How does PM5500 series meter calculates TDD (Total Demand Distortion)
Issue
Is there a more detailed description of how the PM5000 series meter calculates TDD (Total Demand Distortion
Product Line
PM5500 series
Environment
Documentation
Resolution
- Total demand distortion (TDD) is the per-phase harmonic current distortion against the full load demand of the electrical system
- TDD indicates the impact of harmonic distortion in the system
- For example, if your system is showing high THD values but a low demand, the impact of harmonic distortion on your system might be insignificant
- However at full load, the THD value for the current harmonics is equal to TDD, so this could negatively impact your system
- TDD (total demand distortion) evaluates the harmonic currents between an end user and a power source
- The harmonic values are based on a point of common coupling (PCC), which is a common point where each user receives power from the power source
- The meter uses the following equation to calculate TDD:
- Where ILoad is equal to the maximum demand load on the power system and HC is Harmonics Count
- Harmonic content (HC) is equal to the RMS value of all the non-fundamental harmonic components in one phase of the power system.
- The meter uses the following equation to calculate HC: