Lecture 2 – Storage Applications Flashcards
What is a U.P.S?
The U.P.S. is a systems that can avoid
power losses for a short time or/and can
prevent damages to critical loads such as
medical equipment, computer controlling
important processes, etc…
What are some Application for UPS systems (examples)?
- Computing, server centres
- Safety relevant applications
- (e.g. control of traffic lights, blade control in
- wind turbines)
- Communication infrastructure
- Critical production processes
- (e.g. clean room processes, paper
- H ospitals
What is the most used Battery Tech. for UPS applications and why?
- far the most important technology due to their robustness and low costs
- Best lifetimes for lead acid batteries can be achieved at full state of charge operation
- Supply times from a few minutes to some hours
- High reliability required: Supervision of individual cells is an interesting option
- Batteries are charged continuously
Which Different Types of UPS Systems are there ?
- Rotary (motors and generators)
- Static UPS (with powerelectronics)
- Storage technologies such as Flywheels, SuperCups, Batteries
Explain the rotary UPS and its Advantages and Disadvantages?
It has mechanical Components and consists of a generator, motor and energy storage.
* Advantage is the higgh realiblty in moment of the Grid failure due the stabilisation of the rotating masses of the maschines
* Disadvantage is significant continuous losses and big size loses
Explain the Static UPS with the VFI (VFI (Voltage and Frequency Independent) UPS
it has no mechanical parts and consists of inverters, storage and rectifiers. UPS is is always on and takes over the supply when the grid fails because it also connected to the DC busbar.
- Advantage: Pre conditions power supply, no power delay
- Disadvantage: significant efficiency losses.
Explain the Static UPS with the VFD (Voltage and Frequency dependent) UPS
In contrast to the Static UPS with VFI in this case the loas is directly supllied by the grid and the UPS is bypassed in the normal case, electrnics switched on during Failure.
- Advantage: lower investment costs, low losses in normal operation
- Disadvantage: Only basic features, delay to supply power during switching, not as realible as the VFI
For very high reliability more than one UPS system
can be operated in …… (e.g. in nuclear power
plants typically 4 redundant UPS systems are used)
parallel
Which types of battery tech. are used in the portable devices?
NickelCadmium and Nickelmetallhydride Batteries were used before the LiIon Batteries but because they have a less energy density levels they were mostly replaced with LiIon Batteries. Then there is Fuel Cell Btteries.
Why can’t Bio Fuels be a solution for the climate neutral fuel for cars ?
Because Yield from 2nd generation BTL biomass (60,000 km/ha/year) almost 16 times less than what we can achieve with the Electrity production with PV in the same field area. Yield from photovoltaics in Germany:
1,000,000 km/ha/year
What is a fuel cell in means of electromobilty?
- If we decompose water by hydrolysis into H2 and O we need of course electricity from the grid and H2 can then be used as fuel in the car. In the end effect it is produced by electricity and of course water but is CO2 free.
- Input energy requirement for hydrogen use is about 2.5 x higher than for electric vehicles
