Title :
Choosing the correct transfer switch
Author :
Ransom, Daniel L.
Author_Institution :
Basler Electr. Co., Highland, IL, USA
Abstract :
Standby generation systems in low-voltage and medium-voltage applications connect to the utility power system in a number of different ways. Typically, an automatic transfer switch is a part of most power system connections. Engineers can choose three-pole or four-pole transfer switches for the intertie point. The application´s sensitivity to a power interruption during switching helps determine transfer switch selection. The transfer switch can be contactor or circuit-breaker based or it can be a bypass design. At medium voltage, special requirements must be considered. Ultimately, the correct arrangement must be chosen depending upon grounding locations and neutral bonding. Incorrect power system bonding and grounding can cause unwanted transients or hazardous multiple grounds (improper ground-fault protection) depending upon transfer-switch selection. Improper design can create unintentional current paths and defeat ground fault protection. A transfer switch must be chosen for robust operation and maintenance at the beginning of the design process.
Keywords :
circuit breakers; earthing; power generation faults; power generation protection; automatic transfer switch; circuit-breaker; contactor; correct transfer switch; four-pole transfer switches; ground fault protection; grounding locations; hazardous multiple grounds; improper ground-fault protection; low-voltage applications; medium-voltage applications; neutral bonding; power interruption; power system bonding; power system connections; power system grounding; standby generation systems; three-pole transfer switches; transfer switch selection; unintentional current paths; unwanted transients; utility power system; Circuit faults; Contacts; Generators; Grounding; Maintenance engineering; Switches; Transfer switches; closed transition; ground fault protection; high-resistance grounded; open transition; separately derived sources; solidly grounded; ungrounded;
Conference_Titel :
Pulp and Paper Industry Technical Conference (PPIC), Conference Record of 2012 Annual IEEE
Conference_Location :
Portland, OR
Print_ISBN :
978-1-4673-0406-1
DOI :
10.1109/PPIC.2012.6293009