Power System Studies
Arc Flash Hazard Analysis
Colwell & Associates, Inc. performs Arc Flash Studies to determine the available incident energy levels present at various points within the facility’s electrical system. Our engineers work with clients to provide proper arc flash evaluation, labeling and training to ensure a safe work environment for facility personnel and compliance with OSHA requirements.
Short Circuit Analysis
A short circuit analysis is performed to determine the adequacy of your interrupting devices such as circuit breakers and to identify correct set points for instantaneous elements. A short circuit analysis is required for proper sizing of circuit breakers and/or fuses
Protection and Coordination
Electrical system protection and coordination studies are essential to verify that a facility’s electrical system is operating in a safe and reliable manner. Proper system coordination ensures that equipment is properly protected while preventing nuisance trips and ensuring that only the faulted zone of your system is de-energized when a short circuit occurs.
A load flow study calculates the currents, voltages, phase angles for each bus in your system and the power flow and losses in each transformer and feeder. This information is used to determine proper size and ratings of current carrying equipment, to identify overloaded circuits, and to determine locations where power factor correction may be required.
A motor starting study is performed to determine the voltages, currents, and starting times involved when starting large motors. Such a study is critical before installing a large motor to make certain that your system can start and accelerate the motor successfully while not adversely other operating loads.
Reliability analysis studies are performed to identify and eliminate system deficiencies in order to maintain safe, stable power system operating conditions. Such deficiencies may include lack of protection, non-redundant sources, equipment, and circuits and poor installation conditions. Using standard IEEE models, your system configuration will be analyzed and compared to industry norms. Outage records which exceed industry standards are pinpointed and corrective actions are recommended.
Grounding Systems Evaluation
New or existing grounding systems are designed or analyzed according to IEEE standards to confirm adequate ground current carrying capability and to ensure that step and touch potentials and ground potential rise (GPR) values are within tolerable limits. Properly designed grounding systems are essential for safe and reliable power system operation.
Harmonic studies involve a two phase approach. First your system harmonic levels are measured using recording equipment. Second, using a computer model, harmonic load flows, voltages, and currents are calculated. The results from the two studies are compared, and trouble spots are identified. The results of these studies can then be used to prepare corrective actions such as filters.
Transient stability studies analyze the system response to disturbances such as the loss of generation, line-switching operations, faults, and sudden load changes in the first several seconds following the disturbance. Following a disturbance, synchronous machine frequencies undergo transient deviations from synchronous frequency. The objective of a transient stability study is to determine whether or not machines will return to synchronous frequency following a disturbance.
Your system installations are reviewed by our field experienced engineers. Protective schemes, classified locations, conductor sizing, transformer sizing, grounding, and many other items are inspected and compared to the NEC, NESC, IEEE, ANSI, and other applicable design and safety standards. If upgrading or modifications are required, they are identified in the final report.
The condition of your power system equipment is analyzed by a combination of on-site inspections, operational reviews, and test records analysis. Trouble spots are identified and corrective recommendations developed.