Short Circuit and Coordination Studies Ensure the Integrity of Your Electrical Systems: Avoid unnecessary damage to equipment Services For Business-Critical Continuity™ An Evaluation of Your Electrical System’s Protective Devices Short Circuit and Coordination Studies from Emerson Network Power Service are ideal for facilities undergoing power infrastructure enhancements or facilities that have experienced load changes. Inadequately rated or uncoordinated protective equipment can cause extensive damage to your systems, lead to prolonged downtime, and even result in personnel injury. Ensure personnel safety Reduce downtime when a fault does occur Isolate faulty circuits without loss of power to other parts of the system Identify under-protected equipment before it’s too late Short Circuit Study — Determines the magnitude of fault current and whether equipment is properly rated to interrupt or withstand the short circuit. Protective Device Coordination Study — Determines characteristics, settings and sizes to evaluate whether protective devices are coordinated to isolate faulty equipment in a manner which will maintain a balance between equipment protection and selective device operation. Ensuring the Safety and Reliability of Your Critical Power Infrastructure 4. Bringing Down Your Entire Operation Due to poor breaker coordination the short circuit trips all the way back to the main breaker – shutting power down to your entire facility. Your critical electrical distribution system is the foundation of your entire operation. Knowing you have an accurate picture of your power system’s ability to safely handle fault conditions is key to achieving the level of availability that is necessary to sustain business continuity. With our Short Circuit and Coordination Studies, Emerson Network Power Service will provide a comprehensive, detailed and accurate assessment of your power system’s protective device capabilities. Utility Source 3. Causing Equipment Damage At minimum, the short circuit destroys the improperly rated breaker. At worst, the arc causes damage to other equipment including switchgear. 1. A Fault Occurs A faulty piece of equipment in one of your mini-computer rooms creates a Short Circuit. 2. An Improperly Rated Breaker Arcs The distribution breaker designed to localize the risk and de-energize the area is improperly rated. The short circuit arcs through the breaker, and escalates up the facility. A short circuit can create unforeseen, unacceptable problems for your facility. Ensuring the proper rating and coordination of your breaker systems reduces unexpected downtime and the risk of equipment damage from short circuit risks. Short Circuit Study Protective Device Coordination Study Purpose Determine the short circuit current available at each component of the electrical system and confirm whether the component is rated to withstand and/or interrupt the current. Analyze all possible operating scenarios influenced by additions or changes to the electrical system. Purpose Coordination Studies are performed to ensure minimum service interruption under overload and short circuit conditions. What We Do: ■ Review panel and device data, feeder sizes and lengths, transformer nameplate information, generator and automatic transfer switch data (where they exist) and utility source information. ■ Perform short circuit analysis, protective device evaluation and protective device coordination. Studies will be performed using SKM PowerTools for Windows software. ■ Identify any suspect equipment, recommended corrective action and device settings to allow for selective coordination of protective devices consistent with system operation. ■ Provide a summary table that compares the available fault currents to the withstand rating of the equipment and devices within the study. ■ Test the devices at the recommended settings to assure operation within the manufacturer’s tolerances. It will ensure the protective device closest to the overload or short circuit condition is the one that operates in order to isolate the failure as quickly as possible. If the circuit breaker or other protective devices are improperly set too low, or not rated for the available in-rush current from an upstream feeder, then the protective devices may trip unnecessarily causing critical loads to be dropped. Conversely, if protective devices are improperly set too high then the protective device closest to the failure may not trip at all, causing another protective device further upstream to trip –- the result, an outage to a much larger part of your distribution system and possibly even a complete blackout of your facility. What We Do: ■ Evaluate and select proper settings or sizes for relays, breakers and fuses. ■ Compare the operating levels and times of the protective devices to withstand levels and times that the equipment can sustain without damage or failure. ■ Identify and recommend corrective action for under-protected equipment. What You Get: A detailed report that includes: ■ ■ ■ ■ ■ A full description of the basis, purpose and scope of the study. Tabulations of the data used to model system components and a corresponding one-line diagram. Descriptions of the scenarios evaluated and identification of the scenario used to evaluate equipment short circuit ratings. Tabulations of equipment short circuit ratings versus available fault duties. The tabulation identifies percentage of rated short circuit and clearly note equipment with insufficient ratings. Conclusions and recommendations. What You Get: A detailed report that includes: ■ The basis, description, purpose and scope of the study plus a corresponding one-line diagram. ■ Time-current curves demonstrating the coordination of time-overcurrent protective devices. ■ Tabulations of protective devices identifying circuit location, manufacturer, type, range of adjustment, IEEE device number, current transformer ratios, recommended settings or device size, and referenced time-current curve. ■ Conclusions and recommendations. The Largest Service Organization in the World Dedicated to Maximizing Availability of Infrastructure Required for Mission-Critical Systems Emerson Network Power Liebert Services 610 Executive Campus Drive Westerville, Ohio 43082 USA 614 841 6400 Phone 614 841 6405 FAX [email protected] Email liebert.com Batteries UPS DC Power EmersonNetworkPower.com Switchgear Customer Resolution Center Generators Mission Critical Cooling l tica Cri ce Spa 800 LIEBERT ture struc Infra While every precaution has been taken to ensure accuracy and completeness in this literature, Emerson Network Power, Inc. and Emerson Electric Power Co. assume no responsibility, and disclaim all liability for damages resulting from use of this information or for any errors or omissions. Emerson Network Power, Inc. is a division of Emerson Electric Power. 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