Capacitor Bank
Specification
Voltage: Up to 690V AC, 50Hz
Reactive power: Fixed: 5–1000 kVAr per bank; APFC: multi-step up to 2000 kVAr
Capacitor standard: IEC 60831 (self-healing film capacitors)
Controller: Circutor, Lovato, or Schneider APFC relay (12-step auto)
Detuning reactor: 5.67% or 7% detuning (p=0.14 or 0.07 options)
Switching: Contactor (standard) or thyristor static switch (fast switching)
Enclosure: Wall-mount or floor-standing; IP32, IP54
Earthing: Capacitor discharge resistors; earth bar with test terminal
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Capacitor Bank & Power Factor Correction Panels in UAE Fixed and Automatic APFC
Poor power factor results in higher electricity bills, increased current draw on cables and switchgear, and potential DEWA reactive power penalties for commercial and industrial consumers in the UAE. Power factor correction (PFC) capacitor banks compensate for reactive power demand by injecting reactive current locally reducing the apparent power drawn from the utility, improving system efficiency, and eliminating reactive power charges. Team Switchgear and Control LLC designs and manufactures fixed and automatic power factor correction (APFC) capacitor banks from our Dubai facility, built to IEC 61439 and IEC 60831 standards.
Fixed vs Automatic Power Factor Correction
Fixed capacitor banks: A fixed reactive power compensation value is permanently switched into the circuit. Cost-effective and simple for loads with stable, predictable reactive power demand such as single motors, transformers, and fixed lighting installations.
Automatic PFC (APFC): A power factor controller continuously monitors the system power factor and switches capacitor steps in or out to maintain the target power factor (typically 0.95 lagging or better). Required for facilities with varying loads commercial buildings, industrial plants, and facilities with multiple motor drives.
Detuned Capacitor Banks
In facilities with significant harmonic distortion from VFDs, UPS systems, and non-linear loads, standard capacitor banks can be overloaded or damaged by harmonic resonance. Detuned (reactor-protected) capacitor banks include series reactors that shift the resonant frequency away from dominant harmonic orders (5th, 7th), protecting the capacitors and preventing harmonic amplification. We supply detuned capacitor banks as standard for any facility with more than 20% non-linear load.
Applications
- Commercial buildings improving power factor to avoid DEWA reactive power penalties
- Industrial plants reducing reactive power demand on LV switchgear and cables
- Hospitals and data centres improving power quality and reducing cable losses
- Hotels and retail centralised APFC for building LV main switchboard
What power factor does DEWA require, and what are the penalties?
DEWA tariff regulations require commercial and industrial consumers to maintain a power factor of 0.85 or above. Consumers falling below this threshold are subject to a reactive power penalty charge on their monthly electricity bill. The penalty is typically applied to the total kVArh consumed below the 0.85 threshold. Improving power factor to 0.95 or above typically eliminates the penalty charge entirely and may also reduce the maximum demand kVA charge component of the tariff.
How do I know what size capacitor bank I need?
The required reactive power compensation (in kVAr) is calculated from the measured power factor, total kW load, and the target power factor. The formula is: Required kVAr = kW × (tan φ₁ − tan φ₂), where φ₁ is the current power factor angle and φ₂ is the target power factor angle. We carry out a site power factor survey using a power analyser, identify the load profile across operating hours, and size the capacitor bank (fixed or APFC) to achieve the target power factor at minimum capital cost.