Varspeed ICEM Rev1 part1+2

Imagination at work

Variable Speed Pumped Storage

Dr. Alexander SchwerySeptember 5th, 2016 Lausanne

GE Proprietary Information – Class II (Internal)

Advantages - Developments - Status

Advantages of Varspeed

Seasonal storage• Higher prices for production in

winter than summer• Large capacity• Small variation in head• Less operation changes

Grand-Dixance• 385 Mio m3

www.grande-dixance.chP S W N a n t d e D r a n c e I 1 5 . J u n i 2 0 0 7 I P a g e 4 I

B l i c k a u f E m o s s o n v o n V ie u x E m o s s o n a u s

Pumped storage once and today

Weekly and daily storage• Volatile prices of electrical

energy• Smaller capacities• Large head variation• Many changes in operating

conditions

Nant-de-Drance• 11.4 Mio m3

www.nant-de-drance.ch

Variable speed pumped storage – ICEM – AS - September 2016

Advantages of variable speed pumping

Higher head variation• More possible sites become

economically interesting

Discharge

Head

nrated

nmin

nmax

Adjustable power• Also in pump mode the power

can be adjusted• Primary frequency control in

pump modeHead

PowerPump Range

Turbine Range


Advantages of variable speed (outlook)Conventional PSP

Varspeed PSP

Power set point

Power response

Power set point

Speed response

Power response

Power set point

Power set point

Power response

Power set point

Speed response

Power response

Power set point


Developments

Pump-turbine

Electrical machine

VSI - Power electronics

Control system / Protection

�Development of a new generation of pumped storage plants

Varspeed PSP main components


Synchronous machine

DFIG machine

Classical PSP

Varspeed PSP

Double fed Induction Generator


Testing of brushes

Electrical machine development (extract)

Dimensioning - Performances

• Dimensioning tool− Electromagnetics− Main and detail dimensions− Temperatures− Losses

• Detailed analyses− CFD for cooling and

ventilation− 3d electromagnetic

computation− 3d mechanical computation

• Simulations− Grid interaction− Real time hardware in the loop

for control and protection


Testing of brushes

Rotor of the Linthal 2015 PSP project (Switzerland)


Validation of components

• Full scale model of rotor

• Testing of individual parts− Slip rings and brushes− Retaining bolts− Installation of bars− Rotor winding


Testing of brushes


Rotor Winding Insulation System

• Critical − PD because of air distances− Surface voltage on bars

• Innovation – new grading system− Grounded insulation caps− High conductive tapes

⇒ No visible PD, no damages, no temperature rise


Converter Specification

Conditions to be considered- Best efficiency speed in

turbine mode- Power range in pump

mode- Transmission Code- Starting requirements- …

� Impact on converter and generator design

Converter


Power range - Speed range - Inverter Voltage

Iterative interdisciplinary optimization required

� Power range in pump mode� Efficiency in turbine mode� Converter voltage range� Rotor insulation system

Pump – Motor – Converter

Pump Range

Head

Po

wer

Turbine Range

Pump Range

Po

wer

Speed Variation

Turbine Range

Vo

ltag

e


Transmission Code – entso-e

Converter

• Different requirements in different countries

• Fault Ride Through- 3 phase short circuit at

connection point- 150 milliseconds

� Impact on speed range� Converter must be sized

accordingly


Converter

Transmission Code – Fault ride through


Starting requirements

Converter

Start up time depends on- Friction torque- Converter voltage

� Required start up time has an impact on the converter design


IEEE, optimization of startup time …, Pannatier

Start-up Procedure

Step 1: magnetization and start-up in fully-fed operation (high flux-weakening)

IM

S3

18 kV

400 kV

S1

S4

S2

Pump

Step 1 Step 2

t [s]

0

5

10

15

20

25

30

35

40

45

0 20 40 60 80 100 120 140 160 180 200

roto

r fr

eque

ncy

50Step 3

demagnetization of machine to open S3 without current


Step 2: magnetization and synchronization with grid

IM

S3

18 kV

400 kV

S1

S4

S2

Pump

Step 1 Step 2

t [s]

0

5

10

15

20

25

30

35

40

45

0 20 40 60 80 100 120 140 160 180 200

roto

r fr

eque

ncy

50Step 3

Start-up Procedure


Step 3: acceleration to reference speed in doubly-fed operation mode

IM

S3

18 kV

400 kV

S1

S4

S2

Pump

Step 1 Step 2

t [s]

0

5

10

15

20

25

30

35

40

45

0 20 40 60 80 100 120 140 160 180 200

roto

r fr

eque

ncy

50Step 3

Start-up Procedure


Specific development for Rotor Protection

• Specific requirements– Low frequency currents on the rotor

during start up and braking– GE policy: rotor protection

independent from VSI control system

• New protection relay– Non-conventional instrument

transformers for low frequency signals

– Active earth fault protection(non sinusoidal voltages and low frequency currents)

Alstom protection relay

Protection of Varspeed units

ICEM, development of a novel …, WechslerVariable speed pumped storage – ICEM – AS - September 2016

• Dedicated controller to guide excitation and governor • Best efficiency and dynamic control mode• Frequency and Voltage regulation

System validation – real time simulations

Structure of Alstom control system

Control structure of Varspeed units


• Real time test bench− Real hardware controllers− Hydraulic and electrical machines

simulated in real time

• Checking of interfaces between controllers

• Optimization of sequences

System validation – real time simulations

Control structure of Varspeed units

Real time testing in cooperation with GE Energy


Status

Project Linthal 2015 (Axpo, Switzerland)

Power 4 x 250 MWHead 560-724 mSpeed 500 ± 6 % rpm

Source: Axpo

Muttsee2450 m a.s.l. 25 Mio m3

Limmernsee1857 m a.s.l. 92 Mio m3

Cavern1700m a.s.l.

Variable Speed PSPProject Execution

Source: Axpo


Machine data Linthal

Number of units 4

Apparent power 280 MVA

speed 470–530 min-1

Rated head 700 m

Starting time in turbine mode 120 s

Starting time in pump mode 240 s

Rated voltage 18 kV

Rotor diameter 4672 mm

Weight of complete shaft arrangement

410 t+60 t

converter power (AC excitation) 34 MW

First machine synchronized Dec. 2015



Supply chain and transportation

• Deliverables from Alstom factories and supplier− Supervision and inspection− Quality and scheduling− Transport

• Transport at site (cavern)− Road haulage− Cable car and access tunnel

• Site assembly− Incoming goods− Space available− Work preparation

Office and warehouse

Transportation of spiral case Spiral case at cable car in cavern



P/T head cover (Baroda, India)

Manufacturing

P/T runner (Grenoble, France) Stator and rotor bars (Birr, Switzerland)

Spherical valve (Grenoble, France) Stator laminations (Baroda, India)

Slip ring (Bilbao, Spain)



Erection of electrical machine- Impressions

Motor Generator Stator

Motor Generator RotorMotor Generator



Conclusion

• Varspeed power plants offer essential advantages to grid operators and power plant owners

• Specific developments were done on the machine level but also in the systems surrounding it

• The optimization of Pump-Turbine, Motor-Generator and Converter requires an in-depth understanding of all major components and interfaces

Variabe speed pumped storage


Documents

Varspeed ICEM Rev1 part1+2