ABB UNITROL5000 Excitation Systems for Medium and Large Synchronous Machine
The UNITROL 5000 is the most powerful product in the ABB Switzerland
UNITROL® series of excitation systems. The microprocessor-based voltage
regulator uses the latest available technology. The development is based
on more than 40 years experience with semiconductor voltage regulators
and more than 15 years experience with microprocessor technology for
this application.
Application areas
• Static Excitation Systems (SES) for
50 Hz, 60 Hz or 16 2
/3Hz power supply
with field currents from 1000 ADC to
more than 10,000 ADC
• Automatic Voltage Regulating Systems
(AVR) for exciter machines with special
functions, supply frequencies from
16 2
/3Hz to 400 Hz.
Regulator highlights
Additional regulator redundancy
• Dual-channel system with backup
current regulator
Digital input processing
• Three-phase voltage measurement
• Three-phase current measurement
• Digital processing of the input values
with a signal processor
Additional functions
• Software solutions only – without
additional hardware
Additional inputs and outputs
• Easy to extend to the required number
with ARCnet® devices
• Digital and analog
Event and error log
• With real-time stamp
• Remote interrogation possible.
Power section highlights
Power converter redundancy
• Up to a maximum of eight parallel
power converters are possible
• Power converter redundancy is com pletely independent of the regulator
configuration
Intelligent power converter
electronics
• Active equalization of the current
between the power converters
• 4-quadrant operation (negative
excitation current is possible)
• Thyristor current monitoring
• Fan control and monitoring
• Monitoring of fuses, power converter
temperature and cooling-air flow
• Bridge current display.
Communication with the
system
• The most frequently used protocols
for higher level control systems are
supported
• A second control panel in the control
room is possible, up to a maximum
distance of several 100 m
• Remote diagnostics by an ABB service
office is available via Internet using
the PC software “AVRview”.

The UNITROL 5000 is designed as a modular “building-block system”. More
than 80 % of all systems can be made from type-tested system components.
This guarantees higher quality and makes shorter delivery times possible.
The power section consists of one or more thyristor power converters, field
breaker on the AC or DC side, the field flashing circuit and the solid state
de-excitation system with Crowbar.
Fig 2: The standard configurations of the voltage regulator
section and power converter units can be combined at
will, e.g. S5T, D5E, A5S, Q5T
Less wiring thanks to the internal
ARCnet® field bus
The exchange of data within the system,
e.g. between the voltage regulator, power
components and interface devices takes
place via the serial ARCnet bus.
Additional interfaces or control panels can
be located and operated up to a distance
of several 1000 m via an optical link.
Powerful and reliable power
converters
Either compact power converters of the
DCS 500 series or type UNL 13300 or
Verithyr power converters are used for
the UNITROL 5000. The type and the
number of parallel power converters are
based on the required field current, the
ceiling voltage and the maximum duty cycle required by the customer.
The following options are available:
• Natural or forced cooling
• Redundant fans
• Possibility to do maintenance work
on one power converter during the
operation of the system (with 5-pole
isolator).
Equal distribution of the current
between several power
converters
For the first time for parallel power con verters, a new ABB development offers
regulated distribution of the total cur rent between the active units. This can
prevent the overloading of individual
thyristor branches due to unsymmetrical
current flows and significantly reduces the
probability of a failure of the individual
power converters (see Fig. 3 on page 5).
AVR: Voltage regulator (AUTO) with field current
regulator (MAN)
BFCR: Backup-field current regulator
High availability due to the additional
backup current regulator
To further increase the availability of the excitation
system, in addition to the voltage regulator (AUTO)
and the excitation current regulator (MAN), an
independent current regulator (separate device
with power supply, measurement and gate control
circuits) can be used. Because of the follow-up
control for all the inactive regulators, in the case of
failure of the active regulator a smooth switch-over
to a ready-to-operate regulator channel is guaran teed.