Secondary Surge Arrester Series
Transients are defined as power line disturbances that occur in less than 1/2 cycle (less than 8.33 milliseconds). They can occur anywhere on the AC sine wave and can be either positive (spike), or negative (notch). A Secondary Surge Arrester will protect against
Voltages Surges, Sags Or Brownouts
A surge is an increase in voltage that occurs over a period of time greater than 1/2 cycle (8.33ms). A voltage sag or brownout is the opposite of the surge and is a decrease in voltage that occurs over a period of time greater than 1/2 cycle. A Secondary Surge
Arrester will not protect against surges, sags or brownouts.
Causes Of Transients
Demand power load switching by utility companies
Transient Duration In Relationship To Time
Utility power load correction
Nearby lightning strikes
Second = 1.0 Microsecond = .000001
Transient Voltage Surge Can Be:
Millisecond = .001 Nanosecond = .000000001
(1) 300V peak or more but typically 1200V to 5600V in severity.
Equipment Affected By Transient Voltage
(2) 10 ns to 50 ms but typically are 1 Ás to 1 second in duration.
What a Surge Arrester Should do
||Oil Field Equipment
||VCR's & Cable TV Boxes
Take repetitive hits
Operate in parallel with the load
Respond Rapidly Be maintenance free
C62.1 - 1989 Standard for Gapped Silicon-Carbide Surge Arresters for AC Power Circuits
Voltage Wave Form 1.2 x 50
C62.1 I - 1987 IEEE Standard for Metal-Oxide Surge Arresters for AC Power Circuits
C62.41 - 1991 IEEE Recommended Practice on Surge Voltages in Low-Voltage AC Power Circuits
Leading edge builds from 10% to 90% of peak in 1.2 microseconds (Ás). Leading edge from 0% through peak and decrease to 50% in 50 microseconds. This is considered by many experts to be about the worst case transient a secondary surge arrester would typically
Current Wave Form 8x 20
Leading edge builds from 10% to 90% of peak in 2.0 Ás. Leading edge from 0% through peak and decrease to50% in 20 Ás.
Unit of energy equal to one watt-second.
The AC or DC current flowing from input to output and/or chassis of an isolated device at a specified voltage.
See Secondary Surge Arrester
MCOV (Maximum Continuous Operating Voltage)
The maximum designated RMS value of power frequency voltage that may be applied continuously between the terminals of the arrester.
MOV (Metal Oxide Varistor)
Metal Oxide Varistor. A solid state component designed to handle large amounts of current which reacts in the low nanosecond time range. Shunts or directs large amounts of current to ground when voltage exceeds a threshold level above the MCOV.
Maximum (crest) value of a wave form, surge or impulse, reached during a specific particular cycle or operating time.
Applies to an AC sine wave, the RMS (Root Mean Square) is also known as effective voltage. i.e. 120 VAC 60Hz sinewave would have a peak voltage of 169.7 or 1.414 times the RMS voltage. Conversely the RMS voltage is 0.7071 times the Peak Voltage.
A protective device for limiting surge voltages on equipment by diverting surge current and returning the device to its original status. It is capable of repeating these functions as specified and is also called a lightning arrester.
Classification of Arresters (IEEE)
- Station - (Utility / Power Company)
- Intermediate - (Utility / Power Company>
- Distribution - (Utility / Power Company>
Secondary - 1, 2, 3a, 3b are designed for use by the Power Utility companies. Guardian Angel manufactures Secondary Surge Arresters for use on residential, industrial and farm electrical equipment.
Description: Long branch circuits more than 10 meters (33 feet) from a Category B location.
UL Test: Ring wave with 6,000 volt, 200 Amps
Description: Main Feeder Circuits, short branch circuits, distribution panels, heavy appliance circuits plus receptacles than 10 meters (33 feet from a category C circuit.
UL Test: Ringwave of 6,000 volts and 500 amps plus impulse wave of 6,000 volts and 3,000 amps.
Description: Outside and service entrance main service panels and any overhead lines to separate structures (weatherhead).
UL Test: Impulse of 10,000V and 10,000 Amps.
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