1MAC050144-MB C
Section 5
Protection related functions
615 series ANSI
401
Technical Manual
5.4.5
Application
Electric power lines experience faults for many reasons. In most cases, electrical faults
manifest in mechanical damage, which must be repaired before returning the line to
service.
Most of these faults are ground faults. Conventional protection systems based on
overcurrent, impedance, or other principles are suitable for detecting relatively low
impedance faults, which have a relatively large fault current.
However, a small percentage of the ground faults have a very large impedance. They are
comparable to load impedance and consequently have very little fault current. These high
impedance faults do not pose imminent danger to power system equipment. However, they
are a considerable threat to people and property. The IEEE Power System Relay
Committee working group on High Impedance Fault Detection Technology defines High
Impedance Faults as those that 'do not produce enough fault current to be detectable by
conventional overcurrent relays or fuses'.
High impedance fault (HIZ) detection requires a different approach than that for
conventional low impedance faults. Reliable detection of HIZ provides safety to humans
and animals. HIZ detection can also prevent fire and minimize property damage. ABB has
developed innovative technology for high impedance fault detection with over seven years
of research resulting in many successful field tests.
Summary of Contents for 615 Series ANSI
Page 1: ...Relion Protection and Control 615 series ANSI Technical Manual ...
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Page 29: ...1MAC050144 MB C Section 615 series ANSI 22 Technical Manual ...
Page 389: ...Section 4 1MAC050144 MB C Protection functions 382 615 series ANSI Technical Manual ...
Page 485: ...Section 6 1MAC050144 MB C Supervision functions 478 615 series ANSI Technical Manual ...
Page 635: ...Section 10 1MAC050144 MB C Other functions 628 615 series ANSI Technical Manual ...
Page 711: ...Section 16 1MAC050144 MB C Glossary 704 615 series ANSI Technical Manual ...
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