Transformer capacity increase refers to increasing transformer capacity to meet growing power demand. This typically involves upgrading or replacing existing transformers with larger capacity ones. For three-phase power systems, the capacity increase process requires consideration of three-phase load balance and phase matching. Below are detailed steps and considerations for transformer capacity increase.

Steps for Transformer Capacity Increase
1. Demand Assessment: First, a detailed assessment of the load demands of the existing power system is required, including maximum load, average load, and load growth forecasts.

2. Capacity Calculation: Based on the load demand assessment results, calculate the required transformer capacity. Generally, the rated capacity of the transformer should be higher than the maximum load to provide a safety margin.

3. Transformer Selection: Select a transformer of appropriate capacity. Considering possible future load growth, a transformer slightly larger than current requirements may be necessary.

4. Electrical Parameter Matching: Ensure that the electrical parameters of the new transformer (such as voltage level, impedance, and connection group) match those of the existing system.

5. Installation Preparation: Before installing a new transformer, the installation site must be prepared, including civil engineering, transformer foundations, and cable trenches.

6. Transformer Installation: Install the transformer according to the manufacturer's instructions and electrical specifications. Ensure that the three-phase windings are properly connected and that they are balanced.

7. Connecting the Load: After confirming that the transformer is correctly installed and that the electrical parameters match, connect the load gradually to avoid overloading the transformer by suddenly adding load.

8. System Testing: Before the transformer is put into operation, perform a comprehensive system test, including insulation resistance testing, withstand voltage testing, and temperature rise testing.

9. Monitoring and Maintenance: After the transformer is put into operation, perform regular monitoring and maintenance to ensure stable operation.

Precautions for Increasing Three-Phase Power
1. Three-Phase Balance: During the capacity increase process, pay special attention to maintaining balanced three-phase loads to avoid phase voltage imbalances caused by load imbalance.

2. Phase Matching: Ensure that the phase of the new transformer matches that of the existing system to avoid equipment damage caused by phase errors.

3. Harmonic Impact: During capacity expansion, pay attention to the impact of harmonics, especially when there are a large number of nonlinear loads.

4. Overload Protection: Equip the new transformer with appropriate overload protection devices, such as circuit breakers and overload relays.

5. Heat Dissipation: The increased transformer may generate more heat, so heat dissipation needs to be considered to ensure the transformer does not overheat.

6. Electromagnetic Compatibility: During capacity expansion, pay attention to electromagnetic compatibility (EMC) issues to avoid interference with other electronic equipment.

7. Grounding System: Ensure the transformer's grounding system is complete to improve system safety.

8. Cable Upgrade: If the output current of the increased transformer increases, the cables connecting the transformer and the load may need to be upgraded.

9. Harmonic Control: For large-capacity transformers, harmonic control measures such as filters and reactors may be necessary.

10. Professional Guidance: Transformer capacity expansion is a complex process and should be carried out in accordance with the manufacturer's instructions and local electrical codes. If necessary, seek the assistance of a professional electrical engineer.

Conclusion
Increasing transformer capacity is a systematic project, involving multiple steps, including needs assessment, capacity calculation, transformer selection, installation, testing, and maintenance. When increasing three-phase power capacity, special attention must be paid to three-phase balance, phase matching, harmonic effects, overload protection, heat dissipation, electromagnetic compatibility, grounding systems, cable upgrades, and harmonic control. Proper design and installation can effectively increase transformer capacity to meet growing power demand. At the same time, regular monitoring and maintenance are crucial to ensuring stable transformer operation. When increasing transformer capacity, adhere to relevant electrical codes and standards, and seek the assistance of professional technicians when necessary.