Calculator #005 Power factor correction IEC 60831 IEC 61921 Pro-ready engineering

Reactive Power Compensation Calculator - Capacitor Bank Sizing

International preliminary engineering tool for capacitor bank sizing. It calculates kvar demand, distinguishes simultaneous loads from alternative operating cases, proposes a step bank, flags undersizing / overcompensation / harmonic risk, and generates a DOCX report with explicit engineering statuses and limitations.
Developed by the ieccalc.com engineering team
Join the discussion -
Electrical Designers Middle East
Advertisement slot #1Reserved integration area
Advertisement slot #2Reserved integration area
Project settings and basic network data
Workflow: fill only this basic project block and load cases first. The calculator will size kvar, propose bank options, then auto-preselect protection and cable. Advanced studies are collapsed below.

The design current factor is 1,43 by default, which is the figure IEC 60831-1:2014 Clause 21 states itself: a capacitor unit must be suitable for continuous operation at 1,3 times the current at rated voltage and frequency, and "taking into account the capacitance tolerances of 1,1 C(N), the maximum current can reach 1,43 I(N)". The two numbers answer different questions. 1,30 is what the capacitor has to withstand; 1,43 is the current that can actually flow, so it is what the switching device, the cables, the CTs and the enclosure have to be sized for. Use 1,30 only where the capacitance tolerance is separately accounted for.

Qc = P x (tan(arccos(PF1)) - tan(arccos(PF2))); Qc_required = Qc_raw x (1 + sizing margin / 100)
Design current factor is configurable and is not stated as universally mandatory. Verify final device, fuse, cable and busbar ratings using manufacturer data, applicable standards and project requirements.
Compensation technology selection PRO / FACTS
Load cases
The capacitor bank sizing depends on whether the listed load cases are simultaneous operating loads or alternative operating scenarios. This assumption shall be confirmed by the designer.
Step bank optimization PRO
Professional optimization, controller and project deliverable settings PRO
Use explicit demo marking instead of detecting words inside project names.
Professional engineering dashboard
Multi-option engineering comparison
Load profile and step response simulation
Manufacturer-neutral specification and issue lists
Calculation result and equipment options not checked
Automatic protection and cable preselection
Minimum load overcompensation check PRO
Large load rejection and controller-state simulation PRO
Voltage rise risk and harmonic screening PRO
Protection, cable and heat loss preliminary inputs PRO
Economic assessment PRO
Imported equipment database and model suggestions PRO
The library holds the series; the kvar in every suggestion below is this project’s requirement, not a catalogue rating.
The database is a preliminary international catalogue-family selector, not a live stock or exact order-code configurator. Exact model, voltage, duty class, enclosure, country approval and accessories shall be verified with manufacturer or supplier documentation before procurement.
Calculation summary
Engineering visuals
Input completeness matrix and required actions
FREE example mode and PRO feature split
EXAMPLE The free example is locked to the built-in demonstration data. The user may press Recalculate and download the example DOCX report without payment; exported report is marked EXAMPLE in red.
ModuleAccessImplementation hookPurpose
Basic Qc, Ic, PF and kVA comparisonFREEalways enabledPreliminary sizing lead calculation.
Basic undersized warning and THDi warningFREEvisible on main screenCritical warnings are not hidden in report only.
Load case combination modesPROdata-pro="combination"Simultaneous, alternative or custom simultaneity.
Step bank optimization and manufacturer templatesPROdata-pro="steps"Practical controller step proposal with status.
Overcompensation, harmonics, protection, cable, ventilation, economicsPROsection-specific data-pro hooksProfessional engineering checks and placeholders.
Professional DOCX / PDF / schedule exportsPROdocxBtn, scheduleBtnClient-ready report package.
Glossary and references
Built-in checks
CheckExpectedActualStatus