Electrical Engineering Capability

Reliable Industrial Power Systems

The electrical engineering skillset in heavy industries is becoming somewhat rare, with many of the top engineers in the area recently retired. To compound the problem, the world is becoming more and more electrical each year, and in most plants now a loss of electrical power can mean full plant shutdown and a lengthy and stressful restart. Not many people thoroughly understand the equipment that is humming away behind the doors of those switch rooms and there is a significant need for power systems that are safe, reliable, easy to operate, uncomplicated, and easy to maintain.

This page specifically covers the reliability aspect.



Ray Vella

Principal Electrical Engineer


"A loss of electrical power can mean full plant shutdown, with significant production and cost impacts, along with a lengthy and stressful restart."

Expertise


Expertise means knowing the answer before you are asked the question. At Process Consultants we don’t need to learn on the job, carry out exhaustive studies or produce computerised models of your plant electrical system. We have almost certainly seen your problem before and can quickly and efficiently move into the implementation of focused electrical reliability upgrades.

Maintainability 


'If equipment doesn’t have a method of isolation so that maintenance can be performed, then it won’t be maintained or even inspected'

In pipework, isolation valves and bypass lines are built in to make it possible to maintain particular parts of the process plant without shutting down the whole facility. In the electrical system it is actually even more important to have a similar arrangement, because the electrical supply needs to be running during the plant shutdown periods to power lights, tools, water systems, and safety systems. You can never really afford to completely turn off the power.

If equipment doesn’t have a method of isolation so that maintenance can be performed, then it won’t be maintained or even inspected. Ultimately this will lead to equipment failure at a time that is completely unpredictable. It is not a hopeless situation though, there are some clever ways to make it possible to maintain electrical equipment without major replacements or full electrical shutdowns

Reliability of supply


What is going to stop the electrical power supply getting to your plant?

The obvious first place to look is the source of the power. If you generate your own power then generators tripping out is a major exposure. There are a great many things that can be done to improve the reliability of onsite generation. Generators usually trip because of an issue with the fuel supply, a defect in the control and instrumentation, or because of overly conservative hair trigger in the protection settings. The risk of a generator tripping can be mitigated by running an N+1 number of generators. It is possible to install a load shedding system that is designed to rescue the power system in the event of a generator trip. Also, there are many things that can be done to decrease the likelihood of generators tripping by adjusting settings or upgrading critical components of the generator controls and package instrumentation. The reliability of the fuel supply can be addressed.

If you rely on the public grid then a blackout from storms or overhead line damage will put you in the dark. Most methods to avoid this failure such as connecting at a higher voltage level or installing onsite generation will be prohibitively expensive. However, our multidiscipline team can determine how to keep key equipment healthily idling at your plant to make the restarting process faster.

Tripping out


Many electrical outages occur from the wrong breaker tripping within the plant. Typical power distribution systems are equipped with hundreds of circuit breakers and fuses whose sole purpose is to disconnect the power – at the right time. The problem is that if they are not set up properly then they could be overly helpful and trip a whole section of plant unnecessarily. This is called selectivity. For example, if there is a failure or overload on one machine, that only the circuit breaker on the faulty circuit on that machine trips – and nothing else. This is relatively easy to achieve when there are only a small number of layers of distribution and all of the circuit breakers are the same brand, but it needs expert involvement when there are fuses and different types of breakers working together.

The irony of designing selectivity is in the area of earth faults, the term given for when a live wire shorts out with something earthed such as a metal cabinet. This scenario requires the most expertise to design for, and therefore most of the mistakes or oversights are made here. Ironically 80% of electrical faults that occur are earth faults. One example of how this can affect reliability is at one plant we were brought in to carry out an investigation where an air compressor motor had a short circuit from the winding to the motor frame, probably due to water ingress. The motor protection did nothing, or the three layers of protection above it. After 10 seconds the power authority’s feeder tripped the entire plant. This kind of incident can be prevented by a combination of good design and maintenance of the electrical system.


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