Static Var Compensators (SVCs) are devices that can quickly and reliably control line voltages. An SVC will typically regulate and control the voltage to the required set point under normal steady state and contingency conditions and thereby provide dynamic, fast response reactive power following system contingencies (e.g. network short circuits, line and generator disconnections). In addition, an SVC can also increase transfer capability, reduce losses, mitigate active power oscillations and prevent over voltages at loss of load.
The Static Var Compensators (SVCs) is customized to fit each customer with their specific needs. The SVC consists of a number of fixed or switched branches, of which at least one branch includes thyristors, and the combination of branches can be varied a lot depending on requirements. An SVC typically includes a combination of at least two of the given items below (e.g. TCR/FC or TCR/TSC/FC):
Most common topologies for Static Var Compensators are: TCR/FC or TCR/TSC/FC. The main advantage for using a topology with TSC branch(es) is to reduce the losses (by reducing the filter size). Hitachi Energy's SVC control system can be utilized for controlling new or existing external shunt banks.
A Static Var Generator (SVG) is an advanced power quality device designed to provide real-time reactive power compensation and improve power factor. Unlike traditional capacitor banks, SVG offers dynamic, stepless adjustment, ensuring stable voltage and efficient power distribution. It is widely used in industrial facilities, renewable energy systems, data centers, and commercial buildings where power quality and stability are critical. Below are some frequently asked questions to help you understand SVG technology better.
A Static Var Generator (SVG) is a power quality device for dynamic reactive power compensation. It helps stabilize voltage levels and improve power factor by injecting or absorbing reactive power as needed. Unlike traditional capacitor banks, SVG provides real-time compensation and works effectively under varying load conditions.
When choosing an SVG, consider the following factors:
-Reactive power demand: Determine the required kVAR rating based on the power system’s reactive power needs.
-Load type: Suitable for industries with fluctuating reactive power demands, such as welding, data centers, and steel plants.
-Response time: Look for fast response times (typically
-System voltage and capacity: Ensure compatibility with the existing electrical infrastructure.
-Installation environment: Consider indoor or outdoor installations and environmental factors like temperature and humidity.
SVG: Uses advanced power electronics (IGBT-based technology) for real-time reactive power compensation, providing continuous, stepless control.
Capacitor Bank: Uses fixed or switched capacitors to compensate for reactive power in discrete steps, which may lead to overcompensation or undercompensation.
SVG is ideal for voltage stability and reactive power control.
AHF is better for harmonic-rich environments and power quality improvement.
For complete power quality solutions, SVG and AHF can be used together in complex electrical systems.
SVG is ideal for dynamic loads that require reactive power compensation and power factor correction, including:
Welding equipment (arc welding machines, resistance welding machines)
Elevators, cranes (rapidly changing loads)
Renewable energy systems (wind power, solar PV)
Industrial applications (steel, chemical, cement industries)
Data centers, hospitals, airports (high power quality requirements)
However, SVG has limited effects on pure resistive loads (e.g., electric heaters).
No, SVG and AHF can work together to improve overall power quality:
SVG focuses on reactive power compensation and power factor improvement.
AHF eliminates harmonics and reduces Total Harmonic Distortion (THD).
Using both in combination is ideal for environments with nonlinear loads such as VFDs, UPS, and electric arc furnaces.
STATCOM (Static Synchronous Compensator) and SVG operate on similar principles, both using IGBT-based technology for fast and precise reactive power compensation.
Key difference: STATCOMs are used in high-voltage transmission systems, while SVGs are more common in low- to medium-voltage industrial and commercial applications.
Modern SVGs use IGBT (Insulated Gate Bipolar Transistor) technology, with response times of ≤5ms, much faster than traditional thyristor-switched capacitor (TSC) or Static Var Compensator (SVC) systems, making them suitable for rapidly changing reactive power demands.
SVG is recommended for rapidly changing loads, while TSC is better for more stable load conditions. They can also be used together for optimal performance.
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Yes, SVG is widely used in wind power, solar PV, and energy storage systems, providing benefits such as:
Reactive power compensation to improve power factor, ensuring compliance with grid standards (e.g., IEEE-519).
Balancing three-phase currents, reducing grid instability.
Minimizing voltage fluctuations and flicker, particularly in wind and solar systems with variable power output.
SVG does not directly save energy, but it can reduce power losses, leading to indirect cost savings by:
Improving power factor, avoiding penalties for reactive power usage.
Reducing line losses, and decreasing the load on transformers, cables, and switchgear.
Stabilizing voltage, enhancing equipment efficiency and lifespan.
The required SVG capacity (kVAR) depends on the reactive power demand of the system. General guidelines:
Measure the system’s reactive power requirement (kVAR).
Select an SVG with a rating slightly higher than the peak reactive demand to prevent under-compensation.
In complex load environments, distributed compensation (multiple SVG units) may be more effective.
Yes, SVGs support modular parallel operation, allowing for flexible expansion as power demands grow. Example applications:
Scaling up capacity by adding more SVG units.
Distributed installation in different electrical branches to optimize compensation efficiency.
SVG should be installed as close to the load as possible to maximize compensation efficiency. Typical installation locations:
At substations or distribution panels (centralized compensation).
Near production areas or load centers (decentralized compensation).
Close to specific equipment (such as VFDs, elevators, welding machines).
SVGs primarily use electronic components, with an expected lifespan of 15-20 years, significantly longer than traditional capacitor banks.
Maintenance includes periodic cooling system checks, dust cleaning, and monitoring operational status, but overall maintenance is minimal.
SVGs help reduce power losses, improve power factor, and avoid penalties, leading to an ROI of 1-3 years, depending on:
Electricity tariffs and power factor penalty policies.
Cost savings from reduced reactive power charges.
Lower maintenance and extended equipment lifespan.
SVG is ideal for industries with dynamic loads, fluctuating power factors, or high reactive power demand, such as:
✅ VFDs, large motors, data centers, steel, chemical plants
✅ Welders, elevators, cranes, port equipment
✅ Solar PV, wind power, energy storage systems
SVG can be used alone or combined with AHF, TSC, or SVC to provide a comprehensive power quality solution.
Tags: dynamic reactive power compensation, power quality device, SVG Static Var Generator, Capacitor Bank.
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