Basic principles of reactive power compensation

Reactive power is different from the actual power (active power) we use in daily electricity. It is a part of power used to establish an electromagnetic field in an AC circuit. Although it does not do actual work, reactive power is essential to maintaining grid voltage stability. In a solar power generation system, devices such as inverters and transformers will generate reactive power requirements.

When the reactive power in the system is insufficient, it will cause problems such as voltage drop, equipment heating, and increased line losses, which directly affect the power generation efficiency. Reactive power compensators help maintain system voltage stability and reduce line losses by providing or absorbing reactive power, thereby improving overall power generation efficiency.

 

Applications of Reactive Power Compensation Devices in Solar Energy Systems

1. Improve power factor: Increase the power factor from 0.8 to above 0.95, and reduce line losses by up to 30%.

2. Stabilize voltage level: The Compensation Device can quickly respond to voltage fluctuations and maintain the system voltage within a reasonable range of ±5%.

3. Reduce equipment capacity requirements: The optimized system can reduce the capacity configuration of equipment such as transformers and cables, saving initial investment.

4. Avoid grid fines: Many regions charge additional electricity fees to enterprises with power factors below the standard value, and the Compensation Device can avoid such expenses.

 

 

How to Choose Voltage Compensation Cabinets 

Common reactive Power Compensation Device on the market include static VAR compensators (SVCs), static synchronous compensators (STATCOMs), and smart capacitor banks. The following factors should be considered when selecting a Compensation Device suitable for a solar energy system:

1. Response speed: The output of photovoltaic power generation changes quickly, and a Dynamic Compensation Device with a millisecond response is required.

2. Compensation accuracy: The ability to accurately adjust reactive output according to real-time needs.

3. Environmental adaptability: Outdoor installations need to consider environmental factors such as temperature, humidity, and dust prevention.

4. Harmonic suppression capability: Devices with filtering functions can further improve power quality.

5. Scalability: Modular design facilitates future system expansion.

For small and medium-sized distributed photovoltaic projects, smart capacitor banks are the first choice because of their high cost-effectiveness and simple maintenance; large ground power stations use more dynamic compensation Dynamic Compensation Solutions for Electrical Systems such as SVC or STATCOM.

 

Installation and maintenance recommendations

The installation location of the reactive Power Compensation Device should be as close to the load center as possible. It is usually recommended to:

• Centralized compensation: Install on the low-voltage side of the substation.

• Group compensation: Install near large electrical equipment.

• On-site compensation: Direct compensation for particularly large single equipment

Daily maintenance mainly includes:

• Regularly check whether the capacitor has bulging and leakage.

• Monitor whether the Compensation Device is switched on and off normally.

• Clean the heat dissipation holes to ensure good ventilation.

• Record the change of power factor and evaluate the compensation effect.

Although the reactive Power Compensation Device is not the most eye-catching part of the solar energy system, it is a key link to improve power generation efficiency and ensure grid stability. With the continuous increase in photovoltaic penetration and the increasingly stringent requirements of the power grid on power quality, the reasonable configuration of Reactive Power Compensators will become the standard configuration of solar power stations. It is recommended that owners consult professional power designers when choosing compensation plans, customize the best solution according to the characteristics of specific projects, and give full play to the potential of solar power generation systems.