Undergrounding

Does undergrounding of distribution cables improve your customers’ power quality, or not… ?

While undergrounding distribution cables might seem like a good idea to protect customers from trees or animals hitting distribution lines, the only real value for the customer is that it is aesthetically more pleasing to the neighborhood.

The reason is that the undergrounded cable will only protect the customers from any events that take place on their own direct feeder; this is not where the majority of the problems occur. The customer suffers more from adjacent feeder and transmission system events, neither of which are protected by undergrounding that one line.

A very cost effective way to protect your customer from most events is to install an Active Voltage Conditioner (AVC) at the service entrance. Undergrounding cable is very expensive. It costs the Utility the same per mile for a 500kVA customer as it would for a 5000kVA customer, as the wire size will most likely be the same  and the work to install is identical.

The AVC provides the Utility the option of providing protection sized exactly for the load and it can be located very close to the customer. This reduces the number of events the customer will see. The AVC will now correct any event* that occurs upstream of the system, whether or not it was on its own feeder, an adjacent distribution feeder or on the transmission system.

For more information on AVC.

* The type of events corrected will be determined by the ratings and specifications of the AVC selected by the customer/utility.