The increase in system voltage from 220V to 260V due to solar inverter export is a common issue in distributed generation systems. This over-voltage occurs because the inverter injects excess power into the grid, especially in areas with high solar penetration or weak grid infrastructure. Here are several solutions to overcome this problem:
1.Adjust Inverter Settings
Voltage Limit Configuration: Ensure the inverter is set to comply with grid standards (e.g., IEEE 1547 or IEC 61727) and trip if voltage exceeds safe limits (typically +10% of nominal voltage).
Power Factor Adjustment: Modify the inverter’s power factor (e.g., from PF=1 to PF=0.95 lagging/leading) to reduce reactive power contribution, which can help stabilize voltage.
Voltage Rise Compensation: Some inverters have a “volt-watt” or “volt-var” function that reduces active power output when voltage rises beyond a set threshold.
2.Grid Reinforcement & Infrastructure Upgrades
Transformer Tap Changing: Adjust the tap settings on distribution transformers to better regulate voltage.
Line Upgrades: Replace undersized cables or conductors to reduce impedance and voltage rise.
Voltage Regulators: Install automatic voltage regulators (AVRs) to maintain stable voltage levels.
3.Energy Storage (Battery Systems)
Store excess solar energy in batteries instead of exporting it to the grid, preventing voltage rise
4.Demand-Side Management
Load Shifting: Increase local consumption (e.g., water heating, EV charging) during peak solar generation to minimize export.
Smart Load Controllers: Use automated systems to absorb excess power when voltage rises.
5.Advanced Inverter Functions (If Supported)
Dynamic Voltage Support: Inverters with advanced grid-support functions can automatically curtail power or inject reactive power to stabilize voltage.
Remote Monitoring & Control: Use SCADA or IoT-based systems to dynamically adjust inverter output based on real-time grid conditions.
6.Regulatory & Grid Code Compliance
Ensure the solar system complies with local grid codes, which may require export limits or mandatory reactive power control.
7.Consult the Utility Company
The utility may need to revise feeder settings, implement curtailment schemes, or approve export limiting to prevent over-voltage.
Conclusion
The best solution depends on the specific cause of the voltage rise. A combination of inverter settings adjustment, grid upgrades, and energy storage is often the most effective approach. If the problem persists, consult a solar engineer or the utility provider for a detailed assessment.