DEMO 3 UPGRADING OF MULTI-TERMINAL INTERCONNECTORS

“UPGRADING EUROPE’S GRID TO NEW HIGH-CAPACITY TECHNOLOGIES” BEST PATHS DISSEMINATION WORKSHOPBERLIN, 26 OCTOBER 2016

Diego Cirio

RSE

27 October 2016

1967: Sardinia-Mainland

1987: 50 MW tap station in

Corsica

Converters Submarine cables

Land cables

Overhead

lines /

insulation

Converters

TOSHIBA

EUROPE

Submarine cables

NEXANS

Land cables

NEXANS

Overhead

lines /

Insulation

DE ANGELI

RSE

TERNA

TERNA RSE

TERNA

System

DEMO 3: OVERVIEWSardinia – Corsica - mainland Italy (SACOI)

2

3-terminal interconnection, 300 MW, ± 200 kV monopolar with sea electrodes

Complete “rehabilitation” decided and included in the Italian national grid development plan and in ENTSOE TYNDP 2016

Good laboratory for demonstrating new HVDC technologies!

DEMO 3: ACTIVITIES

HVDC CONVERTERS

Toshiba Europe

3

Converter technology – Toshiba T&D EuropeFocus on DC fault on OHL section

SACOI-II

upgrade to

Bipolar

HVDC/VSC

Link

4

Converter technology – Toshiba T&D EuropeDEMO Work - Circuit-topology VSC-converter developed by Toshiba

A buffer-reactor free, half-bridge VSC converter with a special converter transformer:

• Small footprint

• Small leakage flux (low induction currents in nearby metallic structures, e.g., in offshore platforms)

• High reliability (applying state-of-art IGBT device (Toshiba IEGT) )

• full current, pro-rated voltage MMCs (real scale half-bridge modules and controls)

• MV scaled converter transformer

• equipment manufacturing, site installation and operational testing

5

Converter technology – Toshiba T&D Europe

DEMO Work - Circuit-topology VSC-converter developed by Toshiba

6

DC power of the full DC Current

12 MW, +10 kVdc, 1200 Adc

Converter technology – Toshiba T&D EuropeDEMO Work - Circuit-topology VSC-converter developed by Toshiba

7

DEMO 3: ACTIVITIES

HVDC CABLES

Land & Submarine

Nexans

8

Test loop energized June 2016

9

HVDC XLPE Submarine Cable

• 400 kV• 1600 mm2 Cu • Compact conductorto minimize overalldimensions

• Minimized weightto allow deep seainstallation with reduced axial tension

Successfully produced a prototype length

Successfully tested water penetration100 Bars (1000 m depth)

• water penetration 2.4 m -- > Test Passed

Test loop energized April 2016

10

HVDC XLPE Land Cable

• Successfully produced a prototype length• 2500 mm2 Al Conductor (Milliken)• 21 mm XLPE Insulation• Metallic screen, Al laminated• Outer protective jacket,

HDPE/HFFR + SC skin

HVDC Extruded Repair Joint Cutaway

Design is identical to Land Field Joint

Additional features: external Steel case to withstand deep sea Laying tension

Bend stiffeners to avoid excessive bending (exactly like in phone charger)

The Mechanical Preconditioning for 500m depth

DEMO 3: ACTIVITIES

CONDUCTORS for HVDC overhead lines

De Angeli Prodotti

RSE

TERNA 13

ACFR Conductor

Kevlar® Fibres Core

Aramid fibre core

Rated Tensile Stength

Kevlar RopeStructural Applications

Aberfeldy’s bridge,Scotland

Built in 1992, total length 113 mwith a span of 63 m

Aluminium Alloy wires

Carbon core multistrand

Extruded tube

Tape

Carbon Multistrand

• Identified reliable Kevlar/carbon

suppliers with good production capacity

• Realized first conductor prototype (~300m) for both ACFR & Carbon

• ACFR: Developed special fittings for the core material

• Carbon:

• Finished aging test

• Stranded multi-strand carbon core

RECAP:

NEXT STEPS:

•Installation test

• Installation pilot line• Characterizations test @RSE lab

• Carbon: Stranding conductor

prototype

ADVANTAGES

• Increasing of capacity and at the same time

reduction of line losses

• Reduction of the noise due to corona effect

compared to other HTLS conductors with metallic core

• High flexibility of the core

Set of performances not achievable with existing HTLS

technologies

New technologies permit to obtain:

ECONOMICAL EVALUATIONS

ACSR Ø31,50mm

Carbon fiber solution

Aramid fiber solution

Cost* [€/km] ~5000 ~25000 ~20000

Rel. @370A [Ω/km] 0,0613 0,0589 0,0548

Losses @370A [kW/km] 8,392 8,063 7,502

1 year cost of losses [€/km] 5477 4944 4600

Saving per year [€/km] = 533 877

Pay-back time [y] - 37,5 17,1

* Budgetary cost

Cost of energy = 0,07 €/kWh

Comparison between ACSR and new conductors

ACSR Ø31,50mm

Carbon fiber solution

Cost* [€/km] ~5000 ~25000

Rel. @370A [Ω/km] 0,0613 0,0589

Losses @370A [kW/km] 8,392 8,063

1 year cost of losses [€/km] 5477 4944

Saving per year [€/km] = 533

Pay-back time [y] - 37,5

ACSR Ø31,50mm

Cost* [€/km] ~5000

Rel. @370A [Ω/km] 0,0613

Losses @370A [kW/km] 8,392

1 year cost of losses [€/km] 5477

Saving per year [€/km] =

Pay-back time [y] -

DEMO 3: ACTIVITIES

INSULATIONof HVDC overhead lines

RSE

TERNA

20

Insulation of overhead DC lines

21

• Higher accumulation of pollutants

due to electrostatic fields

• Lower dielectric strengths under DC voltage

• Use of Room Temperature Vulcanizing (RTV) silicon coating (high hydrophobicity)

• Definition of test procedures to characterize the behaviour of new and from service RTV coated insulators (fully and partially coated)

Insulation of overhead DC lines

22

• Design and realization of the test set-up for carrying out long duration, multi-stress(sun, rain, salt fog…) ageing test on 6 RTV covered insulator chains (fully and partially coated)

• Design and realization of device for daily monitoring of the level of contamination of insulators under DC voltage

• Installation in Sardinia in July 2016

• Measurements are ongoing

--- > comparison with AC Amicodevice, already installed in the site

Innovative

Multiscale approach -

small & large scale solver

• A set of 56 chemicalspecies and over 600reactions is involved

• The net production of O3is included as well

• small scale simulation computes the ion emission and electric field on the conductor

Ions currents & electric fields

• Large scale solver gives a pictureof the ions currents and theelectric field around theconductors (relevant for corona)

and on the ground (disturbances

on humans)

DEMO 3: ACTIVITIES

SYSTEM ASPECTS

RSE

TERNA

24

Context

• SACOI connects 2 (or 3) electrical AC islands

• Sardinia and Corsica have weak grids

• Large RES penetration and stability issues in Sardinia

• Another HVDC (LCC) from Sardinia to mainland Italy

Objectives

• Stable operation with the new

SACOI VSC

• Restoration of Sardinia via SACOI

• Aspects of SACOI as «embedded»

HVDC

• Evaluation of the renewable

penetration increase thanks to

new SACOI

Contingencies

Event type

Location of event

“SARCO” AC line

initial state

Initial SACOI

configuration

Initial SACOI power

flow

Initial HVDC SAPEI

state

Complex dynamics,

reduced stability margins

Frequency,

transient,

voltage,

oscillatory stability issues

Controls design ongoing

Outage of Suvereto (Tuscany)Sardinia takes over control of Vdc

-40

-30

-20

-10

0

10

20

30

40

50

0.98 1.48 1.98Act

ive

imp

ort

in S

ard

inia

[MW

]

Time [s]

P Pref

Power reversal in Sardinia

Restoration: SACOI VSC as…

27

1. Black start unit

2. STATCOM

Set-up of a methodological framework and tools for the techno-economicassessment of SACOI 3 and similar HVDC systems

Application to regional and European contexts

Focus on key aspects: reliability, social welfare, RES integration, CO2 emissions, grid losses, flexibility

Ongoing activities:

Pan-European zonal modeling implementation

in 2030 scenarios (ENTSOE TYNDP 2016 visions 1 and 3)

Set-up of nodal model including Italy+Corsica for

detailed evaluations of SACOI3 impact

by a probabilistic tool

Techno-economic evaluations of three-terminal HVDC systems

Source: ENTSO-E CBA methodology

CONTACT

29

Demo 3 leader: TERNA

Contact:

Antonio Iliceto

antonio.iliceto@terna.it

Presented by

Diego Cirio

diego.cirio@rse-web.it

www.bestpaths-project.euFollow us on Twitter: @BestPaths_eu