System Planning and Studies

Alpha Engineering, Inc (AEI) offers several different types of system planning and analysis options to develop safe, reliable, and efficient electrical systems. The primary modeling and analytical software packages that we use for these studies are SKM System Analysis, Inc's Power*Tools® and Milsoft Utility Solutions' WindMil© and LightTable©.

Construction Work Plans

Construction Work Plans are used to determine and document an electrical system's 2 to 4 year construction needs that are the most feasible, environmentally acceptable, and economical. New construction is periodically required in order to provide and maintain adequate and reliable electric service to a system's new and existing members. A Construction Work Plan is a valuable reference for the preparation of annual construction budgets and schedules.*

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Long Range Plans

Long Range Plans guide an electrical system's most practical and economical means of serving future loads while maintaining high quality service to consumers. Long Range Plans also outline anticipated system changes in terms of major facilities, demand levels, and associated costs. Finally, Long Range Plans serve as an indication of future system costs for financial planning and decision making. System planning is a continuing and dynamic process that results in a plan that is flexible enough to allow for revisions based upon changing circumstances.**

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Load Flow Studies

Load flow or power flow studies are performed by applying numerical analysis to an electrical power system. The power system being examined is approximated or modeled so the numerical analysis can be performed. The models typically emphasize the real, reactive, or apparent power rather than simply the voltage and current. Using computer analysis programs allows AEI to examine power systems in normal, contingency, and proposed configurations.

Load flow studies make it possible to plan for future power system expansions and upgrades and can be used to determine the best operating practices for existing systems. The principal information obtained from the load flow study is the magnitude and phase angle of the voltage at each bus and the real and reactive power flowing in each line.

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Voltage Fluctuation Analysis

Voltage fluctuations or voltage flickers are sharp decreases in voltage which persist for only a few cycles or seconds. Large loads can cause voltage fluctuations either at the consumer creating the flicker or also on the primary electrical system and adversely affecting nearby consumers. Consumer annoyance due to fluctuations is a function of the magnitude of the voltage dip and the frequency at which it occurs. Since large numbers of consumers are affected by primary flicker, limits on voltage fluctuations are more stringent on the primary feeder than on the secondary feeder.

Voltage fluctuation studies allow predictions to be made about how new loads will affect the electrical system. If the new loads are expected to cause unacceptable voltage fluctuations to occur, then system improvements can be implemented prior to the new load being energized to avoid the unacceptable voltage fluctuations.

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Fault Studies

An electrical fault is any unwanted connection between conductors and ground. Faults such as broken conductors or downed trees in lines are said to be permanent faults. Faults such as lightning, intermittent tree contact or whipping conductors are known as temporary faults. Faulted conditions can cause permanent damage to power system equipment or harm consumers. Thus, fault conditions must be detected and removed from the electrical system.

Fault studies are used to calculate the available fault current at any given point on the electrical system. The available fault current is the maximum current that can flow under the worst possible fault conditions. This data is needed to coordinate protective equipment, to ensure that equipment interruption ratings are not exceeded, and for arc-flash hazard assessments.

AEI uses analysis software to perform fault studies. The analysis software uses symmetrical components for network analysis to determine fault data throughout an electrical system. These techniques permit any system configuration to be analyzed and permit multiple independent systems to be analyzed as a single study.

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Protective Device Evaluation Studies

Protective device evaluation studies are performed to determine if device interrupting ratings exceed calculated fault levels at each device. Device ratings are typically provided in symmetrical kA. The normal system configuration is used when comparing calculated fault current levels to the device ratings. Devices whose interrupting ratings are found to be less than the available fault current are summarized in each device evaluation study.

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Coordination / Sectionalizing Studies

Coordination studies are done to develop overcurrent protection that cost-effectively prevents hazards to the public, minimizes equipment damage, and maintains service continuity to customers. Coordination is the systematic selection, placement, and setting development for overcurrent devices that allow normal currents to flow, but sense abnormally high currents and open the circuit to remove the fault or overload from the system. The protective devices are coordinated to remove the faulted portions of the electrical system from service while maintaining electrical service to as much of the remaining system as possible.

AEI uses analysis software to perform coordination studies. The analysis software provides graphical representations of the device coordination as well as tabulated equipment information such as manufacturer, catalog number, size, and settings.

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Arc Flash Hazard Analysis

An arc flash is a serious electrical hazard created when energy is released during an arcing fault. An arc fault occurs when an energized conductor comes in contact with another object that cannot handle the short-circuit capacity of the energy source. Once the short-circuit current begins to flow, conductive materials can be vaporized or they can be moved by the mechanical force of the current flow. Either way, current can continue to flow through conductive plasma until the system voltage can no longer sustain the arc or a protective device interrupts the flow of electricity. Because the system voltage must sustain the arc, arc faults usually only occur on systems whose voltage is greater than 120 volts.

When an arc fault is flowing through plasma, electrical energy is converted into other forms of energy including light, heat as high as 35,000° F, noise, and a rapid pressure wave. The pressure wave can launch projectiles such as plasma, molten metal, ionized gases, or any other object near the arc flash throughout the vicinity. Consequentially, an arc flash can harm nearby personnel by causing hearing or vision damage, severe burns, or even death.

AEI can provide a complete arc flash evaluation using modeling and analytical software to analyze electrical systems and create a report. An arc flash evaluation determines trip times for the protective device, arcing fault current values, the incident energy, and arc flash boundaries. Benefits of an Arc Flash study include:

  • Development of a single-line diagram
  • Creation of safe working distances from energized electrical equipment
  • Completion of a fault study that includes the utility contribution, system impedance, and X/R ratios to determine calculated three phase and single phase faults.
  • Completion of a protective device evaluation to determine the adequacy of all protective devices.
  • Completion of an equipment device coordination study to determine optimum settings of over current protective devices to help assure the nearest device isolates the fault so other equipment is not unnecessarily shutdown.
  • Mitigate arc flash hazards keeping the flash hazard category to the lowest possible class.
  • Create hazard labels indicating the potential hazard and required PPE at equipment locations throughout a facility.
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Power Quality Investigations

AEI performs power quality investigations by examining specific parameters such as voltage, current, harmonic content, and frequency. These parameters will often be outside of industry-accepted boundaries if an electrical system is functioning poorly. Examples of power quality concerns include outages, surges, under or over voltage conditions, and harmonic content. The essence of power quality is ensuring equipment is working properly and that the electrical system's parameters are within acceptable limits.

In order to investigate an electrical system, a site survey is performed. The four basic components to a site survey are:

  • Determine soundness of the wiring and grounding system.
  • Determine quality of the AC supply.
  • Determine sources and impact of disturbances on equipment performance.
  • Acquire and analyze survey data to guide system improvements or corrective actions if necessary.
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Rate Studies

AEI offers multiple electrical retail rates services. Rate analysis addresses cash requirements, consumer classification, and cost of service. Rate design provides revenue to a utility from its various consumer sectors. These sectors typically include residential, commercial, industrial, and lighting classifications. Utility revenue sources include energy charges, demand charges, consumer service charges, environmental surcharges, fuel adjustments, and other miscellaneous charges. Cost-of-service analysis uses utility records to categorize expenses, revenues, and utility plant. Finally, rate schedule preparation addresses necessary descriptions, consumer classifications, terms, and conditions.

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Expert Witness Services

AEI offers complete expert witness services. Our knowledge and experience leave us well qualified to provide expert opinions in injury, property, or other legal proceedings pertaining to the power delivery industry.

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*RUS Bulletin 17240-101B, System Planning Guide, Construction Work Plans
**RUS Bulletin 1724D-101A, Electric System Long-Range Planning Guide