{"id":380740,"date":"2024-10-20T03:08:14","date_gmt":"2024-10-20T03:08:14","guid":{"rendered":"https:\/\/pdfstandards.shop\/product\/uncategorized\/bs-en-iec-60255-187-12021\/"},"modified":"2024-10-26T05:40:45","modified_gmt":"2024-10-26T05:40:45","slug":"bs-en-iec-60255-187-12021","status":"publish","type":"product","link":"https:\/\/pdfstandards.shop\/product\/publishers\/bsi\/bs-en-iec-60255-187-12021\/","title":{"rendered":"BS EN IEC 60255-187-1:2021"},"content":{"rendered":"

This part of IEC 60255 specifies the minimum requirements for functional and performance evaluation of (longitudinal) differential protection designed for the detection of faults in ac motors, generators and transformers. This document also defines how to document and publish performance test results.<\/p>\n

This document covers the differential protection function whose operating characteristic can be defined on a bias-differential plane. It includes specification of the protection function, measurement characteristics, compensation of energizing quantities, additional restraint or blocking methods (for overexcitation and magnetizing inrush), starting and time delay characteristics. This document also covers unrestrained differential protection functions traditionally combined with the restrained (biased) differential element to form a single differential relay.<\/p>\n

This document defines the influencing factors that affect the accuracy under steady state conditions and performance characteristics during dynamic conditions. The test methodologies for verifying performance characteristics and accuracy are also included in this document.<\/p>\n

This document also includes current transformer requirements for the protection functions.<\/p>\n

The differential protection functions covered by this document are as follows:<\/p>\n

This document does not specify the functional description of additional features often associated with biased differential relays such as current transformer (CT) supervision (CTS), switch onto fault (SOTF) and detection of geo-magnetically induced currents (GIC).<\/p>\n

This document does not cover differential relays designed for bus bar protection (including high impedance differential protection and low impedance differential protection) or line protection. Additionally, this document does not explicitly cover generator incomplete longitudinal differential protection, generator split-phase transverse differential protection, self-balancing or magnetic balanced protection scheme, differential protection of phase-shifting transformers, directional restricted earth fault protection, railway transformers, convertor transformers and reactors. However, the principles covered by this document can be extended to provide guidance on these applications.<\/p>\n

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PDF Pages<\/th>\nPDF Title<\/th>\n<\/tr>\n
2<\/td>\nundefined <\/td>\n<\/tr>\n
5<\/td>\nAnnex ZA(normative)Normative references to international publicationswith their corresponding European publications <\/td>\n<\/tr>\n
7<\/td>\nEnglish
CONTENTS <\/td>\n<\/tr>\n
16<\/td>\nFOREWORD <\/td>\n<\/tr>\n
18<\/td>\n1 Scope <\/td>\n<\/tr>\n
19<\/td>\n2 Normative references
3 Terms and definitions <\/td>\n<\/tr>\n
22<\/td>\nFigures
Figure 1 \u2013 Explanatory diagram for start time, operate time and disengage time <\/td>\n<\/tr>\n
23<\/td>\n4 Specification of the function
4.1 General
Figure 2 \u2013 Simplified biased differential functional block diagram <\/td>\n<\/tr>\n
24<\/td>\n4.2 Input energizing quantities\/energizing quantities
4.2.1 General
4.2.2 Connections
4.3 Binary input signals <\/td>\n<\/tr>\n
26<\/td>\nFigure 3 \u2013 Primary current reference direction <\/td>\n<\/tr>\n
27<\/td>\n4.4 Functional logic
4.4.1 General
4.4.2 Phase biased differential protection <\/td>\n<\/tr>\n
28<\/td>\nFigure 4 \u2013 Typical restrained element (biased) characteristic
Figure 5 \u2013 Typical unrestrained element characteristic <\/td>\n<\/tr>\n
29<\/td>\n4.4.3 Biased restricted earth fault protection
Figure 6 \u2013 Example of combined characteristicusing restrained and unrestrained elements <\/td>\n<\/tr>\n
30<\/td>\n4.4.4 Compensation of energizing quantities <\/td>\n<\/tr>\n
31<\/td>\n4.4.5 Additional restraint or blocking methods <\/td>\n<\/tr>\n
32<\/td>\n4.5 Binary output signals
4.5.1 General
4.5.2 Start (pick-up) signals
4.5.3 Operate (trip) signals
4.5.4 Other output signals
4.6 Additional influencing functions and conditions
4.6.1 General <\/td>\n<\/tr>\n
33<\/td>\n4.6.2 Operation during CT saturation
4.6.3 Switch onto fault
4.6.4 Energizing quantity failure (CT supervision)
4.6.5 Off-nominal frequency operation
4.6.6 Geomagnetically induced currents (GIC) <\/td>\n<\/tr>\n
34<\/td>\n5 Performance specification
5.1 General
5.2 Effective and operating ranges
5.3 Steady state accuracy tests in the effective range
5.3.1 General
Tables
Table 1 \u2013 Example of effective and operating ranges of differential protection <\/td>\n<\/tr>\n
35<\/td>\n5.3.2 Test related to the declared thermal withstand current
5.3.3 Basic characteristic accuracy
5.3.4 Ratio compensation accuracy
Figure 7 \u2013 Basic error of the operating characteristic <\/td>\n<\/tr>\n
36<\/td>\n5.3.5 Phase (vector) compensation validity
5.3.6 Zero sequence compensation validity
5.3.7 Harmonic restraint basic accuracy
5.3.8 Basic accuracy of time delay settings
5.3.9 Disengage time <\/td>\n<\/tr>\n
37<\/td>\n5.4 Dynamic performance in operating range
5.4.1 General
5.4.2 Typical operate time
5.4.3 Relay stability for external faults <\/td>\n<\/tr>\n
38<\/td>\n5.4.4 Relay behaviour for internal fault preceded by an external fault
5.5 Stability during magnetizing inrush conditions
5.6 Stability during overexcitation conditions
5.7 Presence of harmonics on load
5.8 Performance during saturation of current transformers <\/td>\n<\/tr>\n
39<\/td>\n5.9 Behaviour of differential protection with digital interface for the energizing quantities
6 Functional tests
6.1 General <\/td>\n<\/tr>\n
40<\/td>\n6.2 Test related to the declared thermal withstand current
6.3 Steady state accuracy tests in effective range
6.3.1 General <\/td>\n<\/tr>\n
41<\/td>\nTable 2 \u2013 Frequencies for steady state accuracy tests whenthe frequency effective range is equal to \u00b15 % of nominal frequency
Table 3 \u2013 Frequencies for steady state accuracy tests whenthe frequency effective range is larger than \u00b15 % of nominal frequency
Table 4 \u2013 Example frequencies for steady state accuracy tests whenthe frequency effective range is narrower than \u00b15 % of nominal frequency <\/td>\n<\/tr>\n
42<\/td>\n6.3.2 Basic characteristic accuracy
Figure 8 \u2013 Example of an operating characteristicin the IDIFF\/IREST plane with a tolerance band <\/td>\n<\/tr>\n
43<\/td>\nTable 5 \u2013 Test points for differential characteristic basic accuracy <\/td>\n<\/tr>\n
44<\/td>\nFigure 9 \u2013 Test cases for differential characteristic basic accuracy
Table 6 \u2013 Test lines on the differential characteristic (Figure 10) <\/td>\n<\/tr>\n
45<\/td>\nFigure 10 \u2013 Example of a differential characteristic with test lines “a” to “h”
Figure 11 \u2013 Machine differential protection <\/td>\n<\/tr>\n
47<\/td>\nFigure 12 \u2013 Test sequence for basic characteristic accuracy <\/td>\n<\/tr>\n
48<\/td>\nFigure 13 \u2013 Machine restricted earth fault protection
Table 7 \u2013 Basic characteristic accuracy <\/td>\n<\/tr>\n
49<\/td>\n6.3.3 Ratio (magnitude) compensation accuracy
Figure 14 \u2013 Example for documenting the test results for differential relay characteristic <\/td>\n<\/tr>\n
50<\/td>\n6.3.4 Phase (vector) compensation validity
Figure 15 \u2013 Ratio (magnitude) compensation accuracy test <\/td>\n<\/tr>\n
51<\/td>\nFigure 16 \u2013 Secondary three-phase and double-phase injection for Winding 1 (example) <\/td>\n<\/tr>\n
52<\/td>\n6.3.5 Zero sequence compensation validity
Table 8 \u2013 Example of start ratios resulting from phase (vector) compensation <\/td>\n<\/tr>\n
53<\/td>\nFigure 17 \u2013 Secondary single-phase and three-phase injections for Winding 1 (example) <\/td>\n<\/tr>\n
54<\/td>\nFigure 18 \u2013 Zero sequence current injection on the Y side of the transformer
Figure 19 \u2013 Zero sequence current injection on the delta side of the transformer <\/td>\n<\/tr>\n
55<\/td>\n6.3.6 Harmonic restraint basic accuracy test under steady state conditions at nominal frequency
Table 9 \u2013 Example of start ratios resulting from zero sequence compensation <\/td>\n<\/tr>\n
56<\/td>\nTable 10 \u2013 Test points for rated frequency harmonic restraint <\/td>\n<\/tr>\n
57<\/td>\n6.3.7 Accuracy related to time delay setting
Figure 20 \u2013 Example of a rated frequency harmonic restraintcharacteristic with visualization of test lines
Table 11 \u2013 Reporting example of test results for harmonic restraint basic accuracy test <\/td>\n<\/tr>\n
58<\/td>\nTable 12 \u2013 Results of time delay tests
Table 13 \u2013 Reported time delay <\/td>\n<\/tr>\n
59<\/td>\n6.3.8 Determination and reporting of the disengage time
Figure 21 \u2013 Sequence of events for testing the disengage time <\/td>\n<\/tr>\n
60<\/td>\n6.4 Dynamic performance tests
6.4.1 General
Table 14 \u2013 Results of disengage time for all the tests
Table 15 \u2013 Frequencies for dynamic performance tests whenthe frequency operating range is equal to \u00b110 % of nominal frequency
Table 16 \u2013 Frequencies for dynamic performance tests whenthe frequency operating range is wider than \u00b110 % of nominal frequency <\/td>\n<\/tr>\n
61<\/td>\nTable 17 \u2013 Example frequencies for dynamic performance tests when the frequency operating range is narrower than \u00b110 % of nominal frequency <\/td>\n<\/tr>\n
62<\/td>\n6.4.2 Operate time for double infeed network model (restrained operation)
Figure 22 \u2013 Double infeed network model for operate time tests <\/td>\n<\/tr>\n
63<\/td>\nTable 18 \u2013 Double infeed network model <\/td>\n<\/tr>\n
64<\/td>\nTable 19 \u2013 Source impedances for double infeed network model \u2013Restrained operation (e.g. 50 Hz \u00b1 10 % operating range) <\/td>\n<\/tr>\n
66<\/td>\nFigure 23 \u2013 Test sequence for double infeed network model \u2013Restrained operation (transformer) <\/td>\n<\/tr>\n
67<\/td>\nFigure 24 \u2013 Double infeed network model for operate time tests
Table 20 \u2013 Double infeed network model <\/td>\n<\/tr>\n
68<\/td>\nTable 21 \u2013 Source impedances for double infeed network model \u2013Restrained operation (e.g. 50 Hz \u00b1 10 % operating range) <\/td>\n<\/tr>\n
70<\/td>\nFigure 25 \u2013 Test sequence for double infeed network model \u2013Restrained operation (REF) <\/td>\n<\/tr>\n
71<\/td>\nFigure 26 \u2013 Double infeed network model for operate time tests
Table 22 \u2013 Double infeed network model <\/td>\n<\/tr>\n
72<\/td>\nTable 23 \u2013 Source impedances for double infeed network model \u2013Restrained operation (e.g. 50 Hz \u00b1 10 % operating range) <\/td>\n<\/tr>\n
73<\/td>\n6.4.3 Operate time for double infeed network model (unrestrained operation) <\/td>\n<\/tr>\n
74<\/td>\nFigure 27 \u2013 Test sequence for double infeed network model \u2013Restrained operation (generator) <\/td>\n<\/tr>\n
75<\/td>\nTable 24 \u2013 Source impedances for double infeed network model \u2013Unrestrained operation (e.g. 60 Hz \u00b1 10 % operating range) <\/td>\n<\/tr>\n
77<\/td>\nFigure 28 \u2013 Test sequence for double infeed network model \u2013Unrestrained operation (transformer) <\/td>\n<\/tr>\n
78<\/td>\n6.4.4 Operate time for radial single infeed network model (restrained operation)
Figure 29 \u2013 Single infeed network model for operate time tests <\/td>\n<\/tr>\n
79<\/td>\nTable 25 \u2013 Single infeed network model
Table 26 \u2013 Source impedances for radial single infeed network model \u2013Restrained operation (e.g. 50 Hz \u00b1 10 % operating range) <\/td>\n<\/tr>\n
82<\/td>\nFigure 30 \u2013 Test sequence radial single infeed network model \u2013 Restrained operation <\/td>\n<\/tr>\n
83<\/td>\nFigure 31 \u2013 Single infeed network model for operate time tests
Table 27 \u2013 Single infeed network model <\/td>\n<\/tr>\n
84<\/td>\nTable 28 \u2013 Source impedances for radial single infeed network model \u2013Restrained operation (e.g. 50 Hz \u00b1 10 % operating range) <\/td>\n<\/tr>\n
86<\/td>\nFigure 32 \u2013 Test sequence for radial single infeed network \u2013Restrained operation (generator) <\/td>\n<\/tr>\n
87<\/td>\nFigure 33 \u2013 Single infeed network model for operate time tests
Table 29 \u2013 Single infeed network model <\/td>\n<\/tr>\n
88<\/td>\nTable 30 \u2013 Source impedances for radial single infeed network model \u2013Restrained operation (e.g. 50 Hz \u00b1 10 % operating range) <\/td>\n<\/tr>\n
90<\/td>\nFigure 34 \u2013 Test sequence for radial single infeed network \u2013Restrained operation (motor) <\/td>\n<\/tr>\n
91<\/td>\n6.4.5 Operate time for radial single infeed network model (unrestrained operation)
Table 31 \u2013 Source impedances for radial single infeed network model \u2013Unrestrained operation (e.g. 60 Hz \u00b1 10 % operating range) <\/td>\n<\/tr>\n
93<\/td>\nFigure 35 \u2013 Test sequence for radial single infeed network \u2013 Unrestrained operation <\/td>\n<\/tr>\n
94<\/td>\n6.4.6 Reporting of typical operate time
Table 32 \u2013 Fault statistics for typical operate time of transformer protection(nominal frequency only) <\/td>\n<\/tr>\n
95<\/td>\nTable 33 \u2013 Fault statistics for typical operate time of biasedrestricted earth fault protection (nominal frequency only)
Table 34 \u2013 Fault statistics for typical operate time of generator protection(nominal frequency only)
Table 35 \u2013 Fault statistics for typical operate time of motor protection(nominal frequency only) <\/td>\n<\/tr>\n
96<\/td>\nTable 36 \u2013 Operate time classes
Table 37 \u2013 Corresponding operate time classes <\/td>\n<\/tr>\n
97<\/td>\nFigure 36 \u2013 Example of distribution of the operate time for one application
Table 38 \u2013 Number of operate times and percentage <\/td>\n<\/tr>\n
98<\/td>\nTable 39 \u2013 Example of typical operate time at nominal frequency (mode, median, mean) <\/td>\n<\/tr>\n
99<\/td>\nFigure 37 \u2013 Operate time as a function of the off-nominal frequency values(effective range is the specified range of \u00b110 % of nominal frequency)
Table 40 \u2013 Examples of operate times (50 Hz nominal, CT configuration 500 A\/1 Aand 1 000 A\/1 A, power transformer protection) <\/td>\n<\/tr>\n
100<\/td>\n6.4.7 Stability for external faults
Figure 38 \u2013 Operate time as a function of the off-nominal frequency values(accuracy range beyond the specified range of \u00b110 % of nominal frequency <\/td>\n<\/tr>\n
101<\/td>\nFigure 39 \u2013 Double infeed network model for stability tests
Table 41 \u2013 Double infeed network model <\/td>\n<\/tr>\n
102<\/td>\nTable 42 \u2013 Source impedances for double infeed network model stability tests(e.g. 50 Hz \u00b1 10 % operating range) <\/td>\n<\/tr>\n
104<\/td>\nFigure 40 \u2013 Sequence of fault injection for stability due to external faults (transformer) <\/td>\n<\/tr>\n
105<\/td>\nFigure 41 \u2013 Double infeed network model for stability tests
Table 43 \u2013 Double infeed network model <\/td>\n<\/tr>\n
106<\/td>\nTable 44 \u2013 Source impedances for double infeed network model stability tests(e.g. 50 Hz \u00b1 10 % operating range) <\/td>\n<\/tr>\n
108<\/td>\nFigure 42 \u2013 Sequence of fault injection for stability due to external faults (REF) <\/td>\n<\/tr>\n
109<\/td>\nFigure 43 \u2013 Double infeed network model for stability tests
Table 45 \u2013 Double infeed network model <\/td>\n<\/tr>\n
110<\/td>\nTable 46 \u2013 Source impedances for double infeed network model stability tests(e.g. 50 Hz \u00b1 10 % operating range) <\/td>\n<\/tr>\n
112<\/td>\nFigure 44 \u2013 Sequence of fault injection for stability due to external faults (generator) <\/td>\n<\/tr>\n
113<\/td>\nFigure 45 \u2013 Double infeed network model for stability tests
Table 47 \u2013 Double infeed network model <\/td>\n<\/tr>\n
114<\/td>\nTable 48 \u2013 Source impedances for double infeed network model stability tests(e.g. 50 Hz \u00b1 10 % operating range) <\/td>\n<\/tr>\n
116<\/td>\nFigure 46 \u2013 Sequence of fault injection for stability due to external faults (motor) <\/td>\n<\/tr>\n
117<\/td>\n6.5 Relay behaviour for internal fault preceded by an external fault
6.5.1 General
6.5.2 Application specific considerations: transformer differential
Figure 47 \u2013 Double infeed network model for internal fault preceded by an external fault <\/td>\n<\/tr>\n
118<\/td>\nTable 49 \u2013 Double infeed network model
Table 50 \u2013 Source impedances, fault resistances and pre-fault conditions for internal fault preceded by an external fault (e.g. for 50 Hz power system frequency) <\/td>\n<\/tr>\n
120<\/td>\n6.5.3 Application specific considerations: biased restricted earth fault <\/td>\n<\/tr>\n
121<\/td>\nFigure 48 \u2013 Double infeed network model for internal faultpreceded by an external fault test
Table 51 \u2013 Double infeed network model <\/td>\n<\/tr>\n
122<\/td>\nTable 52 \u2013 Source impedances, fault resistances and pre-fault conditions for internal fault preceded by an external fault tests (e.g. for 50 Hz power system frequency) <\/td>\n<\/tr>\n
124<\/td>\n6.5.4 Application specific considerations: generator differential
Figure 49 \u2013 Double infeed network model for internalfault preceded by an external fault test <\/td>\n<\/tr>\n
125<\/td>\nTable 53 \u2013 Double infeed network model
Table 54 \u2013 Source impedances, fault resistances and pre-fault conditions for internal fault preceded by an external fault tests (e.g. for 50 Hz power system frequency) <\/td>\n<\/tr>\n
127<\/td>\n6.5.5 Reporting
Table 55 \u2013 Operate time for internal fault preceded by an external faultand for internal fault when the relay always operated <\/td>\n<\/tr>\n
128<\/td>\n6.6 Stability during inrush conditions
6.6.1 General
6.6.2 Application specific considerations: transformer differential
Table 56 \u2013 Operate time for internal fault preceded by an external faultand for internal fault when the relay did not always operate <\/td>\n<\/tr>\n
129<\/td>\nFigure 50 \u2013 Power transformer inrush current waveform
Table 57 \u2013 Coefficients of the inrush current waveforms <\/td>\n<\/tr>\n
130<\/td>\nFigure 51 \u2013 Comparison of waveforms
Table 58 \u2013 Nameplate data for test-transformers
Table 59 \u2013 Parameter k values <\/td>\n<\/tr>\n
131<\/td>\nFigure 52 \u2013 Connection for the relay when current is injected from Y winding <\/td>\n<\/tr>\n
132<\/td>\nFigure 53 \u2013 Connection for the relay when current is injected from delta winding <\/td>\n<\/tr>\n
133<\/td>\n6.7 Stability during overexcitation conditions
6.7.1 General
6.7.2 Application specific considerations: transformer differential <\/td>\n<\/tr>\n
134<\/td>\nFigure 54 \u2013 Power transformer overexcitation current waveform injected from Y winding
Figure 55 \u2013 Overexcitation current waveform injected from delta winding <\/td>\n<\/tr>\n
135<\/td>\nFigure 56 \u2013 Comparison of the waveforms injected from Y winding
Table 60 \u2013 Coefficient of the overexcitation waveforms <\/td>\n<\/tr>\n
136<\/td>\nFigure 57 \u2013 Comparison of the waveforms injected from delta winding
Table 61 \u2013 Test data for the transformer <\/td>\n<\/tr>\n
137<\/td>\nFigure 58 \u2013 Three-phase overexcitation current waveform injected from Y winding <\/td>\n<\/tr>\n
138<\/td>\n6.8 Performance with load harmonics
6.8.1 General
6.8.2 Application specific considerations: transformer differential
Figure 59 \u2013 Three-phase overexcitation current waveform injected from delta winding
Figure 60 \u2013 Test with superimposed harmonics on load \u2013 Transformer protection <\/td>\n<\/tr>\n
139<\/td>\nTable 62 \u2013 Transformer data for the superimposed harmonics on load test
Table 63 \u2013 Fundamental component of load current in pu
Table 64 \u2013 Harmonic content for superimposed harmonics on load test
Table 65 \u2013 Harmonic phase angles for superimposed harmonics on load test <\/td>\n<\/tr>\n
142<\/td>\n6.8.3 Application specific considerations: generator or motor differential
Figure 61 \u2013 Three-phase load current waveform on the Y sideof the transformer with superimposed harmonics
Figure 62 \u2013 Three-phase load current waveforms on the delta side ofthe YNd1 transformer with superimposed harmonics <\/td>\n<\/tr>\n
143<\/td>\nFigure 63 \u2013 Test with superimposed harmonics on load
Table 66 \u2013 Generator or motor data for the superimposed harmonics on load test <\/td>\n<\/tr>\n
144<\/td>\nTable 67 \u2013 Harmonic phase angles for superimposed harmonics on load test <\/td>\n<\/tr>\n
145<\/td>\n6.8.4 Application specific considerations: biased restricted earth fault
Figure 64 \u2013 Test with superimposed harmonics on load \u2013Restricted earth fault protection <\/td>\n<\/tr>\n
146<\/td>\nTable 68 \u2013 Transformer data for the superimposed harmonics on load test
Table 69 \u2013 Harmonic phase angles for superimposed harmonics on load test <\/td>\n<\/tr>\n
147<\/td>\n6.8.5 Reporting <\/td>\n<\/tr>\n
148<\/td>\n7 Documentation requirements
7.1 Type test report
7.2 Other user documentation <\/td>\n<\/tr>\n
149<\/td>\nAnnex A (informative)Examples of phase (vector) compensationand zero sequence compensation schemes
A.1 General
Figure A.1 \u2013 Example of a transformer
Table A.1 \u2013 Transformer data <\/td>\n<\/tr>\n
150<\/td>\nA.2 Y\u2192d conversion
A.2.1 Current conversion
Figure A.2 \u2013 Current vectors <\/td>\n<\/tr>\n
151<\/td>\nA.2.2 Three-phase fault at Y (star\/wye) side <\/td>\n<\/tr>\n
152<\/td>\nA.2.3 Phase-phase fault at Y (star\/wye) side
A.2.4 Single-phase fault at Y (star\/wye) side
Figure A.3 \u2013 Three-phase injection at Y (star\/wye) side
Figure A.4 \u2013 Phase-phase injection at Y (star\/wye) side <\/td>\n<\/tr>\n
153<\/td>\nA.2.5 Three-phase fault at delta side
Figure A.5 \u2013 Single-phase injection at Y (star\/wye) side <\/td>\n<\/tr>\n
154<\/td>\nA.2.6 Phase-phase fault at delta side
A.2.7 Single-phase fault at delta side
Figure A.6 \u2013 Three-phase injection at delta side
Figure A.7 \u2013 Phase-phase injection at delta side <\/td>\n<\/tr>\n
155<\/td>\nFigure A.8 \u2013 Internal single-phase fault at delta sidewith neutral grounding transformer in the system
Figure A.9 \u2013 Single-phase injection at delta side <\/td>\n<\/tr>\n
156<\/td>\nFigure A.10 \u2013 External single-phase fault at delta sidewith neutral grounding transformer inside protected zone <\/td>\n<\/tr>\n
157<\/td>\nA.2.8 Ratio between start currents under different fault types
A.3 d\u2192Y conversion
A.3.1 Current conversion
Table A.2 \u2013 Start currents under different fault types <\/td>\n<\/tr>\n
158<\/td>\nA.3.2 Three-phase fault at Y (star\/wye) side
A.3.3 Phase-phase fault at Y (star\/wye) side
A.3.4 Single-phase fault at Y (star\/wye) side <\/td>\n<\/tr>\n
159<\/td>\nA.3.5 Three-phase fault at delta side
A.3.6 Phase-phase fault at delta side <\/td>\n<\/tr>\n
160<\/td>\nA.3.7 Single-phase fault at delta side
A.3.8 Ratio between start currents under different fault types
Table A.3 \u2013 Start currents under different fault types <\/td>\n<\/tr>\n
161<\/td>\nAnnex B (normative)Calculation of mean, median and mode
B.1 Mean
B.2 Median
B.3 Mode
B.4 Example <\/td>\n<\/tr>\n
162<\/td>\nAnnex C (normative)CT requirements
C.1 General <\/td>\n<\/tr>\n
164<\/td>\nTable C.1 \u2013 Levels of remanent or remaining flux to be considered for external faults
Table C.2 \u2013 Levels of remanent or remaining flux to be considered for external faultswhen the difference of size between the CTs is limited <\/td>\n<\/tr>\n
165<\/td>\nFigure C.1 \u2013 Fault positions to be considered for specifying the CT requirements <\/td>\n<\/tr>\n
166<\/td>\nC.2 Transformer differential protection
C.2.1 General
C.2.2 Fault 1
Figure C.2 \u2013 Fault positions to be considered for transformer differential protection <\/td>\n<\/tr>\n
167<\/td>\nC.2.3 Fault 2
C.2.4 Fault 3 <\/td>\n<\/tr>\n
168<\/td>\nC.3 Transformer restricted earth fault protection
C.3.1 General
C.3.2 Fault 1
Figure C.3 \u2013 Fault positions to be considered for the restricted earth fault protection <\/td>\n<\/tr>\n
169<\/td>\nC.3.3 Fault 2
C.3.4 Fault 3 <\/td>\n<\/tr>\n
170<\/td>\nC.4 Generator differential protection
C.4.1 General
C.4.2 Fault 2
Figure C.4 \u2013 External fault position to be consideredfor the generator differential protection <\/td>\n<\/tr>\n
171<\/td>\nC.4.3 Criteria and additional conditions
C.5 Motor differential protection
C.5.1 General
C.5.2 Fault 1
C.5.3 Criteria and additional conditions
Figure C.5 \u2013 Internal fault position to be considered for the motor differential protection <\/td>\n<\/tr>\n
172<\/td>\nC.5.4 Start of motor, security case
C.5.5 Criteria and additional conditions
C.6 Reporting <\/td>\n<\/tr>\n
173<\/td>\nAnnex D (informative)CT saturation and influence on the performance of differential relays <\/td>\n<\/tr>\n
175<\/td>\nFigure D.1 \u2013 Fault positions to be considered for specifying the CT requirements
Figure D.2 \u2013 Additional fault position to be considered in case of summation of currents <\/td>\n<\/tr>\n
178<\/td>\nAnnex E (informative)Guidance on dimensioning of CTs for transformer differential protection
E.1 General <\/td>\n<\/tr>\n
179<\/td>\nE.2 Example 1
E.2.1 General
Figure E.1 \u2013 Transformer differential relay example 1
Table E.1 \u2013 Fault currents <\/td>\n<\/tr>\n
180<\/td>\nE.2.2 Verification of CT1 \u2013 Internal fault
E.2.3 Verification of CT1 \u2013 External fault <\/td>\n<\/tr>\n
181<\/td>\nE.2.4 Verification of CT2 <\/td>\n<\/tr>\n
182<\/td>\nE.3 Example 2
E.3.1 General
Figure E.2 \u2013 Transformer differential relay example 2
Table E.2 \u2013 Fault currents <\/td>\n<\/tr>\n
183<\/td>\nE.3.2 Dimensioning of CT1 <\/td>\n<\/tr>\n
184<\/td>\nE.3.3 Dimensioning of CT2 <\/td>\n<\/tr>\n
186<\/td>\nAnnex F (informative)Examples of test procedures to determine CT sizingrequirements for differential protection
F.1 General <\/td>\n<\/tr>\n
188<\/td>\nF.2 Test data
F.2.1 General
F.2.2 Network model for CT requirement tests for the transformer differential protection <\/td>\n<\/tr>\n
189<\/td>\nFigure F.1 \u2013 Network models and fault positions for transformer differential protection <\/td>\n<\/tr>\n
190<\/td>\nTable F.1 \u2013 Specification of test cases for the transformer differential protection \u2013Internal and external faults with one saturated CT <\/td>\n<\/tr>\n
191<\/td>\nTable F.2 \u2013 Specification of test cases for the transformer differential protection \u2013External faults with two saturated CTs
Table F.3 \u2013 Example time constants with corresponding R\/X ratios <\/td>\n<\/tr>\n
192<\/td>\nF.2.3 Network model for CT requirement tests for the transformer restricted earth fault protection
Figure F.2 \u2013 Network models and fault positions for transformerrestricted earth fault protection <\/td>\n<\/tr>\n
193<\/td>\nTable F.4 \u2013 Specification of test cases for the transformer restricted earth fault protection \u2013 Internal and external faults with one saturated CT
Table F.5 \u2013 Specification of test cases for the transformer restricted earth fault protection \u2013 External faults with two saturated CTs <\/td>\n<\/tr>\n
194<\/td>\nF.3 CT data and CT models <\/td>\n<\/tr>\n
195<\/td>\nTable F.6 \u2013 Excitation characteristic data for the high-remanence basic CT <\/td>\n<\/tr>\n
196<\/td>\nFigure F.3 \u2013 Excitation characteristic for the high-remanence basic CT <\/td>\n<\/tr>\n
198<\/td>\nFigure F.4 \u2013 Magnetization curve for the high-remanence type basic CT
Table F.7 \u2013 Magnetization curve data for the high-remanence type basic CT <\/td>\n<\/tr>\n
199<\/td>\nFigure F.5 \u2013 Secondary current at the limit of saturation causedby the AC component with no remanent flux in the CT
Figure F.6 \u2013 Secondary current in case of maximum DC offset <\/td>\n<\/tr>\n
201<\/td>\nFigure F.7 \u2013 Excitation characteristics for non-remanenceand high-remanence type basic CTs
Table F.8 \u2013 Excitation characteristic datafor the non-remanence type basic CT <\/td>\n<\/tr>\n
202<\/td>\nF.4 Test summary
Figure F.8 \u2013 Magnetization curve for non-remanence type basic CTs
Table F.9 \u2013 Magnetization curve data for non-remanence type CT <\/td>\n<\/tr>\n
204<\/td>\nAnnex G (normative)Ramping methods for testing basic characteristic accuracy
G.1 General
G.2 Pre-fault condition
G.3 Pseudo-continuous ramp <\/td>\n<\/tr>\n
205<\/td>\nFigure G.1 \u2013 Secondary injected currents for the simulation of a through load of 30 %
Table G.1 \u2013 Restraining and differential currents for differentdefinitions of the restraining current <\/td>\n<\/tr>\n
206<\/td>\nG.4 Ramp of shots
Figure G.2 \u2013 Pseudo-continuous ramp in the restraining current \u2013Differential current plane in the time domain <\/td>\n<\/tr>\n
207<\/td>\nFigure G.3 \u2013 Ramp of shots showing differential step change and the time step
Figure G.4 \u2013 Ramp of shots with binary search algorithm <\/td>\n<\/tr>\n
208<\/td>\nAnnex H (informative)Example of COMTRADE file for an evolving fault test case <\/td>\n<\/tr>\n
209<\/td>\nAnnex I (normative)Definition of fault inception angle
Figure I.1 \u2013 Graphical definition of fault inception angle
Table I.1 \u2013 Fault type and reference voltage <\/td>\n<\/tr>\n
210<\/td>\nBibliography <\/td>\n<\/tr>\n<\/table>\n","protected":false},"excerpt":{"rendered":"

Measuring relays and protection equipment – Functional requirements for differential protection. Restrained and unrestrained differential protection of motors, generators and transformers<\/b><\/p>\n\n\n\n\n
Published By<\/td>\nPublication Date<\/td>\nNumber of Pages<\/td>\n<\/tr>\n
BSI<\/b><\/a><\/td>\n2021<\/td>\n212<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n","protected":false},"featured_media":380748,"template":"","meta":{"rank_math_lock_modified_date":false,"ep_exclude_from_search":false},"product_cat":[512,2641],"product_tag":[],"class_list":{"0":"post-380740","1":"product","2":"type-product","3":"status-publish","4":"has-post-thumbnail","6":"product_cat-29-120-70","7":"product_cat-bsi","9":"first","10":"instock","11":"sold-individually","12":"shipping-taxable","13":"purchasable","14":"product-type-simple"},"_links":{"self":[{"href":"https:\/\/pdfstandards.shop\/wp-json\/wp\/v2\/product\/380740","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/pdfstandards.shop\/wp-json\/wp\/v2\/product"}],"about":[{"href":"https:\/\/pdfstandards.shop\/wp-json\/wp\/v2\/types\/product"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/pdfstandards.shop\/wp-json\/wp\/v2\/media\/380748"}],"wp:attachment":[{"href":"https:\/\/pdfstandards.shop\/wp-json\/wp\/v2\/media?parent=380740"}],"wp:term":[{"taxonomy":"product_cat","embeddable":true,"href":"https:\/\/pdfstandards.shop\/wp-json\/wp\/v2\/product_cat?post=380740"},{"taxonomy":"product_tag","embeddable":true,"href":"https:\/\/pdfstandards.shop\/wp-json\/wp\/v2\/product_tag?post=380740"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}