Static VAr Compensator Solutions

Premier Automation manufactures Solid State Valves and Control Systems designed to operate filtered capacitors. Systems can be rated for direct connection from 1,200 to 13,800 volts AC, 50 or 60 Hz. Systems using these parts provide power system voltage stability, adjusting volts/VARS on each phase each cycle, operating billions of times without mechanical wear. Premier Automation also provides application expertise across hundreds of applications and, if preferred, complete turnkey solutions.

What is a Static VAr Compensator?

A Static VAr Compensator or SVC can be thought of as a “fast, local supply of VAr’s”. They belong to the flexible alternating current transmission systems or FACTS device family, primarily designed to supply a precise and adjustable amount of reactive power to the connected system.

The term “static” within SVCs corresponds to the absence of any moving parts within the device, as SVCs use thyristor switches to stabilize voltage by injecting/consuming the required amount of reactive power. How does this occur?

  • Under capacitive loading, the thyristor-controller reactors come into effect, consuming VAr’s from the system to lower the voltage.
  • Under inductive loading, the thyristor-controlled capacitors are switched in, resulting in a higher system voltage.

Furthermore, an SVC can monitor and respond to changes in phase angles and excessive harmonics.

A simple SVC arrangement is as follows:

Since an SVC is a solid-state device, it can operate at very high frequencies, such as 60 times a second, making its operation nearly instantaneous. In addition, it holds the following characteristics:

  • Transient free operation
  • Can be installed outside the plant, and requires no environmental conditioning equipment
  • Hold the ability to handle highly imbalanced loads such as welding and furnaces
  • Does not require PLC controls and sync transfer packages
  • Simple maintenance and comprehension

An SVC is classified as a “Made to Order” equipment, meaning it is assembled from standard controls, solid-state filters, and capacitors with the end-user providing specific inputs depending on the application so that it can be tailored accordingly.

An SVC’s capacity is identified as the largest level of compensation the SVC will need to apply at any given time. Another factor that’s vital in determining the size of the SVC is its voltage resolution, which depends on the application and proposal location. For example, it may be 2–3% for motor starting applications, and 1% or less for continuous motor applications.

Through identification of these parameters, tweaks can be made to the SVC so it fulfills its specific purpose.

Voltage Stability

Who needs it?

Whenever voltages changes are big enough to affect customers [or power delivery systems] and too fast for a conventional remedy, a Solid State Volt/VAR system is called for. Traditionally called Static VAr Compensators [SVCs] or Thyristor-Switched Capacitor Systems [TSCs], they can address most voltage flicker or voltage sag, whether caused by utilities or by large power customers.

Utilities traditionally purchase a limited number of large Solid State Volt/VAR systems. Industrial Power Users purchase more systems, which vary in capacity from small to large and vary in application voltage from 5 to 15 kV.

Benefits of SVCs

Power Transfer Capacity

An SVC improves the power factor of electricity flowing through the grid, directly reducing the amount of current as well as the amount of utility bills. The reduction in power means network units such as transformers, cables, and distribution plants can operate at rated or below-rated values, resulting in elongated lifespan. This also allows plants to comply with rules set forth by distribution and transmission companies with respect to the consumption of reactive power. This also cuts down huge amounts of penalties.

Flicker Reduction

When reactive power varies rapidly, it causes voltage fluctuations to occur at points of common coupling. The most common sight of voltage fluctuations is flickering of lights. This can become a point of concern if the workers rely on well-established lighting to carry out their day-to-day tasks. A Static VAR Compensator can reduce this flicker.

Ease of Use

An SVC can be made operational in highly environmentally challenging situations. They don’t require room inside the plant floor, and can be installed outside for minimal maintenance costs. The operation is near instantaneous due to its solid-state build, allowing it to operate 60 times a second. It’s ability to ward off harmonics makes it a top contender for reactive power control, something illustrated in the diagram below and explained in the next section.

System Integration

Getting from our unique components [solid state switches and controls] to a Solid State Volt/VAR System System is all about system integration.  Doing that well requires three elements:

  • Analysis of exactly what’s required for the system.  This includes determining how large and complex it needs to be.  This work is performed using industry-standard analysis techniques based on IEEE-519 and 1452, based on customer and utiity information. This can be done by us, or the customer’s  consultant, in which case we review his study and findings.
  • A decision on the final system design and purchased parts.  These include certified components (circuit breakers, fuses, capacitors, reactors) from major vendors like ABB, GE and Eaton, for a design compliant with NEMA, IEEE and IEC standards.
    Once customer approval is received…
  • A job proceeding smoothly to system assembly, completion, inspection, and test.