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State-owned power utility Eskom has started to deploy a hybrid smart grid model that supports its legacy time- division multiplexing management system, while gradually introducing an Internet Protocol (IP) packet communication system, which will enable smart demand-side management, automatic correction and the connection of variable, renewable-energy generation capacity.
However, Eskom acting GM for research, technology and development Barry MacCollnotes that the business case still needs to be demonstrated. The utility is optimistic, though, that by deploying smart grids, it will increase the combustion efficiency of its coal fleet, be in a position to monitor and increase the reliability of renewable generation capacity, such as solar and wind, as well as improve the visibility and reliability of equipment.
“The business need is important. While the technology and devices need information and communication technology architecture that can cope with the data burden, we must be able to deploy and interface with our existing systems,” MacColl said at an Eskom smart grid conference in February.
“We are looking at rolling out advanced metering infrastructure. But it is crucial that such devices can interface with our billing system, for example. These are the questions management asks again and again, and [this is] usually where suppliers do not focus enough attention.
“We are focusing too much on the technology and not the reasons for implementing the technology. We need to be able to do demand-side management [and] revenue management, and a smart grid must improve the safety of the system, as well as have a common language to enable all devices to talk to one another,” he stipulates.
He mentioned that the response to stimuli must be part of the smart grid, with devices able to make decisions, but that this would require millions of devices talking to each other.
“If a circuit trips, the system must be aware of the load on the lines [and] the temperature of any equipment pieces, and if there is anyone in the switching yard before making a decision.
“Eskom grids are pretty smart, but rely on human intelligence. We need to be able to control many different devices, whether [we have to switch] off home devices as part of demand-side electricity management, or [get] data and information from equipment. There will be a massive flow of data to control the energy, pricing and intelligence to enable customer devices to respond to different pricing and demand times.”
This will enable Eskom to, rather than load-shed, increase the price of electricity to reduce demand. If devices were intelligent and responded to a high-price stimulus, they would be able to make certain decisions regarding power use.
“The introduction of independent power producers to the grid is increasing the need for such a smart system, so that a smelter, for example, can decide whether to use electricity from a solar installation, a wind farm or the grid.
“Real-time pricing and the flow of money will be crucial in making such decisions,” emphasises MacColl.
Further, Eskom has done a lot of research on community-scale smart grids with power sharing between different houses with small photovoltaic (PV) and wind generators. However, the use of such small-scale devices may change, depending on the price of electricity, with devices set to charge batteries or to use the energy when Eskom power is too expensive, or for the home system to switch to the Eskom grid when there is no wind, he says.
“The microscale grid is what I find exciting, because I believe the day is rapidly approaching where every middle-income and above-average- income household will have some form of PV installation on the roof. There are 6 GWh of solar PV installed on rooftops in Germany.
“It does not have to power the whole house, but can be used to power the lights, television and a computer, for example,” he says.
However, the rapid flow of data on energy availability and cost, and the ability to manage supply and demand, are critical to enable the utility and its customers to determine how and when to produce or use electricity.
“It is possible to have up to 300-million different addresses on such a network. And, depending on the packet sizes that we are now sending between these devices and the data speeds, that is a lot of data.”
Further, there is a need for near real-time networks. The Internet is beginning to become near real time and the energy system may soon be near real time. This is important because there is a need to be able to control devices immediately, whether as a customer switching off devices during times of high prices or as Eskom increasing generation or the network automatically correcting a fault, says MacColl.
Smart Grid Catalyst
The ever-increasing demand for electricity, load management and demand response are some of the catalysts for introducing smart grids. Further, on constrained grids, a smart system can enable a utility to safely exploit the maximum capacity available, says network infrastructure equipment company ECI Telecom global utility market manager Erez Koren.
“The number of people in Africa not connected to the grid is set to increase as the population grows, in contrast with other parts of the world where the number of people not connected is decreasing.”
It is not uncommon to lose up to 25% of generated electricity in parts of Africa, far above acceptable losses of between 6% and 7% in most developed-country utilities, he says.
“This makes the use of a smart grid important, because we want to support the maximum number of people we can on the existing network.”
He notes that a hybrid model can be deployed to support the convergence of legacy systems, which can then be converted into a single secure and efficient IP network.
Further, the systems can remain time- division multiplexing and synchronous digital hierarchy networks, which will enable com- panies to use a single network without the need to duplicate any infrastructure before the roll-out of the IP/MPLS (multiprotocol label switching) network is complete.
“The network must support ease of use, but must be able to perform complex IP network operations. We need to ensure the ability of the network to route a mix of different data traffic,” says Koren.
However, the crucial long-term view that must be addressed in South Africa is the issue of regulations.
“The pace of regulation is slow and the transparency of regulatory decisions must improve because the cost of blackouts is increasing and there is a need for a secure supply of electricity,” he notes.
Further, utility network company Smart-Grid Technologies technology and business solutions director Jako Winter says the utility has identified a need for the communication standardisation of smart meters and devices, because many devices work on different protocols.
“For the different machines to communicate properly, we have to implement a standard- based information and communication technology (ICT) solution. We have to ensure interoperability between systems and that we stay with the standards set. What we implement today will affect what we will be able to do with a smart grid in the future,” he says.
For example, Winter has done a number of studies with Eskom on using IT to improve and stabilise its distribution grid. Eskom has implemented smart grid technologies successfully on parts of its 400 000 km of lines and has rolled out fibre-optic cables to most of its larger distribution substations, using a technique called Skywrap that winds the cables along the earth conductor of existing power lines, and has microwave and general packet radio service (GPRS) communication with its more remote distribution substations.
“Eskom is busy building an IP network, a ring fibre network, between all the substations, so that they can get that level of the distri- bution network onto the sought-after communication technology.”
“Further, on the distribution side, the visibility of equipment is important to Eskom, so, within the utility, there is a drive for network visibility. However, a problem Eskom has with its current ultrahigh-frequency network is that it does not cover the whole country, especially the rural areas, where you have automatic reclosers at the end of a 300 km line.
“These equipment pieces operate independently; however, Eskom wants to be able to see the status of the equipment and what is happening on the line. It cannot currently see the end of the line at the customer’s premises and can only measure lines to the end of the distribution substation. However, if we know there is a fault and where the point of failure is, resource visibility is of significant benefit in reducing the duration of outages,” says Winter.
From 2004, Eskom has been evaluating GPRS based on its footprint and possible cost reduction advantages. What has emerged is that, because it is also an IP-based system, Eskom distribution engineers and field engineers now often ask for new capabilities, which are possible because there is an IP link to equipment in the field.
“This has made a significant difference in the types of applications that are available for use on the equipment now and in the future,” notes Winter.
“Eskom’s north-west division has imple- mented automatic metering to improve resources and has also identified a chance to use the global cellular system for mobile communications to measure voltage on the lines, which can be used to pinpoint a failure before the customer calls in.
“Customer service is a key driver for Eskom. If we know about the fault and where the fault is, we can send technicians to the fault. From a resource perspective, implementing a smart system is a significant benefit to enable the company to see the problem at the point of failure,” says Winter.
Meanwhile, global network technology company Alcatel-Lucent global utility market business development VP Lynn Hunt says collaboration between utilities and ICT companies is important to extend grid visibility and control to include customers.
“There is no single technology for this and, even in single utilities, such as Eskom, several different communication solutions may be employed, depending on what existing assets can be leveraged, the topography, population density and the business drivers.
“We see multiple technologies being deployed to enable full smart coverage of the electricity grid, including wireless, wire-line, and long-term evolution, or 4G, networks. The 4G network also affords utilities the opportunity to build private LTE networks to get high bandwidth and reach to cover their field area networks,” he says.
A successful model in the US has utilities sharing public communication channels, such as the public safety channel, with other organisations, often including State-mandated organisations.
“However, it is key that the technology choices we make should not be made in silos, or only as pilot projects, but in a holistic fashion, aiming for a fully deployed smart grid. Make choices that you will be able to leverage in the future on the investments you make now,” he concludes.