BS EN 62689-2:2017
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Current and voltage sensors or detectors, to be used for fault passage indication purposes – System aspects
| Published By | Publication Date | Number of Pages |
| BSI | 2017 | 56 |
IEC 62689-2:2016 describes electric phenomena and electric system behaviour during faults, according to the most widely diffused distribution system architecture and to fault typologies, to define the functional requirements for fault passage indicators (FPI) and distribution substation units (DSU) (including their current and/or voltage sensors), which are, respectively, a device or a device/combination of devices and/or of functions able to detect faults and provide indications about their localization. By localization of the fault is meant the fault position with respect to the FPI/DSU installation point on the network (upstream or downstream from the FPI/DSU’s location) or the direction of the fault current flowing through the FPI itself. The fault localization may be obtained – directly from the FPI/DSU, or – from a central system using information from more FPIs or DSUs, considering the features and the operating conditions of the electric system where the FPIs/DSUs are installed. This part of IEC 62689 is therefore aimed at helping users in the appropriate choice of FPIs/DSUs (or of a system based on FPI/DSU information) properly operating in their networks, considering adopted solutions and operation rules (defined by tradition and/or depending on possible constraints concerning continuity and quality of voltage supply defined by a national regulator), and also taking into account complexity of the apparatus and consequent cost. This part of IEC 62689 is mainly focused on system behaviour during faults, which is the “core” of FPI/DSU fault detection capability classes described in IEC 62689-1, where all requirements are specified in detail.
PDF Catalog
| PDF Pages | PDF Title |
|---|---|
| 2 | National foreword |
| 7 | English CONTENTS |
| 10 | FOREWORD |
| 12 | INTRODUCTION |
| 13 | Figures Figure 1 – General architecture of an FPI |
| 14 | 1 Scope 2 Normative references 3 Terms, definitions, abbreviations and symbols |
| 15 | 3.1 Terms and definitions related to neutral point treatment 3.2 Abbreviations and symbols 4 Choice of FPI/DSU requirements related to fault detection according to network operation mode and fault type 4.1 General 4.2 FPIs/DSUs for isolated neutral system 4.2.1 Earth fault detection |
| 16 | 4.2.2 Polyphase fault detection 4.3 FPIs/DSUs for resonant earthed (neutral) system – arc-suppression-coil-earth (neutral) system 4.3.1 Earth fault detection |
| 17 | 4.3.2 Polyphase fault detection 4.4 FPIs/DSUs for solidly earthed neutral systems (systems with low-impedance earthed neutrals) 4.5 FPIs/DSUs for impedance earthed neutral system (resistive impedance earthed neutral system ) 4.5.1 Earth fault detection |
| 18 | 4.5.2 Polyphase fault detection 4.6 FPIs/DSUs for systems with high presence of DER 4.7 Summary of FPI/DSU requirements with respect to fault detection according to network operation mode and fault type |
| 19 | Table 1 – Summary of FPI/DSU requirements referred to fault detectionaccording to network operation mode and fault type |
| 20 | 5 Fault detecting principles according to network and fault type 5.1 General |
| 21 | Figure 2 – General three-phase diagram of an earth fault in isolated neutral system |
| 23 | 5.2 Earth fault detection and neutral treatment 5.2.1 General 5.2.2 Earth fault detection in isolated neutral systems Figure 4 – Isolated neutral system – detection of earth fault current direction from FPI/DSU upstream from the fault location(fault downstream from the FPI’s/DSU’s location) |
| 24 | Figure 5 – Isolated neutral system – detection of earth fault current direction from FPI/DSU downstream from the fault location(fault upstream from the FPI’s/DSU’s location) |
| 26 | Figure 7 – Relationship between FPI/DSU regulated current threshold and earth fault current in case of non-directional earth fault current detection. Fault downstream from FPI/DSU A4-2 |
| 27 | Figure 8 – Relationship between FPI/DSU regulated current threshold and earth fault current in case of non-directional earth fault current detection. Fault downstream from FPI/DSU A4-1 and upstream from FPI/DSU A4-2 |
| 28 | Figure 9 – Relationship between FPI/DSU regulated current threshold and earth fault current in case of non-directional earth fault current detection. Fault on MV busbar (upstream from any FPI/DSU) |
| 29 | 5.2.3 Earth fault detection in resonant earthed systems |
| 30 | Figure 10 – Pure resonant earthed system – detection of earth fault current direction from FPI/DSU upstream from the fault location (fault downstream from the FPI’s/DSU’s location) Figure 11 – Pure resonant earthed system – detection of earth fault current direction from FPI/DSU downstream from the fault location (fault upstream from the FPI’s/DSU’s location) |
| 32 | Figure 12 – Pure resonant earthed system – vector diagrams related to Figure 10 and Figure 11 |
| 33 | Figure 13 – Resonant earthed system with inductance and permanent parallel resistor – detection of phase to earth fault current direction from FPI/DSU upstream from the fault location (fault downstream from the FPI’s/DSU’s location) Figure 14 – Resonant earthed system with inductance with parallel resistor system – detection of phase to earth fault current direction from FPI/DSU downstream from the fault location (fault upstream from the FPI’s/DSU’s location) |
| 35 | Figure 15 – Resonant earthed system with inductance with parallel resistor system – vector diagrams related to Figure 13 and Figure 14 |
| 37 | Figure 16 – Earthing resistor system – detection of phase to earth faultcurrent direction from FPI/DSU upstream from the fault location(fault downstream from the FPI’s/DSU’s location) Figure 17 – Earthing resistor system – detection of phase to earth faultcurrent direction from FPI/DSU downstream from the fault location(fault upstream from the FPI’s/DSU’s location) |
| 41 | Figure 20 – Overcurrents in a radial network with negligible DER presence – correct current detection by non-directional FPI/DSU(good sensitivity concerning overcurrent detection) |
| 42 | 5.2.5 Overcurrent detection in presence of a large amount of DER (significantly increasing short circuit current values) |
| 43 | Figure 21 – Overcurrents in a radial network with a large amount of DER – unreliable fault detection by non-directional FPIs/DSUs (incorrect detection or extremely low sensitivity) |
| 44 | Annex A (informative)Example of a possible solution for fault detectionthrough FPIs/DSUs on closed loop feeder A.1 General A.2 Double bipole model Figure A.1 – Double bipole |
| 45 | A.3 Analysis of zero-sequence values in case of fault on a line out of the closed loop |
| 46 | Figure A.2 – Cascade of double bipoles |
| 47 | A.4 Analysis in case of fault on the closed-loop |
| 48 | Figure A.3 – Closed loop double bipoles Figure A.4 – Equivalent model in case of fault |
| 49 | A.5 Example of on-field application |
| 50 | Annex B (informative)Example of fault detection coordination techniqueamong FPIs/DSUs and MV feeder protection relays B.1 Autonomous fault detection confirmation from FPIs/DSUs |
| 51 | Figure B.1 – Correctly coordinated fault selection among FPIs/DSUs and protection relay |
| 52 | Figure B.2 – Incorrectly coordinated selectionamong FPIs/DSUs and protection relay. Case 1 |
| 53 | B.2 Fault detection confirmation from FPIs/DSUs through voltage presence/absence detection Figure B.3 – Incorrectly coordinated fault selectionamong FPIs/DSUs and protection relay. Case 2 |
| 54 | Bibliography |
