TDK Electronics · TDK Europe

PQvar™ Presentation

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Static Var Generator (SVG) for higher energy efficiency and load balancing

The EPCOS Static Var Generator PQvar makes energy more efficient by stepless power factor correction.


PQvar is a new approach to power factor correction and load balancing. The modular design and compact structure make it the ideal solution for active stepless PFC and load balancing in industrial applications and commercial buildings. Compared to conventional PFC systems, PQvar offers a response time of less than 15 ms and a dynamic reaction time of less than 50 µs. It can compensate both inductive and capacitive loads and achieve a power factor of 0.99.

By means of the Advanced Multi Controller (AMC), PQvar can be combined with conventional passive LV-compensation stages. The MV-level is covered by systems for 6 kV, 10 kV and 35 kV, with outputs of between 2000 kvar and 12,000 kvar. All modules are available for 3-phase grids with or without neutral conductors. Depending on customer requirements for output and size, the modules are designed as slide-in units for control cabinets, as wall-mounted units for LV-systems or as control cabinets for MV-systems.

Compensation of reactive power with SVG PQvar Series

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SVG PQvar Series load balancing for 3P3W and 3P4W

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The 3P3W (three phase three wire) PQvar can balance load currents between phases, the 3P4W (three phase four wire) type may additionally reduce neutral conductor currents. Therefore, PQvar is perfect solution at applications having reactive power requirements along with unbalanced loads, which is the case at e.g electricity distribution lines in rural areas, or different industrial applications.

PQvar at a glance:


  • Controllable reactive current source
  • Extremely rapid dynamic compensation reaction time of less than 50 µs and a state response time of less than 15 ms
  • Active compensation device for usage without capacitors or reactors to avoid resonance conditions
  • Compensation of both inductive and capacitive reactive power
  • Provides load balancing
  • Installation with conventional capacitor banks possible
  • Available for low-voltage and medium-voltage levels
  • Wide range of compensation outputs from 30 kvar to 12,000 kvar

Typical applications

Applications with the need for rapid reactive power compensation, e.g.:

  • Data centers
  • UPS systems
  • Renewable power generation (e.g. photovoltaics and wind turbines)
  • Industrial production machines
  • Electrical welding systems
  • Plastic industry machinery (e.g. extruders, injection molders)

Safety features

  • Highest safety and reliability
  • Overload protection
  • Internal short-circuit protection
  • Overheating protection
  • Overvoltage and undervoltage protection
  • Inverter bridge protection
  • Fan fault alarm

Technical data

Low-voltage SVG PQvar series 400 V690 V
Rated voltage400 V; –40 … +20%690 V; –30 … +15%
Mains frequency50/60 Hz (range: 45 … 63 Hz)
Parallel operationUnlimited
Response time< 15 ms
Overall efficiency> 97%
Power grid structure3P3W / 3P4W
Current transformerss150/5 … 10000/5
Circuit topology3-level
Single-module compensation capacity30/50 kvar100/200kvar50/75 kvar95/110 kvar
Module net weight21/35 kg48/66 kg66/66 kg66/66 kg
Dimensions (W × D × H)30 kvar: 440 × 445 × 150 mm (module)
50 kvar: 500 × 510 × 190 mm (module)
100 kvar: 500 × 470 × 270 mm (module)
200 kvar: 500 × 650 × 350 mm (module)
50 kvar: 544 × 640 × 250 mm (module)
75 kvar: 544 × 640 × 250 mm (module)
95 kvar: 544 × 640 × 250 mm (module)
110 kvar: 544 × 640 × 250 mm (module)
Cooling modeSmart air cooling: 220 L/secSmart air cooling: 405 L/secSmart air cooling: 220 L/secSmart air cooling: 405 L/sec
Target power factorAdjustable from –1 … +1
Cabinet mountingFloor-mounted, wall-mounted
Communication portsRS485, CAN, and network port
Communication protocolsModbus and PMBus
Noise level< 65 dB (depending on the model)
Protection functionsOvervoltage, undervoltage, short-circuit, inverter bridge inverse, over-compensation
Operating temperature–10 … +40 °C, other temperature ranges upon request
Relative humidity5 … 95%, non-condensing
Protection classIP20 (other IP classes are customizable)
Panel colorRAL7035 light grey
Altitude1500 m, 1% derating per 100 m plus
General safety requirements for SVG PQvar Series use and operation areaEN 50178:1997/ IEC 50178:1997
EMC requirementsEN 61000_6_2(2005)/ EN55011, GROUP1, CLASS A
IEC 61000_6_2(1999)/ CISPR11, GROUP1, CLASS A
Performance requirementsEN 50091-3/ IEC 62040-3/ AS 62040-3(VFI SS 111)


Fast reaction

Extremely rapid reactive power generation, in order to achieve target PF, right at the SVG PQvar Series switch on.

 Pic PQvar Chart Compensation_1

Perfect compensation

SVG PQvar Series identifies the system reactive power requirement and generates a reactive current same in magnitude but opposite in phase to ensure perfect compensation result.

 Pic PQvar Chart Compensation_2

High performance

  • Reactive power compensation up to cos ϕ = 0.99
  • Load balancing between phases
  • Fully inductive and capacitive current

Fast compensation response

  • Compensation in real-time with steady state response time less than 15 ms
  • Immediate load change of reaction time less than 50 μs
  • Accurate power factor correction, no over-compensation and under-compensation, no system harmonic resonance
  • Capacity will not be affected in case of system voltage drop, output will be equal to rated capacity

Real-time tracking

If system reactive current changes, SVG PQvar Series also can generate dynamic real time compen-sation current to satisfy the changing power system requirement.

 Pic PQvar Chart Compensation_3

Reverse and overlapping

The reversed waveform of reactive current generated by SVG PQvar Series overlaps with the power sys-tem reactive current.

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Modular design

The SVG PQvar Series is based on a unit assembly system.

  • Maximum rated capacity of one single module is 200 kvar
  • Customizable cabinet and maximum output capacity of a cabinet is 800 kvar
  • Easily to operate, maintain and transport

Different combinations

  • SVG PQvar Series
  • SVG PQvar Series with capacitor banks
  • SVG PQvar Series with AHF (reactive power and harmonic compensation)

Hybrid PFC

Using the Advanced Multi Controller (AMC), the PQvar system can be combined with conventional passive low-voltage compensation stages.

SVG PQvar Series plus discrete compensation (SVG modules plus LC reactive compensation)

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Operating principle of SVG with LC banks and AMC

Performance comparison between SVG with LC banks discrete and traditional reactive compensation

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Technical Data

Hybrid PFC-Solution - SVG PQvar and classic PFC by Advanced Multi Controller (AMC)
Operating voltage24 V DC
Compensation performance
Target PF–1 … +1
Reactive power compensation rate> 99% (target PF is 1)
Response time< 15 ms
Reaction time< 50 μs
Capacitor switching performance
Compensation methodThree-phase/ split/ mixed compensation
Capacitance coding methodOptional
Capacitor switching methodStack/ normal/ cycle/ individual
Switching mannerAuto/ manual
External ports
RS485 port 1Communication with SVG modules
RS485 port 2External communication port
Network portExternal communication port
USB portCode upgrading port
Temperature detectionMeasuring system’s operating temperature or ambient temperature
Fan controlling dry contactControlling SVC cooling fan
Alarm indicator dry contactFor reserved external alarm indicator
Control output - contact stepsControl outputs, up to 18 at most
Contact support: 120 V AC / 10 A, 220 V AC / 8 A, 400 V AC / 3 A, 110 V DC / 0.2 A, 60 V DC / 0.6 A, 24 V DC / 5 A
Level signal: 12 V DC / 30 mA
Reserved dry contactOne input / one output
Communication protocolModbus
Protection functionsUndervoltage, overvoltage, underfrequency, overfrequency, phase failure, high harmonic voltage,SVG overload, SVG overtemperature
Display7” touch screen
Installation requirements
Power consumption< 25 W
Protection classIP41 for the front panel, and IP20 for the rear panel
Operating environment
Ambiet temperature–20 … +60 °C
Altitude≤ 2500 m
Humidity≤ 95%
Storage temperature–40 … +70 °C
CT ratio150/5 … 10000/5