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ISLAMABAD, Aug 12 (APP):As dawn breaks over the Punjab plains, the Control Room at the Sahiwal 1,320 MW Coal-Fired Power Plant hums with purpose. The shift-change handover unfolds with disciplined precision.
The off-going shift lead briefs the incoming team in low tones: yesterday’s boiler start-up curve, minor voltage fluctuations at the 500 kV switchyard, status of circulating water pumps, and the day’s anticipated grid demands. No sub-headings, just the human rhythm of continuity, guarded by strict record-keeping and disciplined trust.
Operators settle at the Distributed Control System (DCS) consoles, two banks of workstations glowing with charts, alarms, and trend graphs: turbine speed, boiler pressure, coal feeder rates, FGD absorption currents, ESP voltage, stack gas temperature and the all-important heat rate index. Their eyes skim numbers and color codes as vigilantly as a pilot scans the horizon. One engineer adjusts the coal feeder screw-speed setpoint by a fraction, responding to a gradual drop in steam pressure. Elsewhere, another monitors generator reactive power, ready to tweak the exciter output to hold terminal voltage steady for the grid.
Mid-morning, the team breaks for buffet-style refreshments a modest but welcome ritual. Steam-heated tea, chapatis, eggs, fruit, and chai restore energy for what comes next. Lunch and evening tea follow a similar pattern: communal moments that build camaraderie in an environment where a moment’s distraction could ripple into a grid event.
Routine site inspections proceed in parallel: the operations head walks to the turbine hall with the shift supervisor, lamps and helmets in place. They check valve actuators, listen for odd vibrations, verify coal conveyor alignment, and glance at ash-handling lines. Back in the control room, another operator reviews Permit-to-Work (PTW) logs. Each permit outlines scope, safety measures, isolation points, and valid times. Ticket generation and closing routines follow exacting procedures: every PTW must be backed by authorization from engineering, operations, and safety officers. Once work is done, tickets are closed only after a certified inspection ensuring equipment is re-energized safely and correctly.
In the DCS, operators toggle between automatic and manual modes depending on grid conditions. During mid-day peak demand, the grid dispatch center (ISMO) may request ramp-up of unit output around 100 MW. The operator activates a predefined ramp program, which steadily increases boiler heat input and adjusts furnace pressure, guided by sliding pressure control.
The entire ramp is logged in the DCS archive for post-analysis maintaining compliance. As the afternoon wears on, the site safety officer walks past control-room windows, checking the enclosed alphanumeric log board that displays status: shift names, active PTWs, alarms cleared, any holdover issues.
Suddenly, a minor alarm: ESP inlet temperature nudges high.
The operator swiftly acknowledges it, traces possible causes, notes that an auxiliary fan is drawing a marginally elevated current, and calls for an ash hopper inspection. In parallel, a secondary operator lines up a spare fan for hot-swap replacement, ready to seal the hopper inlet if vibration peaks. The airtight choreography between control-room vigilance and field teams quelches the issue before it escalates.
Meanwhile, on the central plant network sometimes called the Operations Management Information System shift logs, maintenance tickets, safety records, and DCS trend archives are updated in real time. The plant’s automated reports begin compiling for the daily operations meeting: generation delivered, heat-rate performance, grid frequency compliance, emissions levels from CEMS, and any permit activity or safety incidents.
The night shift supervisor will present these at the handover briefing, ensuring full visibility across shifts.
Later, lower afternoon light falls across the yard as a PTW is issued for the lubrication of the condenser vacuum pump. Operators verify isolation at feed water valves, lock out tags applied correctly, and log the event.
The centralized shift engineer keeps an eye on the condenser vacuum and cooling water temperatures if the vacuum drifts or the temperature dips, an alarm will cue them immediately to reverse action or close valves.
The evening ramp begins as the national grid transitions from hydropower to thermal during purple and white load stages. ISMO commands an incremental 50 MW output increase over 30 minutes to maintain frequency at 49.98 Hz. Operators follow preset governor droop settings, adjust boiler spray valves, and monitor steam reheater temperature to avoid overheating.
The DCS logs every adjustment. Later, meal break again tea and samosas this time when the night shift arrives.
The incoming team gathers round as the outgoing lead recounts furnace draft anomalies, feed-water preheater maintenance due next shift, and production forecasts for the midnight-to-dawn off-peak window. The incoming staff sign off in the log and insert their shift names.
In the quieter hours, operations tense up again when the grid frequency dips to 49.90 Hz abruptly, signaling a sudden drop in upstream generation possibly a hydel unit tripping. The DCS triggers fast ramp controls. Operators watch turbine governors feather up within seconds, excitation systems stabilize voltage, and auxiliary feed pumps maintain boiler pressure. In minutes the frequency steadies. The incident reflects the plant’s role as gird-stabilizer, and operator’s vigilance.
Throughout the night, regular spot checks continue: flue gas desulfurization injection rates are monitored to maintain SO2 compliance, ash hopper levels are watched to prevent buildup, coal mill temperatures are tracked to avoid ignition risk. Each instrument, each gauge, stands as a silent sentinel watched by human hands and electronic eyes.
Day turns to pre-dawn again. Operators complete shift-handover paperwork, settle the outgoing team’s final logs, transfer open PTWs to the incoming shift, and close out any administrative tickets.
In one final symbolic act, the new shift lead looks around: calm DCS screens, no unacknowledged alarms. Behind the high-voltage lines and megawatt-scale turbines, this is where the heartbeat of Sahiwal’s power generation pulses through disciplined people, clear protocols, automated systems, and a daily devotion to reliability. It’s where power flows not just through generators, but through well-oiled human routines, communication, and quiet confidence. And it’s this choreography buffet meals, shift-handover rituals, DCS vigilance, tickets open and closed, field inspections that ensures that every kilowatt delivered rests on a foundation of operational excellence.
That is a day in the life of Sahiwal’s control room where operations meet precision, and where the grid finds its steady pulse.