Electrical and Power
Electrical and power systems are key to any nonresidential building type and are designed by an electrical engineer. Depending on the building and its occupants’ needs, it may include backup, emergency and standby power systems. Other systems that come into play are wiring and cabling, switchgear, uninterruptible power supplies and fuses and breakers. Electrical engineers who design these systems must understand harmonic mitigation, electrical safety, smart grids and the various codes and standards that define them.
Electrical and Power Articles
Picking software to model electrical systems
As electrical power and lighting systems become more complex, modeling for safe and reliable electrical operations becomes increasingly important
- Discover several major electrical power system and lighting software tools.
- Consider integrating software options with a building information modeling package.
- Review an example of using electrical power system software.
As electrical power system in facilities such as generation stations, industry complexes, hospitals, water pumping stations, water treatment plants, processing plants and other similar facilities expand and become more complex — specifically with integrating microgrid systems for system reliability and cost savings — electrical distribution system model development and proper system analyses become increasingly important.
These systems require advanced industrial electrical software tools for modeling and performing different studies, especially with the increasing availability of convertible equipment such as inverters, variable frequency drives and distributed energy resources such as photovoltaic and battery energy storage systems.
From the conceptual design to operating these complex systems, facility personnel must consider as it is a “living” entity that changes significantly over time as loads increase, equipment is replaced or upgraded, systems are enhanced or utility interconnection parameters change.
Electrical design, analysis software tools
There are numerous industrial electrical system analysis software tools currently available for designers and engineers to analyze power systems, such ETAP, SKM PowerTools, EasyPower, PowerWorld, PSS E, PSCAD, CYME, DIgSILENT. These tools are capable of building complex electrical generation, distribution or transmission system models and performing a variety of system studies, such as load flow, motor starting and voltage stability, short circuit, protective device coordination and equipment protection, arc flash, harmonic, reliability, real time automation, control and monitoring.
In addition, there are available online software tools that can be used to perform, for example, equipment sizing calculations for generator sizing to verify the adequacy of existing or new generators under different loading conditions.
Electrical lighting design software such as agi32 and Elumtools by Lighting Analysts, Visual Lighting Software by Acuity Brands and DIALux by Dial Gmbh are a few commonly used suites used to perform lighting photometric calculations, daylighting simulations and lighting-based visual renderings.
Lighting design software, such as Elumtools, allows designers to perform photometric calculations in the building information modeling application because designers are typically already using BIM to develop models and engineering drawings. This integration allows the lighting designer to seamlessly use model parameters input into the BIM model to perform lighting calculations.
Figure 1: This shows the Autodesk Revit Electrical BIM design package with the ETAP modeling and analysis software tool. Courtesy: ETAP
In general, several of these electrical and lighting software packages such as ETAP, SKM PowerTools, EasyPower or Elumtools can integrate into BIM workflows. Used in conjunction with data exchange modules, these software options can exchange data with BIM modeling software, such as Autodesk Revit to maintain the overall integrated design approach and consistency.
These bi-directional data exchange packages simplify and reduce cost of the electrical design process in short and long terms by using the data that already exist in the Revit to automatically generate electrical models to perform electrical system study (see Figures 1 and 3) or use it to design and analyze lighting calculations.
Figure 2: This highlights the Autodesk Revit Electrical BIM design package with electrical data exchanged by the ETAP modeling and analysis software tool. Courtesy: ETAP
Importance, selection of software
Each facility may select or prefer to use any of the previously mentioned software or another software, based on:
- Specific application.
- Alternating current direct current or real-time module availability.
- Prior experience.
- Vendor support and training.
- Software quality programs.
- User friendliness.
It is difficult to properly evaluate the right software and its limitations without making significant labor and financial investments. Regardless of the electrical software used, it is important for a facility to have such a model available and to regularly maintain it. Having a facility model can help to identify electrical system limitations and issues, improve system reliability and personnel safety and helps engineers with variety of system modifications such as microgrid to provide an alternative source for reliable and cost-saving operation.
Figure 3: This shows a lighting photometric calculation using ElumTools fully lighting calculation add-in for Autodesk Revit. Courtesy: CDM Smith
Learning to use electrical design software
The following example illustrates the need for an electrical software tool to model and perform a feasibility study for integrating a microgrid into the existing facility and evaluate different system configurations. Note that for this study, no Revit integration is used due to the small facility size. Revit integration is typically applicable to much larger and complex system where it can offer more benefits.
This facility is fed from 13.2 kilovolt circuits via a single 1,000 kilovolt-amperes service transformer, an on-site 800 kilowatts backup generator and 500 kilowatts DER (including PV and BESS).
The DER is connected to utility system by a 500-kilowatt bi-directional inverter that can supply (from PV or BESS) or absorb (BESS charging) power. A simplified electrical system when the facility is fed from utility source is shown in Figure 4.
Figure 4: This shows an electrical distribution system ETAP model when a facility is fed power from the utility source only. Courtesy: CDM Smith
How much DER can support when the facility is in parallel or when is in island operation? What is the impact to the system parameters such as bus voltages?
One of the advantages of having a facility electrical system model is to evaluate different system conditions and scenarios. Having a model will expedite time and accuracy to perform such modification and evaluate possible impact as far as system parameters such as power flow, available fault current, etc.
As shown in Figure 4, in this scenario, all demands are supplied from utility source with approximately 680 kilovolt-ampere demand including system voltages at each location.
When the DER (PV) is connected in parallel with the utility source, more than half a required demand, 375 kilovolt-ampere, is provided by this system that owns by the facility. This system can also be used as an alternative source when utility is disconnected (i.e., island operation). The load flow for this scenario is shown in Figure 5. Other configurations such as system in island operation could also be analyzed the same way as discuss here to understand system behavior.
Figure 5: In this example, an electrical distribution system ETAP model when a facility is fed power from both utility and distributed energy resources sources is shown. Courtesy: CDM Smith
Codes and standards
The following standards are applicable to performing power system studies such as the load flow, short circuit, protective device coordination, motor starting, harmonic, reliability and arc flash analyses:
- ANSI/IES LP-7-20 Lighting Practice: The Lighting Design and Construction Process.
- ANSI/IES TM-32-19 Technical Memorandum: Lighting Parameters for Building Information Modeling.
- IEEE 519-2014: IEEE Recommended Practice and Requirements for Harmonic Control in Electric Power Systems.
- IEEE 1547-2018: IEEE Standard for Interconnection and Interoperability of Distributed Energy Resources with Associated Electric Power Systems Interfaces.
- IEEE 1584-2018: IEEE Guide for Performing Arc-Flash Hazard Calculations.
- IEEE 2: IEEE Draft Recommended Practice for Conducting Load-Flow Studies of Industrial and Commercial Power Systems.
- IEEE 3: IEEE Draft Recommended Practice for Conducting Short-Circuit Studies of Industrial and Commercial Power Systems.
- IEEE 7: IEEE Recommended Practice for Conducting Motor-Starting Studies and Analysis of Industrial and Commercial Power Systems.
- IEEE 8: IEEE Draft Recommended Practice for Conducting Harmonic-Analysis Studies of Industrial and Commercial Power Systems.
- NFPA 70: National Electrical Code.
Designing new facilities or making system modifications and improvements without having electrical modeling and analyses can lead to costly failures and jeopardize personnel safety. It is highly recommended to invest and build electrical distribution system models — especially for facilities that are more complex and plan to or already have additional uninterruptable sources such as a microgrid system. This is necessary to understand the facility’s capability for safe and reliable operation.
Electrical and Power FAQ
What is the difference between power and electricity?
Power and electricity are related, but they are not the same thing.
Power refers to the rate at which energy is being used or generated. It is measured in units of watts (W) or kilowatts (kW). For example, a lightbulb that uses 100 watts of power will use 100 joules of energy per second.
Electricity, on the other hand, is the flow of electrical energy or charge. It is measured in units of amperes (A) or volts (V). For example, a lightbulb that runs on 110 volts and uses 0.9 amperes of current will use 99 watts of power (110 V x 0.9 A = 99 W).
In summary, power is the rate at which energy is being used or generated, while electricity is the flow of electrical energy or charge. Power is measured in units of watts or kilowatts, while electricity is measured in units of amperes or volts. Power consumption and electricity flow are related, but different concepts.
What are the three types of electrical power?
The three types of electrical power are direct current (DC), alternating current (AC) and single-phase AC.
What is the relationship between electricity and power?
Electricity is the flow of electric charge through a conductor, while power is the rate at which that electric charge is flowing. In other words, power is the amount of energy being used per unit time. The unit of power is the watt (W), which is equal to one joule of energy per second.
What is meant by electrical power?
Electrical power refers to the rate at which electric energy is transferred or used. It is typically measured in watts (W) or kilowatts (kW). The amount of power used by a device or system is determined by multiplying the voltage applied to it by the current flowing through it. For example, a 100-watt light bulb uses 100 watts of power when it is turned on. Electric power is used to operate lights, appliances, machines and other equipment in homes, businesses and industry.
Some FAQ content was compiled with the assistance of ChatGPT. Due to the limitations of AI tools, all content was edited and reviewed by our content team.