IEEE 367-1996 pdf download IEEE Recommended Practice for Determining the Electric Power Station Ground Potential Rise and Induced Voltage From a Power Fault
3.7 ground potential rise (GPR): The product of a ground electrode impedance, referenced to remote earthand the current that flows through that electrode impedance.
3.8 inducing current: The current that flows in a single conductor of an electric supply line with groundreturn to give the same value of induced voltage in a telecommunication line (at a particular separation) asthe vectorial sum of all voltages induced by the various currents in the inductive exposure as a result ofground fault.
3.9 longitudinal voltage: A voltage acting in series with the longitudinal circuit
3.10 mutual impedance: The ratio of the total induced open-circuit voltage on the disturbed circuit to thedisturbing electric supply-system phase current, with the effect of all conductors taken into account.
3.11 per-unit system (pu): The reference unit, established as a calculating convenience, for expressing allpower system electrical parameters on a common reference base. One per unit (pu) is 100% of the base chosen. The pu system in power systems engineering is used to obtain a better comparison of the performance ofthe power system elements of different ratings, similar to the decibel system used for equating the losses andlevels of different telecommunication systems
3.12 remote earth: That distant point on the earth’s surface where an increase in the distance from a groundelectrode will not measurably increase the impedance between that ground electrode and the new distantpoint.
3.13 subtransient reactance: The reactance of a generator at the initiation of a fault. This reactance is usedfor the calculation of the initial symmetrical fault current. The current continuously decreases, but it isassumed to be steady at this value as a first step, lasting approximately 0.05 s after a suddenly applied fault.
3.14 susceptibility: The property of equipment that describes its capability to function acceptably whensubjected to unwanted interfering energy
3.15 synchronous reactance: The steady-state reactance of a generator during fault conditions used to cal-culate the steady-state fault current. The current so calculated excludes the effect of the automatic voltageregulator or governor.
316 telluric currents: Currents circulating in the earth or in conductors connecting two grounded pointsdue to yoltages in the earth.
3.17 transient reactance: The reactance of a generator between the subtransient and synchronous statesThis reactance is used for the calculation of the symmetrical fault current during the period between the subransient and steady states. The current decreases continuously during this period but is assumed to be steadyat this value for approximately 0.25 s.
3.18 volt-time area: The area under a curve plotted with voltage versus time with areas of positive and negative polarities added algebraically, The volt-time area that is generally of concern consists of the net accu-mulated volt-time area that occurs during a certain number of power frequency cycles of the groundpotential rise (GPR). The area is a function of the magnitude and decay rate of the dc offset.
3.19 X/R ratio: The ratio of the system inductive reactance to resistance. It is proportional to the time con-stant L/R and is, therefore, indicative of the rate of decay of any dc offset. A large X/R ratio corresponds to alarge time constant and a slow rate of decay, whereas a small X/R ratio indicates a small time constant and afast rate of decay of the dc offset.
IEEE 367-1996 pdf download
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