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PSPP Kaprun / Oberstufe Limberg I (Austria)

The PSPP Kaprun Oberstufe was originally commissioned

1955-1956 with two horizontal machines sets consisting

of Francis turbine, motor-generator and a two-stage radial

pump. The overall installed power of this power plant was 112MW.

In 2018 the modernisation started. To increase the efficiency

and adapt on the new requirements of the energy market, the

Verbund decided to modernize the existing pumped storage

station Kaprun Oberstufe. In 2017 the tendering process for

both machine groups started. They shall be equipped as a

variable speed application with fully fed technology consists

of pump turbine, motor-generator as synchronous machine

and frequency converter. The converter is located between

synchronous machine and main step-up transformer and is

feeding the energy to the grid in turbine mode. Since mid of

2021 the first machine group is now producing energy and

one year later mid of 2022 the second machine group is

connected to grid as well.

Power Conversion’s scope includes:

• Four 6.6kV converters in sum 80MVA for the variable speed synchronous machines

• Main step-up transformers 110/6.4kV; 85MVA

• Control excitation equipment to start-up the machine and synchronize the units to the grid

• SEE units for the synchronous machines

• Overvoltage control protection

• Low voltage ride through (LVRT) ability according to Austrian grid code

PSPP Linthal (Switzerland)

The PSPP Linthal was commissioned and handed over to

operator AXPO in 2016 and is producing energy since then.

The 1000MW PSPP is one of the most advanced

hydroelectric power plants in the world.

It is equipped with four rotating machines of 250MW each.

where the decision was taken to use the variable speed

technology to improve operation behaviors and increase the

advantages in regard of efficiency in full load and especially

the significant improvement in part load operation.

Power Conversion’s scope includes:

• Four 48/48MVA converters for the variable speed asynchronous machines

• Four excitation transformers 18/3.0kV; 28MVA

• Control excitation equipment to start-up the machine and synchronize the

units to the grid

• Overvoltage control protection (crowbar) for rotor of the machine

• Low voltage ride through (LVRT) ability according to Swiss grid code

Power Conversion’s references

PSPP Goldisthal (Germany)

The PSPP Goldisthal is located in Thüringen (in the east-

southern region of Germany) and has a capacity of 1060MW.

The project has begun in 1997 and produced energy since

2003. There are two variable speed machine sets with

AC-excitation and asynchronous machine and two fixed

speed machine sets with start-up frequency converter and

synchronous machines.

Goldisthal is one of the first pumped storage power plants

where the decision was taken to use the variable speed

technology to improve operation behaviors and increase the

advantages in regard of efficiency in full load and especially

the significant improvement in part load operation.

Power Conversion’s scope includes:

• Two 100MVA converters for the variable speed asynchronous machines

• Two SFCs with 18kV / 40MW for starting up all machines

• Two static excitation equipment (SEE) units for the synchronous machines

Our advantages

• Proven technology & decades of experiences in power

electronics

• Wide range of systems architecture tailored to projects

specifics

• Grid code compliance simulation / grid forming control

• Integrated solution with mechanical OEM

• Numerous references of large pump storage system,

including largest projects in Europe

• Centralized expert team in Germany (Center of Excellence)

• Global partner with strong regional presence

• Strong presence in North America (local facility with

manufacturing, engineering and service)

Multiple reasons for investing in PSPP

When investing in a pumped storage power plant, decision

makers identify and define the main requirements the plant

has to fulfill. Reasons may vary, for example with the main

drivers being to produce power from water as a renewable

energy source, to balance the grid or to build a large-scale

energy storage system to help manage the power grid

and security of supply. Investors and decision-makers need

to identify the best technology suitable to meet the project’s

specific purpose.

Power Conversion’s technology for

variable PSPP applications

The heart of Power Conversion’s converter systems

are press-pack IGBTs.

Power Conversion uses rugged, robust press-pack IGBT

technology, which is superior to standard grade IGBT

technology. Press-pack IGBT yields better surge current

rating, improved thermal cycling and longest lifetime.

Press pack IGBTs do not use failure prone bond wires.

Power Conversion’s control technology supports different

algorithms for line side control, as well as various operation

modes that are required by grid operators around the world.

If required, Power Conversion offers support for grid

approvals with HIL simulators.

Needed space inside the power plant is strictly

connected to the specific requirements on our equipment and

design of the machine set. Power Conversion is investigating

and checking all relevant data to provide the best solution to fit

in the appropriate rooms for green field and brown field projects.

Power Conversion builds customized solutions

to meet your specifi c space requirements

Examples for possible arrangements for each kind of topology

which reflected pumped storage power plants with variable

speed approach. Needed space inside the power plant is strictly

connected to the specific requirements on our equipment and

design of the machine set. Power Conversion is investigating

and checking all relevant data to provide the best solution to fit

in the appropriate rooms for green field and brown field projects.

Power Conversion uses rugged, robust press-pack IGBT

technology, which is superior to standard grade IGBT

technology. Press-pack IGBT yields better surge current

rating, improved thermal cycling and longest lifetime.

Press pack IGBTs do not use failure prone bond wires.

Power Conversion’s control technology supports different

algorithms for line side control, as well as various operation

modes that are required by grid operators around the world.

Voice of our customers

With our expertise and extensive know-how with large scale

PSPP projects, we are able to support our customers with

customized solutions that help minimize costs while

maximizing output.

Available operation modes

• Variable speed in turbine mode

• Variable speed in pump mode

• Braking mode

• Statcom operation

• Black start

• Island mode

• LVRT/HVRT capability

• Virtual inertia (dynamic grid support)

Support for grid model and approvals

• Support grid approval with hardware

in loop simulator (HIL)

• RMS models DIG silent power factory & PSSE

• Transient models MATLAB & PSCAD

• Model validation with HIL

Extensive expertise in

variable speed projects for hydro

With our variable speed drive technology, pumped storage plant

operators are better able to meet the need for peak supplies

of power while in turbine mode. Also, the plant achieves higher

efficiency levels in partial-load conditions because the machine

speed can be adjusted to meet the grid’s changing power

requirements while maintaining the turbine close to its highest

efficiency point. At last operators have greater control over the

plant’s performance in pump mode, by being able to control

the power consumed from the grid while refilling the upper reservoir.

However, in order to react to changing wind and solar power

conditions that can undermine grid reliability, pumped storage

power plants need to have greater flexibility and shorter

response time. Reversible pump turbines with variable speed

motor-generator provide adjustable discharge and power in

both turbine and pump operation, plus enhanced grid services

like virtual inertia.