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SPDC Terms S
SAG
A rms reduction in the ac voltage, at the power frequency, for durations from a half-cycle to a few seconds.
[C62.48–1995]
SEALED TANK SYSTEM
A method of oil preservation in which the interior of the tank is sealed from the atmosphere and in which the gas plus the oil volume remains constant over the temperature range.
[STD 32–1990]
SED
Static Electric Discharge; an alternate name for ESD.
[C62.47–1992]
SERIES GAP
An intentional gap(s) between spaced electrodes: it is in series with the valve elements of the arrester, substantially isolating the element from line or ground, or both, under normal line-voltage conditions.
[C62.1–1989 & C62.2–1987]
An intentional gap(s) between spaced electrodes in series with the valve elements across which all or part of the impressed arrester terminal voltage appears.
[C62.11–1987 & C62.22–1991]
SHORT CIRCUIT
An abnormal connection of relatively low impedance, whether made accidentally or intentionally, between two points of different potential in a circuit.
[C62.31–1987]
An abnormal connection of relatively low impedance, whether made accidentally or intentionally, between two points of different potential in a circuit.
NOTE: The term is often applied to the group of phenomena that accompany a short circuit.
[C62.32–1987]
SHORT TIME RATING (OF A GROUNDING DEVICE)
A rated time of ten minutes or less.
[STD 32–1990]
SHUNT GAP
An intentional gap(s) between spaced electrodes that is electrically in parallel with one or more valve elements.
[C62.11–1987]
SOLIDLY GROUNDED
Grounded through an adequate ground connection in which no impedance has been inserted intentionally.
NOTE: Adequate as used here means suitable for the purpose intended.
[STD 32–1990]
SPARKOVER
A disruptive discharge between electrodes of a measuring gap, voltage control gap, or protective device.
[C62.31–1987 & C62.1–1989 & C62.11–1987 & C62.32–1987]
STANDARD LIGHTNING IMPULSE
The wave shape of standard impulse used (when it is not in conflict with product standards) is 1.2/50µs.
[C62.2–1987 & C62.22–1991]
STANDARD SWITCHING IMPULSES
The wave shapes of standard impulse tests depend on equipment being tested.
[C62.2–1987 & C62.22–1991]
STARTING TEMPERATURE (FOR A GROUNDING DEVICE)
The winding temperature at the start of the flow of thermal current.
[STD 32–1990]
STATIC DISSIPATIVE
Having a level of resistivity that typically leads to charge dissipation.
[C62.47–1992]
STATISTICAL BIL
Applicable specifically to self-restoring insulations. The crest value of a standard lightning impulse for which the insulation exhibits a 90% probability of withstand (or a 10% probability of failure) under specified conditions.
[C62.2–1987]
STATISTICAL BSL
Applicable specifically to self-restoring insulations. The crest value of a standard lightning impulse for which the insulation exhibits a 90% probability of withstand (or a 10% probability of failure) under specified conditions.
[C62.2–1987]
STEADY-STATE TEMPERATURE RISE (FOR A GROUNDING DEVICE)
The maximum temperature rise above ambient which will be attained by the winding of a device as the result of the flow of rated continuous current under standard operating conditions. It may be expressed as an average or a hot spot winding rise.
[STD 32–1990]
SUBASSEMBLY
Subassemblies are items, not completed equipment or individual components, that have an identifiable function.
[C62.38–1995]
SURGE (SURGE-PROTECTIVE DEVICE)
A transient wave of voltage or current. The duration of surge is not tightly specified but is usually less than a few milliseconds.
[C62.48–1995]
A transient wave of current, potential, or power in an electric circuit.
[C62.11–1987 & C62.22–1991 & STD. 100-2000]
A transient wave of current, potential, or power in an electric circuit
NOTE: The use of this term to describe a momentary overvoltage consisting of a mere increase of the mains voltage for several cycles is deprecated. See swell.
[C62.41–1991 & C62.1–1989 & C62.2–1987 & C62.37–1996]
SURGE ARRESTER
A protective device for limiting surge voltages on equipment by discharging or bypassing surge current; it prevents continued flow of follow current to ground, and is capable of repeating these functions as specified.
[C62.22–1991]
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.
[C62.11–1987]
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.
NOTE: Hereafter, the term arrester as used in this standard shall be understood to mean surge arrester.
[C62.1–1989 & C62.2–1987]
SURGE LET-THROUGH
That part of the surge that passes by a surge-protective device with little or no alteration. See: surge remnant.
[C62.45–1992]
SURGE PROTECTOR
A protective device, consisting of one or more surge arresters, a mounting assembly, optional fuses and short-circuiting devices, etc, which is used for limiting surge voltages on low-voltage (<1000 V rms or 1200 V dc) electrical and electronic equipment or circuits.
[C62.31–1987]
The term used to refer to a specific complete device (generally the equipment under test in the context of the present guide), as opposed to a component of the surge protector or a generic surge-protective device.
[C62.45–1992]
An assembly of protective devices consisting of one or more series, parallel, or any combination of elements used to limit surge voltages, currents, or both to a specified level. Syn: protector.
[C62.36–1991]
SURGE REMNANT
That part of an applied surge that remains downstream of one or several protective devices. See: surge let-through and surge response voltage.
[C62.45–1992]
SURGE RESPONSE VOLTAGE
The voltage profile appearing at the output terminals of a surge protective device and applied to downstream loads, during and after a specified impinging surge, until normal, stable conditions are reached.
[C62.45–1992]
SURGE-PROTECTIVE DEVICE
The generic term used to describe a device by its protective function, regardless of technology used, ratings, packaging, point of application, etc.
[C62.45–1992]
SUSCEPTIBILITY
The inability of a device, equipment, or system to resist an electromagnetic disturbance. Note: Susceptibility is the lack of immunity.
[C62.45–1992]
SWELL
A momentary increase in the power frequency voltage delivered by the mains, outside of the normal tolerances, with a duration of more than one cycle and less than a few seconds. See surge.
[C62.41–1991]
SWITCHING CURRENT
(IS)
The instantaneous current flowing through the device at the switching voltage, VS.
[C62.37–1996]
SWITCHING OVERVOLTAGE
Any combination of switching surge(s) and temporary overvoltage(s) associated with a single switching episode.
C62.2–1987 & C62.22–1991]
SWITCHING POINT
The point in the principal voltage-current characteristic which the thyristor regenerates and initiates switching into the on-state. This point occurs at the termination of the breakdown region and the start of the negative differential-resistance region.
[C62.37–1996]
SWITCHING QUADRANT
A quadrant of the principal voltage-current characteristic in which the device is intended to switch between the off-state and the on-state. For a bi-directional thyristor the switching quadrants will be 1 and 3. For a reverse blocking or reverse conducting thyristor the switching quadrant will be quadrant 1. For a forward conducting thyristor the switching quadrant will be quadrant 3.
[C62.37–1996]
SWITCHING RESISTANCE
(RS)
The equivalent slope resistance of the breakdown region, RS, computed by:
(VS - V(BO))/(IS - I(BO))
[C62.37–1996]
SWITCHING SURGE
A heavily damped transient electrical disturbance associated with switching. System insulation flashover may precede or follow the switching in some cases but not all.
[C62.2–1987 & C62.22–1991]
SWITCHING VOLTAGE
(VS)
The instantaneous voltage across the device at the final point in the breakdown region prior to switching into the on-state.
[C62.37–1996]
SYSTEM (CIRCUIT) VOLTAGE
The root mean square (rms) phase-to-phase power frequency voltage on a three-phase alternating-current electric system.
[C62.2–1987]
The root-mean-square power-frequency voltage from line to line as distinguished from the voltage from line to neutral.
[C62.1–1989 & C62.11–1987 & C62.22–1991]
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