RTCC Panel in Transformer and Working Principle

RTCC stands for Remote Tap Changer Control. It is 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. OLTC controls the winding tap position of the Transformer and it resulted in the output voltage also changes.

Working Principle

AVR (Automatic Voltage Regulator) Relay is available inside the RTCC panel. The AVR relay works like a brain to control the whole process. The OLTC tap position signals and Transformer input and output signals are coming to the AVR relay. Based on the programmed algorithm it will calculate the OLTC tap position as per the requirement of output voltage.

The RTCC has two types of modes they are AUTO and MANUAL. Under the auto mode, the RTCC will change the Tap position of the transformer automatically to achieve the target voltage at on load condition. Under the manual mode, the tap position can be changed manually by pressing the upward and downward switch available at the RTCC panel.

RTCC panel
RTCC panel

Single AVR relay can control for a single OLTC device. In case multiple transformers are connected to the same bus voltage, the same number of AVR relays are also required to control all the OLTCs at the same time.

For controlling multiple AVR, One number AVR relay will set as Master mode and others relay will set as follower mode. All the settings will be done in the Master AVR relay and it will control the follower relays.

Use of RTCC Panel

RTCC panel is used to control the transformer output voltage automatically by changing the OLTC tap positions. It is mainly used for the parallel operation of OLTCs when multiple transformers are connected to the same bus voltage. It is also used for monitoring of OLTC tap position and transformer output voltage as an event record.

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