Working Principle

The SVG (Static Var Generator) operates by connecting a voltage-source converter (VSC), composed of a self-commutated bridge circuit using IGBT devices, in parallel with the power grid through a transformer or reactor. By controlling the switching of the IGBT modules, the DC voltage is converted into an AC output with adjustable amplitude and phase.

For an ideal SVG with negligible active power loss, reactive power compensation is achieved solely by adjusting the output voltage amplitude:

• When the output voltage is lower than the grid voltage, the SVG operates in an inductive mode, absorbing reactive power (acting like a reactor).

• When the output voltage is higher than the grid voltage, it operates in a capacitive mode, supplying reactive power (acting like a capacitor).

SVG systems are categorized into:

• Direct-connection type: typically used for 6kV, 10kV, and 35kV applications.

• Step-down connection type: generally applied on a 10kV low-voltage side.

The choice of connection depends on the grid voltage level at the point of interconnection and the required compensation capacity.

The system uses a cascaded H-bridge topology, and the connection structure can be configured as either star (Y) or delta (Δ), depending on the application requirements.

Product Advantages

1. Intelligent Human-Machine Interaction, Simplified Commissioning
FGSVG features an intelligent startup self-check function, significantly reducing commissioning complexity and shortening the deployment cycle. With intuitive operation and optimized user interface, it delivers a seamless user experience for operators and maintenance teams.

2. Advanced Recording and Diagnostic Functions
Equipped with real-time waveform recording and fault trace analysis, including a 16-channel oscilloscope function, FGI’s SVG enables precise monitoring and fast troubleshooting during operation.

3. Self-Adaptive Phase Sequence Recognition
No need to manually determine phase sequence — the system automatically identifies and adapts, further streamlining installation.

4. Multi-Level Networking, Seamless Capacity Expansion
FGSVG supports high-speed optical fiber communication (10M/10km), enabling ring-networked, master-slave parallel operation across multiple devices. This design supports easy reactive power capacity expansion, fully addressing users’ scalability concerns.

5. Intelligent Operating Mode Switching
The system automatically switches between normal and fault operating modes. Especially useful in critical applications such as railway substations where automatic adaptation is needed during bus tie switch operations.

6. Remote Monitoring via APP & Flexible Communication Interfaces
Monitor industrial equipment anytime, anywhere via mobile APP. FGI SVG offers rich communication interfaces including RS485, CAN, Ethernet, and GPRS. It is fully compatible with major industry protocols such as Modbus-RTU, Profibus, CDT91, and IEC104.

Technical Specifications

Installation and Maintenance Guidelines

• Indoor Cleanliness
  Ensure the installation environment is clean and dry. Accumulated dust may affect system performance and cooling.

• Pest Control
  Implement anti-rodent measures to prevent small animals from entering the SVG cabinet and causing damage.

• Temperature Management
  Maintain an indoor ambient temperature below 38°C. When temperatures rise, use ventilation or air conditioning to cool the area.

• Post-Startup Fastening Check
  About one week after commissioning, shut down the device and disconnect the main power. Tighten all conductive connections, grounding screws, and bolts to ensure reliable contact.

• Daily Inspection
  Inspect SVG status daily. If unusual noises are heard, airflow is weak or absent, or abnormal smells (especially ozone) are detected:

  • Immediately shut down and disconnect power.

  • Check for obstructions in the air intake, clogged exhaust ducts, or fan failure.

  • Replace cooling fans or clean ducts as needed.

  • Contact the manufacturer if persistent abnormality occurs.

• Annual Preventive Maintenance
  

  Schedule a shutdown at least once per year to inspect internal components:

  • Open one power unit and examine the capacitors.

  • Ensure film capacitors have a smooth, glossy black surface and intact seals.

Cases

Case 1: Ferroalloy Furnace Application in Zhengzhou, Henan

Location: Zhengzhou City, Henan Province
Compensation Capacity: -2000kvar to +2000kvar
System Voltage: 6kV

Load Characteristics:
Compared to arc furnaces, ferroalloy (submerged arc) furnaces are more stable. However, the site encountered serious three-phase load imbalance and a low power factor.

Compensation Results:

• Significant reduction in three-phase imbalance

• Power factor improved to meet utility requirements

• Stable operation of the furnace under optimized power conditions

Case 2: Wind Power Station Application in Yantai, Shandong

Location: Yantai City, Shandong Province
Compensation Capacity: -10000kvar to +10000kvar
System Voltage: 35kV

Load Characteristics:
Due to the intermittent nature of wind resources, the system suffered from frequent voltage fluctuations, with instantaneous power factor dropping as low as 0.81.

Compensation Results:

• System voltage stabilized within 35.5–35.7kV

• Meets national standard GB/T 12325-2008 (Voltage Deviation Assessment)

• Real-time power factor raised to 0.96

• Complies with GB/T 14549-1993 (Harmonics in Public Power Grid)

• Supports Low Voltage Ride-Through (LVRT) requirements

Case 3: Induction Furnace Application in Xuzhou, Jiangsu

Location: Xuzhou City, Jiangsu Province
Compensation Capacity: -4000kvar to +4000kvar
System Voltage: 6kV

Load Characteristics:
The load exhibits a wide frequency spectrum with serious harmonic current distortion, especially at the 5th, 7th, 11th, and 13th orders.

Compensation Results:

• Harmonic current compensation efficiency up to 70% below 19th order

• 5th, 7th, 11th, and 13th harmonic currents reduced to meet national standard

• Complies with GB/T 14549-1993 (Harmonics in Public Power Grid)

Dimensions

Applications

1. Renewable energy integration in solar and wind farms, intermittent generation causes voltage fluctuations, SVG offers:

• Injects or absorbs current in real time to stabilize voltage.
• Improves power factor compliance with grid codes.
• Enhances grid reliability, reducing voltage flicker.

2. Industrial power quality management heavy industrial loads often lead to voltage drops and low power factors, SVG offers:

• Dynamic current compensation, stabilizing voltage and improving power factor.
• Reduced energy costs by minimizing reactive power penalties.
• Enhanced equipment protection by preventing voltage dips.

3. Grid and Transmission Line Stability In long-distance power transmission, SVG offers:

• Voltage stability during load variations.
• Power factor regulation, reducing line losses.
• Grid reliability by preventing voltage collapse.

About Us

With over 50 years of R&D experience since 1970, we are fully capable of meeting the grid standards of various countries.
For the past 20 years, we have been dedicated to the research, development, and manufacturing of SVG products. With steadily increasing customer satisfaction, we are confident in our ability to solve your power quality challenges.

Production Base: Jincheng Road, Economic Development Zone, Wenshang County, Jining City, Shandong Province, China

Email: overseas@fengguang.com