SPDC Terms beginning with C

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.
capacitance

C
Capacitance between two terminals of the device measured at a specific frequency and bias
NOTE—Also known as CJ.
[C62.35-2010]

capacitance (Varistor)

C
Capacitance between the two terminals of the varistor measured at specified frequency and bias.
[C62.33-1982]

cascade coordination

The planned interaction between two or more surge-protective devices (SPDs) on the same power distribution system.
[C62.72-2007]

cathode

The electrode by which current leaves the thyristor, when the thyristor is in the on-state with the gate open-circuited.
NOTE: This term does not apply to bi-directional thyristors.
[62.37-1996]

certification tests

Tests run on a regular, periodic basis to verify that selected, key performance characteristics of a product or representative samples thereof have remained within performance specifications.
[C62.11-2005]

characteristic

An inherent and measurable property of a device. Such a property may be electrical, mechanical, thermal, hydraulic, electromagnetic, or nuclear, and can be expressed as a value for stated or recognized conditions. A characteristic may also be a set of related values, usually shown in graphical form.
[62.37-1996]

clamping (suppression) voltage

The peak voltage across the varistor measured under conditions of a specified peak pulse current and specified waveform.
NOTE: Peak voltage and peak current are not necessarily coincident in time.
[C62.41.1-2002]

clamping factor (CF)

Ratio of the measured clamping voltage (VC) at a specified peak impulse current (IPP) to breakdown voltage (V(BR)): CF = VC / V(BR).
[C62.35-2010]

clamping voltage

VC
Peak voltage across the device during the application of a peak impulse current (IPP) for a specified wave shape.
NOTE —The clamping voltage VC is the peak voltage value measured neglecting any voltage overshoot caused by the inductance of the device packaging.
[C62.35-2010]

clamping voltage

VC
Peak voltage across the Varistor measured under conditions of a specified peak pulse current and specified waveform.
NOTE: Peak voltage and peak current are not necessarily coincidental in time.
[C62.33-1982]

clamping voltage

Peak voltage across the SPD measured under conditions of a specified peak pulse current and specified waveform.
NOTE: Peak voltage and peak current are not necessarily coincident in time.
[62.37-1996]

class of grounding

A specific range or degree of grounding; e.g., effectively and noneffectively.
[C62.92.1-2000]

classification of arresters

Arrester classification is determined by prescribed test requirements of this standard. These classifications are station, intermediate, distribution heavy duty, distribution normal duty, distribution light duty.
[C62.11-2005]

classifying current

The designated current used to perform the classification tests.
[C62.11-2005]

coefficient of grounding (COG)

The ratio, ELG/ELL (expressed as a percentage), of the highest root-mean-square (rms) line-to-ground power-frequency voltage ELG on a sound phase, at a selected location, during a fault to ground affecting one or more phases to the line-to-line power-frequency voltage ELL that would be obtained at the selected location with the fault removed.
[C62.22-2009]

combination wave

The combination wave is delivered by a generator that applies a 1.2/50 µs voltage impulse across an open circuit and an 8/20 µs impulse current into a short circuit. The voltage and current and waveforms that are delivered to the surge protective device (SPD) are determined by the generator and the impedance of the SPD to which the surge is applied. The ratio of open-circuit voltage to peak short-circuit current is 2 ω.
[C62.41.1-2002]

combination wave (1.2/50, 8/20)

A wave delivered by a generator that applies a 1.2/50 voltage impulse across an open circuit and an 8/20 impulse current into a short circuit. The voltage, current, and waveforms that are delivered to the surge-protective device (SPD) are determined by the generator and the impedance of the SPD to which the surge is applied. The ratio of open-circuit voltage to peak short-circuit current is 2 Ω.
[C62.34-1996]

common-mode

The instantaneous algebraic average of two signals applied to a balanced circuit, both signals referred to a common reference.
[C62.72-2007]

component surge-protective device — voltage limiting type

A component surge-protective device that has a high impedance when no surge is present, but that can limit voltage by progressively and smoothly reducing its impedance when responding to a surge.
Examples are component varistor and avalanche junction semiconductor surge-protective devices.
NOTE - Also commonly referred to as a "voltage clamping" device.
[ C62.42-2005]

component surge-protective device — voltage switching type

A component surge-protective device that has a high impedance when no surge is present, but that can have a sudden voltage collapse to a low impedance state when responding to a surge.
Examples are component air gap and gas tube surge-protective devices.
NOTE - Also commonly referred to as a "crowbar" device.
[ C62.42-2005]

component surge-protective device (component SPD)

A discrete surge-protective device involving a single specific technology and intended to be installed as a component within a surge protector or as a component housed within the equipment to be protected.
NOTE — Examples are "component air gap surge-protective device", "component gas tube surge-protective device", "component varistor surge-protective device" and "component avalanche junction semiconductor surge-protective device". The term surge arrester is also used to describe a single component.
[ C62.42-2005]

conformance tests

Tests made, when required, to demonstrate selected performance characteristics of a product or representative samples thereof.
[C62.11-2005]

continuous operating current

Ic
The peak current flowing through the SPD when energized at the maximum continuous operating voltage.
[C62.34-1996]

conventional basic lightning impulse insulation level (BIL)

Applicable specifically to nonselfrestoring insulations. The crest value of a standard lightning impulse for which the insulation does not exhibit disruptive discharge when subjected to a specific number of applications of this impulse under specified conditions. See also: statistical basic lightning impulse insulation level (BIL).
[C62.11-2005]

conventional basic switching impulse insulation level (BSL)

Applicable specifically to nonselfrestoring insulations. The crest value of a standard switching impulse for which the insulation does not exhibit disruptive discharge when subjected to a specific number of applications of this impulse under specified conditions. See also: statistical basic switching impulse insulation level (BSL).
[C62.11-2005]

conventional BIL

The crest value of a standard lightning impulse for which the insulation shall not exhibit disruptive discharge when subjected to a specific number of applications of this impulse under specified conditions, applicable specifically to nonself-restoring insulations.
[C62.22-2009]

conventional BIL (basic lightning impulse insulation level)

The crest value of a standard lightning impulse for which the insulation shall not exhibit disruptive discharge when subjected to a specific number of applications of this impulse under specified conditions, applicable specifically to non-self-restoring insulations.
[C62.82.1-2010]

conventional BSL

The crest value of a standard switching impulse for which the insulation does not exhibit disruptive discharge when subjected to a specific number of impulses under specified conditions, applicable to nonself-restoring insulations.
[C62.22-2009]

conventional BSL (basic switching impulse insulation level)

The crest value of a standard switching impulse for which the insulation does not exhibit disruptive discharge when subjected to a specific number of impulses under specified conditions, applicable to non-self-restoring insulations.
[C62.82.1-2010]

conventional withstand voltage

The voltage that an insulation system is capable of withstanding without failure or disruptive discharge under specified test conditions.
[C62.82.1-2010]

conventional withstand voltage

The voltage that an insulation is capable of withstanding with a 0% probability of failure.
[C62.22-2009]

coordination of insulation

The selection of insulation strength consistent with expected overvoltages to obtain an acceptable risk of failure.
[C62.22-2009]

counterpoise

A conductor or system of conductors arranged beneath the line; located on, above, or most frequently below the surface of the earth; and connected to the grounding system of the towers or poles supporting the line.
[C62.23-1995]

coupling factor

The ratio of the induced voltage to the inducing voltage on parallel conductors.
For example, at the tower, the shield or coupling wires and tower crossarms are at practically the same potential (because of lightning stroke travel time). The stress across the insulator string is one minus the coupling factor multiplied by the tower top potential.

Stress = (1.0 -Kfc ž VTT)

where
Kfc is the coupling factor
VTT is the tower top voltage
[C62.23-1995]

coupling wire

A conductor attached to the transmission line structure and below the phase wires, with proper clearance, and connected to the grounding system of the towers or the pole supporting the line.
[C62.23-1995]

cracking

The rupture of the weathershed material to depths greater than 0.1 mm.
[C62.11-2005]

crest (peak) value (of a wave, surge, or impulse)

The maximum value that it attains.
[62.37-1996]

crest (peak) value (of a wave, surge, or impulse)

The maximum value that a wave, surge, or impulse attains.
[C62.11-2005]

crest value (of an impulse)

The maximum value that an impulse attains. Synonym: peak value.
[C62.22-2009]

crest value (peak value)

The maximum absolute value of a function when such a maximum exists.
[C62.82.1-2010]

critical flashover voltage (CFO)

The amplitude of voltage of a given waveshape that, under specified conditions, causes flashover through the surrounding medium on 50% of the voltage applications.
[C62.82.1-2010]

critical flashover voltage (CFO)

The amplitude of voltage of a given waveshape that, under specified conditions, causes flashover through the surrounding medium on 50% of the voltage applications.
[C62.22-2009]

critical rate of rise of off-state voltage

dv/dt
The maximum rate of rise of voltage (below VDRM) that will not cause switching from the off-state to the on-state.
[62.37-1996]

critical rate of rise of on-state current

di/dt
Rated value of the rate of rise of current which the device can withstand without damage.
[62.37-1996]

current chopping (rotating electric machinery)

A current wave in the machine circuit forced to zero by an interrupter at other than a fundamental frequency current zero in the interrupted phase and with a forcing duration in the order of microseconds or less.
Example: vacuum circuit breaker, or a superimposed high-frequency switching surge current with a magnitude greater than the fundamental frequency current.
[C62.21-2003]

current turnoff time

The time required for the gas tube to restore itself to a non-conducting state following a period of conduction. This definition applies only to a condition where the gas tube is exposed to a continuous specified dc potential under a specified circuit condition.
[C62.31-2006]

current zero (rotating electric machinery)

That instant when an oscillatory current wave passes through zero magnitude.
[C62.21-2003]