Terms beginning H - Q

The SPDC Glossary is a compilation of the terms extracted from SPDC 2011 active Standards, Guides and Recommended Practices. The last line of each term definition references the document number the term came from. There are 135 terms with multiple entries as the term has occurred in several documents. There are over 400 unique terms in the Glossary. The Glossary terms are alphabetically arranged, with a page for each letter. If the Glossary is directly accessed, a randomly selected term and definition is given at the top of the page. Once a particular letter page is selected, the random term disappears.

Clicking on a term on this page will take you to that Glossary page for that term definition. The following terms are defined in the Glossary:

H – holding current

I – immunity (to a disturbance), impedance grounded neutral system, impulse, impulse protective level, impulse protective volt-time characteristic, impulse reset time, impulse sparkover voltage, impulse sparkover voltage-time curve, impulse sparkover volt-time characteristic, impulse wave, impulse withstand voltage, indoor arrester, In-Line SPD, insertion loss, insulation configuration, insulation coordination, insulation level, insulation resistance, internal insulation, ionization current, ionization voltage

L – lifetime rated pulse currents, lifetime rated pulse currents (Varistor)., lightning, lightning impulse protective level of a surge-protective device, lightning overvoltage, lightning surge, line terminal, liquid-immersed type arrester, local surge (rotating electric machinery), longitudinal (common) mode voltage, longitudinal insulation configuration, longitudinal overvoltage

M – main overcurrent protective device, main terminal 1, main terminal 2, main terminals, mains, maximum continuous operating voltage rating (MCOV), maximum design cantilever load-static (MDCL-static), maximum discharge current, maximum junction temperature, maximum rating (absolute maximum rating), maximum system voltage, means of grounding, measured limiting voltage, mechanical unit, metal-oxide surge arrester (MOSA), Mode of Protection, multiport surge protector

N – negative differential-resistance (region), negative-breakdown resistance thyristor surge protection device (SPD), n-gate thyristor, nominal discharge current, nominal rate of rise (of an impulse wave front), nominal rate of rise(of an impulse), nominal system voltage, nominal Varistor voltage, nonlinear exponent, nonlinear load, nonlinear load current, non-repetitive current rating, non-repetitive peak forward current, non-repetitive peak on-state current, non-repetitive peak pulse current, non-self-restoring insulation, normal interruption (rotating electric machinery), normal lightning current, normal-mode

O – off-state capacitance, off-state current, off-state of a thyristor surge protection device (SPD), off-state voltage, one-port SPD, on-state (region), on-state current, on-state voltage, open-circuit voltage (OCV), operating duty cycle, oscillatory surge, oscillatory surge, overhead groundwire (lightning protection), overshoot duration (Varistor), overvoltage

P – parameter, partial discharge (PD), peak forward recovery voltage, peak gate switching current, peak impulse current, peak nominal Varistor voltage, peak off-state gate current, peak pulse impulse current, peak value, per unit (pu), per unit surge voltage (rotating electric machinery), performance criterion, p-gate thyristor, phase-to-ground insulation configuration, phase-to-phase insulation configuration, positive-breakdown-resistance thyristor surge protection device (SPD), power cross, power-frequency sparkover voltage, power-frequency withstand voltage, preferred values, principal current, principal voltage, principal voltage-current characteristic, production tests, prorated section, prospective (available) short-circuit current (at a given point in a circuit), prospective overvoltage, protective margin (PM), protective ratio (PR), protector, pulse life, puncture

Q – quadrant