SPDC Terms beginning with S

Terms and definitions extracted from current SPDC published documents
Click one of the capital letters above to advance the page to terms beginning with that letter.
secondary arrester

A surge-protective device that is intended to be connected to the low-voltage ac supply mains (1000 V rms and less, frequency between 48 Hz and 62 Hz) at locations between and including the secondary terminals of the distribution transformer and the main service entrance panel.
[C62.34-1996]

self-restoring insulation

Insulation that completely recovers its insulating properties after a disruptive discharge caused by the application of a test voltage; insulation of this kind is generally, but not necessarily, external insulation.
[C62.82.1-2010]

self-restoring insulation

Insulation that completely recovers its insulating properties after a disruptive discharge caused by the application of an overvoltage; insulation of this kind is generally, but not necessarily, external insulation.
[C62.22-2009]

series gap

Intentional gap(s) between spaced electrodes in series with the valve elements across which all or part of the impressed arrester terminal voltage appears.
[C62.11-2005]

series gap

An intentional gap between spaced electrodes: It is in series with the valve or expulsion element of the arrester, substantially isolating the element from line or ground, or both, under normal line?voltage conditions.
[C62.41.1-2002]

series gap

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.
[C62.22-2009]

service entrance equipment

The necessary equipment, usually consisting of a circuit breaker(s) or switch(es) and fuse(s) and their accessories, connected to the load end of service entrance conductors to a building facility, or other structure, or an otherwise designated area, and intended to constitute the main control and cutoff of the electrical service supply.
[C62.72-2007]

service equipment

<p>The necessary equipment, usually consisting of a circuit breaker(s) or switch(es) and fuses and their accessories, connected to the load end of service conductors to a building or other structure, or an otherwise designated area, and intended to constitute the main control or cutoff of the supply. <br>[C62.41.1-2002]</p>

service voltage

The voltage at the point where the electric system of the supplier and the electric system of the user are connected.
[C62.41.1-2002]

severe lightning current

Lightning currents greater than 65 kA but not greater than 100 kA. See also: normal lightning current.
[C62.11-2005]

shield wire (electromagnetic fields)

A wire employed to reduce the effects on electric supply or communication circuits from extraneous sources.
[C62.23-1995]

shielding angle

The angle between a vertical line through the overhead ground wire and a line connecting the overhead ground wire to the shielded conductor.
[C62.23-1995]

short circuit

An abnormal connection of relatively low impedance, whether made accidentally or intentionally, between two points of different potential in a circuit.
[C62.31-2006]

short-circuit current (SCC)

The current that the test set-up (surge generator, coupling circuit, back filter, connecting leads) can deliver at the terminals where the surge protective device (SPD) under test will be connected, with the SPD replaced by bonding the two lead terminals. (Sometimes abbreviated as ?SCI.?)
[C62.41.1-2002]

short-circuit current rating (SCCR) of a surge-protective device

The level at which a surge-protective device (SPD) is suitable for use on an ac power circuit that is capable of delivering not more than the declared root-mean-square symmetrical current at a declared voltage during a short-circuit condition.
[C62.72-2007]

short-circuit current rating (SCCR) of an SPD

The level at which a surge-protective device (SPD) is suitable for use on an ac power circuit that is capable of delivering not more than the declared root-mean-square symmetrical current at a declared voltage during a short-circuit condition.
[C62.62-2010]

shunt gap

Intentional gap(s) between spaced electrodes that is electrically in parallel with one or more valve elements.
[C62.11-2005]

sparkover

A disruptive discharge between electrodes of a measuring gap, voltage control gap, or protective device.
[C62.31-2006]

stand-by current

ID
Current that flows through the device at rated stand-off voltage at the specified temperature.
NOTE 1—It may also be called leakage current (IR).
[C62.35-2010]

stand-off (nonconducting) region

The portion of the volt-ampere characteristic occurring in a reverse-biased p-n junction where there is a high resistance to the passage of current.
[C62.35-2010]

standard chopped wave impulse voltage shape

A standard lightning impulse that is intentionally interrupted on the tail by sparkover of a gap or other equivalent chopping device. Usually the time to chop is 2?3 µs.
[C62.82.1-2010]

standard lightning impulse

The wave shape of the standard impulse used is 1.2/50 æs (when not in conflict with products standards).
[C62.22-2009]

standard lightning impulse voltage shape

An impulse that rises to crest value of voltage in 1.2 µs (virtual time) and drops to 0.5 crest value of voltage in 50 µs (virtual time), both times being measured from the same origin and in accordance with established standards of impulse testing techniques. It is described as a 1.2/50 impulse.
[C62.82.1-2010]

standard power-frequency short-duration voltage shape

A sinusoidal voltage with frequency between 48 Hz and 62 Hz, and duration of 60 s.
[C62.82.1-2010]

standard switching impulse voltage shape

A full impulse having a time-to-crest of 250 µs and a time-to-half value of 2500 µs. It is described as a 250/2500 impulse.
NOTE — Some apparatus standards use a modified waveshape where practical test considerations or particular dielectric strength characteristics make some modification imperative (see IEEE Std 4-1995).
[C62.82.1-2010]

standard switching impulses

The wave shapes of standard impulse tests depend on equipment being tested:
a) For air insulation and switchgear: 250/2500 µs
b) For transformer products: 100/1000 µs
c) For arrester sparkover tests:
      1) 30-60/90-180 µs
      2) 50-300/400-900 µs
      3) 1000-2000/3000-6000 µs (The tail duration is not critical)
[C62.22-2009]

statistical basic lightning impulse insulation level (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. See also: conventional basic lightning impulse insulation level (BIL).
NOTE: See ANSI Std C62.2-1987..
[C62.11-2005]

statistical basic switching impulse insulation level (BSL)

Applicable specifically to self-restoring insulations. The crest value of a standard switching impulse for which the insulation exhibits a 90% probability of withstand (or a 10% probability of failure) under specified conditions. See also: conventional basic switching impulse insulation level (BSL).
NOTE: See ANSI Std C62.2-1987.
[C62.11-2005]

statistical BIL

The crest values of a standard lightning impulse for which the insulation exhibits a 90% probability of withstand (or a 10% probability of failure) under specified conditions applicable specifically to self-restoring insulation.
[C62.82.1-2010]

statistical BIL

The crest values of a standard lightning impulse for which the insulation exhibits a 90% probability of withstand (or a 10% probability of failure) under specified conditions, applicable specifically to self-restoring insulations.
[C62.22-2009]

statistical BSL

The crest value of a standard switching impulse for which the insulation exhibits a 90% probability of withstand (or a 10% probability of failure), under specified conditions applicable to self-restoring insulation.
[C62.82.1-2010]

statistical BSL

The crest value of a standard switching impulse for which the insulation exhibits a 90% probability of withstand (or a 10% probability of failure), under specified conditions, applicable to self-restoring insulations.
[C62.22-2009]

statistical withstand voltage

The voltage that an insulation is capable of withstanding with a given probability of failure, corresponding to a specified probability of failure (e.g., 10%, 0.1%).
[C62.82.1-2010]

statistical withstand voltage

The voltage that an insulation is capable of withstanding with a given probability of failure, corresponding to a specified probability of failure (e.g., 10%, 0.1%).
[C62.22-2009]

steep-front surge (rotating electric machinery)

A voltage surge having a rise time of less than one microsecond.
[C62.21-2003]

surge

A transient wave of current, potential, or power in an electric circuit.
[C62.22-2009]

surge

A transient wave of voltage or current. (The duration of the surge is not tightly specified but is usually less than a few milliseconds.)
[C62.72-2007]

surge

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 also: swell.
[C62.41.1-2002]

surge

A transient wave of current, potential, or power in an electric circuit.
[C62.11-2005]

surge

A transient wave of voltage or current. The duration of a surge is not tightly specified, but it is usually less than a few milliseconds.
[C62.34-1996]

surge

A transient wave of current, potential, or power in an electric circuit.
[62.37-1996]

surge arrester

A protective device for limiting surge voltages on equipment by discharging or bypassing surge current; it limits the flow of power follow current to ground, and is capable of repeating these functions as specified.
[C62.22-2009]

surge arrester

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.
[C62.11-2005]

surge let-through

The part of the surge that passes by a surge protective device (SPD) with little or no alteration. See also: surge remnant.
[C62.41.1-2002]

surge protective device (SPD)

a) A device intended either to limit transient overvoltages or divert surge currents, or both. It contains at least one nonlinear component.
b) An assembly of one or more components intended to limit or divert surges. The device contains at least one nonlinear component.
c) A device that is intended to limit transient overvoltages and divert surge currents. It contains at least one nonlinear component.
[C62.41.1-2002]

surge protector

A specific complete surge-protective device, as opposed to a component of a surge protector or a generic surge-protective device.
[ C62.42-2005]

surge protector

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.
[C62.36-2000]

surge protector

A protective device, consisting of one or more surge-protective device components, 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.
[C62.31-2006]

surge remnant

The part of an applied surge that remains downstream of one or several protective devices. See also: surge let-through.
[C62.41.1-2002]

surge response voltage

The voltage profile appearing at the output terminals of a surge protective device (SPD) and applied to downstream loads, during and after a specified impinging surge, until normal, stable conditions are reached.
[C62.41.1-2002]

surge-protective device

An assembly of one or more components intended to limit or divert surges. The device contains as least one nonlinear component.
[C62.72-2007]

surge-protective device (SPD)

A device that is intended to limit transient overvoltages and divert surge current. It contains at least one nonlinear component.
[C62.34-1996]

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 also: surge.
[C62.41.1-2002]

switching current

IS
The instantaneous current flowing through the device at the switching voltage, VS.
[62.37-1996]

switching impulse protective level of a surge-protective device

The maximum switching impulse expected at the terminals of a surge-protective device under specified conditions of operation.
NOTE — The switching impulse protective levels given by the higher of either: 1) the switching impulse discharge voltage for a specified current magnitude and waveshape, or 2) the switching impulse sparkover voltage for a specified voltage waveshape.
[C62.82.1-2010]

switching overvoltage

A transient overvoltage in which a slow front, short-duration, unidirectional or oscillatory, highly damped voltage is generated (usually by switching or faults).
[C62.82.1-2010]

switching overvoltage

Any combination of switching surge(s) and temporary overvoltage(s) associated with a single switching episode.
[C62.22-2009]

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.
[62.37-1996]

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.
[62.37-1996]

switching resistance

Rs
The equivalent slope resistance of the breakdown region, RS, computed by (V(BO) - VS) / (IS - I(BO))
[62.37-1996]

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.
[C62.22-2009]

switching voltage

VS
The instantaneous voltage across the device at the final point in the breakdown region prior to switching into the on-state.
[62.37-1996]

system (circuit) voltage

The root-mean-square (rms) power-frequency voltage from line to line as distinguished from the voltage from line to neutral.
[C62.41.1-2002]

system voltage

The root-mean-square (rms) phase-to-phase power frequency voltage on a three-phase alternating-current electric system.
[C62.22-2009]

system voltage

The root-mean-square (rms) power-frequency voltage from line to line as distinguished from the voltage from line to neutral.
[C62.11-2005]

system voltage

The rms power-frequency voltage from line-to-line as distinguished from the voltage from line- to-neutral.
[C62.72-2007]