By Tim Spearing, Automation Product Manager at Lucy Electric
The move away from centralised electricity generation – gas, coal and oil, and the large power stations that go with this – to generation from distributed energy resources (DER) using renewables is a great opportunity and a major issue not just across Africa but globally.
The article appeared in ESI Africa Issue 1-2021.
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This change has comprehensive support from governments and society as countries look to decarbonise their power generation, but how easily can small and decentralised renewable energy sources be integrated seamlessly into the network to replace fossil fuel-based generation?
While everyone acknowledges that this must happen, there are many challenges around making it happen. There has been significant investment in power grids across Africa in the last few years, but it will now require more investment to deal with the new reality of power generation in the 21st century.
One of the key challenges around the new regime is the intermittent nature of renewable generation and its effects on grid stability. Compared to gas turbine power stations, renewable energy sources cannot match the consistency and response speed.
Voltage control and fluctuation is also an issue. With less reliance on or accessibility of large power stations, there is the potential for a reduction in the network operators’ ability to maintain local voltage levels within required margins, in part due to the loss of reactive power.
Fault identification and reduction are also important, with DER reducing existing grid protection’s ability to recognise when power system faults occur accurately. The data and experience of utilities using Lucy Electric’s Gridkey technology are that the increased visibility is improving fault identification, response and resolution times, which drive improvements in service quality and increase customer satisfaction.
Then there is network access and capacity. The conventional approach to the integration of DER has been to plan for the maximum required load, with fast-acting protection to curtail renewable generation in the event of any network outages or constraints. However, this ‘fit and forget’ approach limits ambitions to incorporate DER because of the costs of reinforcing the network. The digitisation of the network through real-time monitoring provides valuable insight and actionable intelligence about the network’s demands, the capacity available and the health of assets.
As networks are forced to adapt to the changing voltage requirements or reverse power flows from renewables, battery storage or EVs on the LV network, they must consider the additional headroom needed.
The implications of these fluctuations are becoming more urgent as the migration to more generation from renewable sources accelerates. The consequences of not addressing them could make networks more unreliable, increasing faults and reducing the benefits that rural connections and local renewables can have to both decentralise and democratise energy.
This is where digitisation plays an integral part in keeping the decentralised energy system in sync. Advanced management and control algorithms will be needed to keep grids in balance, optimising renewables and preventing faults through real-time monitoring and Active Network Management.
DER and the diversity in electricity supply mean distribution network operators will need to adapt to the changes in consumers, suppliers and network demands. However, the network operators will still need to make the best use of assets through optimisation. It will be more important than ever that utilities can take predictive action rather than reacting to changing situations.
Power grids will need to adapt and become overlaid with a combination of sensors, measurements, and communications devices, to create systems that mutually support each other. The physical layer – the power lines, transformers, and electrical devices such as ring main units – uses smart technology to enhance grid management.
As much as being the vehicle for energy flow, the grid becomes a flow of data and information between supplier and consumer. Recognising this development led Lucy Electric to adapt our Aegis range of Ring Main Units to link these two layers. Using the remote communications technology of our Gemini RTUs, the Aegis Plus gathers information and processes the data actuating a response from the physical infrastructure. This decision-making can range from electrical switches’ basic operation to managing demand dynamically through automation schemes and software controls.
Synchronising local resources
Digitisation and data processing are key to unlocking the potential of decentralised grids by truly understanding local areas’ demands. Adding to local demand considerations, DERs need to be synchronised with the system’s overall demand, both in terms of frequency and usage.
With the rapid growth in renewables, it will not be possible to effectively manage and operate an electrical distribution network without using smart switchgear and real-time software support. Smart control will not only enable the network to accommodate more DER, but it will also do it by releasing network capacity and, therefore, improving network access for developers and communities.
In the past, utilities only had to deal with seasonal or known demand patterns, such as the classic post soap opera or football match surges as people put the kettle on, but with DER, this has changed. An upstream adjustment in generation can no longer address peaks of demand or fluctuations in voltage – the local grid conditions and characteristics are more complex and varied.
Making the best use of digitalisation is key to managing this new environment. The deployment of sensors on switchgear such as ring main units and overhead load break switches provides the ability to measure the voltage. The ability to operate these switches remotely or to automate them enables the localised control needed to manage the DER.
Decarbonisation demands that we embrace distributed energy resources and the new way of operating networks – and digitalisation will help us make the new future a reality. ESI
Learn more from Tim Spearing
Access the webinar recording where Tim discussed these challenges, the role of data and digitisation, and the solutions being deployed across African utilities in more detail.
About the company
Lucy Electric are experts in secondary distribution solutions, enabling the safe and efficient distribution of electricity to homes and businesses across Africa. Our experienced engineers work at the forefront of the design and implementation of automation projects, from concept to deployment, and we use our engineering excellence to design and manufacture best-in-class automated switchgear products and services. www.lucyelectric.com