CA01065E_Catalog 70

ARRESTERS

Temporary Overvoltage (TOV)

MOV type surge arresters are by nature voltage sensitive devices. At normal line-to-ground voltage, an arrester is energized at or below its MCOV and conducts very little power frequency current. Disturbances on the system can expose the arrester to higher power frequency voltage and thus higher current through the arrester. The power frequency voltage withstand capability of an arrester is best expressed graphically. The following two graphs depict the TOV capability versus time for Hubbell IEEE and IEC distribution class surge arresters. The Optima designs demonstrate enhanced TOV capability. Please refer to the appropriate type test report for each product line for additional details.

TOV Capability – IEEE Arresters (no prior duty)

1.65

1.60

1.55

1.50

1.45

1.40

Per unit MCOV

1.35

1.30

1.25

1.20

0.1

1

10

100

1000

10000

0.01

Time (seconds)

PDV-100 Optima

PDV-65 Optima

PVR- Optima

70-14 | www.hubbellpowersystems.com