UEGCL · Meter Commissioning Review

Load Profile Analysis — LGZ28400000

Meter Serial: LGZ28400000 Recording Period: 2026-09-16 to 2026-09-24 Interval: 1-hour LP1 Prepared: 2026-09-25

§1Operating Summary (Normal Period)

Active Power Avg

38.52 MW

Range: 35.19 – 39.53 MW

Reactive Power

0.98–5.08 Mvar

High day-to-day variation

Voltage (L-N avg)

6.34 kV

Implies 10.98 kV L-L (~11 kV nominal)

Frequency

49.78–50.35 Hz

Within ±0.5 Hz tolerance

Total Energy

6,398 MWh

167 operating hours

Current Imbalance

2.19 %

L1=1.994 L2=2.009 L3=2.038 kA

§2Reactive Power Profile

Mvar vs Time (2026-09-16 – 2026-09-24)

Date	Min Mvar	Max Mvar	Avg Mvar	Day Range	Assessment
2026-09-17	2.01	3.80	2.33	1.79	Moderate variation
2026-09-18	0.98	5.08	3.04	4.10	⚠ Very large swing — multiple step-changes detected
2026-09-19	0.99	5.05	2.60	4.06	⚠ Very large swing — multiple step-changes detected
2026-09-20	3.02	5.07	3.73	2.05	⚠ Step-changes present — likely AVR or compensation switching
2026-09-21	3.01	3.07	3.03	0.06	✓ Stable — normal variation
2026-09-22	1.01	4.09	2.89	3.08	⚠ Step-changes present — likely AVR or compensation switching
2026-09-23	4.01	4.09	4.05	0.08	✓ Stable — normal variation
2026-09-24	4.02	4.09	4.05	0.07	✓ Stable — normal variation

§3Key Findings

CriticalVoltage changed after load-on: 11.4 kV → 6.3 kV

Before load (pre-load rows) phase voltages read 11.4 kV. Once load came on they settled to 6.3 kV. These are not compatible as the same mode: 11.4 kV is the line-to-line voltage of a 11 kV bus; 6.3 kV is the line-to-neutral voltage (11000 ÷ √3 = 6351 V). A VT ratio or reporting-mode change occurred during the commissioning window.

If UEGCL's reference system expects 11 kV (L-L) and the meter is reporting 6.3 kV (L-N), this single configuration difference explains the "wrong voltage" complaint without any physical re-wiring.

Pre-load: V1 = 11.4 kV (apparent L-L) Post-load: V1 = 6.3 kV (apparent L-N) 11 kV L-N = 11000 ÷ √3 = 6351 V ← matches ✓

WarningReactive power varies in large step-changes — max daily range 4.10 Mvar

Active power holds steady at ~38.5 MW throughout. Reactive power jumps between discrete levels in sharp step-changes that hold for several hours. Worst day: 2026-09-18 with 4.10 Mvar range (min 0.98, max 5.08 Mvar). MW does not move when Mvar jumps — this rules out load changes.

This is the behaviour of AVR setpoint adjustments or capacitor bank switching. 3 day(s) are rock-stable (<0.5 Mvar range), confirming the meter holds steady Q readings when the system is stable.

Mvar range: 0.98 – 5.08 Mvar MW range over same period: 35.19 – 39.53 MW (flat) Worst daily swing: 4.10 Mvar on 2026-09-18

WarningMeter powered on 4 recording interval(s) before first load reading

The meter recorded 4 zero-load interval(s) before the generator came online. The kWh register showed 32,094.68 kWh at the first loaded interval.

Confirm all CT/VT ratio parameters were finalised before the generator was synchronised, and that no parameters were changed after load came on.

NormalEnergy accumulation is internally self-consistent

The hourly kWh delta matches the instantaneous MW reading to within ±2% across all 167 operating intervals. The billing quantity is not in question.

InfoPhase current imbalance: 2.19% — Below 5% limit but above 1% ideal — monitor

L1 = 1.9940 kA, L2 = 2.0088 kA, L3 = 2.0381 kA. Below 5% limit but above 1% ideal — monitor.

Info2 hour(s) with active power above normal baseline

Coherent across V, I, P — not a metering artefact. Confirm with control-room log.

2026-09-24 14:00:00: 39.53 MW (avg 38.52 MW) 2026-09-24 15:00:00: 39.39 MW (avg 38.52 MW)

NormalFrequency, export energy, and status register are all nominal

Frequency 49.78–50.35 Hz (within ±0.5 Hz tolerance). Export energy stayed essentially constant throughout — no reverse-power flow events. Status register held a consistent code from first load interval onward.

§4Metering Configuration Cross-Check

Parameter	Meter Reading	Cross-check	Status
System voltage (L-N)	6.34 kV avg	11 kV ÷ √3 = 6351 V ✓	Verify VT mode
Phase current (avg)	L1=1.9940 L2=2.0088 L3=2.0381 kA	Expected ~2.0254 kA at 38.5 MW ✓	Consistent
kWh Δ vs MW	Δ kWh/h ≈ MW×1000 ±2%	Verified across all 167 rows	Verified ✓
Power factor range	0.9912 – 0.9997	Expected >0.99 for large hydro	Normal
Current imbalance	2.19%	Limit 5%, ideal <1%	Borderline

§5Questions to Probe the UEGCL Team

Use these to narrow down what "not reading what we expect" means before drawing conclusions.

CT / VT Configuration

What are the CT and VT nameplate ratios at this bay, and what ratios are programmed in the meter?

The meter shows 6.34 kV (L-N) and ~2.014 kA per phase avg. If the VT secondary is 63.5 V L-N and CT secondary is 5 A, the programmed ratios must match exactly. A 5% ratio error means MW and kWh are wrong by 5% across the entire record.

Expected vs Actual

Which specific parameter is different from what you expected: MW, kWh total, voltage, or Mvar?

The meter's MW (38.5 MW avg), kWh delta, and phase V/I are all internally self-consistent. Without knowing which parameter UEGCL believes is wrong, and what their reference value is, a metering error cannot be confirmed or denied.

Reference Comparison

Do you have a SCADA or EMS reading for this unit over the same period, and by how much does it differ?

The meter records 38.5 MW average for 167 hours = 6,398 MWh. A ratio difference points to a scale factor error; a fixed offset points to an auxiliary load or metering boundary issue.

Reactive Power Control

Who controls the AVR setpoint, and were there deliberate reactive power changes during the recording period?

The Mvar record shows a 4.10 Mvar max daily swing while MW stays constant — the signature of AVR setpoint changes or capacitor bank switching, not metering error. The control-room dispatch log will confirm.

Commissioning Sequence

Were CT/VT ratio parameters finalised before the generator was synchronised, or were any parameters changed after load came on?

The pre-load voltage (11.4 kV) differs significantly from the loaded reading (6.3 kV), suggesting a configuration change during commissioning.

Metering Boundary

Is this meter on the generator terminals or the grid side of the step-up transformer, and what is the unit's rated capacity?

The voltage of 6.34 kV (L-N) implies a ~11 kV metering point. If UEGCL expects higher voltage because their reference is on the HV side of a transformer, the metering point location explains the difference. If the unit is rated above 39 MW, station auxiliary load may account for the gap.

CT Polarity

Was a CT injection test done to verify polarity and phase sequence before energisation?

Export energy has stayed essentially constant — no reverse-power flow detected. A reversed CT polarity would flip Q sign on one phase. The observed Mvar step-changes look like deliberate setpoint changes rather than polarity issues, but this check eliminates the possibility entirely.

Old Meter Baseline

What was the old meter's final kWh reading at changeover?

The new meter started at 32,094.68 kWh. Without the old meter's closing reading, the absolute kWh total cannot be validated. The internal delta-vs-MW check confirms the meter is accumulating correctly from its own reference point.

§6Recommended Next Steps

Action 1Verify VT ratio programming and voltage reporting mode (L-N vs L-L)

Compare the VT nameplate ratio against the programmed value in OBIS 1-4:32.5.0. Confirm L-N or L-L convention. This single check resolves the most common "wrong voltage" complaint.

Action 2Obtain SCADA kWh/MW for the same period and compute the ratio

A ratio error points to a CT or VT scale factor problem. An offset points to metering boundary or auxiliary load. A ratio within ±1% confirms the meter is correctly scaled.

Action 3Get the AVR setpoint log from the control room for the recording period

Confirms whether Mvar step-changes are deliberate (normal) or unintended. Either outcome closes the reactive power finding.