Mell What is on load tap changer transformer?
On-load tap changer (OLTC), also known as On-circuit tap changer (OCTC), is a tap changer in applications where a supply interruption during a tap change is unacceptable, the transformer is often fitted with a more expensive and complex on load tap changing mechanism.
How do you change a tap on a transformer?
Tap changing in Transformers This can be done by changing the transformer turns ratio. The taps are leads or connections provided at various points on the winding. The turns ratio differ from one tap to another and hence different voltages can be obtained at each tap.
Why tap changing is generally performed on load?
Needs For Tapping Frequently change in load changes the voltage of the system. The tap changing in the power transformer is mainly done for keeping the output voltage within the prescribed limit. Nowadays almost all the large power transformer is provided with on-load tap changer.
What happens when off load tap changer operated on load?
In case of Off-Load Tap Changer, it must be ensured that Transformer is de-energized as Off-Load Tap Changing is not Make Before Break type. If the Off-Load Tap Changer is used while the Transformer is energized, heavy sparking will take place which will damage the winding and insulation.
What is the function of a tap changer?
The purpose of a tap changer is to regulate the output voltage of a transformer by altering the number of turns in one winding and thereby changing the turns ratio of the transformer.
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.
What is the function of tap changer?
The purpose of a tap changer is to regulate the output voltage of a transformer by altering the number of turns in one winding and thereby changing the turns ratio of the transformer. There are two types of tap changers: a de-energized tap changer (DETC) and an on-load tap changer (LTC).
How does a no load tap changer work?
No-load tap changers (NLTC), also known as de-energized tap changers (DETC), off-load tap changers, and, off-circuit tap changers (OCTC), employ manually operated switching equipment that changes the transformer turns ratio of the three phases simultaneously and by the same amount.
How do you calculate tap changer?
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. Since the objective is to raise V2 back to nominal, then N1 must be reduced. Therefore N1 must be reduced by (1 – 0.974) = 0.026 or 2.6 %.
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.
What does on load tap changing transformer do?
Definition: An On-Load Tap Changing Transformer (OLTC) consists of an open load tap changer, it is also known as an on-circuit tap changer (OCTC). They are used in areas where there is an interruption in the power supply due to an unacceptable tap change. The ratio of the number of turns can be changed without breaking the circuit.
How does on load tap changer work?
On-load tap changers (or circuit tap changers), as the name suggests, permit tap changing and hence voltage regulation with the transformer on-load. Tap changing is usually done on the HV winding for two reasons: Because the currents are lower, the tap changer contacts, leads, etc., can be smaller.
What is a no load tap changer?
No-load tap changer. No-load tap changer (NLTC), also known as Off-circuit tap changer (OCTC) or De-energized tap changer (DETC), is a tap changer utilized in situations in which a transformer’s turn ratio does not require frequent changing and it is permissible to de-energize the transformer system.
What is transformer tap changing?
A tap changer is a mechanism in transformers which allows for variable turn ratios to be selected in distinct steps . This is done by connecting to a number of access points known as taps along either the primary or secondary winding.