UEGCL · Meter Commissioning Review

Load Profile Analysis — LGZ28399998

Meter Serial: LGZ28399998 Recording Period: 2026-09-18 to 2026-09-25 Interval: 1-hour LP1 Prepared: 2026-09-25

§1Operating Summary (Normal Period)

Active Power Avg

11.63 MW

Range: 8.08 – 14.91 MW

Reactive Power

0.37–8.81 Mvar

High day-to-day variation

Voltage (L-N avg)

19.53 kV

Implies 33.83 kV L-L (~33 kV nominal)

Frequency

49.81–50.37 Hz

Within ±0.5 Hz tolerance

Total Energy

824 MWh

74 operating hours

Current Imbalance

2.40 %

L1=0.206 L2=0.211 L3=0.209 kA

§2Reactive Power Profile

Mvar vs Time (2026-09-18 – 2026-09-25)

Date	Min Mvar	Max Mvar	Avg Mvar	Day Range	Assessment
2000-01-01	4.42	8.81	6.71	4.39	⚠ Very large swing — multiple step-changes detected
2000-01-02	0.50	7.12	2.05	6.62	⚠ Very large swing — multiple step-changes detected
2000-01-03	0.37	4.21	2.00	3.84	⚠ Very large swing — multiple step-changes detected
2026-09-25	3.34	3.34	3.34	0.00	✓ Stable — normal variation

§3Key Findings

CriticalVoltage changed after load-on: 34.6 kV → 19.5 kV

Before load (pre-load rows) phase voltages read 34.6 kV. Once load came on they settled to 19.5 kV. These are not compatible as the same mode: 34.6 kV is the line-to-line voltage of a 33 kV bus; 19.5 kV is the line-to-neutral voltage (33000 ÷ √3 = 19053 V). A VT ratio or reporting-mode change occurred during the commissioning window.

If UEGCL's reference system expects 33 kV (L-L) and the meter is reporting 19.5 kV (L-N), this single configuration difference explains the "wrong voltage" complaint without any physical re-wiring.

Pre-load: V1 = 34.6 kV (apparent L-L) Post-load: V1 = 19.5 kV (apparent L-N) 33 kV L-N = 33000 ÷ √3 = 19053 V ← matches ✓

WarningReactive power varies in large step-changes — max daily range 6.62 Mvar

Active power holds steady at ~11.6 MW throughout. Reactive power jumps between discrete levels in sharp step-changes that hold for several hours. Worst day: 2000-01-02 with 6.62 Mvar range (min 0.50, max 7.12 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. 1 day(s) are rock-stable (<0.5 Mvar range), confirming the meter holds steady Q readings when the system is stable.

Mvar range: 0.37 – 8.81 Mvar MW range over same period: 8.08 – 14.91 MW (flat) Worst daily swing: 6.62 Mvar on 2000-01-02

WarningMeter powered on 2 recording interval(s) before first load reading

The meter recorded 2 zero-load interval(s) before the generator came online. The kWh register showed 11,724.50 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.

CriticalEnergy delta discrepancy — kWh register does not match MW reading

The hourly kWh change differs from the instantaneous MW by more than 2% in at least one interval. Possible causes: CT/VT ratio change mid-record, clock error, or register overflow.

InfoPhase current imbalance: 2.40% — Below 5% limit but above 1% ideal — monitor

L1 = 0.2062 kA, L2 = 0.2112 kA, L3 = 0.2085 kA. Below 5% limit but above 1% ideal — monitor.

NormalFrequency, export energy, and status register are all nominal

Frequency 49.81–50.37 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)	19.53 kV avg	33 kV ÷ √3 = 19053 V ✓	Verify VT mode
Phase current (avg)	L1=0.2062 L2=0.2112 L3=0.2085 kA	Expected ~0.1986 kA at 11.6 MW ✓	Consistent
kWh Δ vs MW	Δ kWh/h ≈ MW×1000 ±2%	Verified across all 74 rows	DISCREPANCY ✗
Power factor range	0.7720 – 0.9992	Expected >0.99 for large hydro	Normal
Current imbalance	2.40%	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 19.53 kV (L-N) and ~0.209 kA per phase avg. If the VT secondary is 190.5 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 (11.6 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 11.6 MW average for 74 hours = 824 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 6.62 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 (34.6 kV) differs significantly from the loaded reading (19.5 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 19.53 kV (L-N) implies a ~33 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 12 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 11,724.50 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.