IEC 60255-187-1:2021/COR1:2023

 IEC 2023
INTERNATIONAL ELECTROTECHNICAL COMMISSION
COMMISSION ÉLECTROTECHNIQUE INTERNATIONALE
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IEC 60255-187-1 IEC 60255-187-1
Edition 1.0  2021-07 Édition 1.0  2021-07

MEASURING RELAYS AND PROTECTION RELAIS DE MESURE ET DISPOSITIFS DE
EQUIPMENT – PROTECTION –
Part 187-1: Functional requirements for Partie 187-1: Exigences fonctionnelles pour
differential protection – Restrained and la protection différentielle – Protection
unrestrained differential protection of motors, différentielle avec et sans caractéristique de
generators and transformers retenue des moteurs, générateurs et
transformateurs
CO RRI G E NDUM 1
Corrections to the French version appear after the English text.
Les corrections à la version française sont données après le texte anglais.

Table 18 – Double infeed network model
Replace, in the existing footnote c, in the first dashed list item, the words "zero winding losses
(zero resistance and leakage reactance)" with "zero winding joule losses and leakage
reactances".
Table 20 – Double infeed network model
Replace, in the existing footnote c, in the first dashed list item, the words "zero winding losses
(zero resistance and leakage reactances" with "zero winding joule losses and leakage
reactances".
6.4.4.2 Application specific considerations: transformer differential
Replace, in the existing bulleted list item preceding Figure 30, in the second paragraph, the
words "between sources A and B" with "of source A".
6.4.4.3 Application specific considerations: generator differential
Replace, in the existing bulleted list item preceding Figure 32, in the second paragraph, the
words "between sources A and B" with "of source A".
6.4.4.4 Application specific considerations: motor differential
Replace, in the existing bulleted list item preceding Figure 34, in the second paragraph, the
words "between sources A and B" with "of source A".
IEC 60255-187-1:2021-07/COR1:2023-04(en-fr)

– 2 – IEC 60255-197-1:2021/COR1:2023
 IEC 2023
6.4.5.2 Application specific considerations: transformer differential
Replace, in the existing bulleted list item preceding Figure 35, in the second paragraph, the
words "between sources A and B" with "of source A".
6.4.7.2 Application specific considerations: transformer differential
Replace, in the existing bulleted list item preceding Figure 40, in the second sentence of the
second paragraph, number "2 560" with "2 048".
Table 43 – Double infeed network model
Replace, in the existing footnote c, the second dashed list item with the following item:
– infinite magnetizing impedance.
Add, in the existing footnote c, after the existing dashed list, the following new paragraph:
The zero-sequence impedance is modelled with the neutral-to-ground impedance ZN.
Table 51 – Double infeed network model
Delete, in the existing footnote c, the last dashed list item.
Add, in the existing footnote c, after the dashed list, the following new paragraph:
The zero-sequence impedance is modelled with the neutral-to-ground impedance ZN.
6.8.3.1 General
Replace, in the existing paragraph following Table 67, the words "Formulae (17) to (22)" with
"Formulae (16) to (21)".
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