ABB REL670 2.2 IEC - The Basics of the High Impedance Principle

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IEC05000163-4-en.vsd
IEC05000163 V4 EN-US
Figure 47: Different applications of a 1Ph High impedance differential
protection HZPDIF function
7.1.2.1 The basics of the high impedance principle
SEMOD54734-153 v9
The high impedance differential protection principle has been used for many years
and is well documented in literature publicly available. Its operating principle
provides very good sensitivity and high speed operation. One main benefit offered
by the principle is an absolute stability (that is, no operation) for external faults
even in the presence of heavy CT saturation. The principle is based on the CT
secondary current circulating between involved current transformers and not
Section 7 1MRK 506 369-UEN B
Differential protection
130 Line distance protection REL670 2.2 IEC
Application manual