Schweitzer Engineering Laboratories
How a North Carolina utility applied the SEL-FT50 and SEL-FR12 System to ensure reliable power
The town of Clayton, North Carolina, recently installed the SEL-FT50 and SEL-FR12 Fault Transmitter and Receiver System to improve their power system protection by blocking reclosing for underground faults. The system will minimize power outages for the town’s residents and protect expensive equipment from damage.
Clayton Public Power is focused on maintaining reliable power for their customers while improving protection. The feeders in their Northside Substation are set for two-shot reclosing to clear momentary faults, preventing sustained customer power outages. However, the SEL-651R Advanced Recloser Controls in their substation cannot determine if a fault is on the underground feeder cables leaving the substation or on the overhead lines. This ambiguity could lead to unnecessary equipment damage if the system recloses into a permanent fault at the voltage regulators or on the underground lines. To ensure that the system only recloses for faults on overhead lines, Clayton Public Power installed the SEL-FT50 and SEL-FR12 System.
Clayton Public Power installed three SEL-FT50 transmitters at the beginning of each of their four overhead conductor lines at the Northside Substation, and they mounted an associated SEL-FR12 at each SEL-651R in the substation.
The SEL-651R controls were programmed to use the presence or absence of a fault signal from the SEL-FR12 to reclose or block reclosing. Clayton Public Power also wanted to have the system default to reclose in the event of an equipment or communications link failure and accomplished this by supervising the default-to-reclose logic with the link status from the SEL-FR12.
The SEL-FT50 and SEL-FR12 System helps Clayton Public Power maintain their power system reliability for customers while minimizing the potential for equipment damage from unnecessary reclosing on underground segments.
SEL-FR12 receivers are installed in the SEL-651R cabinets at the Clayton Public Power Northside Substation.
Clayton Public Power employees apply SEL-FT50 transmitters to their overhead line with a hot stick.
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