Powerco is New Zealand’s second largest network company delivering energy to 312,000 consumers in the rural heartland of the country’s North Island. The utility serves four provincial cities and some of the world’s most productive sheep, beef, dairy and kiwifruit farms. In May 2009 Powerco placed orders with Landis+Gyr for six large ripple control injections indicating that ripple control will be part of New Zealand’s AMM solution in the future. More injection orders are likely to follow.
Load management in New Zealand
Major restructuring of the New Zealand (NZ) electricity industry, which began in 1999, changed the market and led to uncertainty about the future of ripple control
among utilities and the industry as a whole. The market was split into the ownership of electricity distribution lines and retail business and load management was left in between these two functions. From a technical point of view, a lot of industry know-how was lost and, from a commercial standpoint, the position of load control in the new free market was uncertain.
The development of the load management industry has taken a positive turn in the last five years. The most notable change has been New Zealand’s Electricity Commission’s Model Use of System Agreement, which highlights the importance of grid and network security of supply and control of transmission peaks.
Powerco invest for the future
In order to support Powerco during this market change, long associated Landis+Gyr (previously known as Enermet) drafted an Asset Management Plan in 2004 which covered all of Powerco’s 53 plants that had ripple control injections. The Landis+Gyr report concluded that the backbone of a good load management system was in place with low frequency ripple coverage of most of Powerco’s operating area. 14 new ripple injections were recommended to complete low frequency coverage of all areas and for replacement of some plant that was approaching 30 years in age. New Zealand market developments and the ripple control capabilities provided the certainty Powerco needed to invest in the refurbishment of its ripple control system.
Proven ripple control technology
In the last 2 years, Powerco has invested in eleven new ripple control plants from Landis+Gyr in order to catch up on the system backlog. Powerco chose Landis+Gyr’s ripple control injections consisting of Enermet Outdoor Couplings, Enermet SFU-K transmitters and Enermet EPL controllers. The well-known injections stand for a very robust low frequency design and ensured a signal distribution in excellent quality. Thanks to the efficient and reliable technology direct load control is again guaranteed for many years.
Total control with coherent infrastructure
In a separate project, Powerco is also replacing its various supervisory control and data acquisition (SCADA) systems, which are used for controlling power plant infrastructure, with a new system. All the Enermet SFU-K transmitters delivered by Landis+Gyr are controlled through Enermet EPL controllers, which are designed to interface Powerco’s new SCADA. The coherent infrastructure enables Powerco to switch the controlled load with a single mouse click across their territory.
These investments ensure Powerco to optimise peak time purchasing and distribution network costs while keeping the expected service levels.
About Ripple Control
Ripple Control is an early and very robust one-way power line communication system using the existing distribution network as a communication channel. The Ripple Control telegram is injected into the high, medium or low voltage in substation or transformer station and propagated in real-time throughout the distribution area where Ripple Control receivers pick up the signal and switch loads, streetlights or tariffs accordingly.
