For panel builders, understanding how to build an electrical power distribution system is important. As noted in the introductory article, this can be done by following IEC 61439 or an appropriate local standard as well as component manufacturer specific instructions about assembly and derating, along with using the correct grade and type of conductor.

It is important to adhere to the standard and manufacturer instructions and to test for compliance to them. Doing so ensures performance will be acceptable for the life of the installation, thanks to built-in operating margins.

Panel builders can achieve this using flat busbars that are custom crafted. IEC 61439 provides tables that set bar size depending on the current load for a given ambient temperature. Pursuing customization places the entire burden of calculation and compliance testing directly on the panel builder.

An alternative is to use pre-fabricated busbars and components. These are validated by the manufacturer, with the main tests proving compliance to the standard already done. Pre-fabricated solutions eliminate any costs or delays associated with certification, thereby saving panel builders time and money.

Ideally, a pre-fabricated power distribution solution should include several different types of components because this gives the greatest flexibility in an installation. Busbars, for instance, should be available in a compact comb busbars configuration to ensure proper connections are always made.

Another part of a pre-fabricated solution should be a device feeder that allows maximum flexibility to balance phases and quickly repartition connection points while still offering a completely tested and inexpensive option. Distribution blocks should also be available because these are compact and have cabling capacity for dozens of connection points.

An electrical panel should also include flat or profiled busbars according to the need (e.g., IP, In, Icc Surface treatment for specific environment, etc.).  If you use a prefabricated system, it is easy to find all the components you need for your electrical distribution.

Our Linergy line of products including: comb busbars, distribution blocks, device feeders, and power busbars,  are fully code compliant, flexible and integrated, see Figure 1.

Figure 1

For more information, visit our low-voltage switchbaord solutionspageand download our free eGuide. Also, be sure to register for our dedicated panel builder resource center.

My first post went over the reasons behind the introduction of IEC 61439 and how following it can help specifiers get the outcome they want and avoid the undesirable ones. Here, I’m going to go over some technical reasons behind the temperature rise tests and the resulting need to define or prescribe the right and reliable rated current of the various components incorporated in the assembly.

To see why, think about an electrical panel or switchboard designed for a train operating in, say, Mumbai or another similarly hot environment. At first, everything works fine. But, then one day the heat and accelerated ageing phenomena it causes catches up to the electrical gear, with the result being fireworks – a scenario that might have happened when a Mumbai monorail caught fire.

Accounting for this in a temperature rise test is important because doing so ensures the electrical safety of a switchboard to avoid the effects from your overheated equipment such as:

  • Connections can overheat and be damaged
  • Components may be impaired
  • Insulation performance could be compromised
  • The burn risk for operators can increase
  • And, finally, there can be a lack of service continuity – which is expensive

More than that, the overheating, if is not detect, can move to thermal runaway (technical thermal avalanche) and create short-circuit or internal arc inside the assembly.

So, the testing in IEC 61439 verifies that temperature rise limits are acceptable for different components of the assembly, including busbar, connections and functional units. Each circuit alone and all collectively must be able to carry the rated current without excessive hot spots.

Such testing, however, also must take into consideration real-life conditions. Suppose the room ambient temperature is 35oC, (reference temperature of the IEC 61439). In that case, a typical temperature rise inside a cabinet could push many of the components to their specified environmental limits, increasing the chance of failure. By the way, 35oC is about the average high temperature for Mumbai in April, Houston, USA in August, and Madrid, Spain in July.

The example below explains why sometimes it’s important to use the rated current given in the documentation of the original manufacturer, as technical guide, to ensure respect of the temperature rise limits.

We should manage the nominal current defined and validated on a device alone in the free air to a rated current into an enclosure where we install the same device with others. Due to the increase of the internal air ambient, the rated current shall be adjusted to guarantee the performance during the life of the assembly.

derating

Example of derating for an electrical room without air conditioning.

Some customers, with more usage in critical buildings, can use the panel in an electrical room with air conditioning. If so, then the rated current shall be adjusted.

derating

Example of derating for an electrical room without air conditioning.

IEC 61439 section 10.10 states that busbars and functional units should be tested. These evaluations are done using the worst-case conditions. So, busbars must be mounted in the assembly enclosure with all normal covers and partitions in place, and the tests must be done at the rated current.

Functional units shall be mounted in the enclosure as they would be in normal use. Again, all covers and internal partitions must be in place. Also, as before the rated current should flow through each unit, with this multiplied by the diversity factor. This recognizes the fact that not all functional units will be at their maximum rated load at the same time. Thus, the energy dissipated as heat will not simply be the sum of the maximum of each individual component. Instead, it will be somewhat less, with this determined by the diversity factor.

The maximum temperature is 140oC for copper busbars, 125oC for individual components (in accordance with the component manufacturer’s instructions), and 105oC for external insulated conductors. The last limit is lower because the performance of insulation degrades with temperature to a greater degree than does bare metal performance. This is important in situations where support links are insulated.

So, for an ambient temperature that is 35oC, the maximum temperature rise is:

  • 105oK for copper (140°C -35°C),
  • 90oK for incorporated components (in accordance with the component manufacturer’s instructions) (125°C-35°C) and
  • 70oK for terminals, external insulated conductors (105°C-35°C).

For insulated busbar support, then the minimum temperature for that part would be 140oC. Going through such a derating ensures that individual parts of the assembly will not degrade or fail. It also guarantees that the entire assembly will safely and reliably function for its operational lifetime. Finally, it means that electrical panel specifiers and designers can concentrate on other aspects of the project, without having to worry about safety and service continuity failures.

Maybe following IEC 61439 would have kept the monorail mentioned above – and other trains – running on time. Instead, the line shut down for hours, making the daily commute challenging.

The next post in this series will cover clearance and creepage distances, why they are important, and how to ensure they meet the standard.

Schneider Electric has a complete range of main and distribution busbars, prefabricated connections and distribution blocks, and thermal rules in its catalog. For more information on our offering in this area, click here.

This is the second blog post in a four part series on digital transformation in Oil & Gas. Read the first blog post on mobile operator rounds here, and keep an eye out next week for the next blog post on unified supply chain management.

Among the many challenges that O&G companies face in the market today, volatile feedstock prices have the most impact on the bottom line. Feedstock prices can shift dramatically over very short periods of time, making it difficult to maintain profitability. Due to these pressures, forward-thinking O&G companies are looking to maintain the same level of operational excellence, while reducing costs.

This blog post will cover one of the best ways to achieve these goals, by moving process design to the cloud.

See how digital transformation helps improve process design

Read our whitepaper to see how digital transformation helps O&G companies streamline process innovation

Benefits of the Cloud

Hosting functions in the cloud has several benefits. Because the cloud has near-infinite storage capability and processing power, cloud solutions are inherently scalable. This makes it extremely easy to scale from a pilot to covering an entire plant, from a plant to an entire enterprise, or even scaling down when necessary. Cloud solutions also increase information access by breaking down silos and making it possible to access valuable process design data from anywhere in the plant.

From a business perspective, the cloud’s extreme technical and commercial flexibility means O&G operators using cloud solutions can provision, design and configure exactly the solutions they need, when they need it. This means a level of efficiency that is hard to achieve with traditional on-premise solutions. Finally, cloud solutions do not require on-premises software installations, or an extensive IT staff, reducing total cost of ownership (TCO).

See how digital transformation helps improve process design

Digital transformation helps O&G companies develop agile business models – read our whitepaper to learn more!

Cloud Process Design

Process design in the cloud opens up a new range of possibilities for O&G companies. The improved agility from the cloud allows operators to continually adjust production processes. This facilitates the continuous improvement process, and allows companies in the upstream, downstream and midstream market to rapidly adjust operations when necessary to meet market requirements or comply with new regulatory guidelines. An open model writing environment on a cloud architecture enables users to extend simulation benefits downstream to areas such as reactors, polymers and specialty materials.

Digital Transformation

In addition to the collaboration and low TCO benefits, cloud process design solutions integrate well with other digital transformation efforts. For instance, by integrating cloud process design with augmented reality (AR), users can see a complete Digital Twin from design and conception through to its current operational state and maintenance history. Visit our website to learn more about digital transformation in O&G and the benefits your company can achieve.

Greg Hale, Chief Editor of ISSSource

We are pleased to host Greg Hale, chief editor of ISSSource, as our guest blogger in the Oil & Gas section as he shares the outcome of interviewing several Schneider Electric experts on the topic of safety and reliability:

Author’s remarks…Increased connectivity in the oil and gas industry is already here, but that connectivity – and the advancement of the Industrial Internet of Things (IIoT) – can bring additional agita to safety and security professionals working on any platform.  Attacks against critical infrastructure are increasing. As the attack against a Saudi Arabian gas facility showed, a connected system linked to a safety system has the potential to fall victim if there is a lack of proper cybersecurity practices, policies and procedures. The same is true for the attacks against the Ukrainian power grid in 2016 and 2017. That all could sound like a hopeless situation. But the reality is there are answers and solutions.The following story can help guide users to finding the right solution to protecting and keeping safety systems safe so they can do their job.

Safety, Connectivity and IIoT

Increased connectivity across any manufacturing enterprise, from the oil and gas industry all the way to making buttons for a clothing line, has the potential to hike business intelligence, productivity and profitability.

The catch is, though, with the coming age of that hike in connectivity, better known as the Industrial Internet of Things (IIoT), cybersecurity becomes a huge factor that can make or break a manufacturing enterprise. Add in the potential for an increased attack surface with more Internet-connected devices and not only do automation systems face turbulent waters, but so does the last line of defense: Safety systems.

As the attack against a Saudi Arabian gas facility that occurred in August 2017 showed, a connected system linked to a safety system has the potential to fall victim if there is a lack of proper cybersecurity practices, policies and procedures.

While that may sound dire, the reverse is true. With manufacturers taking cybersecurity seriously and with proper cyber hygiene, any facility can prosper in the age of IIoT.

“It is definitely recognized getting security right is just as important as getting safety right. If you compromise any part of the safety system, it doesn’t matter how much time, money and effort you have spent designing and implementing the system correctly, if they are defeated they will not do the job you need,” said Sven Grone, Safety Services Practice Lead Asia Pacific & Middle East for ‎Schneider Electric.

With IIoT continuing its growth curve, Gartner, Inc. forecasted 8.4 billion connected things will be in use worldwide this past year, which was up 31 percent from the year before, and will reach 20.4 billion by 2020. Total spending on endpoints and services was predicted to almost $2 trillion last year.

Ample Connectivity

With the forecasted increase in connected things of almost 250 percent by 2020, there is no doubt that safely managing connectivity will increasingly be the focus for any manufacturing facility.

“The more information you extract from devices in the field, the better you can manage your system and be armed with information to deal with potential issues before they become an incident,” Grone said. “Getting the information from the field and being able to act on it lets you operate the plant in a safer fashion, provided you’ve recognized the potential vulnerabilities these increasingly connected devices bring, and you have a comprehensive plan in place to mitigate and manage these.”

Along those lines, the opposite is true: Not having a solid cybersecurity program could stall the growth of IIoT and the potential benefits of increased productivity and reduced costs, which are goals of manufacturers today.

“Unless we adequately address cybersecurity, I don’t see any IIoT in a high criticality environment, but on the reverse, maybe 90 percent of processes are not critical,” said Yusuf Kapadia, Principal Technical Safety Consultant, Safety Systems Portfolio at Schneider Electric. “So, something in an organization that produces specific components in the multi-millions in a day, these industries are very much Internet-connected and have produced massive amount of improvement in terms of throughput in profitability. Oil and gas is a different thing though, almost everything falls under a high criticality environment.”

Avoiding Hype

With increased connectivity, a well-thought out plan involving the entire manufacturing team is needed, one important factor is not getting caught up in the hype – especially when it comes to safety.

“Number one, you only connect where it makes sense,” said Steve Elliott, Senior Director at Schneider Electric. “Everybody is on the back of the tidal wave of emotion saying I have got to have IIoT and be connected and digital. Does it make sense to my business? Is it solving a business problem? You need to follow three simple steps: Does it makes sense? If so, what are the risks and threats that can hit me? And then how do I protect against it and what do I have to do. It is that simple, there is no rocket science in it.”

With that boost in connectivity, collecting and analyzing safety data is key, however, getting that information and not compromising the system in the process remains vital.

“You want the data from the safety system because there is valuable information to be had. If you listen to what the safety systems are telling you, you’ll find a lot of hidden value,” Elliott said. “So, get the data and save it somewhere securely so the user can consume it. You will not write to the safety systems, as a matter of fact, you should keep this as far away from that as possible.”

“IIoT does have a play from a safety vigilance perspective from a dashboard type of application providing plants with a much better understanding of about how safe their plants are in any given hour,” said Michael Chmilewski, Vice President Process Safety Business at Schneider Electric. “But not from a perspective of ever putting a safety system anywhere near devices connected to anything outside the plant.”

Employing Good Practices

This was one of the problems the Saudi Arabian gas facility faced in that attack in August 2017 when an Internet facing system fell victim to the attack called Triton, Trisis or HatMan and affected the DCS and safety system.

“What happened with Triton was a complete failure in good practices, policies and procedures when it comes to cybersecurity,” Chmilewski said.

With a safety system, the argument has circulated for years about whether it should be separate, interconnected or interfaced with the control system and that discussion has just ratchetted up over the past six months.

Safety as an Island

“You will never have a safety system that is a black box sitting in the corner just doing its thing like you would have had 40 to 50 years ago,” Grone said. “Nowadays, the systems need to be managed because you have to get information out of them. The key is understanding what they are connected to, recognizing what the potential threats are, and have the right risk mitigation plan in place.”

“Safety as an island is the next default,” Kapadia said. “You would need some kind of data intelligence and some kind of value driven software. As long as you place it within an island, it should be OK.”

“I think it is important to isolate the safety system as much as possible and monitor and manage whatever network traffic between the two there is,” Chmilewski said. “So, you are only sharing the information you need for the DCS to do its job, which should be allowing only the protocol and the traffic that is necessary to pass data back and forth between the two.”

No matter if the safety system is separate or connected, IIoT’s increased connectivity promises great rewards, but manufacturers need to heed the call to understand and adopt a solid cybersecurity regimen to ensure a protected safety system.

“Safety is your last line of defense,” Kapadia said, “If you are not cybersecure, then you’re not necessarily safe. Learn from others, not from your own mistakes.”

To learn more…Downlonad your FREE WhitePaper Five steps for enhancing industrial process safety through IIoT and Digitization here