Prescription · Full case
Stagger Kiln 1 co-start with Mill 2 by 10 minutes
Kiln 1 and Raw Mill 2 co-started into the 10–11 TOD peak window, pushing rolling MD to 4,680 kVA — only 6.4% headroom below CMD 5,000 kVA. Staggering the second large load by 10 minutes avoids MD coincidence charges.
Potential savings
₹84,000
per month
₹10,08,000 / yr modeled
Root-cause analysis
- No interlock between Kiln 1 warm-up sequence and Mill 2 start permission.
- Shift handoff defaults allow simultaneous large-load starts.
- Peak TOD window (10–11) overlaps with routine pyro + grinding ramp.
Recommended action
- Immediate: hold Mill 2 start until Kiln 1 load settles below 95% (no CAPEX).
- Operator playbook: rotate co-starts so only one large load enters the 10–11 TOD window.
- Long-term: sequencer interlock + 2 m³ buffer on shared air/process header if dips persist.
MD coincidence window
| Asset | Load % | MD contribution (kVA) | Comment |
|---|---|---|---|
| Kiln 1 | 108% | 1,860 | Above design — critical |
| Raw Mill 2 | 72% | 640 | Co-start with Kiln 1 |
| Main incomer | 94% | 4,680 | Rolling 15-min MD peak |
Two large loads entered the peak TOD band simultaneously. A 10-minute stagger on Mill 2 start keeps rolling MD below the penalty threshold.
Hold Mill 2 start until Kiln 1 load settles below 95%. Monitor rolling MD for 15 min — should drop ≥120 kVA if stagger holds.
Cost–benefit & ROI
MD coincidence risk — potential penalty exposure on CMD breach + peak TOD energy premium.
| Scenario | Modeled impact / mo |
|---|---|
| Status quo (co-start) | ₹84k penalty risk |
| 10-min stagger (no CAPEX) | ₹0 – ₹12k residual |
| Sequencer interlock (long-term) | ₹0 – ₹5k residual |
Immediate fix is sequence change only. Long-term: sequencer interlock + buffer (~₹2L) if pressure/throughput dips persist.
- 6.4% → 8%+ MD headroom
- Reduced peak TOD kWh share
- Lower transformer stress
Risks & mitigations
| Risk | Mitigation |
|---|---|
| Pressure/throughput dip on step-load | Add +2 min stagger before relaxing hold; monitor kiln draft. |
| Operator re-enables both early | Log override; require supervisor PIN to override. |
KPIs & alerts
| KPI | Target | Alert |
|---|---|---|
| Co-starts in 10–11 TOD | 0 / shift | >0 |
| Rolling MD headroom | ≥ 8% | < 6% |
| Kiln 1 load at Mill 2 start | < 95% | ≥ 95% |
Commissioning & verification
- Confirm stagger rule in shift log for 3 consecutive shifts.
- Capture rolling MD before/after for savings verification (Option C baseline).
- Acceptance: zero co-starts in peak TOD for 7 days; MD headroom ≥ 8%.
Ledger entry
Manager takeaway
A 10-minute sequence change avoids ₹84k/mo MD risk with zero CAPEX. Long-term interlock locks in the discipline.