|
SPDC Terms O-Q
OFF STATE OF A THYRISTOR SPD
The state of a thyristor SPD, in a quadrant in which switching can occur, that corresponds to the high dynamic-resistance portion of the characteristic between the origin and the beginning of the breakdown region.
[C62.37–1996]
OFF-STATE CAPACITANCE
(CO)
The capacitance in the off-state measured at specified frequency, f, amplitude, Vd and dc bias, VD.
[C62.37–1996]
OFF-STATE CURRENT
(ID)
The dc value of current that results from the application of the off-state voltage, VD.
[C62.37–1996]
OFF-STATE VOLTAGE
(VD)
The dc voltage when the device is in the off-state.
[C62.37–1996]
OIL-IMMERSED (FOR A GROUNDING DEVICE)
Means that the windings are immersed in an insulating oil.
[STD 32–1990]
OIL
Includes synthetic insulating liquids as well as mineral transformer oil.
[STD 32–1990]
ON-STATE CURRENT
(IT)
The current through the device in the on-state condition.
[C62.37–1996]
ON-STATE (REGION)
The condition of the thyristor corresponding to the low-resistance low-voltage portion of the principal voltage-current characteristic in the switching quadrant(s).
[C62.37–1996 & STD. 100-2000]
ON-STATE VOLTAGE
(VT)
The voltage across the device in the on-state condition at a specified current IT.
[C62.37–1996]
OPERATING DUTY CYCLE
One or more unit operations, as specified.
[C62.1–1989 & C62.11–1987]
OSCILLATORY SURGE
A surge that includes both positive and negative polarity values.
[C62.1–1989 & C62.11–1987]
OUTDOOR ARRESTER
An arrester that is designed for outdoor use.
[C62.1–1989 & C62.11–1987]
OVERSHOOT DURATION (VARISTOR)
The time between the point at which the wave exceeds the clamping voltage level (VC) and the point at which the voltage overshoot has decayed to 50% of its peak. For the purpose of this definition, clamping voltage is defined with an 8/20 µs current waveform of the same peak current amplitude as the waveform used for this overshoot duration.
[C62.33–1989]
OVERSHOOT DURATION
The time between the point at which the wave exceeds the clamping voltage level VC and the point at which the voltage overshoot has decayed to 50% of its peak.
[C62.35–1987]
OVERVOLTAGE
Abnormal voltage between two points of a system that is greater than the highest value appearing between the same two points under normal service conditions. Overvoltages may be low-frequency, temporary, and transient (surge).
[C62.2–1987 & C62.22–1991]
PARAMETER
A device descriptor that is measurable or quantifiable, such as a characteristic or rating.
[C62.37–1996]
PEAK FORWARD RECOVERY VOLTAGE
(VFRM)
The maximum value of forward conduction voltage across the device upon the application of a specified voltage rate of rise and current rate of rise following a zero or specified reverse-voltage condition.
[C62.37–1996]
PEAK GATE SWITCHING CURRENT
(IGSM)
The maximum value of current through the gate terminal during the transition from the off-state to the switching point, when a specified gate bias voltage, VG, is applied.
[C62.37–1996]
PEAK NOMINAL VARISTOR VOLTAGE
Voltage across the varistor measured at a specified peak ac current, IN(ac), of specific duration. IN(ac) is specified by the varistor manufacturer.
[C62.33–1989]
PEAK OFF-STATE GATE CURRENT
(IGDM)
The maximum gate current that results from the application of the peak off-state gate voltage, VGDM.
[C62.37–1996]
PEAK PULSE IMPULSE CURRENT
(IPPM)
Rated maximum value of peak impulse pulse current (IPP) applied for 10 pulses with 10 X 1000µs waveform and maximum duty factor of 0. 0l % without causing failure.
[C62.35–191987]
PERMANENTLY GROUNDED DEVICE
A grounding device designed to be permanently connected to ground, either solidly or through current transformers and/or another grounding device.
[STD 32–1990]
P-GATE THYRISTOR
A three-terminal thyristor in which the gate terminal is connected to the p-region adjacent to the region to which the cathode is connected and that is normally switched to the on state by applying a positive signal between the gate and cathode terminals.
[C62.37–1996]
POSITIVE-BREAKDOWN-RESISTANCE THYRISTOR SPD
A thyristor SPD whose static breakdown characteristic has a net positive-resistance slope prior to switching.
[C62. 37–1996]
POWER-FREQUENCY SPARKOVER VOLTAGE
The root-mean-square value of the lowest power-frequency sinusoidal voltage that will cause sparkover when applied across the terminals of an arrester.
[C62.1–1989 & C62.11–1987]
POWER-FREQUENCY WITHSTAND VOLTAGE
A specified root-mean-square test voltage at power frequency that will not cause a disruptive discharge.
[C62.1–1989 & C62.11–1987]
PRINCIPAL CURRENT
A generic term for the current through the device excluding any gate current.
NOTE - It is the current through both main terminals.
[C62.37–1996]
PRINCIPAL VOLTAGE
The voltage between the main terminals.
NOTES:
1 -In the case of reverse blocking and reverse conducting thyristors, the principal voltage is called positive when the anode potential is higher than the cathode potential, and called negative when the anode potential is lower than the anode potential.
2 -For bi-directional thyristor, the principal voltage is called positive when the potential of main terminal 2 is higher than the potential of main terminal 1.
3 -For forward-conducting thyristors the principal voltage is called positive when the cathode potential is higher than the anode potential, and called negative when the cathode potential is lower than the anode potential.
[C62.37–1996 & STD. 100-2000]
PRINCIPAL VOLTAGE-CURRENT CHARACTERISTIC
The function, usually represented graphically, relating the principal voltage to the principal current. Syn: principal characteristic.
[C62.37–1996]
PRORATED SECTION
A complete, suitably housed part of an arrester, comprising all necessary components, including gaseous medium, in such a proportion as to accurately represent, for a particular test, the characteristics of a complete arrester.
[C62.1–1989 & C62.11–1987]
PROXIMITY ESD
See indirect ESD event. Also called proximity discharge.
[C62.47–1992]
QUADRANT
When the principal voltage-current characteristic is expressed graphically, the voltage, v, and current, I, axes create four areas called quadrants. These quadrants are numbered counter clockwise as 1 through 4. The characteristic occurs in quadrant 1, +v and +i, and quadrant 3, -v and -i.
[C62.37–1996]
|
