Build it. Check it. Explain the result.

These are provisional teaching inputs and relay settings. Some example duties fail or remain indeterminate. Reproducing a result demonstrates software use; it does not approve the electrical design or authorize relay settings for service.

1. Draw and organize your circuit

1. Start a new SLD. Set a meaningful drawing title, project, revision and 50 Hz system frequency. Create 132 kV, 33 kV and 11 kV voltage levels. Keep grid snap on.
2. Place three 33 kV buses in one horizontal row. Name them Bus A, Bus B and Bus C. Give each bus a 900 px drawing length and 2000 A continuous-current rating.
3. Place Bus Coupler 1 between Bus A and Bus B, and Bus Coupler 2 between Bus B and Bus C. Rotate each coupler horizontally and connect its terminals to the facing bus ends.
4. Build the two grid incomers, six generator branches and three motor feeders listed below. Follow the video to place, rotate, name, connect and parameterize one example of each equipment type.
5. Duplicate complete branches to save time. Review every copied name, voltage, rating and service state. Copying a branch preserves its electrical data; it does not make those values correct for a different feeder.
6. Align equipment centres before straightening wires. Use vertical feeder paths and horizontal bus-coupler paths. Automatic wire routing removes unnecessary manual bends. Reserve space for bus taps, labels and relay links.
7. Place the 15 relays. Assign each relay's measured breaker terminal, CT ratio, stage settings and trip breaker. Electrical conductors, relay measurement associations and relay trip links serve different purposes.
8. Save your editable project. Compare it with the completed practice file: 52 equipment, 51 explicit connections, 15 relays, two open breakers. Dashed measurement associations can need an elbow to reach a different measurement terminal; the explicit power and trip connections in this practice drawing are straight.

Branch plan

Open the complete drawing at full size. The completed SLD download is the editable electrical model.

2. Enter the parameter schedules

Open an equipment item with a double-click or Edit properties. The field names and units below match the study forms. Some inputs appear under the full Load flow, Short circuit or Earthing tabs rather than Essentials. Expand advanced sections when needed. A blank field is not zero: leave unspecified values blank and review any resulting warning.

Use these schedules for every repeated branch. The neutral-grounding-transformer symbol and its actual electrical grounding resistance are both included where used. Check both.

Expand all schedules Collapse schedules Print all schedules

3. Check every terminal connection

Use these endpoints when repeating the drawing. Bus tap identifiers are intentionally shown as “Bus tap”; place each tap above or below the corresponding branch so its conductor stays vertical. Horizontal couplers connect facing bus ends.

4. Run, interpret and compare the studies

Operating cases and load flow

1. Use the normal operating case with 100% load and generation. Generator 1 and Generator 5, their transformers and breakers are out of service/open; the other four generator branches and both couplers are in service.
2. Run Load flow and check the validation messages before reading the result cards. Inspect bus voltage, loading, real/reactive power, losses and source contributions.
3. Create a second case called Reduced load. Set load scaling to 80%, keep generation at 100%, run it, then compare both cases. A change of sign in grid power indicates import versus export.
4. Return to the normal case before the fault and coordination exercises. Changing a model or case requires a new calculation.

Short circuit and equipment duty

Select the normal operating case. Use a bolted fault (0 Ω resistance and reactance), 1 s fault duration, 100 ms minimum breaking time, established sources and automatic peak-factor method. Include generators and motors for the maximum case. Compare maximum three-phase, minimum three-phase and maximum phase-to-earth cases; inspect the study scope and contributions in each result.

Relay coordination

1. Set a maximum three-phase fault at the Motor Load A terminal. Select Relay 11 as the primary and Relay 14 as the backup in the coordination wizard.
2. Check CT assignments, local relay currents, curve families and the 0.30 s grading requirement. Compare maximum and minimum fault cases. The two relays do not necessarily measure the same current.
3. Read the TCC and the worst-case timing table together. A pass for one declared pair is not proof of coordination across the entire network.

Healthy and failed-breaker sequences

Run the healthy sequence and record which breaker clears the fault. Then select Breaker 11 as stuck closed and run again. Read the full event list: compare the fault-clear time, the failed device state and every additional breaker opened. This is a stuck-breaker sequence study; it is not a simulation or commissioning test of a dedicated breaker-failure protection scheme.

Try a setting proposal on a copy

Keep Relay 11 fixed. For the exercise only, assume Relay 14 maximum normal current is 1000 A; use 25% pickup headroom, minimum fault/pickup ratio 1.5, pickup step 0.01 A secondary, time-multiplier step 0.01, margin 0.30 s and maximum clearing time 3 s. The recorded candidate is 0.66 A secondary (1320 A primary) and time multiplier 0.28, with about 0.305 s maximum-case and 0.455 s minimum-case margin. Review, apply to a training copy, rerun and save it separately. Undo or reload the original before reproducing the original report results. The assumed 1000 A is not a verified operating limit.

5. Prepare the report and download your evidence

1. Set the drawing title, project number, revision and preparation details. Populate checker and approver fields only with real review information; the tutorial leaves them unapproved.
2. Open the report for the active study. Review the study matrix, input provenance, unresolved findings and completeness. Calculate every case needed for your report, rather than assuming the currently displayed result covers all cases.
3. Download the audit CSV and preliminary PDF. Keep separate load-flow and short-circuit reports; each has its own scope and assumptions.
4. Download the protection review and coordination results from their respective study panels. Preserve the actual settings and event sequence alongside the report.
5. Open every downloaded file. Check title, revision, case names, current snapshot, units, findings and the input/output schedules. A successful download does not mean the design is approved.
6. Save the editable SLD project JSON. Use Export SVG for a vector image, or Export PDF with A2 landscape and fit-to-page for this wide drawing. Use tiled pages when a single sheet makes text too small.

Keep the different file types straight

6. Prove you can repeat the workflow

• Create a new project, draw a branch and explain the voltage on each side of its transformer.
• Connect actual terminals, then move and align equipment without leaving a disconnected or needlessly bent wire.
• Enter source, line, transformer, generator, motor, bus and breaker data with correct units; explain the difference between a system voltage and a nameplate rating.
• Duplicate a branch, rename it and correct its copied ratings and service state.
• Save and reopen your own project without using the completed file.
• Create two operating cases and explain why lower demand can change grid import to export.
• Compare maximum and minimum faults, distinguish RMS from peak current, and identify a failed or indeterminate equipment-duty check.
• Assign relay CTs and a trip breaker, read primary versus secondary pickup, and check the primary/backup grading margin.
• Run a failed-breaker case and identify every breaker opened, the final clearing time and the effect on healthy feeders.
• Review a setting proposal, apply it to a copy, rerun and preserve both original and candidate projects.
• Prepare the study matrix, preserve unresolved findings and download/reopen all required reports and drawing files.

If any task is unclear, return to its chapter and repeat the action in your own project. Use verified equipment and utility data for real studies, and have the design and protection settings reviewed before use.

SLD Studio course · version 2.10.5 · 16 chapters · captions only · no narration.