Calculations that come up on site, in the browser.
Small, focused calculators for the arithmetic that gets done on the back of a work pack — free, no sign-up, and no data leaves your browser. Every tool states the method it uses, the assumptions behind it and where it stops being valid, because a calculator that doesn't show its working is not one you should make a decision with.
A reading taken on a cold morning is not comparable with a rated filling pressure quoted at 20 °C until it has been corrected.
Corrects sealed-enclosure gas pressure between any two temperatures, in either direction. Absolute or gauge input with adjustable atmospheric pressure, in bar, MPa, kPa or psi, with a live plot and a printable table across the −40 to +60 °C range. Valid for dry air, nitrogen, oxygen and carbon dioxide up to about 10 bar absolute; not for SF6 at service density.
Below the liquefaction point, pressure stops tracking density — and the density switch stops meaning what it is supposed to mean.
Finds the temperature at which SF6 begins to condense at a given filling pressure, and the margin between that point and the coldest temperature the equipment will see. Uses the Funke, Kleinrahm and Wagner (2009) vapour-pressure equation, verified against the published saturation table to within 0.01 % from −50 to +45 °C. Live saturation curve showing the gas-only and liquid-present regions, and a printable table.
Relative dielectric strength of SF6/N2, SF6/air and SF6/CO2 mixtures against SF6 content, cross-checked across four independent published models — an empirical power law, a mixing rule, an ionisation-coefficient calculation and a transport-theory critical-field table — with the uniform, coaxial and point–plane field utilisation factors. Where the models disagree is itself the useful output.
Unit conversion is the easy half. The half that causes trouble is the zero point — and on a 6 bar system that is a 17 % error.
Converts between MPa, bar, kPa, Pa, mbar, psi, atm, mmHg and kgf/cm², showing every unit at once with absolute and gauge side by side. Atmospheric pressure is adjustable for altitude, and the conversion factors used are listed with their definitions.
Partial pressures and filling sequence for SF6/N2 and SF6/CF4 mixtures at a target ratio and total pressure, with the liquefaction temperature of the resulting mixture — the reason mixtures are used in cold climates in the first place.
Strength scales with pressure to the power 0.71, so a gas at 40 % of the strength of SF6 needs not 2.5 but 3.6 times the pressure.
Puts dielectric strength, global warming potential and boiling point for SF6, CO2, air/N2 and C4F7N/CO2 mixtures on one screen, and calculates the pressure an alternative would need to match SF6 at a given operating pressure. Relative strengths are indicative literature-consistent values for scoping a substitution, not design data.
More tools are being added. If there is a calculation you find yourself doing on paper in the field, tell us — that is where this list comes from.
HVPACE is the trading name of Power Asset Condition Engineering Limited, a New Zealand-based supplier of test and diagnostic instruments and selected specialty equipment — such as cable sheath voltage limiters and other low-volume, mission-critical components — for high-voltage power systems. Backed by hands-on engineering expertise, including field-tested condition assessment techniques and AI-based signal analysis, we support customers with diagnostic guidance, methodology development and fault investigation.
These tools are free to use and free to share. They are provided for reference and cross-checking, and do not replace equipment manufacturers' data, nameplate values or operating instructions.
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