1.6 Creep (Start-up/No load)

The metrology firmware includes support for start-up and no load (creep) detection features. The following creep thresholds are available:

• Global creeps, affecting the pulses and the pulse accumulators ACC_Tx:
  • CREEP_THRESHOLD_I
  • CREEP_THRESHOLD_P
  • CREEP_THRESHOLD_Q
  • CREEP_THRESHOLD_S
• Per-phase creeps, affecting the pulses and the pulse accumulators ACC_Tx, and additionally the integration period and per-cycle accumulators:
  • CREEP_THRESHOLD_I_A
  • CREEP_THRESHOLD_I_B
  • CREEP_THRESHOLD_I_C
  • CREEP_THRESHOLD_P_A
  • CREEP_THRESHOLD_P_B
  • CREEP_THRESHOLD_P_C
  • CREEP_THRESHOLD_Q_A
  • CREEP_THRESHOLD_Q_B
  • CREEP_THRESHOLD_Q_C

Current creep:

Energy measurements (I²-hour, Watt-hour, Var-hour, VA-hour) for any phase x (x = A, B, or C) will not be accumulated if the RMS current value is below the global threshold, CREEP_THRESHOLD_I. The individual thresholds enable the configuration of distinct creep thresholds for each phase, allowing for more precise control and customization.

Active power creep:

The total active energy is accumulated only when the active energy in a full cycle is greater than CREEP_THRESHOLD_P.

Similarly, active energy for each individual phase (A, B, or C) is accumulated only when the phase’s active energy in a full cycle exceeds its respective threshold, CREEP_THRESHOLD_P_x.

Reactive power creep:

The total reactive energy is accumulated only when the reactive energy in a full cycle is greater than CREEP_THRESHOLD_Q.

Similarly, reactive energy for each individual phase (A, B, or C) is accumulated only when the phase’s reactive energy in a full cycle exceeds its respective threshold, CREEP_THRESHOLD_Q_x.

Apparent power creep:

The total apparent energy is accumulated only when the apparent energy in a full cycle is greater than CREEP_THRESHOLD_S.

The “PIC32CXMTx Metrology Reference Guide (DS50003461)” provides example calculations for each one of the thresholds.