GE P444

Application Notes
P44x/EN AP/Hb
6
MiCOM P40 Agile P442, P444
(AP) 5-
3
CONTENTS
1 INTRODUCTION 7
1.1 Protection of overhead lines and cable circuits 7
1.2 MiCOM distance relay 7
1.2.1 Protection Features 7
1.2.2 Non-Protection Features 8
1.2.3 Additional Features for the P442 Relay Model 9
1.2.4 Additional Features for the P444 Relay Model 10
1.3 Explanation about specific symbols used in the logic diagrams 10
2 DISTANCE ALGORITHMS 11
2.1 Distance and Resistance Measurement 11
2.1.1 Phase-to-earth loop impedance 13
2.1.2 Impedance measurement algorithms work with instantaneous values (current and voltage).14
2.1.3 Phase-to-phase loop impedance 14
2.2 "Delta" Algorithm 15
2.2.1 Fault Modelling 16
2.2.2 Detecting a Transition 17
2.2.3 Confirmation 20
2.2.4 Directional Decision 20
2.2.5 Phase Selection 21
2.2.6 Summary 21
2.3 "Conventional" Algorithms 22
2.3.1 Convergence Analysis 23
2.3.2 Start-Up 23
2.3.3 Phase Selection 24
2.3.4 Directional Decision 25
2.3.5 Directional Decision during SOTF-TOR (Switch On To Fault/Trip On Reclose) 25
2.4 Faulted Zone Decision 26
2.5 Tripping Logic 27
2.5.1 General 27
2.5.2 DDB inputs / outputs for General trip logic 27
2.6 Fault Locator 29
2.6.1 Selecting the fault location data 30
2.6.2 Processing algorithms 30
2.7 Double Circuit Lines 31
3 DISTANCE PROTECTION AND DISTANCE SCHEME FUNCTIONS 33
3.1 Fault distance characteristics (“Distance elements” menu setting) 34
3.1.1 Line setting 34
3.1.2 Zone setting 34
3.1.3 Fault locator 44