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1MAC050144-MB C
Section 5
Protection related functions
615 series ANSI
399
Technical Manual
5.4.2
Function block symbol
Figure 196:
Function block symbol
5.4.3
Functionality
A small percentage of 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
substantial threat to humans and properties; people can touch or get close to conductors
carrying large amounts of energy.
ABB has developed a patented technology (US Patent 7,069,116 B2 June 27, 2006, US
Patent 7,085,659 B2 August 1, 2006) to detect high impedance fault.
The high impedance fault-detector function HIZ also contains a blocking functionality. It
is possible to block function outputs, if desired.
5.4.4
Operation principle
The function can be enabled and disabled with the
Operation
setting. The corresponding
parameter values are Enable and Disable.
HIZ uses a multi-algorithm approach. Each algorithm uses various features of ground
currents to detect a high impedance fault.
Figure 197:
Electrical power system equipped with HIZ
Power system signals are acquired, filtered, and then processed by individual high
impedance fault detection algorithm. The results of these individual algorithms are further
processed by decision logic to provide the detection decision. The decision logic can be
modified depending on the application requirement.
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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