transformer?
Advantages
- The ratio of voltage can be varied without de-energizing the transformer.
- Provides voltage control in the transformer.
- OLTC increases the efficiency.
- It provides adjustment of voltage magnitude and flow of reactive.
How do you calculate tap voltage?
V1/V2 = N1/N2 or V1·N2 = V2·N1 indicates that, to keep the equation in balance with primary voltage and secondary winding turns fixed, either V2 or N1 must be adjusted.
Why tap changer is connected on the HV side?
Why tap changer is placed on high voltage side? The tap changer is placed on high voltage side because: 1. The HV winding generally wound over LV winding hence it is easier to access the HV winding turns instead of LV winding.
What is LTC power?
Most transformers come equipped with taps on the windings to adjust either the voltage transformation or the reactive flow through the transformer. Such transformers are called either load-tap-changing (LTC) transformers or tap-changing-under-load (TCUL) transformers.
Why do we use tap changer in primary side of transformer?
The tap changer of the transformer performs this task to change the turn’s ratio. The tap changer basic function is that it removes or connects some portion of the winding to the load side or source side.
What are the disadvantages of tap changing transformers?
However, its major disadvantage is that although two thyristor are ON over short periods during the tap-changing process, it is permanently connected to the circuit of the deviation switches and it probably gets burnt. This may therefore reduce the reliability of the system.
