In a presentation at the ABB Customer World Africa 2018 recently, Claudio Facchin, the president of ABB’s power grids division, said that the changing generation landscape, including an increase in the penetration of renewable energy sources, has introduced certain challenges. The grid, Facchin said, which was originally built for one-way power flow, has had to adapt and will continue to evolve. The grid of the future will be stronger, smarter and greener than what we have currently.
Following the presentation, Energize asked him to explain what that grid would look like and how it could be used to benefit the more than 600-million Africans who have no access to reliable electricity.
According to Facchin, the increasing penetration of renewable energy sources in many African countries will require grids that can cope with the variability of supply, a common feature of wind and solar energy. ABB has the equipment to provide these countries with reliable electrical supply, he said.
The grid will need to be more resilient, i.e. stronger, to manage the variability of supply – especially in large bulk solar PV and wind installations – which will require more investment in the transmission part of the grid, including more interconnections and ideally, HVDC. As reliable electricity becomes available to more people, the load will increase and new technologies such as electric vehicles will become more common, he says. The grid must therefore be strong enough to meet the demands of these new and future loads.
Power quality, frequency and flow control will have to be managed. This will require smart, digital technologies which the company can already offer. Facchin says that when he speaks of new technologies being greener, he is referring to more than simply integrating greener energy sources into an existing network. The company is investing its R&D spend on designing new products with sustainability in mind, such as reducing losses in transmission lines and transformers, while moving away from SF6 in circuit breakers to non-greenhouse gases, he says.
The benefit of microgrids
Facchin says that microgrids are ideal in Africa because the great distances between rural communities and urban centres or points of existing generation would make extending traditional transmission lines too costly and would take too long. Microgrids which are disconnected from the grid and fed by localised power generation sources such as PV and wind rather than from diesel generators which are costly to operate and produce unhealthy emissions, and which are built close to the load centres, would be a more practical solution, he adds.
A microgrid, Facchin says, together with energy storage, would manage the supply and load effectively. In some cases, existing HV transmission lines do run near small communities, but the cost and complexity of building traditional substations to supply power to those communities are often uneconomical. He says the company has developed a very simple and affordable technology to allow communities to tap into high voltage power lines. This solution apparently uses a voltage transformer that has been enhanced and could provide a few hundred kW at 400 V for local communities.
Over a longer term, Facchin says, a large scale renewable energy plant, generating hundreds of MW, which provides electricity even more cheaply, could be built to supply these rural communities. This would then require FACTS devices and an HVDC grid to bring the power to those communities efficiently and at low cost.
The importance of security
The scourge of metal and cable theft at electrical installations, as well as various other threats the sector is facing, can be addressed by improving security and making use of modern monitoring equipment, Facchin says. The company recommends the use of grid sensors and asset monitoring equipment to measure both performance and physical condition of electrical assets. Digital monitoring of earthing or overloads on transformers with alarms being sent to control rooms can provide an early alert to utilities under attack and hopefully result in the apprehension of the culprits before too much damage is caused. Physical security, in terms of access control and presence detection at substations, is vital and must be provided by the power utility which owns or operates the substation. According to Facchin, ABB’s SCADA equipment can include functionality to provide such monitoring.
The challenge of ageing equipment
In some places, very old transformers and switchgear are still in operation, Facchin says. To address this challenge, the company is investing in new products which can replace older equipment and offer improved performance with higher reliability. However, he says, the company is aware that the asset base of a power grid is heavy and mission critical. Where existing equipment is very old, it is wise, Facchin says, for the equipment to be monitored by means of sensors. Data from these sensors can be sent to the control room to measure the true state of this older equipment. These steps would help the utility to plan repair or replace programmes. These interventions will save the utility money, lengthen the operating life of existing equipment and ensure a more reliable electrical network with fewer breakdowns.
Regarding the future, Facchin says, the company wants to keep its leading position in the area of power equipment supply and to leapfrog existing technologies by leveraging the digital technology which is becoming common across the industry, making sure that it not only supports the development of traditional hardware, but also adds the digital aspect – the software – and makes sure that the technology is available where needed.
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