Micom P721, Техническое руководство

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Application Guide P72x/EN AP/C21
MiCOM P721/P723 Page 1/52
CONTENTS
1. INTRODUCTION 3
1.1 P72x High Impedance Differential Relay 3
1.2 Busbar Protection 3
1.3 Reactor Protection 3
1.4 Transformer Protection 4
1.5 Generator/Motor Protection 4
2. BUSBAR CONFIGURATIONS 5
2.1 Single busbar 5
2.2 Double busbar with transfer 5
2.3 Triple busbar 6
2.4 Mesh Busbar Scheme 7
2.5 One and a Half Breaker Scheme 8
2.6 High Impedance Differential Protection 9
2.6.1 Use of non-linear resistors 13
2.7 Current distribution - internal and external faults 15
3. APPLYING THE MiCOM P72X 17
3.1 Single phase applications: restricted earth fault and balanced earth fault
protection
17
3.2 Three phase applications 20
3.3 Buswire supervision 23
3.4 Circuit breaker failure 28
4. SETTING EXAMPLES 29
4.1 Restricted earth fault application 29
4.1.1 Example 1 29
4.1.2 Example 2 33
4.2 Busbar applications 37
4.2.1 Stability voltage calculation 39
4.2.2 Current transformers 40
4.2.3 Discriminating zone - Primary operating current 40
4.2.4 Check zone - Primary operating current calculation 41
4.2.5 Stabilizing resistor calculation 41
4.2.6 Non-linear resistor 42
4.2.7 Busbar supervision 42
4.2.8 Relay Settings 43
4.3 Motor / generator applications 44