OFGEM's RPZ philosophy

The Registered Power Zones are intended to encourage Distribution Network Operators to develop new, more cost effective ways of connecting and operating generation that will deliver specific benefits to new distributed generators and broader benefits to consumers generally.

If a Distribution Network Operator employs genuine innovation in the way that it connects generation it can seek to register the connection scheme with Ofgem as a Registered Power Zone. Ofgem will then decide, using published criteria, whether the scheme qualifies and if it does, the incentive element of Ofgem’s Distributed Generation (DG) Incentive is increased for the first five years of operation.

Central Networks has developed the first RPZ in the UK that will allow more generation to be connected to its existing circuits near the East Coast without the need to carry out expensive reinforcement work. Basically, the amount of power that can be carried by an overhead line is related to its temperature. The amount of expansion that takes place which in turn is related to the amount of power transfer and the ambient temperature. The hotter the line gets the more it sags.

In order to ensure that the line doesn’t sag beyond that which is allowed, designers will rate the line for the amount of power it can carry based on the hottest ambient temperature. This means that in the winter months when the weather is cold lines are not always being used to their maximum capacity.

Using an innovative solution,our Engineers have developed an idea that will allow the temperature of the line to be calculated based on the actual ambient temperature and power flowing in the circuit. By knowing the actual line temperature a decision can be made to safely increase the circuit rating. We will be able to communicate automatically with generators to fine tune the amount of power flowing in the circuit using the existing network control system.

We are confident our solution will help support the future development of green generation across the UK.

Geographic area of Registered Power Zone (PDF, 437KB)

Registered Power Zone at Skegness

To facilitate the connection of wind energy, we have introduced an innovative scheme to enhance the capacity of the 132kV electricity network in the Skegness area. This is based on using real time weather measurements to calculate a dynamic line rating which will enable more power to be transmitted than if conventional fixed ratings were used.

RPZ at Skegness (PDF, 1.07MB)