Working as an electrical power systems engineer is rarely an independent task. On almost all real-world projects there are other engineering disciplines or architects that must be coordinated with.
Figure 1: A Typical Pipe Rack, Showing Mechanical Piping, Structural Steel, and Electrical Raceway
Think about actual installation of your system? How will you install your raceway, be it conduit, tray or something else? Likely, you'll need to coordinate with mechanical engineers regarding piping or HVAC ducting that could be routed along similar pathways. Similarly, you'll need to work with structural engineers to ensure that you have a proper support system in place. The list below includes some of the most common inter-discipline coordination points that must be considered by an electrical engineer.
What equipment is on site? This is the easiest question, but the most important! Talking to your project's mechanical engineers to understand what electrical loads will be required. If you don't know the loads in place on the project, your electrical design can't even get started!
What kind of reliability requirements are in place for plant operations? Often, electrical engineers would prefer to use simple radial designs for all power distribution. It is cost-effective, easy to design, and accepted by the industry as an effective means of power distribution. However, there are often other considerations that require electrical engineers to build in additional complexity. Sometimes loads need the ability to be backed up across buses, requiring tie breakers. Sometimes, alternate feeds with synchronism check requirements need to be supplied for special loads.
What will indoor design temperatures be? Outdoor design temperatures are usually easy to find for an electrical engineer. Sources like ASHRAE and the National Weather Service offer databases filled with dry bulb temperature expectations. Inside of a building is a different story. Sometimes, equipment needs to be carefully climate-controlled, leading to lower temperatures. Other times, buildings might have ventilation with no cooling whatsoever. As a result, the indoor design temperature could vary from 25 Celsius to 50 Celsius. That swing makes a big impact on cable ampacity derating.
How will your aboveground raceway be supported? Cable trays and conduit are almost never able to be laid directly on the ground without some kind of formal support system. Perhaps you'll need to support off the side of a wall, ceiling, pipe rack, or similar. Maybe you'll need a dedicated structure to support your cabling. All of this has to be coordinated with a structural engineer.
How will your underground raceway be routed and installed? Underground installations can be just as complicated as aboveground. Electrical engineers need to coordinate underground routing methods with geotechnical engineers, civil engineers, and mechanical engineers. If soils have particularly challenging installation conditions, the cost to install raceways underground or to utilize directly buried conductors may be prohibitive. Even in good conditions, large underground piping or other equipment (especially on brownfield sites) could make an electrical engineer's intended route impractical.
Where will you install primary power distribution equipment? On smaller projects, power may be distributed from a single panel. On larger projects, power may be coming from motor control centers (MCCs), switchboards, switchgear, or even open-air-insulated substations. Where this equipment is installed will require coordination with all other disciplines. Sometimes, what is best for an electrical engineer may be exactly the opposite for a mechanical engineer. Other times, there simply isn't room on site to place equipment properly. Lastly, your equipment will have to be supported somehow. If it's particularly large equipment (like a prefabricated building or a substation), you will need detailed, engineered foundations to support the structure.
How will soil conditions impact design? Underground installation of cables in duct banks, troughs, conduits, or dirt is common. It's a convenient way to remove access limitations, protect conductors from damage, and potentially improve worker safety by minimizing work at heights (like when cable tray is installed on top of a pipe rack instead of underground). However, soil properties that electrical engineers don't often worry about, like moisture retention, can play a major role in design. In low moisture conditions, the thermal resistivity of soils may rise well above the industry-standard value of 90 Celsius*cm/Watt. This could lead to overheating of cables and reduced lifespan. Coordination with civil and geotechnical engineers will help minimize these problems.
And, there are many, many more questions to ask. This is just a sampling of the highlights! Always work with your other engineering disciplines to make sure your design is going to work.
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