Monitoring DC current for power systems monitoring
November 2004
Electrical Power & Protection
DC power is frequently used in many industrial applications including, petrochemical, telecommunications metals and computers. In these applications batteries are frequently used to provide power back-up to protect against power failure.
Monitoring and measurement of DC current is therefore critical for monitoring and regulating these DC systems. Current transformers cannot be used for these DC systems and shunts require supply disruption for installations and introduce losses to the system (Joule effect), Hall effect transducers are therefore the solution.
With over 30 years experience of current measurement using Hall effect technology, LEM has introduced a product range specifically to meet the requirements of the industrial environment. The products are easy to install and require minimal maintenance.
The DK-B, HTR and HOP series cover a wide range of current measurement (50 A to 2 kA), with a variety of physical sizes designed for fitting to cables and bus bars. Voltage and current output options are available, ensuring compatibility with control systems such as PLCs or DCSs.
Clamp-on design facilitates easy installation to cable or bus bars making it suitable for retrofitting existing installations, allowing modernisation and monitoring without interruption of the supply. Typical applications would include:
Industrial electrical heaters
Electric heaters are used to supply heat to manufactured products, storage systems and recirculating material. If a heater fails, the batch or process may have to be scrapped. A realtime indication of heater status improves product quality and production efficiency. Applying a current transducer to the heater lead and integrating the signal with the DCS will allow the user to monitor the heater's on/off status, alarm the failure and automatically switch on a back-up heater.
Telecommunications
Some 'cells' or substations and transmitters/receivers for mobile phones are in remote locations. To keep these units in good working order, manufacturers use energy management systems that monitor the network power supply and auxiliary batteries and activate an alarm should problems develop. Hall transducers are used for the current measurement.
A transducer for the AC to DC converters is included in each conventional power supply application. The transducer can monitor the output current of the power plant going up to 10 kA. Another monitors the current from the battery banks installed to back up the switches. Currents here fall in the range 200 A to 1 kA. The final stage would be the current measurement in the 48 V power distribution lines - a Hall transducer for each circuit.
Further reading:
Four-digit multifunction instrument
Vepac Electronics
Electrical Power & Protection
The OM 403 model series comprises four-digit panel programmable instruments designed for maximum usefulness and user comfort, while maintaining their fair price.
Read more...
New function/arbitrary waveform generator
Vepac Electronics
Electrical Power & Protection
Siglent has released the SDG1000X Plus series Function/Arbitrary Waveform Generator, providing engineers with a more flexible and efficient signal generation solution.
Read more...
World’s fastest 14-bit arbitrary waveform generator
Vepac Electronics
Electrical Power & Protection
The ARB Rider AWG-7000 is the world’s fastest 14-bit arbitrary waveform generator, with a 20 GS/s real time update rate and 14-bit vertical resolution. Thanks to Simple Rider software, it offers best-in-class performances and an easy to use interface.
Read more...
Steam on demand
Electrical Power & Protection
Rental boilers are increasingly popular, offering the convenience of on-demand power and heat without the commitment of a permanent installation. They are an ideal solution while a customer awaits repairs, or only needs a boiler for a particular period, or does not have the capital to invest upfront.
Read more...
High-voltage backup power solutions
Electrical Power & Protection
Businesses are facing increasing pressure to rethink their approach to power. As a result, there’s been a significant uptick in interest in high-voltage installations, either as standalone battery energy storage systems, or as solar installations feeding into battery storage.
Read more...
Rotary friction welding – a first for Tutuka power station
Electrical Power & Protection
Steinmüller Africa has successfully used rotary friction welding in a project with engineering consultant, eNtsa. This innovative technique was applied to fabricating four headers used for high-pressure water heater boiler units installed at Tutuka power station in Mpumalanga.
Read more...
Why it is vital to size soft starters carefully
WEG Africa
Electrical Power & Protection
The application of soft starters has become a well-established strategy to improve the uptime and lifespan for motors and mechanical equipment driven by motors, but they need to be chosen carefully.
Read more...
Changeover switch between two power supplies
Schneider Electric South Africa
Electrical Power & Protection
Schneider Electric South Africa has unveiled the Resi9 Changeover Switch product range which provides the perfect solution to switch manually between two power supplies or circuits.
Read more...
Partial discharge monitoring solution for MV switchgear
Schneider Electric South Africa
Electrical Power & Protection
Schneider Electric South Africa has unveiled its PowerLogic PD100 Partial Discharge Monitoring Solution, designed to be installed on MV switchgear to detect anomalies early, to prevent unplanned downtime.
Read more...
ABB production site reduces total emissions by 80%
Electrical Power & Protection
Continuing its commitment to sustainable manufacturing, ABB’s Mexican production site for load centres and safety switches in Saltillo has reduced emissions by 80% in the past two years.
Read more...
printer friendly version