Standards and classifications
help in UPS selection Raising the Standard for UPS Reliability
By Jorma
Mannerkoski
Director of Product Marketing Powerware EMEA
May 13 -19, 2002
When choosing UPS equipment how can you ensure that
it will perform as expected and the information provided by different
vendors is comparable will be reliable? One way is to look at the
European Union wide standards which govern UPSs.
UPS standards in Europe are created and maintained
by an organisation called the European Committee for Electrotechnical
Standardisation (CENELEC). This body is composed of members from each
EU country as well as members from many other Eastern and Central
European countries. UPS manufacturers normally follow the CENELEC
standards in order to comply with the relevant European Directives.
The UPS standard, EN50091, has three parts. Part
one deals with safety requirements for UPSs and is compulsory for all
UPSs sold in the EU. Part two is also compulsory and deals with
electro magnetic compatibility (EMC). It has two parts — emissions
and immunity. Emissions govern what levels of noise and disturbances
the UPS is permitted to emit into the environment. The immunity
section specifies what levels of disturbance the UPS must be able to
tolerate from outside sources. The final part of the standard
specifies performance. This section, which is not mandatory, provides
benchmark data and a methodology on how to measure the performance and
functionality of different types of UPSs and states specification
methods for UPS values.
The performance standard is intended to aid buyers
and users of UPS equipment in the selection process. The standard
categorises the different UPS topologies:
STAND-BY
Stand-by UPS supplies power to the load directly
from utility until a utility power failure occurs. The UPS then turns
on the inverter and supplies load from the battery. These UPSs are
also called Off-line. These units meet CENECLEC Class VDF or VI
LINE-INTERACTIVE
Line interactive UPS compensates for deficiencies
in utility voltage by running the UPS inverter parallel to utility
voltage when needed. The UPS output is therefore partly dependent of
the quality of the utility power. Several marketing names are used for
these UPSs, Single Conversion, Parallel On-line and Delta Conversion
to name a few. These units meet CENELEC Class VI.
DOUBLE CONVERSION
Double conversion UPS regenerates the electricity
constantly. The output power is completely independent of the input
power. These units are most often called On-Line UPSs. These units
meet CENELEC Class VFI.
The CELELEC performance standard is an excellent
aid in UPS selection, but using it does require some knowledge of UPSs
and electrical systems. It is therefore most beneficial to buyers and
users that who are professionally involved in electrical power either
as consultants, electrical contractors or facility managers.
For most UPS users, especially when those buying in
small and mid-range UPSs, it is not justifiable cannot afford to spend
a lot of time thinking about different UPS topologies and UPS
performance characteristics. Powerware has therefore taken an extra
step to help in their selection procedure.
Powerware has further developed the UPS
classification based on the CENELEC standard. It is based on the UPS's
ability to solve different power problems. There are nine common power
problems in any electrical environment. Powerware offers Series 3,
Series 5 and Series 9 to address the various protection needs.
SERIES 3 UPS
The UPSs are able to correct 3 out of the 9 power
problems (Power failure, Surge and Sag). These UPSs are intended for
protection of PCs and desktop workstation protection in the home and
office environment. They are the most economical UPSs and due to their
small size and virtually no noiseless operation are ideally suited for
desktop use. Series 3 corresponds to Stand-By in CENELEC
classification
SERIES 5 UPS
These UPSs are able to correct 5 out of the 9 power
problems (Power failure, Surge, Sag, and Undervoltage). These UPSs are
designed to be used with Servers in an office environment. As servers
are more critical than individual workstations, the higher protection
level is also justified required. Series 5 corresponds to Stand-by and
Line-interactive in CENELEC classification
SERIES 9 UPS
These UPSs are able to correct all 9 power problems
(Power failure, Sag, Surge, Undervoltage, Line noise, Overvoltage,
Frequency variation, Switching transient and Harmonic distortion).
These UPSs are used with all mission critical electrical equipment
that is not allowed which cannot afford to go down (servers,
communication equipment etc.). Any equipment installed outside office
environment Mission critical equipment both inside and outside the
office environment should always be protected by Series 9 UPS. These
UPSs also feature possibility for extending the battery back up time
up to several hours. Series 9 corresponds to Double-Conversion in
CENELEC classification.
Both CENELEC Performance standard and Powerware
3-5-9 classifications are aimed at helping in the UPS selection. The
CENELEC standard is intended for power professionals and whilst the
Powerware 3-5-9 can be very helpful for a more casual the less
experienced UPS buyer. As a customer you should always make sure the
UPS vendor can provide information about the UPSs CENELEC class and
it's ability to correct the nine power problems.
Another indication of reliability is the CE mark.
This is the manufacturer's declaration that the UPS complies with the
EU requirements. Testing of product compliance with CE regulations is
normally carried out by an independent laboratory. In addition, many
UPS manufacturers, such as Powerware, adhere to the international
quality standards (ISO9000 series) giving customers and users further
assurance of reliability.
ABOUT INVENSYS &
POWERWARE:
Invensys Powerware is a global leader in the power
solutions industry. Offering the broadest range of product and
services available today, Invensys Powerware integrates a full line of
AC and DC power systems, power conversion products, standby batteries,
telephone line surge suppression, power management software, remote
monitoring, turnkey integration services and site support, providing a
seamless solution. Powerware systems and services increase
enterprise-wide systems availability and are utilised in local and
wide area networking, data and voice over IP, co-location facilities,
fixed-line and wireless communication networks, and industrial
manufacturing. Invensys Powerware is headquartered in Raleigh, NC, and
is part of Invensys plc. Invensys plc is a global leader in the
automation and controls industry, with headquarters located in London,
England. Invensys operates in all regions of the world through four
focused divisions — Software Systems, Automation Systems, Powerware
and Control Systems.
ABOUT GEMNET:
GemNet is the authorized distributor for Powerware
Corporation (an Invensys company), and offers a large range of
specialized power related products and services. The company has local
offices in Pakistan (GemNet Private Limited) and Jebel Ali, Dubai,
U.A.E. (GemNet Gulf).
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