CHITEK provides reactive support and harmonic control for utility and distribution networks using SVG for voltage and power factor, and AHF where industrial or traction loads inject harmonics. Distributed generation, long feeders and EV clusters each stress the network differently, so ratings are set from measurements at the point of common coupling.
Transmission and distribution networks carry the combined effect of everything downstream: industrial harmonics, traction unbalance, distributed generation and long-line reactive loss. The usual CHITEK arrangement is an SVG on the busbar for voltage and reactive support, with AHF on the feeders that carry the worst harmonic load.
Reviewed by the CHITEK power quality engineering team · Last updated
On utility and distribution networks the two devices address different network constraints, and both are normally specified together at the planning stage.
| Aspect | AHF (Active Harmonic Filter) | SVG (Static Var Generator) |
|---|---|---|
| What it does | Injects a compensating current that cancels the harmonic current drawn by non-linear loads. | Supplies or absorbs reactive power continuously to hold power factor and support voltage. |
| Primary target | Current distortion (THDi) and harmonic spectrum at the point of common coupling. | Power factor, voltage fluctuation and reactive demand across the load cycle. |
| Typical trigger | VFD banks, rectifiers, welding sets, induction furnaces, LED drivers, UPS rectifiers. | Low or swinging power factor, voltage sag and rise, weak or long feeders, EV load steps. |
| Behaviour at light load | Compensation scales with the measured harmonic current, so output falls as load falls. | Holds output as required to reach the target power factor even at near-zero active load. |
| Use in this sector | Harmonic correction at feeders where industrial or traction loads inject distortion into the network. | Reactive support and voltage control on long feeders, at DG tie-points and at EV charging clusters. |
Network studies set the targets; the equipment ratings follow from the study rather than from a template.
Substation / Distribution / Rural Upgrade
Harmonic Injection from industrial & traction loads
>10%
THD
Grid Disturbance from DG interconnection
±10%
Voltage Fluct.
Long-distance transfer reactive loss
< 0.9
End V (pu)
City Center / Development Zone / Old Residential
Impact surge from fast-charging clusters
120kW+
Load Step
Phase imbalance from single-phase loads
>8%
Unbalance
Capacitive reactive from underground cables
Leading
PF > 0.95
Campus / Island / Remote Area
Harmonic stacking from PV + wind + storage
>12%
THD
Reactive fluctuation from charge/discharge
PF Swing
0.7~1.0
Voltage sag during island/grid transition
>20%
Sag Depth
Each case below is written up the same way: what the site was, what the survey measured before anything was specified, what was installed, and what the acceptance test showed afterwards. Projects marked Typical Configuration are illustrative — sizing for those always starts from a site survey rather than from the table.
Typical Configuration · Power Grid
Illustrative configuration — sizing starts from a site power-quality survey
An illustrative arrangement for a substation or rural feeder upgrade: SVG on the 35 kV / 10 kV busbar for reactive and voltage support, with AHF placed only on the feeders carrying the worst harmonic load.
For substations serving a mix of industrial and traction load, the usual arrangement is an SVG on the busbar for reactive voltage support plus AHF on the critical feeders for harmonics. Ratings are set by a survey, not by a template — the quantities below are a starting point only.
Illustrative configuration — not a specific delivered project. Reference projects in this sector are available on request.
SVG on the busbar for reactive voltage support, AHF on the specific feeders with the highest harmonic load. Treating an entire station for harmonics is rarely economic.
Reactive loss over a long line. As current rises, both the resistive and the reactive drop grow, and the voltage at the far end falls out of the usable band. Reactive support near the load end is usually more effective than raising the source voltage.
Yes. Reverse power flow raises voltage at the connection point and inverters add switching harmonics. Protection coordination and tap changer behaviour both need rechecking when DG capacity grows.
Yes. Cable capacitance generates reactive power at light load and can push the measured power factor leading, which raises voltage and stresses insulation. It also creates a parallel resonance risk with the transformer inductance.
Every project on this page started with a measured survey. Send us your single-line diagram and load list and we will tell you what we would measure first.
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