The reliable and efficient operation of a power system — from a low voltage commercial system serving less than 100kW to a high voltage transmission system delivering hundreds of megawatts — requires a thorough understanding of how the system will perform in both normal operation and during contingencies. The proper and thorough analysis of power systems is required, in both the design and operation stages, in order to maximize safety, reliability, and performance, all while minimizing cost.
Because power systems consist of the interconnection of thousands of individual components — transformers, transmission lines, capacitors, voltage regulators, insulators, surge suppressors, switches, and a variety of loads — the analysis of such systems requires an expertise in both the individual components as well as in the complex interaction of these components to form an interconnected system. This requires the proper application of engineering fundamentals developed over a hundred years ago as well as the latest in software tools to quickly and accurately understand complex systems.
ELECT, P.C. has the expertise, experience, and tools to accurately analyze power systems from the design and planning stage to failure analysis, and from the smallest coordination problem to complex transmission loadflow and stability issues, generator interconnection and control, transient disturbances, protective relaying, and more. ELECT, P.C. has developed an expertise and broad experience base in the following areas:
Short Circuit and Protective Coordination
Regardless of how well a power system is designed, built, or maintained, all power systems are vulnerable to faults. This may be due to aged or worn equipment in an industrial facility, or a storm-related fault on a utility feeder. A faulted system usually, but not always, results in a relatively large short circuit current.
Regardless of the nature of the fault, the reliability and safety of an electrical system requires an understanding of how that system will perform when a short circuit occurs, and a system that is designed and configured to properly respond to the fault.
A properly coordinated system will respond to faults by:
- interrupting the fault current to limit equipment damage and minimize hazards to people, and
- minimize the portion of the system that is impacted by the fault.
Utility Distribution Sectionalizing Studies
A utility distribution system differs significantly from an industrial distribution system in several aspects — the loads are more distributed, circuits are constructed and grounded differently, the fault exposure is greater, and there are cold load and reclosing issues.
Consequently, the protection of a utility distribution feeder is more involved than for an industrial feeder as the engineer must not only coordinate overcurrent devices, but also optimize device location and consider several other factors such as reclosing intervals, outage exposure, distributed generation, and utility service philosophies.
ELECT, P.C. has performed numerous utility distribution sectionalizing studies on a wide variety of systems. We have been successful in helping several utilities improve system reliability by implementing improved sectionalizing schemes. ELECT, P.C. has also assisted in sectionalizing studies which incorporate the use of distribution automation, distribution circuit ties with multiple settings groups in microprocessor based controls and fast bus transfer schemes for sensitive large industrial customers.
Load Flow Studies
The function of a power system is to supply distributed loads with energy in a usable form. When a power system grows in scope or serves additional loads, its ability to maintain a stable, acceptable voltage at all of its load locations may be compromised, and portions of the system may become overloaded or unstable. Solutions to loadflow problems may involve the replacement of equipment, installation of capacitor banks, remote generation, the use of voltage regulators, or other solutions. ELECT, P.C. utilizes both internally developed as well as commercially available software to solve these complex problems.
Where multiple generators are applied on a large or isolated system, the response of the system to a fault must be understood so that the overall system returns quickly to a regulated, steady state condition. Dynamic stability analyses allow the modeling of systems in order to predict system performance under various conditions. The results of these analyses can be used to assist to making recommendations for protective relay settings or simply to determine if a design concept is sound. ELECT, P.C. uses commercially available software to perform dynamic stability analyses.
Arc Flash Risk Assessment
Recently, the hazards associated with electrical arcing events have come under new scrutiny in order to reduce the number of injuries and fatalities associated with these events. An arc flash is a sudden, explosive release of energy that results when a temporary short circuit initiates the formation of a plasma that dissipates large amounts of energy is a short time. Until a protective device operates, energy may be released in the form of extreme heat, sound, and shock, creating an extreme hazard to unprotected workers in the immediate vicinity.
Per the National Electrical Code, an arc flash risk assessment is required to be performed for electrical equipment that is likely to require examination, servicing, or maintenance while energized, in order to warn qualified persons of potential electric arc hazards. NFPA 70E requires that such equipment be labeled with specific information relevant to the potential hazard.
The purpose of an arc flash hazard analysis is to determine the incident energy to which a worker might be exposed during an arc flash event, to establish an arc flash boundary, and to determine a worker’s required personal protective equipment (PPE). The PPE is intended to provide a level of protection against arc flash burns, shock hazards, and eye and hearing damage. The use of the required PPE does not necessarily provide protection against all burns, but any burns experienced should be survivable.
ELECT, P.C. also provides personnel training, both awareness training for general employees and qualified worker training for electrical personnel. Arc flash hazard training is a key component of an overall safety program for your employees.