P28 and P29 studies to facilitate network connection

Posted by: Gary
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Enspec carry out P28 transformer energisation / flicker studies and P29 unbalanced load assessments for proposed generation sites. Such studies are required to assess sites against compliance limits to facilitate network connection.

For a proposed solar park we recently carried out:

• Transformer inrush studies to calculate voltage dip at the PCC during energisations

• Tripping studies to assess voltage step changes for events such as loss of the solar park

• P28 flicker emission calculations at the PCC

• P29 unbalanced load analysis

that concluded:

• Tripping of one to all of the inverter units did not exceed the P28 step change limit

• Flicker emissions from the inverter units are compliant with P28

• The loads are 3-phase, balanced and expected to comply with P29

• Simultaneous or individual energisation of the site’s transformers exceeded the P28 limit at the PCC

As voltage dip at the PCC exceeded the 3% limit specified by P28, consideration was given to managing disruptions to the surrounding network. We were able to advise on mitigation solutions at an early stage and help alleviate this issue prior to proposed site energisation dates. This ensured generation could begin on schedule with no risk of disconnection due to non-compliance and a subsequent loss in revenue.