The advantages high system voltage
are:
• reduced losses because the higher
power achieved with less current
• better cost/benefit ratio for the motor
• cheaper cables with lower cable losses
• fuses can avoided.
Special designs are available kV.
The advantages modular construction
are:
• compactness and robustness
• fast erection site
• adaptability the customer's needs
• ease maintenance
• simple replacement components
• easy handle and ship
High voltage for high power
At the lower end the power range, single
thyristor per branch usually sufficient.
Converters for higher ratings are broken
down into suitable units for shipment.
Higher powers are generally achieved by
connecting thyristors series divide the
voltage rather than parallel share the
current. The series connection thyristors or
thyristor bridges (e.
Special enclosures and proofing are
available comply with higher protection
classes. for 12-pulse operation)
has thus become standard practice for
converters with voltage ratings kV.
The standard DIN enclosure protection class
is IP30 for water-cooled converters and for
air-cooled converters.g.
For powers MW, all the modules are
mounted common base frame and fully
Water-cooled
MEGADRIVE-LCI
Rated power: MW
10
metal clad and are shipped single unit.Converter design and cooling
Part water-cooled
thyristor stack
Compact and modular
The main components converter are:
• thyristor stacks with thyristor heat sinks
• snubber circuits
• gate control units with either magnetic or
optical fibre transmis
sion the control
impulses
• semiconductor
supervision devices
• reactors
• current and voltage
transformers
• fans the case of
air cooling
• cooling unit with
heat exchanger and
pumps the case
of water cooling
• control and protection
equipment
• excitation system
• local control panel
Both the power and control sections the
converter are constructed modular units.
.
A high basic insulation level inside the
cubicles minimises the risk short-circuits
