1. When generation, load, and fault combine
Sebastian Junger’s The Perfect Storm returns because a power bus is another place where several ordinary factors add up to an extraordinary load. A cell in shadow, a sudden compute load, and a second cell with a failing battery can combine to pull the bus close to collapse. The test must exercise those combinations before orbit does.
This entry defines the power distribution test matrix.
2. The test setup
The test uses a representative subset of cells connected to a common bus:
- At least three power-generating or storage cells.
- One or more load cells representing compute, communications, and thermal control.
- Programmable electronic loads to simulate mission power profiles.
- Programmable power supplies or battery simulators to represent solar generation.
- A data logger recording bus voltage, cell currents, switch states, and fault flags.
3. The test matrix
| Case | Condition | Activity |
|---|---|---|
| Baseline | All cells healthy, nominal load | Verify bus voltage, current sharing, and telemetry |
| Load step | Step load from 25% to 100% | Measure transient response and voltage droop |
| Eclipse | One cell loses generation | Verify other cells cover the load |
| Cell disconnect | Open a cell’s bus switch under load | Verify bus remains stable and faulty cell is isolated |
| Cell reconnect | Reconnect the isolated cell | Verify cell rejoins without transient |
| Overcurrent | Apply a short on one load branch | Verify current limit and isolation |
| Undervoltage | Reduce generation until bus sags | Verify load shedding order |
| Unbalanced SOC | Cells at different states of charge | Verify charge balancing or current limits |
| Thermal limit | One cell reports over temperature | Verify power routing reduces load on that cell |
| Ground command loss | Disable ground link during a fault | Verify autonomous recovery to safe state |
4. What is measured
For each case the test records:
- Bus voltage stayed within specification.
- No cell exceeded its current or temperature limit.
- Fault detection and isolation occurred within the required time.
- Loads received power in the expected priority order.
- Telemetry accurately reflected the state of each cell.
- Recovery actions returned the bus to a stable state.
5. What this changes
- The power distribution test has a concrete matrix.
- The matrix covers normal operation, fault injection, and autonomous recovery.
- The next entry will define pass and fail criteria.