The Last 30 Miles And Beyond

An increase in the distributed generation and storage of energy, from sources such as wind, solar, combined heat and power, biomass and geothermal, means the network requirements are changing significantly as energy is being fed into the network at various and variable points as well as times.

This trend has a serious impact and is beginning to make life complicated for utility companies, requiring adjustments at various levels. 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 allow a smart way to 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 company and the consumer (residential or commercial), 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 level down through to the consumer, but it can’t stop at the smart meter. To be able to optimise energy consumption, one requires the appropriate home, building and industrial automation solutions to then control the individual devices and systems within the building or plant accordingly.

Traffic Control

Eaton, as a global leader in electrical components and systems for power quality, distribution and control, has been committed to intelligent energy management for years. The company focuses on providing smart solutions right from the end user and low voltage systems, up to the medium voltage level. Today, Eaton is already able to provide complete smart metering solutions based on proven technology and components in all of the necessary areas such as building and industrial automation, automated distribution, smart metering as well as connecting electric vehicle charging stations and renewable generation from photovoltaic systems to the network.

Eaton’s xComfort, for example, is a wireless system for the smart home that has been tried, tested and refined since its launch in 2003. It offers the user an outstanding level of flexibility both in the installation of components, such as sensors and actuators, and in the logical connection of these components (HVAC, shutters and lighting control). In combination with a smart meter, the capabilities are taken to the next level in terms of monitoring and managing energy consumption, as not only the amount of energy purchased can be measured but connected appliances can also be controlled according to electricity tariffs via the integrated xComfort interface.

Smart meters aren’t only able to provide the end user with remote information and control to monitor and visualise energy consumption on things like TVs and computers, but could also integrate smart appliances like washing machines, dish washers and car charging stations, enabling them to automatically operate at the most energy efficient and cost effective time.

So, looking at what is already reality and what is still wishful thinking, the truth is that transparency and direct feedback 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. Features like flexible tariffs and dynamic pricing, load profiling and power thresholds 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 forward 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 energy generation, then the relevant consumer devices could be switched on accordingly, at a time they normally wouldn’t.

On the industrial side of things, Eaton’s portfolio includes, for example, the metering and communications module NZM-XMC. It has been designed for energy distribution and motor control centres to allow recording of energy usage and support analysis of consumption. This way, the usage can be reduced and the need for information, especially in light of more and more energy audits, can be met. At present, Eaton is seeing a high take up of this solution, especially in the automotive sector. At production plants with machinery that uses a lot of energy — like welding lines — each unit is equipped with an XMC module and can thus be individually controlled as needed: slowed down, shutdown or switched to standby. Another trend in the industry that the metering and communications module supports is sub-metering and real consumption-based invoicing.

Intelligence To The Mid-Level

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 system. 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), or which users are connected or disconnected. Today, Eaton estimates only 5-15% of the sub-stations are actually automated, where some European countries are more advanced than others.

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 utility companies time and money. As a key first step the utilities should look to adjust network reconfiguration aiming 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. Here, the SAIDI (System Average Interruption Duration Index) is the main driver, representing the average outage duration for each customer served and which is used as a reliability indicator by the utilities.

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Within its comprehensive portfolio of medium-voltage switchgear, Eaton does already have a solution to meet this demand. A new generation of RMUs called Xiria is part of the company’s environmentally friendly and SF6-free range of products and has been designed with sustainability, safety and future needs in mind. It is one of the smallest ring main units of its kind, made with exclusively environmentally-friendly materials, based on vacuum technology and is maintenance free. Xiria can be used in compact transformer stations for energy distribution, in accessible stations in the utilities sector and in industry, as well as in decentralised power generation systems such as wind farms. The unit is completely ready for use in fully-automated networks. There are various options available for the system depending on the level of remote signalling and remote control required. These options are modular, so they can quickly and easily be added as needed. Future RMU solutions are not only expected to provide information at the transformer level, but also include intelligence right down to the individual smart meters.

All of this means that, as soon as the remaining Smart Grid politics, regulatory and infrastructure challenges settle down providers will be in a position to deliver intelligent solutions for the last 30 miles and beyond, to the smart grid market.