Page 13 - Energize February 2022

NEWS

Uganda’s power generator legacy

alarm systems upgrade

If the alarm in your house becomes obsolete, you simply update
it in line with the latest technology to keep you and your family
safe. Unfortunately, this common-sense approach doesn’t always
extend to industrial plants.

ere Ian Loudon, international sales and marketing manager at legacy alarm
replacement specialists, Omniflex, discusses how Uganda’s largest generator
Hof electricity easily upgraded its safety-critical alarm systems without having to
overhaul the entire site infrastructure.
To alert operators of an event threatening the safety of assets, people or the
environment, industrial sites rely on alarm annunciators directly hard-wired into various Future-proofing your system
processes. When an event is detected, the relevant window on the annunciator panel The process of retrofitting an alarm system to fit,
lights up and sounds throughout a site, notifying operators to act quickly. form and function properly is relatively straight
For Uganda’s hydroelectric plants in Jinja, this event could be a generator component forward. But the importance of digitalising alarms
failure which, if not caught immediately, could cause costly damage to plant assets. But mustn’t be understated.
in a digital age, where we rely so heavily on computer-based programming, do we still As well as giving local visual and audible
need bulky, hard-wired annunciator panels? The honest answer is yes. indications to notify operators of an abnormal
It’s true that PC-based systems provide efficient monitoring and reporting across occurrence, each annunciator can be connected
a range of communication points in an industrial setting. However, we often see as a Modbus slave device on an RS485 network.
companies overloading their systems with complex visualisations, making it difficult to This means all alarms can be remotely monitored
identify and act on critical alarms when they arise. either on a DCS or a local SCADA system and
Alarm annunciators are therefore critical for operators being able to identify and act can provide historical pre- and post-alarm data
on an event before any serious damage is caused. But what happens when the original needed for auditing and fault diagnostic purposes.
annunciator manufacturer can no longer supply spare parts or support you when you As Uganda’s largest electricity generator,
need to upgrade your system? there’s a lot at stake for Jinja’s power plants.
Simply retrofitting a modern system, with capacity
Fit, form, function for remote monitoring, leverages operator
The problem we now find is that many alarm annunciators used today were installed efficiency and improved alarm management,
decades ago and do not meet the current IEC 61508 safety integrity levels (SIL-1). What’s which all contributes to an efficient running plant
more, former alarm system providers, like Rochester, Highland and Bristol Babcock, no with KPI monitoring.
longer exist to offer system support. This is why ESKOM enlisted Omniflex to replace its To find out more about legacy alarm
obsolete legacy Highland Rochester MPAS90 49-point system. replacement, please visit Omniflex’s website to
Retrofitting a new alarm system needn’t be costly or inconvenient for operators. book your free site survey today.
Alarm annunciator specialists can consult on and manufacture a system that will be
made to replace obsolete alarm systems from any manufacturer. This can be done by Contact Gary Bradshaw, Omniflex UK,
utilising the existing cabling to minimise disruption and installation costs. garyb@omniflex.com, www.omniflex.com
In the case of Uganda’s hydroelectricity stations, the new Omni16R annunciator
system was retrofitted into the existing panel space. The IEC standard 3U rack was About Omniflex
factory engineered to match that of the legacy annunciator, so that it was bench- Omniflex designs and manufactures electronic
ready tested before installation on site. This allowed staff at the facility to make the products and systems for the automation and
retrofit without the need for specialist tools or engineers and the existing wiring was control industry worldwide, specialising in remote
matched with the terminals of the new unit. The old 50Vdc powered energy-intensive monitoring. This includes industrial networking,
incandescent lamp alarm displays were replaced with modern energy-efficient high remote I/O systems, utilities monitoring, process
brightness LED technology. automation systems, signal conditioning, and
The biggest challenge for any company looking to upgrade its alarm system is doing alarm and event management. Omniflex has
it without disrupting existing cabling. For the utility, it requested that all annunciators be offices in South Africa, United Kingdom and
wired to the existing 50 V DC wetted field contacts. This was achieved using 16-channel Australia, and the company’s products are sold
isolated terminal boards, connected via ribbon cables to the rack. The team was able to on five continents through a range of carefully
engineer this off-site to help reduce installation time and disruption to plant productivity. selected solutions partners.

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