This project has received funding from the European Union's Horizon 2020 research and innovation programme under Marie Sklodowska-Curie grant agreement No 675318

Control of Hybrid AC/DC Grids

Adedotun J. Agbemuko INCITE Fellow

1

Personal Introduction

• Adedotun Jeremiah Agbemuko (Ade).

• Nigerian.

• B. Eng. Electrical Engineering (FUT, Minna), 2012.

• MSc. Electrical Power Systems (Delft), 2016.

• PhD (UPC, 2016-?).

2

Project Information

Title: Control of Hybrid (High Voltage) AC/DC Grids

Main Location:

IREC, Barcelona, Spain

Supervisors:

José Luis Domínguez-García (IREC)

Oriol Gomis-Bellmunt (UPC)

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4

• Administration • Documentation • Enrolment at UPC

Literature review: • AC-DC Grid Interaction. • Stability • Oscillation (and damping) • Harmonic interaction • Ancillary services • Controller interaction • …among others.

December October-November September

• Framework for modelling (including modelling philosophy, software, benchmark, tools).

• Software acclimatization. • Multivariable Control Review.

Review Paper on State-of-Art

Extra-curricular Courses • Course on Research Ethics. • Spanish language for beginners

Journey so Far…

Motivation for Project (1)

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2010 2050 Contribution of Renewable energy to electricity consumption and expected contribution up till 2050 Source: EWEA EU Energy Policy to 2050

Motivation for Project (2)

EU Policies to reduce greenhouse gas emissions. Source: EWEA EU Energy Policy to 2050

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2010 2050

Motivation for Project (3)

7

2010 2050

HVAC HVDC Can only connect unique resources – synchronous generators

Can connect characteristically distinct resources – renewables and fossil fuels

Unacceptable environmental footprint Very little environmental footprint

Limited power transfer More power can be transmitted for an equivalent AC system.

Cost grows higher beyond distances of 600km

Cost is much less beyond the same distance

Higher insulation requirements Lower insulation requirements compared

Production and consumption of reactive power

Unity power factor

Overloading is avoided at all cost for stability reasons

Can be overloaded up to 1.2x rated power continuously

Motivation for Project (4)

8

2010 2050 Conventional Power System Stability Classification Source: Definition and Classification of Power System Stability

Motivation for Project (5)

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Development and

Advances

System is changing

and we need to be

able to advise the

TSOs.

Strict requirements

by TSOs on grid integration of RES.

System security

and Stability

Ancillary services

and support

Stability

Technical Issues

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Converters’ interactions within the DC grid and with the AC grid

Harmonic interactions

Stability of both grids Ancillary support

and services

Coordinated control

Inter-operability

Trends • Phenomena mostly studied from perspective of

conventional power system.

• Oscillation damping (part of ancillary services).

• Multi-variable control is gaining ground.

• Communication requirements.

• Determining new CCT of circuit breakers to ensure stability with increasing power electronic converters.

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State-of-Art on AC-DC Interaction • Brilliant contributions towards identification of

AC-DC grid dynamic interactions – but only a few.

• Oscillation damping.

• Controller design and synthesis.

• Influence of system variables on dynamic characteristics and stability of AC-DC grids.

• Study of mainly AC system phenomena.

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State-of-Art on Ancillary Support

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Zero Carbon Biopower

Gaps in Literature (1) • Most focus is on “relatively” short distance.

• Almost exclusively cables (No OHL).

• WPP not modelled in great detail.

• Either AC or DC side modelled in detail.

• Size of one grid overshadows the size of the other – cannot be generalized.

• Scenarios are either on the AC side or on the DC side; rarely both.

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Gaps in Literature (2) • Dynamic system evolution based on progressive

integration of renewables has not given attention.

• Proposals are too specific.

• Almost no studies on harmonic interactions.

• More attention on ancillary support from the DC grid.

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Direction of this Work (1)

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Models to capture both AC/DC side dynamics without sacrificing too much computational time

Further research on identification of AC-DC interactions

New phenomena and mitigation or control strategies

Harmonics and Mitigation strategies

Controller design and synthesis (Extension to MTDC)

Coordination and control

Direction of this Work (2)

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Grid level integration of storage technologies and posible interactions

Distributed contribution from RES (WPPs)

Advanced strategies for ancillary support Influence of physical

properties of grid on interactions and phenomena

Stability assessment

FACTS

Collaborations (Second Year)

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ESR 3.3 WPPs

ESR 2.2/2.3 Energy Storage

ESR 3.2 Stability Assessment

Others? Others?

Others?

ESR 3.1 HVAC/HVDC

Next Steps…(Tentative)

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December

Framework for modelling

Software acclimatization

Multivariable Control Review

Modelling

Extracurricular Courses

Review report/Paper

January-April (May)

Modelling (detailed and averaged)

Developing tools

Model Validation

Extracurricular Courses

Conference/Journal Paper

May(June)-September

Studies (Harmonics, Stability, control)

Conference/Journal Paper

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THANK YOU!