SOP: GOVERNOR LOGIC | FRANCIS UNIT 1
SOP-CTRL-019 REV 3.3

GOVERNOR LOGIC & FREQUENCY

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GRID SYNCHRONIZATION RISK

NO LIVE ADJUSTMENTS

Never adjust Droop settings while synced to the grid. Immediate load shock or trip will occur.

ISLAND MODE

Manual intervention is strictly required before separating from the national grid. No auto-switching permitted.

DROOP LOGIC (THE 4-6% RULE)

Droop determines how much the turbine helps the grid. A 4% droop means the unit changes 100% of its load for a 2Hz frequency shift.

Formula
Droop (%) = (Δf / f_nom) x 100
EXAMPLE (4%)

At 48.0 Hz unit goes 100% Load. At 52.0 Hz unit goes 0% Load.

OPERATING MODE SETTING PURPOSE
Parallel (Grid Sync) 4 - 6% Stable load sharing with national grid.
Parallel (Unit 1+2) MATCHED Ensures symmetric load distribution.
Island Mode (Solo) 0% (Iso) Unit controls local frequency precisely.

ROUGH ZONES & DEAD-TIME

VORTEX ROUGH ZONES

Draft tube vortex induces frequency hunting (±0.1 Hz) regardless of PID tuning.

  • 0 → 0.5 MW CRITICAL VORTEX
  • 0.9 → 1.3 MW STABLE ZONE

DEAD-TIME ANALYSIS

Lag between frequency drop and guide vane corrective stroke.

<500ms
800ms
>800ms

If Poor (>800ms): Check oil aeration or linkage backlash.