IEC 61557-9:20 23 CMV包含官方标准及其注释版本。注释版本为您提供了一种快速简单的方法来比较IEC 61557-9:20 23版4.0和之前的IEC 61557-9:20 14版3.0之间的所有更改。此外，还提供了IEC TC 85专家的意见，以解释最相关变更的原因，或澄清内容的任何部分。 IEC 61557-9:20 23规定了绝缘故障定位系统(IFLS)的要求，该系统可定位出土IT交流系统和标称电压高达1 000 V AC的电连接直流电路的出土IT交流系统中系统任何部分的绝缘故障，以及电压高达1 500 V DC的出土IT DC系统，与测量原理无关。IEC 61557-9:20 23取消并取代了2014年发布的第三版。本版构成技术修订版。 与上一版相比，此版本包括以下重大技术变更: a)关于最大允许定位交流和直流电流和电压的新术语和定义； b)对定位电流和定位电压的要求进行了修订； c)增加了性能要求； d)对定位电流和定位电压的试验要求进行了修订； e)本文件的结构已适应IEC 61557-1:20 19的结构； f)对第A.2条中的限值进行了调整，以适应6.2.3中变更后的试验方法。

IEC 61557-9:2023 CMV contains both the official standard and its commented version. The commented version provides you with a quick and easy way to compare all the changes between IEC 61557-9:2023 edition 4.0 and the previous IEC 61557-9:2014 edition 3.0. Furthermore, comments from IEC TC 85 experts are provided to explain the reasons of the most relevant changes, or to clarify any part of the content.

IEC 61557-9:2023 specifies the requirements for the insulation fault location system (IFLS) that localizes insulation faults in any part of the system in unearthed IT AC systems and unearthed IT AC systems with galvanically connected DC circuits having nominal voltages up to 1 000 V AC, as well as in unearthed IT DC systems with voltages up to 1 500 V DC, independent of the measuring principle. IEC 61557-9:2023 cancels and replaces the third edition published in 2014. This edition constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous edition:
a) new terms and definitions on maximum admissible locating AC and DC currents and voltages;
b) the requirements on locating current and locating voltage have been revised;
c) performance requirements have been added;
d) the test requirements for locating current and locating voltage have been revised;
e) the structure of this document has been adapted to that of IEC 61557-1:2019;
f) the limit values under Clause A.2 were adapted to fit the changed test methods in 6.2.3.