// engineering utilities

🧮 Calculators

Practical IEC 61850 and substation engineering calculators. Results are indicative — always verify against your project specifications and the applicable IEC standard.

Min Time T₀ (ms)

Max Time (ms)

Results will appear here.

Intervals double each retransmission from T₀ until maxTime is reached. TAL = 2× current interval.

APPID value (decimal or 0x hex)

Frame Type

Enter an APPID to validate.

Per IEC 61850-8-1 Ed. 2. APPID must be unique within each VLAN segment.

TCI Hex Value (4 hex digits, e.g. A001)

Enter a 4-hex-digit TCI value.

TCI = PCP (3 bits) + DEI (1 bit) + VID (12 bits). GOOSE requires PCP ≥ 4.

8-byte UtcTime (hex, space-separated)

Paste the 8 hex bytes from a GOOSE frame.

Bytes 0–3: seconds since 1970-01-01 00:00:00 UTC. Bytes 4–6: sub-second (fraction of 2²⁴). Byte 7: quality flags.

CT Ratio (e.g. 1000/5)

Secondary (A)

Lead Resistance (Ω)

Relay Burden (VA)

CT Class / ALF

Fill in CT parameters above.

Checks whether the CT secondary burden is within the rated burden for the selected class.

Number of GoCBs

Avg Frame Size (bytes)

Heartbeat Interval (ms)

Simultaneous State Changes

Fill in parameters above.

Steady-state heartbeat load + worst-case burst on simultaneous state changes (6 retransmissions modelled).

IED Name

Logical Device

Logical Node

FC (Functional Constraint)

Data Object

Data Attribute (optional)

Fill in fields above.

Builds an IEC 61850 object reference in the form IEDName/LDname/LNname.DOname.DAname[FC].

confRev in received GOOSE frame

confRev in subscriber's SCD file

Enter both confRev values.

Per IEC 61850-8-1 Ed. 2: mismatch means the publisher was reconfigured after the subscriber's SCD was compiled. Subscriber should raise an alarm.