From the device list of the sample 132/33 kV substation to a numbered port plan, a cable schedule with lengths and a checked asset register — and the three problems the checks find.
| Station bus | SW1 (132 kV bays: P132_Q01, P132_Q02, P87T_T1) and SW2 (GW1, HMI1, GPS1, BCU_J01), 8 ports each, star with SW1 as core |
| Process bus | PB1, 8 ports: GPS1, P132_Q01, P87T_T1, MU_Q01, MU_T1 |
| Cable rules | Prefix NC; Cat6A copper 15 m, OM3 fibre 60 m, uplinks OM3 30 m |
| Measured routes | BCU_J01 in the 33 kV building: 115 m; MU_Q01 180 m and MU_T1 220 m to the switchyard kiosks |
| Asset data | Entered for all 12 assets; MU_Q01 has no serial number yet |
The sample project loads with these values, so every step can be repeated in the tool.
Devices take the ports from port 1 in the order of the device list; uplinks take the top ports so device ports stay contiguous when devices are added.
| Switch | Ports used | Assignment |
|---|---|---|
| SW1 | 4 / 8 | 1–3 P132_Q01, P132_Q02, P87T_T1; 8 uplink from SW2 |
| SW2 | 5 / 8 | 1–4 GW1, HMI1, GPS1, BCU_J01; 8 uplink to SW1 |
| PB1 | 5 / 8 | 1–5 GPS1, P132_Q01, P87T_T1, MU_Q01, MU_T1 |
Station bus devices default to copper; the process bus, merging units and switch-to-switch links default to multimode fibre.
Twisted-pair Ethernet is limited to a 100 m channel (IEEE 802.3, ISO/IEC 11801). 100BASE-FX on multimode fibre reaches about 2 km.
The VLAN membership uses the same port numbers. On SW2, port 4 (BCU_J01) carries GOOSE VLAN 10 tagged because BCU_J01 publishes and subscribes to GOOSE; GW1, HMI1 and GPS1 need only the untagged data VLAN. Ports 5–7 are unused and are shut down in the template.
The register combines the design (IP addresses, switch ports, VLANs) with the asset data. The checks look for duplicate serials, MAC and IP addresses, multicast MACs entered as device MACs, and models running different firmware.
Two protection relays of the same model on different firmware can behave differently in GOOSE, reporting or settings files. Either upgrade P132_Q02 or record why both versions are approved.
| Check | Requirement | Actual | Status |
|---|---|---|---|
| Every device has a switch port | Yes | 9 devices, 13 cables | ✓ PASS |
| Switch port capacity | Used ≤ ports | SW1 4/8, SW2 5/8, PB1 5/8 | ✓ PASS |
| Copper length NC-SB-007 | ≤ 100 m | 115 m | ✗ FAIL |
| Fibre lengths (process bus) | ≤ 2 000 m at 100 Mb/s | max 220 m | ✓ PASS |
| One firmware per model | Yes | DP-700: 2 versions | ✗ FAIL |
Key insight: Generate the port plan, cable schedule and switch configuration from one inventory, so a moved device changes all three together.
Every input in this example is editable in the live calculator — no signup needed.
Open SCL NetStudio (IEC 61850 network design) calculator →Device ports stay in one block from port 1, so adding a device does not renumber the uplinks — and the cable to the core switch keeps its port.
Every device link and uplink is doubled: cable IDs end in A and B, and the twin switches of LAN A and LAN B use the same port numbers.
Yes. Export the register, fill in panel, manufacturer, model, firmware, serial and MAC in Excel, save as CSV and import it; rows are matched by tag.