Sustainable urban power supply through intelligent control and enhanced restoration of AC/DC networks

Lead Research Organisation: Cardiff University
Department Name: Sch of Engineering

Abstract

China remains the world's largest electric car market, and the UK is leading deployment of electric vehicles (EVs) to meet the new net-zero 2050 emission target. Both nations will face challenges in connecting EVs in urban areas due to limited land space, constraints on carrying additional power over traditional transmission lines and challenges in providing reliable power to critical load centres. This proposal identifies areas of common technical challenges and lays out a joint programme to analyse the issues and assess possible solutions.

Urban areas are the significant location of critical loads such as hospitals, airports, public transport network and data centres. Fully exploiting the potential transfer capacity and resilience of the urban electricity network with a minimum capital investment is important to citizens and governments as 60% of Chinese population and 83% of UK population live in urban areas. To release the capacity of existing AC lines and to increase the reliability, a combined AC/DC configuration is proposed, and contribution of power electronic materials and converters are considered. Coordinated control of EVs, hybrid AC/DC networks and dispersed generation are investigated to optimise transfer capacity and enhance fault-tolerant operation with the support of Internet-of-Things (IoT) tools to enable an efficient decision-making.

Two specific aspects will be investigated: the ability of IoT based data-driven modelling method to enable response services by coordinating dispersed resources in an urban power network and the headroom provided by power converters to accommodate this service. The contribution of IoT in providing useful data that enable the efficient management of urban power network is an emerging paradigm for the realisation of smart cities. As an essential part of daily life, optimal utilisation and reliability of electric energy becomes paramount. However, blackouts affecting the security and stability of the power system is an important issue. EVs storage capacity and optimal scheduling through power converters will be explored and quantified to provide grid support services in the event of an emergency situation. Protection schemes that can achieve fast and reliable identification and isolation with the aids of IoT, EVs and power converters are analysed in detail and re-engineering solutions proposed.

Technical challenges from widespread use of dispersed resources connected to urban energy networks will be studied. Data-driven modelling will be applied to urban power systems to characterise the capacity of EVs and distributed generations that will allow two-way communication that transforms conventional networks into more secure networks. Traditional network topologies with the inclusion of power converters will be reassessed to eliminate potentially wasteful energy conversion stages and support flexibility services. Coordinated control of converters and distributed resources with spatial-temporary coupling and edge-cloud collaboration will be developed to make cost-effective, sustainable, resilient and fault-tolerant urban power system operation.

The key outputs will be the data-driven modelling and analysis methods that can assess the spatial-temporary relation between distributed resources and urban electricity network (useful to system operators and equipment vendors); engineering solutions to map the capability of vehicle to grid services; optimal scheduling using power converters in the event of an emergency situation (useful to system operators, equipment vendors and EV owners); and verification through real-time simulation and scaled laboratory test systems.

The main work programme will be conducted through international partnership with 1 China research institute, 2 China universities and 2 UK universities. Researchers involved in the project will benefit from the unique international collaboration and training.

Planned Impact

The proposed interdisciplinary research will provide significant advances in technologies to deliver large-scale services in energy systems by enabling interactions between EVs and power electronic based dispersed generation through IoT based communication architecture. By supporting the system operation through flexibility services and black start provision, dispersed sources are becoming important assets in contributing government's low carbon targets.

The need to enhance resilience and capacity in urban areas with significant critical loads (hospitals, airports, transport networks and data centres) requires transmission system expansion which places economic burden on a country. It is important for citizens and governments to achieve increased capacity with a minimum of capital assets. Smart grid technologies supported by digital tools are cost effective against building new circuits, as this can increase asset utilisation by coordinated control. Researches in this project on analysis methods and control schemes that demonstrate increased transfer capability, flexible services, reliable operation and fault tolerant capability will lead to lower energy provision cost.

As a project partner, the Newcastle City Council will bring their perspective on community development, quality of life and infrastructure requirements to enable future sustainable cities with digital technologies. Providing software tools to support these requirements with IoT design is a specialist activity undertaken by the likes of Zero Carbon Futures and Plexus Innovation providing the cloud software. The collaborations with these industrial partners in the project have the potential to expand the options to improve transport and air quality in cities.

The consortium includes a UK network operator, Scottish Power Energy Network (SPEN), and China Electric Power Research Institute (CEPRI), representing a China operator, as industrial partners with whom the UK universities have worked closely for many years. SPEN is considering to roll out flexible control devices and IoT in the forefront for actively managing their assets and networks to enable their transition from DNO to DSO. The main obstacle and challenges they face in this transition include understanding of planning, operational, protection and reliability issues. Cardiff University has already assisted SPEN in their flagship MVDC link project to map out various issues. This project will add analysis and simulation of cases studies to progress the understanding through the inputs from partners NR Electric Ltd and Turbo Power Systems, manufacturers of smart grid power converters.

This project brings together the multidisciplinary expertise on IoT, EVs and power electronics for urban energy system modelling and operation. This is not industrial practice yet and progress here would benefit a system operator's understanding of subsystem interactions and an equipment vendor's understanding of transient loadings on their assets. A societal issue for several parts of the world is how capacities available in EVs on dispersed locations can contribute to revenue and grid support services through vehicle to grid connection. This could apply to urban centres in China or UK, where widespread EV uptake is forecasted. A cost-effective means to feed excess energy when EVs are not in use would allow development to be widely stimulated.

The cooperation among the UK and Chinese academic teams in IoT, distribution networks and power electronics, with excellent experimental facilities, will provide an exceptional basis for extensive international collaboration in these areas. Key project findings will be disseminated in international conferences to promote early visibility. This will be followed by high level journal publications to reach wider academic and research communities.

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