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Transformer Heating & Drying System - I2R


This project has been achieved for ABB; a transformer manufacturer ,  in Jefferson City - USA,  in 2007-2008. A compound integration between hardware and software has been employed. This system was meant to:

- Allow a complete automated process for transformer heating, vacuuming and oil filling.

- Monitor, verify and save temperature, pressure, voltage, current and power of key system units
  throughout the whole process.


Transformer heating and drying system consists of 2 drying / oil filling vacuum chambers. These chambers can be operated either manually through touch screens supplied by manufacturer, or remotely from the computer. Each chamber consists of 3 stations for transformers. An I2R system is added to these chambers in order to decrease cycle time by using electric power to heat transformers to target vacuum and oil filling temperature. The I2R consists of three independent sub-systems that can be connected to either chambers .The I2R systems labeled System1, System2, System3 are rated for units up to 4MVA and therefore will be feeding station 1/2/3 of either chambers.

Each subsystem consists of an electronic supply, capacitor banks, a step up transformer, metering transformers (PTs and CTs), and switching hardware. Each of the three subsystems uses two cascaded power supplies. Each two cascaded power supplies are rated for 125 kVA. The step up transformers are rated 750 kVA for the three subsystems. The primary voltage is the maximum output of the electronic supplies. Seven taps exist on the secondary, 400V, 600V, 950V, 1400V, 2100V, 3200V, 4800V. Each system includes a capacitor bank to supply additional kVARs. Each subsystem also consists of PTs and CTs which are used to feed voltage and current information to the Wattmeter. Switching hardware is needed to be able to switch between chambers, to switch between CT ratios, and also to ground the system is necessary. 


The whole system involves various number of hardware components but we'll here by introduce the main hardware.

      - 3-Phase Switching Pacific power supply (6 units, each 2 are cascaded)
- Keithly Multi-meters (1 unit)
- Norma 3 phase Wattmeter (3 units)
- Multi-tap Step up transformer with motorized tap changer
- Allen-Bradley PLC
- Capacitor banks
- Power Switches
- Yokogawa Timer Meters (3 units)
- Yokogawa Current Meters (6 units)

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