We perform power system studies to ensure the long-term functionality of electrical facilities. Our guiding principle is that your electrical facilities must operate reliably without interruption while maintaining both equipment and personnel protection.

Traditional overcurrent protection by itself is not sufficient to fully protect your electrical equipment against damage and your personnel against arc flash hazards. We recognize that your facility has unique requirements such as supplying industrial loads with transient overloading, selectivity to isolate faults within a localized zone, high-speed tripping for optimal equipment protection, and advanced schemes to mitigate arc flash incident energy levels. Our deep understanding of complex AC and DC power protection schemes allows you to establish an electrical distribution system that harmoniously fulfills all your functionality requirements.

Our core competencies:

An effective combination of power system studies can provide results to improve personnel safety, maximize distribution system protection, and optimize operational selectivity. Often just called a study, there is more to it than that:

• Short Circuit Study. This analysis ensures that the interrupting ratings of protective devices and withstand ratings of electrical equipment are suitable based on the balanced and unbalanced fault currents computed for the system model.

• Protective Device Coordination Study. This analysis can yield increased equipment protection and ensure proper selective coordination by setting protective devices to trip in sequence, thereby increasing facility reliability, and limiting the effects of nuisance tripping and disturbances to smaller areas within the distribution system.

• Arc Flash Study. When short circuit and coordination studies have been performed, their results help in compliance with IEEE 1584, NFPA 70E, and OSHA requirements regarding arc flash and shock hazards.  An arc flash study will help determine incident energy levels, arc flash boundary, limited approach boundary, restricted approach boundary, arc flash labels, and to serve as guidance in selecting appropriate PPE.

• Load Flow Study. A load flow analysis of the electrical distribution system will verify that the system can operate without causing undesirable voltage drops between the source and load; and that the overall loading of electrical components does not exceed their nominal ratings.

• Harmonics Study. This analysis determines if the total harmonic distortion of voltage and current at the point of common coupling are within the allowable limits of IEEE 519.  A harmonic analysis also examines the effects of non-linear loads such as a VFD, UPS, or rectifier thus determining their overall impact on the electrical system.

• Motor Starting Study. This analysis confirms that motor starting can be successfully performed for a given electrical system configuration while considering the overall effect of transient inrush current, voltage flicker, nominal system voltage, and frequency stability.

• Grounding Grid Analysis. This analysis determines the adequacy and safety of the subsurface ground system by calculating the earth and conductor potentials for aspects including the ground potential rise, step voltage, and touch voltage profiles.

• Cable Pulling Analysis. This analysis determines the feasibility of pulling cables from the origin to the destination by verifying aspects including jamming, cable clearance, conduit fill, bending radius, sidewall bearing pressure, weight correction factor, and pulling tension.

• Battery Sizing Study. This study determines the adequacy of the battery system equipment by validating the ampere output capacity of the battery charger and confirming the adequacy of the ampere-hour rating of the batteries; thereby ensuring that the overall battery system is properly sized and rated to suit the operational requirements of the electrical distribution system.

• Ductbank Thermal Evaluation. This evaluation determines if cables within a ductbank configuration can support the loading requirements and not cause undesirable conductor overheating by ensuring cable temperatures remain within specified limits based on ambient temperature, conductor grouping, conduit spacing, and peak steady-state loading.

• Transient Switching Stability Analysis. This analysis determines the impact of voltage transient conditions, current chopping, prestrikes, and restrikes associated with capacitor switching, transformer energization, and fault interruption. Based on the analysis performed, solutions for appropriate surge protection and R-C snubber implementation can be ascertained to reduce undesirable transient conditions.

A representational list of our power system study projects:

Railway, Transit & Traction Power Substations

• PATH Substation 7 Red Line - Jersey City, NJ (Learn More)

• WMAT Red/Green/Orange Lines - Washington DC

• WMATA Silver Line - Northern Virginia

• Seattle Monorail - Seattle, WA

• AMTRAK Ivy City, High-Speed Rail Facilities - Washington DC

• NJT Meadows Complex - Kearny, NJ

Data Centers

• WSSC Parkway Water Resource Recover Facility - Laurel, MD (Learn More)

• ReWa Mauldin Road Water Resource Recovery Facility - Greenville, SC

• Baltimore County, Pikesville Water Pumping Station - Pikesville, MD

• WSSC Brighton Dam - Brookeville, MD

• Front Royal Waster Treatment Plant - Front Royal, VA

Commercial Facilities

• Amazon Fulfillment Center - Nottingham, MD

• Shady Grove Hospital - Rockville, MD

• Northern Virginia Community College - Manassas, VA

• Legoland Amusement Park - Goshen, NY

Our blogs related to power system studies:

Testimonials from our power systems study clients:

“Helios brought a unique combination of engineering expertise and common sense to a complex project on which we contracted them.  They identified potential arc flash issues and provided expert real-world solutions to resolve them economically.”

Electrical Distributor (Baltimore, MD)