What is Oltc in transformer?

What is Oltc in 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.

Which side of transformer is Oltc connected?

On load tap changer is preferred on High Voltage Side: Mostly the power transformer is used for both step up and step down action. In that, the power transformer’s turns are in the high voltage side is higher than the low voltage side.

How does a tap changer work on 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. An OLTC varies the transformer ratio while the transformer is energized and carrying load. …

What is Rtcc and Oltc?

RTCC stands for Remote Tap Changer Control. RTCC panel used to control the transformer output voltage by controlling the OLTC unit of the transformer. As we know the OLTC (On Load Tap Changer) is responsible to change the transformer output voltage.

What is Oltc diverter switch?

Diverter switches of OLTC perform switch over operation between the taps of the transformer, in which they are embedded at a leap. Speeds reached during this process are very high.

Why Oltc is used in 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 de energized tap changer?

A de energized tap changer is a switch, which is connected to the winding taps of the transformer. When the tap changer is moved from one position to another, the amount of the tap winding connected into the circuit is changed.

How many tap positions does a transformer have?

The de-energized or off-load tap changer is normally mounted on the main transformer tank and is set to match the high voltage network supplying the transformer. It often has 5 positions (A,B,C,D,E, or 1,2,3,4,5).

Why is Oltc needed?

On-Load Tap-Changer (OLTC) is a device for changing the tapping connections of a winding suitable for operation while transformer is energised and on-load condition to regulate voltage. The downstream bus voltages of the transformer can be regulated by optimal selection of tap position.

What is OSR in transformer?

The protective Oil Surge Relay (OSR) is used to protect the malfunction developed inside the On Load Tap Changer (OLTC). It is installed in the pipe between OLTC head and oil conservator. Any malfunction builds pressure which leads to increased oil flow.

What is on load tap changer OLTC in Transformers?

What is On Load Tap Changer OLTC in Transformers A tap changer is a device fitted to power transformers for regulation of the output voltage to required levels. On-load tap-changers (OLTCs) are indispensable in regulating power transformers used in electrical energy networks and industrial applications.

Can I use the same oil for the power transformer and OLTC?

If the same oil is used for both the power transformer and the OLTC, it is difficult to locate the source of the problem, which means that other methods should be used to supplement it. Fluid assessment tests are used in conjunction with the LTC gas data to provide diagnostic information about the condition of load tap changers.

How to detect OLTC contact degradation in a transformer?

The OLTC contact degradation can be detected by using winding resistance measurement in all tap positions. The winding resistance measurement is performed by passing a DC current through the transformer winding and reading the voltage drop across that winding. The winding resistance is measured in all OLTC positions in all three windings.

What is the OLTC selector arrangement for 16 steps and 17 positions?

The OLTC selector arrangement for 16 steps and 17 positions. In the diagram, the on load tap changer is connected to tapping 4 while changing from tap position 4 to tap position 5, M 1 is opened first and this transfers the load current via A 1 with resistor R 1 in series.