Transformer - AVR

 AVR - stands for Automatic voltage relay

    AVR relay is the relay which gives pulse signal to the OLTC (ON-load Tap changer) to regulate the voltage of the transformer. It automatically sense the voltage of the transformer with the help of voltage sensed by PT (Potential Transformer). The PT output is given as the input to AVR.

AVR BACK SIDE

AVR FRONT SIDE

It is placed in the RTCC Panel of the transformer. RTCC is called as Remote tap change controller or cubicle.

RTCC PANEL

Working 

We have to set the tolerance level in the AVR for both higher and lower voltage. when the AVR senses the voltage of transformer below or above that tolerance level, it will give tap changing command to the OLTC. It also have the indication of Under voltage (worst case of lowered voltage).

Terminal Details:

1,2 Terminals - Input supply for AVR (95 - 260V AC or DC)

3,4 Terminals - PT Input

5,6,7 Terminals - 6 (Common )

                            5 (Rise command to RTCC)

                            7 (Lower command to RTCC)