Total Demand Distortion (TDD) definition
Total Demand Distortion (TDD) means the ratio of the root mean square of the harmonic content, considering harmonic components up to the 50th order, expressed as a percent of the maximum demand current;
Total Demand Distortion (TDD). The total root-sum-square harmonic current distortion, displayed in a percent, of the maximum demand load current. Typically a 15-minute, 30-minute, or 1-hour demand measure. • Total rated-current distortion (‘TRD’): The total root-sum-square of the current harmonics created by the DR unit operating into a linear balanced load divided by the greater of the test load current demand (‘IL’) or the rated current capacity of the DR unit (‘Irated’). • UPS: uninterruptible power supply
Examples of Total Demand Distortion (TDD) in a sentence
When the system is serving balanced linear loads, harmonic current injection into the City’s network shall not exceed the following levels: Odd harmonics (h): 4.0% 2.0% 1.5% 0.6% 0.3% Maximum Total Demand Distortion (TDD) 5.0% Even harmonics: Even harmonics are to be limited to 25% of the odd harmonics shown above.
If there is evidence that the Voltage Total Harmonic Distortion (THD) is greater than or equal to 5%, Current Total Demand Distortion (TDD) is greater than or equal to 5%, or any single harmonic exceeds the distortion limits specified in IEEE Standard 519- 2014, the DG owner would be required to add a filtering system to its installation to meet the requirements of IEEE 519 – 2014.