Experiment No.: -10
Aim of the Experiment: –
Parallel Operation of Three-Phase Transformers.
Apparatus Required: –
| Sl. No. | Name | Specification | Quantity |
|---|---|---|---|
| 1 | Three-phase transformers with compatible ratings | voltage, current, impedance, and kVA | 2 nos. |
| 2 | Three-phase power supply | 440V, 10A | 1 no. |
| 3 | Voltmeters | 2 nos. | |
| 4 | Connecting wires | PVC insulated copper | As per required |
Circuit Diagram: –
Theory: –
Parallel operation of three-phase transformers refers to the connection of multiple transformers in parallel to meet the load requirements of a power system. This configuration provides several benefits, including increased system capacity, improved reliability, and ease of maintenance.
Conditions for parallel operations:
- Voltage Ratio and Turns Ratio should be same.
- Vector Group should be same.
- Polarity should be same.
- Impedance should be same.
Procedure: –
- Place the three transformers side by side, ensuring proper ventilation and clear access for connections.
- Identify and verify the voltage ratings, impedance, and other parameters of each transformer for compatibility.
- Ensure that the transformers are de-energized and disconnected from the power source.
- Connect the primary windings of the transformers in parallel, ensuring proper phase connection (R-Y-B).
- Connect measuring instruments voltmeters to measure the primary and secondary voltages.
- Verify the proper functioning of the measuring instruments and ensure that they are calibrated correctly.
- Gradually apply power to the transformers from the three-phase power supply.
- Record the primary and secondary voltages as per observation table.
Observation Table: –
| Terminal Voltage in Volts. | Terminal Voltage in Volts. | Terminal Voltage in Volts. | Terminal Voltage in Volts. |
|---|---|---|---|
| VA1A2= | Va1a2= | VA1B1= | Va1b1= |
| VB1B2= | Vb1b2= | VA1C1= | Va1c1= |
| VC1C2= | Vc1c2= | VB1C1= | Vb1c1= |
After connecting A2, B2, C2, & a2, b2, c2 in start connection.
| Terminal Voltage in Volts. | Terminal Voltage in Volts. | Terminal Voltage in Volts. | Terminal Voltage in Volts. |
|---|---|---|---|
| VA1A2= | Va1a2= | VA1B1= | Va1b1= |
| VB1B2= | Vb1b2= | VA1C1= | Va1c1= |
| VC1C2= | Vc1c2= | VB1C1= | Vb1c1= |
After connecting both star point (A2, B2, C2, & a2, b2, c2).
| Terminal Voltage in Volts. | Terminal Voltage in Volts. | Terminal Voltage in Volts. |
|---|---|---|
| VA1a1= | VA1b1= | VB1c1= |
| VB1b1= | VA1c1= | VC1a1= |
| VC1c1= | VB1a1= | VC1b1= |
Conclusion: –
To be written by student.