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4.1.6 Supply disturbances

Distortion of the system voltage waveform caused by certain types of equipment may result in annoyance to users of the distribution system or damage to connected apparatus. UK Power Networks may suspend the supply in such an event.

In order to limit these affects Your proposed load should comply with the following:

  • The Distribution Code.

  • Engineering Recommendation P28 that is the national industry standard which applies for voltage fluctuation on the distribution network. Voltage fluctuation is generally caused by customer's equipment such as motors and welders or by voltage depression arising from transformer magnetising inrush current.

  • Engineering Recommendation P29 that is the national industry standard which applies for voltage unbalance on the distribution network.

  • Engineering Recommendation G5/5 is an engineering recommendation that provides the individual and total harmonic voltage distortion planning and compatibility levels that are applicable to UK transmission and distribution networks. This engineering recommendation is an amendment to G5/4 and came into effect on the 17th June 2020. All installations requiring a connection to UK Power Networks' distribution network that involve non-linear and/or resonant plant will be required the meet the requirements of EREC G5/5 if you accept a connection offer made on or after the 17th June 2020. Where you do need to comply with G5/5, you will need to demonstrate to UK Power Networks your installation's compliance with one of the three stages under G5/5. For installations complying with stage 2 or 3, you will need to undertake a harmonic compliance assessment and provide UK Power Networks with a report detailing the finding of the assessment and any proposed mitigating measures necessary to ensure compliance. It may be necessary for us to provide a harmonic specification for you to undertake the harmonic compliance assessment. Where this is required UKPN we will provide this information following your acceptance of the offer. If required, the harmonic specification can be provided prior to acceptance of an offer subject to payment. If you require the harmonic specification prior to offer, please contact the Connections Project Designer/Project Manager allocated to your enquiry to discuss how to proceed further.