LogoLayersflattenedchr
Surge Protective Devices Committee
SPDC Terms C

[Home Page] [SPD Publications] [Terms Glossary] [Terms C]

SPDC Terms C

CAPACITANCE (VARISTOR)
Capacitance between the two terminals of the varistor measured at specified frequency and bias.
[C62.33–1989]

CAPACITANCE
Capacitance between the two terminals of an avalanche surge suppressor measured at specific frequency and bias.
[C62.35–1987]

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.
[C62.37–1996 & STD. 100-2000]

CERTIFICATION TESTS
Tests made, when required, to verify selected performance characteristics of a product or representative samples thereof.
[C62.1–1989]
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.
[C62.11–1987]

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.
[C62.37–1996 & STD. 100-2000]

CHARGE VOLTAGE
The voltage difference between the intruder and the receptor just prior to an ESD.
[C62.47–1992]

CIRCUIT PACK
A printed circuit board (PCB) populated with components, i.e. a PCB assembly, also called a Feature Card.
[C62.38–1995]

CLAMPING FACTOR
Ratio of the measured clamping voltage (VC) at a specified peak pulse current IPP to breakdown voltage. CF = VC/V(BR)
[C62.35–1987]

CLAMPING VOLTAGE
Peak voltage across the SPD measured under conditions of a specified peak pulse current and specified wave form.
NOTE-Peak voltage and peak current are not necessarily coincident in time.
[C62.37–1996]
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.
[C62.33–1989 & STD. 100-2000]

CLASSES OF GROUNDING
A specific range of degree of grounding; for example, effectively and non-effectively.
[C62.92.1–1987]

CLASSIFICATION CURRENT
The designated current used to perform the classification tests.
[C62.11–1987]

CLASSIFICATION OF ARRESTERS
Arrester classification is determined by prescribed test requirements. These classifications are:
(1) Station arrester
(2) Intermediate arrester
(3) Distribution arrester
    (a) Heavy duty
    (b) Normal duty
(4) Secondary arrester
[C62.1–1989 & C62.11–1987]

CLEARING
The characteristic of some types of air gap surge arresters to exhibit a low resistance and then to revert to a high resistance state as a result of an external influence.
[C62.32–1987]

CLEARING SOURCE
A defined electrical source which is intentionally applied as a clearing stimulus to an air gap surge protective device under laboratory test conditions. This stimulus is intended to stimulate conditions encountered during normal usage.
[C62.32–1987]

COEFFICIENT OF GROUNDING
The ratio ELG/ELL, expressed as a percentage, of the highest root-mean-square 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 which (that) would be obtained, at the selected location, with the fault removed.
[C62.2–1987 & C62.22–1991]
The ratio ELG/ELL, expressed as a percentage, of the highest root-mean-square 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 which (that) would be obtained, at the selected location, with the fault removed.
NOTES:
(1) Coefficients of grounding for three-phase systems are calculated from the phase-sequence impedance components as viewed from the selected location. For machines, use the subtransient reactance.
(2) The coefficient of grounding is useful in the determination of an arrester rating for a selected location.
(3) A value not exceeding 80 % is obtained approximately when, for all system conditions, the ratio of zero-sequence reactance to positive-sequence reactance is positive and less than 3, and the ratio of zero-sequence resistance to positive sequence reactance is positive and less than 1.
[C62.1–1989]

CONFORMANCE TEST
Tests made, when required, to demonstrate selected performance characteristics of a product or representative samples thereof.
[C62.1–1989 & C62.11–1987]

CONTACT DISCHARGE METHOD
A method of ESD testing in which the electrode of the ESD simulator is in firm conductive contact with the UUT or coupling plane prior to and during the discharge. The discharge is actuated by a switching device, e.g. a relay, within the simulator.
[C62.38 –1995]

CONVENTIONAL BIL
Applicable specifically to nonself-restoring insulations. 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.
[C62.2–1987]

CONVENTIONAL BSL
Applicable specifically to nonself-restoring insulations. 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.
[C62.2–1987]

COORDINATION OF INSULATION
The process of correlating the insulation strengths of electric equipment with expected overvoltages and with the characteristics of surge protective devices: see ANSI 92.1–1982
[C62.2–1987 & C62.22–1991]

COUPLER
A device, or combination of devices, used to feed a surge from a generator to powered equipment while limiting the flow of current from the power source into the generator. See: coupling network.
[C62.45–1992]

COUPLING FACTOR
The ratio of the induced voltage to the inducing voltage on parallel conductors.
e.g. 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 (1 minus coupling factor) multiplied by (tower top potential)
Stress = (1. 0 - KÉc) x VTT
where KÉc is the coupling factor and VTT is the tower top voltage.
[C62.23–95]

COUPLING NETWORK
Electrical circuit for the purpose of transferring energy from one circuit to another. See: coupler.
[C62.45–1992]

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 pole supporting the line.
[C62.23–1995]

CREST (PEAK) VALUE (OF A WAVE, SURGE, OR IMPULSE)
The maximum value that it (an impulse) attains.
[C62.1–1989 & C62.2–1987 & C62.11–1987 & C62.22–1991]
The maximum value that it attains.
[C62.37–1996]

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.
[C62.37–1996]

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.
[C62.37–1996]

CURRENT TURNOFF TIME
The time required for the arrester to restore itself to a non-conducting state following a period of conduction. This definition applies only to a condition where the arrester is exposed to a continuous specified dc potential under a specified circuit condition.
[C62.32–1987]
The time required for the arrester to restore itself to a nonconducting state following a period of conduction. This applies only to a continuous specified dc potential under a specified circuit condition.
[C62.31–1987]