Pain Points of Reactive Power Compensation in Photovoltaic Power Stations
- Power Generation Fluctuations Leading to Voltage Instability
During peak sunlight hours (e.g., midday), excessive photovoltaic power generation can cause voltage levels to rise beyond acceptable limits (e.g., exceeding 1.07 times the rated voltage). This often forces inverters to disconnect from the grid, resulting in significant power generation losses.
Conversely, during periods of low sunlight (e.g., rainy weather or nighttime), photovoltaic output drops sharply, requiring reactive power absorption from the grid. This can lead to a power factor that fails to meet grid standards, triggering penalties from grid operators.
- Harmonic Pollution and Increased Equipment Losses
Inverters generate harmonics (e.g., 3rd, 5th, and 7th harmonics) due to their switching frequencies. These harmonics can cause transformers to overheat and accelerate the aging of cable insulation.
The presence of harmonics increases system losses by approximately 3% to 8%, reducing overall efficiency and increasing operational costs.
- Ineffectiveness of Traditional Compensation Solutions
Traditional solutions like Thyristor-Switched Capacitors (TSC) have slow response times (>100ms), making them unable to keep up with the rapid, minute-level fluctuations in photovoltaic output.
This often results in over-compensation or under-compensation, failing to provide the precise reactive power support needed for stable grid operation.
Core Advantages of SVG in Photovoltaic Power Stations
- Dynamic Response and Voltage Stability
SVG uses IGBT-based voltage source converters to detect the grid’s reactive power demand in real time. It can deliver capacitive or inductive reactive power within 10 milliseconds, keeping voltage fluctuations within ±1%.
In a 50MW photovoltaic power station, the installation of SVG increased the voltage qualification rate from 82% to 99.5%, reducing grid disconnection losses by over 200 hours annually.
- Precise Compensation and Reduced Losses
After compensation, the power factor remains stable at ≥0.99, ensuring compliance with grid standards and avoiding penalties.
SVG provides a harmonic filtering rate of >85% (THDi <3%), lowering transformer temperature rise by 12℃ and extending the lifespan of equipment.
- Bidirectional Regulation for Photovoltaic-Storage Systems
SVG can switch to inductive reactive mode at night, compensating for the reactive power gap when photovoltaic generation stops.
It works in tandem with energy storage PCS (Power Conversion Systems) to achieve “reactive + active” comprehensive regulation, enhancing the grid integration capabilities of photovoltaic-storage systems.
