Power Factor (PF) Not Close to 1

A CT displays Power Factor (PF) not close to 1, Site and Solar power flows are not representative of actual power flows, and/or negative loads are observed on the landing page

When verifying CT placement and location, it is worth checking the Power Factor read by each CT. When metering normal large residential loads such as a space heater, toaster, etc. the loads have predominantly resistive characteristics and a Power Factor close to 1. When testing with loads greater than 1kW and Power Factor is less than 0.8, it is possible there is a problem with the metering configuration. This method of troubleshooting is especially relevant on three phase systems, where a low Power Factor (e.g. ~0.5) may be a sign of a CT being on a different phase than its voltage reference.

Steps to Troubleshoot

  • Ensure the meter voltage tap is near the measurement point

Refer to the following current transformer issues for troubleshooting steps:

  • Confirm the CTs are facing the correct way:
    1. Locate the CT(s) used to measure the source that is displaying incorrect power flow readings.
    2. Verify the CT(s) are oriented such that the label is facing toward the source (away from the breaker).
      1. Solar Current Transformer: Label toward the Inverter
      2. Site Current Transformer: Label toward the Grid
      Figure 1. Tesla 100 A Current Transformer Orientation in Relation to Power Flow
  • Confirm the CTs are measuring the correct phase:
    1. Locate the CT on the Meter page in Tesla One.
    2. Determine which phase the CT should be measuring.
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      Note
      If using Gateway CTs, the ports are CT 1 (Line 1), CT2, (Line 2), CT 3 (defaults to Line 1 but can be configured as Line 2 in Tesla One).
    3. Verify the CT is measuring the correct phase.
      Figure 2. Gateway CT Measuring Correct Phase (top) and Incorrect Phase (bottom)
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      Note
      In the examples above, the CT is monitoring a solar inverter conductor, which is why only (1) CT is required.
  • Ensure the CTs have been placed in the correct location and are measuring the correct conductor(s):
    1. Verify the CT is clamped properly around the intended conductor(s).
      Warning IconA warning icon, calling your attention to a possibly risky situation
      Warning
      Before installing, disconnecting, and/or adjusting CTs, ensure the circuits being measured are not energized and the system is completely powered down. Failure to de-energize the system may compromise operator and equipment safety.
    2. Verify the CT is not capturing any other conductor(s).
      Informational PurposesAn informational icon, calling your attention
      Note
      If a site has multiple inverter outputs and their conductors are being grouped, ensure every conductor is captured.