Offshore Switchgear

Medium Voltage Switchgears for Offshore

Mario Haim

R&D Director

Barrow (12)

Beatrice (6) Robin Rigg (24)

Horns Rev 2 (14)

Gunfleet

Sands (10) _{Borkum West II (38)} Thornton Banks (85) Alpha Ventus (28) Greater Gabbard (420) Walney I+II (20) Cote D'Albatre (16) Rödsand (16) Veja Mate (34) Ormonde (90) West of Duddon Sands (18)

Global Tech (370) Baltic II (30) Riffgat (12) Dan Tysk (24) Meerwind (32) Nordsee Ost (145)

Our Offshore References

With WS market leader in ≥5 MW offshore Windturbines

With GHA market leader in offshore substations

Mo

re t

han

150

0 p

ane

ls

offsh

ore

in P

rim

ary

ap

plic

atio

ns

Schneider Electric- Infrastructure – Mario Haim – 2012 3

Offer for any MV offshore application

Agenda

●

Market trend

●

Wind park layout & Short circuit level

●

Requirements

●

Overvoltages

& Insulation coordination

Schneider Electric- Infrastructure – Mario Haim – 2012 5

Main areas for Wind Offshore in Europe

Moray Firth

Firth of Forfh

Dogger Bank

Hornsea

East Anglia

Hastings

Isle of Wight

Bristol Channel

Irish Sea

North Sea

Baltic Sea

32 GW

25 GW

5 GW

Le Treport

Fecamp

Courseuilles

Saint‐

Brieuc

Saint‐Nazaire

6 GW

18 GW

10 GW

5 GW

6 GW

*Capacity to be intalled until 2030

*Capacity to be intalled until 2020

Carbon Trust

Carbon Trust has brought together 8 offshore wind developers in a

joint

industry project

to work towards

reducing the cost

of offshore wind

by at least 10% by 2015

.

●

DONG Energy

●

EON,

●

Mainstream Renewable Power,

●

RWE Innogy,

●

Scottish Power Renewables,

●

SSE Renewables

(formerly Airtricity),

●

Statkraft,

●

Statoil,

Schneider Electric- Infrastructure – Mario Haim – 2012 7

Market trend

Clear recommendation:

Go to

66 kV system voltage

in

66 kV in tower + substation

-tower switchgear

at 66 kV

-platform

switchgear

at 66 kV

-transformer

at 66 kV

Schneider Electric- Infrastructure – Mario Haim – 2012 9

Agenda

●

Market trend

●

Wind park layout & Short circuit level

●

Requirements

●

Overvoltages

& Insulation coordination

Schneider Electric- Infrastructure – Mario Haim – 2012 11

4 types of wind turbines

Induction

(asynchronous) generator

Vestas

(Neg

Micon), Siemens (Bonus)

Strong points:

robust and simple

Weak points: low efficiency (fixed speed), flicker, no

control of reactive power

Doubly-Fed induction generator

Vestas, General Electric, Gamesa, Nordex

Strong points: variable speed (wide range), control of

reactive power

Weak points: produces harmonics (but only 25% of the

power goes through the converter)

Induction

(asynchronous) generator

with

slip control

Vestas

(for

US market), Gamesa (for

US market), Suzlon

Strong points:

variable speed (limited range), low

harmonics

Weak points: low efficiency, no control of reactive power

Variable speed induction or

synchronous generator

Enercon, Multibrid,

General Electric, Siemens, Clipper, Vestas

Strong points: total variable speed, control of reactive

power, fast answers to bad electrical conditions coming

from the grid

Weak points: expensive, huge size, produces harmonics

(100% of the power goes through the converter)

GENERATOR INDUCTION COUPLING CAPACITOR BANK G

CAPACITOR

BANK

R

G

L1

L2

8% of manufactured

No converter

Ageing technology

20% of manufactured

No converter

Ageing technology

42% of manufactured

25% power through

converter

Main Onshore

technology

30% of manufactured

100% power through

converter

Wind park layout & grid model for 66 kV

simulation

●

Based on the defined network architecture the

model was created

●

For this model a static simulation (short circuit

level) and dynamic simulation (transient recovery

voltage) had been done

Schneider Electric- Infrastructure – Mario Haim – 2012 13

Static network simulation: Short circuit

level

•

The thermic

short circuit inside the 66 kV network

architecture can be between

11,33 kA and 18,04 kA

&

29,07 kAp

and 46,24 kAp

peak value for short circuit

•

Inside the tower the maximum thermal short circuit level is

between

10,94 kA and 17,13 kA

& the peak value between

27,86 kAp

and 43,17 kAp

A 25 kA System at 66 kV is fully

sufficient

Schneider Electric- Infrastructure – Mario Haim – 2012 16

Agenda

●

Market trend

●

Wind park layout & Short circuit level

●

Requirements

●

Overvoltages

& Insulation coordination

Key Requirements

Cost efficient

Safety

Environment

Reliability

Schneider Electric- Infrastructure – Mario Haim – 2012 18

General Service-Conditions for MV switchgear

according to IEC 62271

●

In principle indoor switchgear according IEC 62271-1

●

Offshore Conditions exceeding the ‘normal’-conditions

●

Standard -5….+40°C, 24h average < 35°C

●

Ambient air not polluted with corrosive materials like salt etc.

●

Relative 24h average humidity not exceeding 95%

●

condensation occasionally

●

Relative monthly average humidity not exceeding 90%

Additional Challenges for the switchgear: Harsh environment

●

saline atmosphere

●

humidity

●

Corrosion resistive

●

Vibration due to operation of Windmill

●

Low temperature operation without external power supply

●

Operation starting at deep ambient temperature without any preload

(cold start)

Schneider Electric- Infrastructure – Mario Haim – 2012 20

Reliability

Design responding to additional challenges

●

Gas Insulated Switchgear

with

●

Sealed Pressure System for Electrical active parts

●

Hermetical closed gas tanks

●

High-voltage parts are contained in a tightly sealed

stainless steel tank

●

Corrosion resistive

components:

●

Drive for devices

●

Housing

●

Connections

●

LV-equipment

●

Vibration withstand

●

Vibration tests with dedicated frequencies

●

Low temperature withstand

●

Mechanical operations tests at low temperature

Safety

●

Optimum safety of operation due to a

complete interlocking system

●

Degree of protection:

IP65

for the primary part

●

Personal safety due to Internal Arc withstand:

IAC AFLR up to 40 kA

●

Switchgear tested and certified

according to

IEC 62271

Schneider Electric- Infrastructure – Mario Haim – 2012 22

Internal arc classification according IEC 62271-203

●

Internal arc events could cause effects like

pressure increase and burn through of enclosure

(no effect on personnel is considered)

●

Durations of 0.1 s up to 0.3 s are considered

(switch off by protection equipment)

●

No test procedure to qualify personnel safety

in high voltage standard

Safety is no Option!

●

Internal arc test as Type Test according t0 IEC 62271-200

Chapter 6.106

safety for personnel as important feature

●

Improved

safety for the operator

(defined areas of access

for the user)

●

Durations of arcing from 0.1 s up to 1 s are considered and

tested (min selectivity)

●

All criteria to pass the test have to be fulfilled:

●

Doors / covers do not open

●

No fragmentation of enclosure

●

No holes on accessible areas

●

Indicators do not ignite

●

Earthing

remains in service

Internal arc classification according IEC 62271-200

Schneider Electric- Infrastructure – Mario Haim – 2012 24

Cost efficient

●

Size is Key!

●

Less material

●

Less weight

●

Less space

●

Less volume inside the tower

●

Less transportation costs

●

Predefined interface between MV switchgear and:

●

wind turbine

●

MV-cable

●

control and protection

●

Metering

Cost efficient

●

Switchgear section preinstalled on base frame

●

Completely pretested in factory

●

Less transport efforts

●

Predefined interface

●

No erection on site

Schneider Electric- Infrastructure – Mario Haim – 2012 26

Environment

● No gas handling

at site

●

Space saving

due to compact design

●

Switching in Vacuum

with Vacuum Interrupter

●

All materials are

fully recyclable

●

At end of life time, the

SF6 gas

will be fed into

recycling process

hence

-

no factory-special tool required for gas removal

-

all gas tanks are equipped with a valve in standard use

Agenda

●

Market trend

●

Wind park layout & Short circuit level

●

Requirements

●

Overvoltages

& Insulation coordination

Schneider Electric- Infrastructure – Mario Haim – 2012 28

Insulation

level based on Ur=72.5 kV

Except

of IEC 62271-1 [1]

U

_sys

= 66kV; Δ

= ±

10%

U

_r

= 72.5 kV

●

Overvoltages

mainly due to

lightning strike

or

switching operations (TRV)

(IEC 60071-2)

●

Lightning strike

mainly in overhead-lines

●

Switching operations, especially

in case of

switching inductive or

capacitive loads

, e.g. cables

Schneider Electric- Infrastructure – Mario Haim – 2012 30

Schneider Electric- Infrastructure – Mario Haim – 2012 31

Lower

Insulation

level required

With surge arrester installed directly at the switchgear

(L=0)

,

the effect of travelling wave can be disregarded. Thus, the

second part of the equation will equal to 0:

BIL ≥

K

_s

·U

_res

As recommended in [2], K

_s

= 1.15 should be applied as

safety factor for internal insulation coordination:

required BIL for the switchgear

BIL = 1.15 x 3.33 x 72,5 kV =

277 kV << 325 kV

Schneider Electric- Infrastructure – Mario Haim – 2012 32

Transient

recovery

voltage

Transient

recovery

voltage

EMTP-ATP simulation

in 66kV windpark

with

one wind

turbine in

operation, in parallel

with

utility network

M

BBAR FAULT

FEEDER FAULT

FAULT

Aux. TR

[email protected]

3.3/66kV

400mm2

155/66kV

400mm2

Aux. TR

Utility data:

Ur (kV) 155 kV

Rated short-circuit power 9000 MVA

Schneider Electric- Infrastructure – Mario Haim – 2012 34

Transient

recovery

voltage

TRV envelopes

for feeder fault

Uc

= 129kV and busbar

fault

Uc

= 114kV

(red)

(green)

Conclusion: TRV parameters

are within

IEC 62271-100,

recalculated

for rated

voltage Usys

= 66kV

69,55

69,68

69,81

69,94

70,07

t.ms

70,20

0

20

40

60

80

100

120

Uc.kV

63,470

0

63,616

63,762

63,908

64,054

t.ms

64,200

30

60

90

120

150

Uc.kV

Lower

Insulation

level required

Maximum voltage level for insulation

coordination including safety factor is

Schneider Electric- Infrastructure – Mario Haim – 2012 36

Agenda

●

Market trend

●

Wind park layout & Short circuit level

●

Requirements

●

Overvoltages

& Insulation coordination

●

IEC 62271 differentiate between applications

(Transmission or Distribution) and voltages (IEC

62271-200 vs. 62271-203)

●

Offshore application inside & between tower is

100% distribution

●

All benefits & requirements of distribution (IEC

62271-200) are mandatory

Preferred Solution

Schneider Electric- Infrastructure – Mario Haim – 2012 38

66 kV switchgear acc. to IEC 62271-200

Reliability:

Fully tested

for required ratings (U

_r

= 72.6 kV, BIL <= 277 kV)

Environment:

Vacuum circuit breaker

,

less material

,

no gas handling

Safety:

IAC acc. IEC 62271-200

Chapter 6.106,

complete interlocking

Cost efficient:

less CAPEX,

less transport costs,

less OPEX

Preferred Solution

What is really needed?

Ratings

Requirements

U

_s

= 66 kV; U

_r

= 72.5 kV

Cost efficient

BIL

<= 277 kV

Reliability

I

_r

= 1,250 A / 2,500 A

Safety is no Option!

I

_sc

= 25 kA

Environmental friendly

Schneider Electric- Infrastructure – Mario Haim – 2012 4040 Schneider Electric

Schneider Electric

Infrastructure

Equipment

Mario Haim

R&D Director

Rathenaustr. 2, 93055 Regensburg, Germany

+49 151 14758993