Insulation coordination calculator — standard method (IEC 60071)

Enter the system voltage, the pollution degree, the site altitude and, if you have it, the surge-arrester residual voltage. The engine looks up the standard insulation level, applies the altitude correction and returns the withstand voltage you need together with the smallest standard level that meets it. Everything is looked up or computed, never assumed.

Inputs (what you can fill in)

All fields are yours to fill; none is silently defaulted. Voltage/altitude/pollution degree drive the lookup and the real calculation; the arrester residual voltage is the easiest value to take from the arrester datasheet.

RequiredRecommendedLeft bar: blue = required, gold = recommended. Optional and advanced fields are collapsed by default.

System nominal voltage (kV)Required= 10 kVEquipment highest voltage Um (kV)OptionalSite altitude H (m)Required= 3000 m

Altitude correction basis

Leave a field blank and the corresponding result is shown as "Not available" - it is never rendered as zero.

Scope and boundary

Three different things on one page, please do not mix them: (1) Um to LI/AC is a LOOKUP from the standard tables - the platform builds no levels of its own; (2) the altitude factor Ka and the required-withstand chain are REAL CALCULATIONS, but K_pr, K_c and K_s are your values, not built in; (3) pollution degree to creepage distance and the air clearance are NEEDS-STANDARD-TABLE items and no number is given. This page does not produce U_rp, does not do switching impulse (Um > 72.5 kV), and does not distinguish internal from external insulation beyond the Ka note. Output is a selection/check reference: it is not a type-test conclusion and not a contractual technical agreement; the final insulation level is per the manufacturer parameter sheet and the test report.

VerdictNot calculated

Not calculated yet - press Calculate.

Key figures

Equipment highest voltage Um

—kV

Standard LI

—kV

Standard AC

—kV

Altitude factor Ka

—

Corrected U_rw,alt

—kV

Smallest standard level that meets it

—

Pollution degree to creepage distance: Needs the standard table: the platform has not loaded IEC 60815-1 / GB/T 26218.1, so no creepage value is given (making one up would put external insulation at risk).

Air clearance from withstand voltage: Needs the standard table: the minimum air clearance table (GB/T 1094.3-2017 / IEC 60076-3:2013, IEC 60071-2 Annex A) has not been loaded, so no clearance value is given. The corrected required withstand voltage above is what you look the clearance up with.

Needs a system study: the representative overvoltage U_rp comes from a system overvoltage study (statistical / EMTP type), which this calculator does not produce. Enter it if your study provides it.

The factor applies to EXTERNAL insulation only; internal insulation does not take Ka.

Figures

Altitude factor Ka vs altitude H

Not calculated yet.

Standard lightning-impulse levels and the requirement

Not calculated yet.

Units (declared and echoed)

Not calculated

Basis and sources

Basis: standard levels per IEC 60071-1 (Table 2, same as GB/T 1094.3-2017); rated voltage to Um per IEC 60038 / GB/T 156-2017; altitude correction per IEC 60071-2 Annex H (m = 1 for power frequency and lightning impulse); arrester coordination ratio K_pr and the coordination/safety factors K_c/K_s are YOUR values (not built in). Pollution degree to creepage distance and air clearance need the standard tables (IEC 60815-1 / GB/T 26218.1 and GB/T 1094.3-2017), which this platform has not yet loaded.