The Czech power supply market is controlled by a monopoly.
The sole power distributor in the country is the company
ENERGETICKE ZAVODY. Lack of competitive environment has had
a negative impact on both power supply reliability and
quality, and the technical condition of remote power
Different anomalies, i.e. power supply failures, are also a
frequent phenomenon in other countrie. Power supply outages
are the most conspicuous of all power supply failures,
but not the most frequent as compared with other network
failures. Other phenomena, e.g. undervoltage, overvoltage,
voltage peaks, disruption and different transient
processes, prove to be of greater importance.
The operating status of certain equipment does not allow
anomalies or power drop-outs, as any failure might cause
extreme financial or other damage to customers, i.e. power
consumers, have no chance to choose from among competing
suppliers for power supply quality and reliability. This
has resulted in an ever growing customer effort to
safeguard power supply quality and reliability. One of the
most reliable appliance protection methods is the use of
back-up power centres ('Power centres') consisting of an
uninterruptible power supply (UPS) with the necessary
capacity and a motor generator set (MTG).
Different vendors offer a variety of such equipment, with
different technical parameters. The diversity of power
centre components from different vendors raises the issue
of central administration and monitoring their operation.
The project objective is to design software and hardware
for both local and central remote power supply monitoring,
compatible with available types of power systems and
making possible remote diagnostics and administration of
power centres. Due to the absence of a product offering a
complex solution on the Czech market, there is an urgent
need to deal with the above issues, in the context of power
The implementation of the above project will enhance power
supply critical management. Remote back-up system
monitoring makes permanent control the technical status of
a back-up system possible, which in its turn allows for
checking operability, as well as forecasting and planning
the necessary service work. A Proactive approach to system
failures increases the reliability of power centres.
Another benefit of the project consists in increasing the
life of accumulators in UPS by as much as 30% as a result
of remote monitoring and diagnostics, and in reducing their
purchase cost by as much as 25%. In addition, the project
will have a positive environmental effect as a result of
lower consumption of accumulators and the subsequent
lower environmental load and lower costs of environmentally
friendly disposal. Last but not least, perfect connect-up
load management with maximum use of power potential will
eliminate the need to change system capacity of power
centres, which will reduce their purchase cost by as
much as 20%.
There are two ways to assure reliable power supply of
1) Uninterruptible power supply are outage-free and
designed to protect powered equipments against network
anomalies. Uninterruptible power supplies for short-time
dropouts are designed with committed back-up time extending
for approximately 10 minutes necessary for a correct
shutdown of the powered equipment. Additional battery
modules can be used for longer outages.
According to the European standard EN 62040-3,
uninterruptible power supplies are divided into:
* VFD (off-line) concept uninterruptible power supplies the
powered equipment against energy outages, short-term
voltage drops and short-term overvoltage;
* VI (line-interactive) concept uninterruptible power
supplies featuring additional protection against
undervoltage and input voltage interference;
* VFI (on-line) concept uninterruptible power supplies
additional protection against overvoltage, transient
processess, frequency fluctuation and harmonic distortion
and belonging to the highest category offering the maximum
possible protection of backed-up equipment.
This system has not been designed for long-term power
2) Systems where permanent operation must be guaranteed
even in a situation of long-term outages extending for
several hours or days require 'Power Centres' consisting
of an uninterruptible power supply and a motor generator
set (MTG). The functioning principle is as follows: when a
power supply outage occurs, the power supply function is
automatically transferred onto the UPS without this having
any impact on the operation of the powered equipment. In
the same moment, the motor generator set starts up to be
ready to take over the load in approximately 30 seconds.
Usually after two minutes (depending on the settings), the
uninterruptible power supplies connects up to the motor
generator (MTG) power supply.
In both the cases, the system is capable of continuous
power supply in different situations of power network
failure, but does not have the capability to identify the
backup power supply demand depending on the technical
status and needs of the backed-up systems. For instance, if
a outage occurs, the power supply source or a power centre
may be covering the whole back-up power supply demand (e.g.
control servers, IT, disk fields, lighting, PBX, etc.),
irrespective of their priority and importance. Therefore
the uninterruptible power supply or the power centre must
be re-dimensioned for the required start-up current of all
such parts of equipment and designed for a longer back-up
time. The system has no capability to assess by the
accumulator status which of the loads are vital and which
are only ancillary, and disconnect the circuits of a lesser
importance in order to guarantee the maximum back-up time
for the vital circuits. Solving the above issue is one of
the goals of the project.
The objective of the project is to develop an intelligent
system: software and hardware for measurement and control
of back-up systems (autonomous UPS or power centres).
The project will be implemented in the following stages:
- research in and development of control software and
- construction of functional models
- implementation of functional models in the environment
- functional model tests, simulation of extreme situations.
Keywords: back-up systems, power centres, congeneration