Static Var Generator (SVG)

InstaSine i - PFC Static Var Generator

i-PFC (Inverter based Power Factor Correction) is trademark name for the Static Var Generators (SVG) developed and manufactured at InstaSine. Making use of advanced controllability of 3-Phase 3-Level IGBT based voltage source inverter architecture, i-PFC SVG does precise power factor and unbalance correction without the need of any passive power factor correction capacitors.

Working Principle of InstaSine i-PFC SVG

  • Excitation control of synchronous machine had been the classical method for power factor control in low and medium voltage systems. In which, a grid connected synchronous machine, acting as a voltage source with series reactance, produces leading VAR (behaving as a capacitor) when over excited, and lagging VAR (behaves as an inductor) when under excited. By controlling its excitation voltage, reactive power output of the synchronous machine can be controlled in a step-less manner in either direction.
  • The i-PFC SVG also act as controlled voltage source with series reactance, principally similar to the grid-connected synchronous machine, however, without any rotating part(s). Internal architecture of i-PFC SVG can be seen in the schematic diagram. The reactive power output of the i-PFC SVG is precisely controlled to the reference value by adjusting waveshape, magnitude and phase angles of the internal AC voltage (with the use of appropriate Pulse Width Modulation technique). The real-time reference value of the reactive power output of the i-PFC SVG is precisely calculated in real-time as per the target power factor entered by the user, and voltage and current values.
  • The i-PFC SVGs are powered with a sophisticated Artificial Neural Network based control algorithm to achieve set power factor within 20 milli seconds, while always working in the background for real-time loss minimization, to achieve improved energy efficiency.
  • The i-PFC SVGs are designed in stackable modular configuration for increased resilience, reliability and redundancy. A robust CAN Bus communication between the i-PFC SVG Modules and Master Display Module enables equal load sharing between all the active modules.
Active Harmonic Filters

i -PFC SVG Features
Technology: i -PFC SVG is a state-of-the-art power factor correction device bosting advanced 3-level inverter architecture, powered by Artificial Intelligence (AI) based control.
Step-less Power Factor Control: Ultra-fast and precise power factor correction capabilities of i -PFC SVG ensures no over or under compensation, resulting near unity power factor operation at the LT/HT incomer.
Bi-directional reactive power compensation: Synchronous condenser like operation of i-PFC SVG allows compensation of both inductive and capacitive reactive power of the loads with ease.
Load current balancing: i -PFC SVGs are also engineered to balance three-phase source currents by compensating the negative sequence part of the load currents.
LT and HT side feedback: i -PFC SVG are compatible with LT or HT Side current sensing, with all groups of transformer configurations. Furthermore, HT side power factor correction from LT side CT sensing is made possible using InstaSine’s Smart-Sense Technology.
Supply voltage independency: low capacity-dependency on supply voltage fluctuations. i-PFC SVG functions as a controlled current source rather than an impedance. Additionally, our units operate, without any problem, even if the supply voltage is highly distorted (up to 15% voltage THD).
Flexibility to site conditions: i - PFC SVGs are compatible with power supply from Grid, DG set, Co-gen and Solar power plants.
Inverter Topology: i -PFC SVG is fostered as 3-Phase 3-Level IGBT based voltage source inverter, among other advantages, helps to reduce the losses and overall size of system.
Modularity: i -PFC SVG’s stackable and modular architecture provides enhanced resilience, reliability and redundancy. Up to 50 modules per CT set can be paralleled.
Response Time: Our sophisticated Artificial Neural Network based control algorithm achieves set power factor within 20 milli-seconds and offers ultra-fast dynamic response time (less than 100 micro-seconds).
Optimized Design: Light in weight, compact in size, quieter in operation while delivering best-in-class performance. Footprint: saves more than 70% of space compared with traditional capacitor banks.
Harsh weather conditions: Designed to operate at 45oC ambient temperature without any derating. PCBs are applied with conformal coating for improved reliability.
Long-lasting: MTBF (mean time between failures) up to 1,00,000 hours.
Best-In-Class Energy Efficiency: i-PFC SVG consists of an intelligent On-The-Fly real-time internal switching loss minimization technique to enhance the converter energy efficiency.
Integrated Best-in-Class HMI Monitor: i-PFC SVG comes with integrated 7-inch TFT touch-screen display to visualize/set the system parameters. Being easy to use it also functions as built-in real-time oscilloscope and power quality analyzer.
Cloud Connectivity: “Connect-Monitor-Control” from anywhere using internet through cloud connectivity.
In-house R&D and manufacturing with better service: The research, development, and the manufacturing activities are fully carried out by InstaSine. This assures guaranteed service even after the end of warranty period.

i -PFC SVG Benefits

  • Near unity displacement power factor operation (on HT or LT side).
  • Negligible gap between the kVAh and kWh units in monthly electricity bills.
  • Balanced three phase currents free from negative sequence component.
  • Reduced energy losses with improved plant efficiency
  • Restored ability of existing electrical infrastructure to operate at full-load capacity
  • No harmonic resonances/amplifications
  • Relatively maintenance free
  • No AC capacitor banks, does not require contactor replacement
  • No capacitor explosion risk and no accidents and/or risk of safety
  • Cost-effective and highly reliable solution

Technical Specifications of i - PFC SVG Module:
Operating Conditions
System Voltage (RMS) 350 - 480 V
System Frequency (Hz) 50 ± 5%
Operating Temperature Range 0 to 45o C (Non-condensing)
Product Specification
Semiconductor Devices IGBTs (3-Level Topology)
Maximum Reactive Power Output @ 480V 125kVAR
Step-less compensation range -100kVAR to +125kVAR
Rated RMS current output 150A
i-Sine AHF configuration 3P3W
Power Factor Correction Yes
Load Current Balancing Yes, Negative Sequence
CT Requirement 3CTs with 1A or 5A Secondary
CT Position Load Side / Source Side
Internal Thermal Losses <2%
Color Black
Integrated Short-Circuit Protection Yes
Dimensions in mm (WxDxH) 800 x 890 x 330
Control and Paralleling:
Controller ARM based MCU
Control Method Adaptive Artificial Neural Network based
Dynamic Response Time 100 micro seconds
Correction Time 10 milli seconds
Parallel Operation Upto 50 modules per CT set
Parallel Communication CAN Bus/Mini-USB
Paralleling Options Master-Slave / Multi-Master
Noise Level <65dB
System Integration
Stackable upto 5 i-PFC modules in each floor mounting 5 rack system.
CT Connections between modules Daisy Chain Type
Display 7” TFT Touch-Screen Display
Software for PC Interface InstaView
Cloud Connectivity Yes
Master Module Dimensions in mm (WxDxH) 800 x 890 x 200

Technical/Performance Comparison - APFC vs APFC+SVG vs Full i-PFC SVG
Functionality/Problems Associated APFC **(Detuned/Not Detuned) Hybrid ## (APFC+SVG/AHF) Full i -PFC SVG
Step-less correction Not Possible Possible Possible
Precisely controlled inverter architecture benefit i -PFC SVGs with step-less reactive power compensation, making them free from over/under compensations. This makes them the ideal solution for maintaining power factors above 0.99 at all times.
Bidirectional Correction Not Possible Part Range Full Range
i - PFC SVGs and only active/SVG part of hybrid solutions, are capable to compensate both inductive and capacitive reactive loads.
Capacitor switching and resultant Voltage surges High High Nil
Full inverter based i -PFC SVGs are free from frequent mechanical operations such as contactor opening and closing (also, free from capacitor charging/discharging). In APFC and hybrid solutions such frequent capacitor switching creates voltage dips/spikes at PCC. These surges may trigger the malfunctioning of sensitive systems connected to the same LT network.
Response time from 0-100% Output Slow (>Few Seconds) Slow (>Few Seconds) Fastest (< 20 Milli Seconds)
During the load changes, i -PFC SVGs can ramp up from 0 to 100% and ramp down from 100% to 0% capacity in less than 20 milli seconds, without causing any transients. Such a feature is most needed at places where frequent start-stop of processes or motors are involved. Hybrid solutions might take few tens of seconds in ramping up and ramping down due to time lags in calculation and switching of corresponding capacitor banks. This hinders their performance in achieving power factors very close to unity.
Harmonic Amplification Chances High High Nil
The i-PFC SVGs cause near-zero current harmonic injection while performing the power factor correction, even if the voltage THD level goes to 15%. Detuned APFC and hybrid solutions cause resonance/amplification of current harmonics which are below their resonance frequencies. And, are highly sensitive to input voltage harmonics. In case of input voltage harmonics above 2-3%, the passive part of APFC panels tend to draw corresponding current harmonics in addition to plant current harmonics. Which is unwanted in true kVAH based tariff structure.
Voltage Dependency of kVAR Capacity High High Low
kVAR capacity of i-PFC SVG is proportional to grid voltage. Detuned APFC and passive part of hybrid solutions kVAR capacities are proportional to square of the voltage. Means, minor voltage fluctuations result in large reactive power swings.
PF and Unbalance correction with 1-Phase and 2-Phase loads Not possible Partly possible Possible
Capability to use the 100% capacity for negative sequence correction, make i-PFC SVGs to be the only contender power factor correction in the presence of large single-phase and two-phase loads.
Maintenance Requirements Very High Very High Low
Having no frequent mechanical operations in i-PFC SVGs make them relatively maintenance free. In detuned APFC or hybrid solutions, there is always a risk of capacitor and/or contactor explosion due to the constant mechanical switching, which is a safety risk.
Footprint Large Medium Small
i-PFC SVG’s minimal footprint saves more than 70% space, compared to the conventional APFC and/or hybrid solutions.

**APFC: automatic power factor correction panels (including detuned and/or non-detuned)

## APFC+SVG: Hybrid solution are the combination of APFC along with a part rated SVG or AHF.


Billing / Savings

1) kWH Billing (old tariff) without i-PFC SVG Installed

Below is the snapshoot of a bill from (one of our clients) for the month of March-2020.

Savings

Analysis of this bill is as follow:

  • Point-1 (#1) in the bill represents 1,48,863 kWH energy consumption by the plant in the month of March-2020.
  • In this particular month the reactive power consumed by the plant was: 40,224 lagging kVAH (#2) and 39,053 leading kVAH (#3).
  • Whereas the recorded kVAH consumption is 1,92,431 kVAH (#4) and total kW and kVA demand are: 614KW (#5) and 690 KVA (#6).
  • In the month of March-2020, power factor in the bill represented displacement power factor, is calculated as below:
  • Savings
  • Whereas the true power factor will be calculated as below:
    Savings
    Difference between the displacement and true power factors above, signify the presence of current harmonics and/or unbalance in the plant load currents.
  • Although kWH consumption (#1) is 1,48,863, the kVAH (#4) is 1,92,431 which is almost 29% higher due to lower true power factor.
  • At the same time, plant’s Maximum kVA demand (#6) of 690 is higher than the Maximum kW demand (#5) of 614. As the Fixed/Demand charges are based on Maximum Demand, at the end it got charged for 690kVA (#7).
  • In KWH billing, the consumer is usually billed based on the billed demand (#7, same as #6), average monthly PF (#8) and total KWH consumption (#9, same as #1).

2) kWH Billing (new tariff) with i-PFC SVG Installed

Savings

Analysis of this bill is as follow:

  • From #1, 1,63,436 kWH energy is consumed by the plant in the month of November-2020.
  • In this particular month the reactive power consumed by the plant was just: 5,125 lagging kVAH (#2) and 4,310 leading kVAH (#3). The significant reduction in both lagging and leading kVAH is due to the installation of i-PFC SVG.
  • The kVAH is consumption is 1,63,764 (#4) which is almost equal (with negligible 0.2% difference) to the plant kWH consumption, that is, 1,63,436 (#1).
  • In KVAH billing, the consumer usually is billed based on the billed demand (#7, same as #6) and total KVAH consumption (#9, same as #4).
  • Note that the billed maximum kVA demand of 589kVA (#7) is same as maximum kW demand of 589kW (#5). This directly contribute to savings.
  • The average power factor (#9) for this month was recorded as 0.998 (almost unity).
  • As in earlier case, calculated displacement power factor is as below:
  • Savings
  • Whereas the true power factor will be calculated as below:
    Savings
    The power factor represented in the bill is true power factor.
  • This demonstrate the savings that can be achieved using InstaSine i-PFC SVG through reducing the Billed Demand kVA (#6) and maintaining almost unity power factor (#8) through the month