In the world of electrical delivery systems, the panel is the common format for specifying electrical information and values both outside the facility in the power grid as well as inside the facility. As most electrical engineers and softwares use a panel, then the issue is: are all panels essentially the same?
Is a panel, a panel, a panel?
Although panels appear similar, the panel inside the facility is very different from panels used to design in the power grid. Why? Because inside the facility the requirements of the National Electrical Code (NEC) must be met. Outside the facility, other codes and standards applicable to the power grid must instead be met.
So, a panel is not necessarily the "right" panel for your design work just because it is a panel. But, as the panel is the common denominator across electrical distribution systems (both outside the facility in the power grid and inside the facility for its electrical distribution system), confusion exists as to what the "panel" does / does not do.
The Difference Between Panels
As software developers, publishers, and electrical professionals, we are periodically asked to explain and review the difference between electrical software programs. Recently, a major equipment manufacturer asked for a review of several software programs and today, we take a first look at ETAP in this series of three articles.
ETAP's panel was initially developed for design in the power grid. It determines whether the connected systems in the power grid and the power distribution system inside the building are compatible and in harmony. Its calculations are typically "studies" focused on the analysis of an engineering design to check that connected systems act together as one electrical system. These analyses include: fault current studies, harmonic current studies, power flow studies, and similar calculations related to the transmission of electricity in the power grid including the connection of the building's power distribution system to the power grid / electrical service.
In contrast, if you design electrical distribution systems inside the facility, the electrical professional does not need to be concerned with "studies". Instead, their design must comply with the National Electrical Code (NEC). Due to these differences in the functions of these programs, and if you are designing electrical distribution systems inside the facility, then your ETAP software is likely sitting on your shelf rather than being used.
Why? Just because ETAP uses a panel for their design, does not mean that their software and panel can effectively and accurately design the power distribution system inside the facility for compliance with the NEC.
Transition to Low Voltage Design
Software programs to design in the power grid were developed before the development of software programs that design electrical distribution systems inside the facility. ETAP and other "power grid" softwares use a "top-down" approach...designing from where electrical energy is produced (i.e., the nuclear or coal plant) to where electricity is delivered to the building.
Following this "expertise", this process was incorrectly adopted for the design of the electrical distribution system inside the building. Electrical software programs inside the building mimic this "top down" approach of power grid softwares. These softwares base their calculations on estimates in a "top-down" approach - estimating the load from where the electrical power is delivered to the building down to the circuit.
At PowerCalc, a very different "bottom-up" approach is implemented for compliance with the NEC. This approach recognizes that inside the facility, the circuit drives all design. PowerCalc uses actual loads (no estimated values) by applying NEC demand factors for exactingly accurate results. PowerCalc is the only software in the industry with a panel that calculates branch circuit values, feeder values, panel characteristic values, voltage drop, and short circuit currents with just 3 inputs per circuit (load kVA, load type and # of poles). And soon to come MCCs, ATSs, double ended switchgears, and unit substations.
Support for this approach is found in the NEC itself. The NEC Handbook starts at Article 210 with Branch Circuits and then moves through each of the elements (215 Feeders, 220 Branch - Circuit, Feeder & Service Load Calculatons, 230 Service, etc.) comprising the electrical distribution inside the building to the connection to the power grid. In short, PowerCalc builds the electrical distribution system inside the building using the same method as the NEC...circuit-by-circuit.
But, we have gotten ahead of ourselves. In our next article in this series, we will take a close look at ETAP's panel (see image above) to examine their "low voltage" applications in detail. etap.com/product/panel-systems-software
And remember, we have a free live / real time demonstration on the first Friday of each month: FREE Demo, Friday, July 9th at 12 pm EST . And here is a video of a recent demo Video of PowerCalc Demonstration Hope you will join us!
Thank you for your support! Stay well.