1、30 November 2017 Product STD22421E IEEE Std C62.92.1 -2016 (Revision of IEEE Std C62.92.1-2000) Errata to IEEE Guide for the Application of Neutral Grounding in Electrical Utility Systems Part I: Introduction Sponsor Surge Protective Devices Committee of the IEEE Power and Energy Society Correction
2、Sheet Issued 30 November 2017 Copyright 2017 by The Institute of Electrical and Electronics Engineers. Inc. All rights reserved. Published 2017 Printed in the United States of America. This correction sheet may be freely reproduced and distributed in order to maintain the utility and currency of the
3、 underlying Standard. This correction sheet may not be sold, licensed or otherwise distributed for any commercial purposes whatsoever. The content of this correction sheet may not be modified. 30 November 2017 Product STD22421E Page 11, change the definition of coefficient of grounding (COG) to read
4、 as follows: 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-freq
5、uency voltage ELL that would be obtained at the selected location with the fault removed. Page 13, change the Notes below Figure 1 to read as follows: NOTE 1 Va , Vb , and Vc are the respective source voltages (line-to-neutral). NOTE 2 RS and XS are the equivalent source resistance and reactance, pe
6、r phase. NOTE 3 Rn and Xn are the neutral resistance and reactance of the system as seen at the source. NOTE 4 Cg is the total system capacitance to ground and is obtained by connecting all three phases together and measuring the capacitance with the neutral grounding branch open-circuited. NOTE 5 C
7、g /3 is the grounded-wye partial, or zero-sequence, capacitance of the system. NOTE 6 CS is the ungrounded wye equivalent of the interphase partial capacitances of the system, obtained by subtracting the zero-sequence capacitance Cg/3 from the positive sequence capacitance C1. NOTE 7 f is frequency
8、in hertz. NOTE 8 The switch S, simulates a single-line-to-ground fault on a-phase. NOTE 9 Vf is the prefault line-to-ground voltage at the fault, the energization voltage. Page 15, the first paragraph under subclause 6.2 should read as follows: Various classes of grounding are available to the syste
9、m designer, each having a unique set of attributes. The response characteristics of the various classes of grounding may be defined or classified in terms of the ratios of symmetrical component parameters, such as the positive-sequence reactance X1, the negative-sequence reactance X2, the zero-seque
10、nce reactance X0, the positive-sequence resistance R1, the negative-sequence resistance R2, and the zero-sequence resistance R0 (see Clarke B6, Wagner and Evans B22, and Willheim and Waters B23). Page 16, change the Notes below Figure 2 to read as follows: NOTE 1 Vf is the Thevenin circuit pre-fault
11、 voltage. NOTE 2 Va is the line-to-neutral source voltage of Figure 1. NOTE 3 3I0 is the fault line current through closed switch S of Figure 1. NOTE 4 The equivalence sign () indicates the result when capacitance is negligible. NOTE 5 The remaining variables are defined in the notes following Figur
12、e 1. Page 16, subclause 6.3 should read as follows: The term coefficient of grounding (COG) is used in system grounding practice. COG is defined as / 100%,LG LLEE where LGE is the highest root-mean-square (rms), line-to-ground power-frequency voltage on a sound phase, at a selected location, during
13、a line-to-ground fault affecting one or more phases. LLE is the line-to-line power-frequency voltage that would be obtained, at the selected location, with the fault removed. The COG for three-phase systems is calculated from the phase-sequence impedance components, as viewed from the fault location
14、. The COG is useful in the selection of a surge arrester rating for a selected location (see IEEE Std 32-1972 B11, IEEE Std C62.2-1987 B13, IEEE Std C62.22-2009 B15, and IEEE Tutorial Course B17). 30 November 2017 Product STD22421E Pages 16 and 17, subclause 6.4 should read as follows: The term grou
15、nd-fault factor (GFF) is, to a limited extent, now used instead of COG. At a selected location on a three-phase system, and for a given system configuration, the GFF is the ratio of the highest rms line-to-ground power-frequency voltage (as measured phase-to-ground) on a sound phase during a fault t
16、o ground (affecting one or more phases at any point) to the rms power-frequency voltage (as measured phase-to-ground) that would be obtained at the selected location with the fault removed (see IEEE Std C62.82.1-2010 B16). Thus, the GFF is related to the COG by 3 , as shown in Equation (1) below: 3
17、100COGGFF (1) where GF is the ground-fault factor COG is the coefficient of grounding expressed as a percentage Page 23, Replace Figure A.1 with the following figure: Page 24, the text between equation (A.9) and equation (A.10) should read as follows: Where COGa, COGb, and COGc are the coefficients
18、of grounding for each respective phase. Z1, Z2, and Z0 are the positive, negative, and zero sequence impedances, respectively, () RF is the fault resistance, () a and a2 are phasor operators 2330 . 5 j 1 1 2 0 ; 0 . 5 j 1 2 4 022aa 30 November 2017 Product STD22421E In order to eliminate one parameter, it is convenient to divide each impedance by X1. Defining the ratios R1= R1/X1; R0=R0/X1, X0=X0/X1, RF=RF/X1 Page 33, equation (B.1) should read as follows: 100.0 592 0.1 736 l og /km60 60 eg DffZj h (B.1)
