By Phil Perry
The responsibility for implementing this major rollout has been given to the five Victorian electricity distribution businesses that have been actively involved in the project from the start. The project will allow users to better manage their energy consumption by providing more detailed information on their electricity use and pricing and by making this information available on a more usable and timely basis
The Victorian electricity industry is fully disaggregated and operates in a fully competitive environment. Competition at the wholesale and retail levels of the electricity supply chain underpins sustainable and efficient energy supply.
However, it was identified by what is now the Essential Services Commission (ESC, the economic regulator of the Victorian electricity industry) in the year 2000 that the accumulation meters used by almost all customers were ineffective for the provision of cost reflective pricing signals to customers. Because of this, in 2002/03, the ESC investigated the business case for the rollout of manually read interval electricity meters. The business case proved positive, with the major benefit being demand response to differentiated tariffs, and the rollout was scheduled to start in 2006.
In 2005 some industry participants felt that there may be a business case to add remote two-way communications to the interval metering rollout. An extensive costbenefit study co-funded by the government and Victoria’s electricity distribution and retail businesses was undertaken and found a positive societal business case to add remote two-way communications to the interval meters. Additional benefits were also identified and an accelerated smart meter (AMI) rollout over four years was justified.
In August 2006, AMI legislation was passed through the Victorian Parliament that enabled formal prescription of AMI functionalities, performance and service levels, an implementation schedule and a cost recovery structure for electricity distribution businesses.
Delivering a project of such large scope requires co-operation between electricity distributors, retailers, consumer groups, government and the community at large. To foster a collaborative approach, the government established an Industry Strategy Group and a number of working groups to provide advice on the development phase of the project.
The initial set of issues that had to be considered included:
- Defining the minimum state-wide functionality that is required to allow retailers to be able to offer a state-wide set of products and services that utilise the capability of AMI
- Determining appropriate service levels that should be required of operators of AMI systems
- Ensuring there are the means for electronic communications between retailers and distributors to initiate AMI system actions and to receive responses and data from meters
- Developing detailed plans for AMI trials, including the nature, scale, funding, timing, operation, transparency and performance reporting of such trials, and
- Developing the content and approach of AMI rollout implementation plans, including the requirements of capital and operating expenditure submissions.
The development phase of the project ran from March 2006 to September 2007. The Victorian government led the requirements development phase and now the implementation phase is being led by the five electricity distribution businesses charged with rolling out AMI.
Whilst the AMI Communications Study Report proposed a set of core AMI functionality, the flexibility of AMI infrastructure allows for additional functionality. Hence a key threshold activity of the project was to determine what functionality suite would be appropriate to the needs of Victoria and could also be financially justified. A Functionality Working Group was established in early 2006, comprising representatives of Victoria’s electricity distributors, retailers, consumer groups, government, and industry participants from other states who are investigating the potential for similar ventures. It should be noted that it was not intended to standardise all functionality for AMI systems, but rather determine a minimum level to apply across the whole state.
After many meetings and extensive consultation with all stakeholders, a minimum functionality specification was finalised in October 2007. The reference architecture used in the specification is given in Figure 1.
All AMI meters are to support connectivity to a range of devices, including in-home displays (IHDs), smart thermostats and customer loads (e.g. air conditioning, pool pumps, dishwashers) via a Home Area Network (HAN) using the ZigBee Smart Energy profile. It is noted that AMI systems do not preclude alternative communications channels with HAN devices and an example of this has been illustrated in Figure 1 with a potential non-AMI communications link between a retailer’s systems and a customer’s IHD.
AMI metering configurations are to allow for the continuation of current load control practice, whereby certain appliances such as storage water heaters or space heaters can be directly connected to an AMI meter via a dedicated electricity circuit (shown as Controlled Load in Figure 1), and will allow these appliances to be remotely controlled with the ability to turn the power to an appliance on or off within the AMI meter itself.
In addition, other appliances (e.g. air conditioners, pool pumps), which might not have dedicated electrical circuits at the customer’s switchboard, may also be remotely controlled directly (shown as Utility Control of other Loads in Figure 1) with appropriate commands sent via the AMI communications infrastructure but not relayed through the AMI meter.
As illustrated in Figure 1, AMI systems include a communications network to allow communications between AMI devices at the customer’s premises and the network management system (NMS). It is noted that in some AMI technologies, data concentrators would be part of this communications network.
The NMS provides connectivity to back-end systems including the connect/disconnect system, meter data management system (MDMS) and other distribution business (DB) systems. Figure 1 also shows the connectivity with retailers’ systems and the National Electricity Market Management Company’s (NEMMCO) B2B hub and MSATS systems.
Within the context of the architecture outlined above the following are the key elements of the functionality suite:
- Measurement of import and export interval energy – all AMI meters are to separately record the half hourly interval energy imported (i.e. the electricity used by the consumer) and exported (i.e. any energy supplied back into the distribution system by, for example, household solar panels)
- Communications – all AMI meters to have two-way communications capabilities allowing interval energy data to be remotely read on a daily basis (all interval energy data for a day to be read by 6 am of the next day). This is to enable retailers to better answer customer enquiries related to energy usage and avoid the need to estimate usage
- Remote disconnect/reconnect – most AMI meters (excluding CT connected meters) are to support both local and remote disconnect and reconnection of customer supply via a connect/disconnect contactor. This will enable electricity supply to be reconnected much more quickly when a customer moves premises, for example
- Quality of supply monitoring – all AMI meters will have the capability to monitor quality of supply (sags and swells), including outages (and blinks), and also record the time these events occurred and how long they lasted. This will enable distributors to better manage their electricity infrastructure
- Controlled load management – AMI will be connected to existing controlled loads (such as electric off-peak water heaters) and enable more efficient control as to when these loads are turned on and off (without adversely impacting on the availability of hot water)
- Supply capacity control – all AMI meters will have the capability to quickly ration supply among customers during a supply emergency and thus reduce blackouts
- A range of other requirements including remote firmware upgrade, tamper detection, self registration on installation and communications security.
A number of other functionalities were investigated but were not included. There is likely to be a final review of the functionality specification in coming months to validate its suitability before the AMI rollout commences.
Service levels were established for each item in the functionality suite to provide guaranteed standards which retailers and NEMMCO could rely upon. Most of the services required of smart meters are to meet retailers’ needs, such as daily meter reading data, connection or disconnection of supply and messaging to IHDs.
The service levels have been initially set at fairly conservative values to allow for the uncertainties surrounding the implementation of AMI and associated systems. The following are indicative service levels:
- Daily reading of half hourly interval energy data from all customers’ meters – 95 percent of previous day’s interval data available to retailers and the market by 6 am
- Remote connect/disconnect – action completed at 90 percent of meters within 1 hour and 99 percent within 2 hours
- Message to IHDs – urgent messages delivered to 98 percent within 4 hours.
The AMI services provided to retailers and the market are planned to be introduced in phases, as shown in Figure 2. Phase 1 services are for initial pilot installations. Phase 2 services are basic services including daily reading and connect/disconnect but not including provision of data to HAN devices. Phase 3 brings in the full range of services.
A key aspect of the preparation for the AMI rollout was the need to conduct technology trials to evaluate commercially available AMI technologies in relation to their capability to meet the two-way communications requirements of the minimum state-wide functionality specification, in both urban and rural areas. The trials also provided better understanding of the performance of AMI systems and the operational issues associated with installations. To oversee the technology trials a Technology Trials Working Group (TWG) was established to:
- Co-ordinate planning of the trials
- Determine evaluation criteria
- Develop standard test scripts
- Ensure comparability of results of trials of different technologies
- Maximise sharing of results
- Report on the trials results against the evaluation criteria.
The scope of the trials has had a principal focus on assessing the performance of the AMI communications systems from the meter to the network management system (see Figure 1). The capabilities of the meters and network management systems themselves were not tested.
Thirteen AMI systems from twelve vendors were trialled covering the following technologies:
- Power line carrier (PLC) – PLC communications can send signals between zone substations and meters that can pass through distribution transformers
- Distribution line carrier (DLC) – DLC systems use the low voltage distribution network as the communications medium between meters and data concentrators located at or near distribution transformers. Both DLMS and LON variants of DLC were trialled
- Mesh radio (MR) – MR is a private radio network-based technology for reading meters, which uses meters as repeaters in a mesh configuration
- GPRS – GPRS allows data services over existing GSM networks. Communications to and from the meters relies on existing public networks.
For most of the technologies two sets of testing were done – bench testing followed by field testing. The bench testing was done to obtain benchmark results in effectively ideal conditions. Field testing was done so as to simulate real installation conditions and also to stress technologies to identify their limits.
The results of the trials were quite enlightening. It was concluded that some technologies did not have sufficient data throughput (or latency was too high) to meet the functionality specification, whereas others did have sufficient data throughput plus some headroom for additional communications.
Smart metering is set to change the face of electricity metering and the way electricity businesses interact with their customers in Victoria and probably in other states in Australia. Electricity customers will at last have more information on their consumption and more options for electricity tariffs that will enable them to respond to price signals and allow them to better manage their energy usage.
Reports and other documentation on Victoria’s AMI rollout are available at www.dpi.vic.gov.au/energy under the smart metering tab.