Berryfields Update

The electricity supply has been restored to the Berryfields site. 

Third Update From GTC Infrastructure Limited (6/2/19 - 10am) – Power Outage on Saturday 2 February at Berryfields

We are pleased to confirm the 11,000 volt cable in Paradise Orchard has now been dug out and repaired. The repair was completed at around 6pm yesterday. The temporary supply arrangement we put in place on Saturday night to restore supplies to all homes is now reversed and the system is operating normally. We would not expect any further issues.

We have heard that some residents are worried about whether the electricity system at Berryfields has enough capacity to cope with the further additional new homes being built and added to the electricity system.

The simple answer is that there is plenty of spare capacity in the system.

For those who would like further technical details, we have included below a brief explanation to explain how GTC can be confident of this.  

  • The development is supplied by 2 completely separate 11,000 volt feeders from UKPN’s sub-station.
  • The GTC 11,000 volt cable system extends as a ring main around the whole development, but in normal operation the ring is not fully closed, a break is kept open half way around.  Very roughly half of the development is fed by each separate limb of the ring from its own independent feed back to the UKPN sub-station. This is the reason why when an outage occurs not all homes are affected.
  • The ring main system is designed with more than twice the capacity needed (taking into account all the future building work planned).
  • This more than double capacity in the ring means that in the event of a problem with one of the 11,000 volt feeders, the other feeder on its own can supply the whole development. This is achieved by closing a switch on the ring, so the ring can operate as a whole from one direction only and all supplies come from just one of the feeders, instead of from both feeders.
  • The ring has been built to operate in both directions, on either of the 2 feeders alone and carry the whole electrical load in that way. In normal operation with the ring split, each side of the ring carries less than half its capacity.   
  • This excess capacity of more than twice what is needed is not theoretical, it is real and gives us great flexibility.
  • GTC used this excess capacity to resolve the outage last Saturday. We closed the ring and then by switching created a break either side of the faulty cable section. The fault location in Paradise Orchard, meant that in effect about three quarters of the development was supplied from one feeder only.

The 11,000 volt ring was deliberately designed and installed to have more than double the capacity we are likely to need in normal operation to give us supply resilience when problems occur. GTC has invested in this excess capacity to give us flexibility for our customers at Berryfields, which allowed us to restore supplies fully to residents long before the cable had been dug out and repaired.

We hope the above explanation helps residents understand there are no reasons to be concerned about the capacity of the system.

As we have made clear in our website statements, the 3 previous outages were all caused by the same issue at the UKPN substation. These outages were load related, as some residents suspected, as when the load on the UKPN substation increased, it exposed that UKPN’s protection settings were too low, causing one of the feeders to trip out. UKPN have now adjusted their settings to the correct level so this should not happen again.

GTC recognises the significant inconvenience caused to the Berryfields residents by the outage and we apologise again unreservedly.


Second Update From GTC Infrastructure Limited (4/2/19 - 6pm) – Power Outage on Saturday 2 February at Berryfields

A number of residents have today asked whether the power supply loss on Saturday 2 February is in any way related to previous power supply outages during the last 3 months. The short answer is no. The outage on Saturday was caused by a fault on the underground high voltage cable located in Paradise Orchard and owned by GTC.

There were 3 previous supply interruptions at Berryfields between November 2018 and January 2019. All of these 3 were caused by the same problem of an incorrect control setting on the equipment owned and operated by the regional power distribution company UKPN. UKPN have previously confirmed this in a letter to the local MP and by e-mail to GTC.

It is very unfortunate (to say the least) that this GTC cable fault has occurred within weeks of the UKPN related issues being finally resolved but to confirm again the incidents are completely unrelated.

We will provide a further update once the high voltage cable has been dug out and repaired and we are able to say with certainty what caused the cable to fault.

GTC recognises the significant inconvenience caused to the Berryfields residents by the outage and we apologise again unreservedly.


Update From GTC Infrastructure Limited (4/2/19 - 1.15pm) – Power Outage on Saturday 2 February at Berryfields

On Saturday 2 February over 900 homes at Berryfields, Aylesbury, suffered a power outage just before 6pm, caused by a fault on an underground  11,000 volt cable. Supplies of power were restored to customers in phases during the evening, and all customers were back on supply just after 9pm. Supplies were restored by re-routing power to bypass the underground fault.

GTC has a fault repair team on site today to locate the exact position of the fault, and then dig down and make a permanent repair.  Once the repair is made the temporary bypass arrangements can be reversed.   We expect supplies to continue with no interruptions during these activities.

GTC recognises the significant inconvenience caused to the Berryfields residents by the outage and apologise unreservedly. The Directors of GTC were personally involved on Saturday to ensure supplies were restored to customers as fast as possible. Our Electricity Networks Director will be on site today to oversee the operation as well as arranging to meet with representatives from the Parish Council.  

We will make a further statement as soon as the fault repair is complete and we will write individually to all the customers who have written to us since Saturday.

Once again we are very sorry for the outage and for the inconvenience it has caused.


 We hope this explains the current situation, however should you have any queries please contact our customer services team on 01359 243292 or at customerservices@gtc-uk.co.uk