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ROUND UP
MPTC protects against gas supply interruptions
ABB has released the first variable
speed drive control software that uses
Model Predictive Control to regulate
the drive’s torque.The MPTC software
was initially developed to ensure the
operation of compressor stations dur-
ing voltage disruptions, caused by
lightning strikes, winter storms or ice
build-up on power lines.
The stations use large compressors,
up to 50 MW, to compress natural gas
for travel through hundreds of miles of
pipeline. Historically gas turbines pow-
ered the compressors, today, more effi-
cient large synchronous electric motors
are used.The motors are controlled by
variable speed drives, such as ABB’s
largest drive, the MEGADRIVE-LCI.
When power supply disruptions hap-
pen, protection systems quickly shut
down the compressors. This halts the
supply of gas. Restarting compressors
lasts from a few hours to days. The
resulting interruption in the gas supply
can mean financial losses that range
into the hundreds of millions USD per
year for large facilities.
Installed in the MEGADRIVE-LCI, the
MPTC uses a control algorithm based
on Model Predictive Control that en-
sures the operation of the drive during
power and grid disturbances in order
to provide the compressor with partial
torque, preventing the compressor
from going into surge.
The MEGADRIVE-LCI application is
the first where MPTC is used to control
a commercial multi-megawatt drive
system with much faster dynamic
behaviour, where the underlying opti-
mization problems need to be solved
in less than a millisecond.
Live testing of the software was
done over the winter at two Statoil gas
facilities in Norway. It was installed on
ABB MEGADRIVE-LCIs used to power
two 42,2 MW compressors at a gas
processing plant in Kollsnes, and three
7,5 MWbooster compressors in Kårstø.
The control software successfully
protected the compressor operation
during voltage dips.
Enquiries: Vilma Lindell.
Email
Portable
oscilloscopes
for harsh
industrial
environments
Fluke, represented locally
by the Comtest Group,
has on offer the first high-
performance portable
oscilloscopes with two
or four independently
insulated input channels,
an IP51 dust and drip wa-
terproof rating and a CAT
III 1000V/CAT IV 600V safety rating. Users can choose from 500 MHz,
200 MHz, 100 MHz or 60 MHz bandwidth models.
Especially designed for plant maintenance engineers, there is a
choice of either a 2- or 4- channel scope for the harsh conditions
or industrial electronics. A 5 000 count digital multimeter (DMM) is
included in the 2- channel models.
The 190 Series II has up to four independent floating isolated inputs,
up to 1 000V and a real time sampling of up to 5 GS/s (depending on
model and channels used).
Frequency spectrum using FFT-analysis and automatic capture and
REPLAY of 100 screens, as well as a deep memory of 10 000 points
per trace waveform capture (scope mode), are all features of this new
generation oscilloscope.
190 Series II software:
• Connect-and-View triggering for intelligent, automatic triggering
on fast, slow and even complex signals
• ScopeRecord Roll mode gives 30 000 points per input channel for
low frequency signal analysis
• TrendPlot paperless recorder mode with deep memory for long-
term automatic measurements
Enquiries:Tel. +27 (0) 10 595 1821 or visit
Mini subs mitigate against vandalism
Electrical substations pose a number of unique challenges
including vandalism and the theft of copper. This is especially
true for mini substations, which are often located in residential
areas and in remote rural areas, and applies to those owned by
power utilities as well as private owners. While larger substa-
tions are often protected using surveillance equipment, this is
not always feasible with mini substations and apart from the
unnecessary disruption of electrical services, the damage done
to these installations could have potentially lethal consequences
for maintenance personnel.Working in collaborationwith Eskom,
WEG Transformers Africa (WTA), part of the Zest WEG Group,
developed a vandal proof mini substationwhich is now approved
by the power utility.
Andre Mans, chief operating officer of WTA, says that this
approval is very important as it confirms the functionality as
well as reliability of the vandal proof mini substation. “This
level of approval not only underpins that the mini substation
meets all the criteria but also gives absolute assurance to the
marketplace,” Mans says. Notably, the mini substations are
targeted at both power utilities and private end users.TheWTA
vandal proof mini substations are ideal for installation in high
risk areas.The entire enclosure, including doors and lock protec-
tion facilities, are constructed from 6 mm steel with the doors
being specially reinforced.The four way locking mechanism is
complemented by heavy duty door hinges.The transformer unit
is sealed, further protecting the installation.
Enquiries: Kirsten Larkan.Tel. +27 011 723 6000 or email
DRIVES, MOTORS + SWITCHGEAR
Electricity+Control November ‘16 24