The last 30 miles and beyond
Extending intelligence to all levels of the grid
Ambitious global efforts are currently being undertaken to push forward the development and implementation of smart grids at various levels. The first steps have already been taken, but there is still a long way to go.
With the increase in distributed generation and storage of energy from sources such as wind, solar, combined heat and power, biomass and geothermal, grid requirements are changing significantly as energy is being fed into the network at variable points as well as times.
This trend has a serious impact and is beginning to make life complicated for utility companies. As a result, Distribution System Operators (DSO) will need to install enough power/copper cable capacity to carry the energy.
A communications infrastructure will have to be created that allows smart applications to occur and for the different components of the network to talk to each other.
Additionally, software applications are required that balance intermittent power generation with intermittent power consumption, whilst maintaining operational parameters for voltage and frequency.
In all of this, an Advanced Metering Infrastructure (AMI), such as smart metering, plays a major role. It enables the recording of relevant data, as well as two-way communication between the utility and the consumer, who is also increasingly playing the role of energy supplier using locally generated power.
The key is to bring the intelligence that already exists at the high voltage and SCADA (supervisory control and data acquisition) level down to the consumer, but it can’t stop at the smart meter. To be able to optimise energy consumption, one requires the appropriate automation solutions to then control the individual devices and systems within the building or plant accordingly.
Smart meters are able to provide the end user with remote information to monitor and visualise energy consumption on things like TV and computers, but could also integrate smart appliances like washing machines, dish washers and car charging stations to be operated automatically at the most energy efficient and cost effective time.
Transparency and direct feed-back on energy consumption data can be made available with existing technology. The points of energy wastage can also be identified to provide the end user with the information they need to act wisely on it.
However, features like flexible tariffs and dynamic pricing, load profiling and power thresholds are still something that will become reality in the short-term future. In the medium-term, the integration of smart home appliances, renewable energy sources and EV charging are expected to materialise and will provide a big step towards matching power generation and consumption.
For example, should energy rates drop during the day in the summer as a result of higher than normal solar generation, the relevant consumer devices could be switched on accordingly, at a time they normally wouldn’t. Once intelligence has been introduced at the low-voltage level, there is still a gap to be bridged to make that information available on the medium-voltage level and allow communication with the SCADA.
In case of a failure, utility companies know where the high-voltage network is down, but they don’t have any details about what is happening at the medium voltage level, (about the last 30 miles) and about which users are connected or disconnected.
Today, Eaton estimates only 5-15% of sub stations are automated. This means that most sub distribution is done manually and the utility company has to send maintenance personnel out to the transformer stations to check for local failure and take appropriate action.
This is costing utilities time and money. As a key first step they should look to adjust network reconfiguration to equip at least 20% of the Ring Main Units (RMU) with Remote Terminal Units (RTU), so that basic data like voltage levels, load floats or temperature can be monitored remotely and managed from the control centre.