IEC 60255-149:2013 specifies minimum requirements for thermal protection relays. This standard includes specification of the protection function, measurement characteristics and test methodologies. The object is to establish a common and reproducible reference for evaluating dependent time relays which protect equipment from thermal damage by measuring a.c. current flowing through the equipment. Complementary input energizing quantities such as ambient, coolant, top oil and winding temperature may be applicable for the thermal protection specification set forth in this standard. This standard covers protection relays based on a thermal model with memory function.<\/p>\n
| PDF Pages<\/th>\n | PDF Title<\/th>\n<\/tr>\n | ||||||
|---|---|---|---|---|---|---|---|
| 6<\/td>\n | English CONTENTS <\/td>\n<\/tr>\n | ||||||
| 8<\/td>\n | 1 Scope 2 Normative references <\/td>\n<\/tr>\n | ||||||
| 9<\/td>\n | 3 Terms and definitions <\/td>\n<\/tr>\n | ||||||
| 10<\/td>\n | 4 Specification of the function 4.1 General <\/td>\n<\/tr>\n | ||||||
| 11<\/td>\n | 4.2 Input energizing quantities\/energizing quantities 4.3 Binary input signals Figures Figure 1 \u2013 Simplified thermal protection function block diagram <\/td>\n<\/tr>\n | ||||||
| 12<\/td>\n | 4.4 Functional logic 4.4.1 Equivalent heating current 4.4.2 Basic (setting) and operating current values for thermal protection <\/td>\n<\/tr>\n | ||||||
| 13<\/td>\n | 4.4.3 Thermal level calculation <\/td>\n<\/tr>\n | ||||||
| 14<\/td>\n | 4.4.4 Time-current limit characteristic equations and curves <\/td>\n<\/tr>\n | ||||||
| 15<\/td>\n | Figure 2 \u2013 Typical examples of characteristic curves for cold state of a first-order thermal system with no previous load before overload occurs <\/td>\n<\/tr>\n | ||||||
| 16<\/td>\n | 4.4.5 Thermal level alarm threshold Figure 3 \u2013 Typical examples of characteristic curves for hot states of a first-order thermal system for different values of previous load before overload occurs <\/td>\n<\/tr>\n | ||||||
| 17<\/td>\n | 4.5 Binary output signals 4.5.1 General 4.5.2 Operate (trip) output signal 4.5.3 Alarm signal 4.5.4 Other binary output signals <\/td>\n<\/tr>\n | ||||||
| 18<\/td>\n | 4.6 Additional influencing factors on thermal protection 4.6.1 General 4.6.2 Influence of ambient temperature on thermal protection 4.6.3 Thermal reset facilities <\/td>\n<\/tr>\n | ||||||
| 19<\/td>\n | 4.7 Behaviour of thermal protective device during auxiliary power supply failure 5 Performance specification 5.1 Accuracy related to the characteristic quantity 5.2 Accuracy related to the operate time <\/td>\n<\/tr>\n | ||||||
| 20<\/td>\n | 5.3 Performance during frequency variations 6 Functional test methodology 6.1 General Tables Table 1 \u2013 Limiting error as multiples of assigned error <\/td>\n<\/tr>\n | ||||||
| 21<\/td>\n | 6.2 Determination of steady-state errors related to the operating current value 6.3 Determination of steady-state errors related to the characteristic quantity and the operate time 6.3.1 Accuracy determination of the cold curve <\/td>\n<\/tr>\n | ||||||
| 22<\/td>\n | 6.3.2 Accuracy determination of the hot curves Table 2 \u2013 Test points of the cold curve <\/td>\n<\/tr>\n | ||||||
| 23<\/td>\n | 6.4 Performance with specific cooling thermal time constant Table 3 \u2013 Test points of the hot curve <\/td>\n<\/tr>\n | ||||||
| 24<\/td>\n | 6.5 Performance with harmonics 6.6 Performance during frequency variations Table 4 \u2013 Test points of the cold curve with harmonics Table 5 \u2013 Test points of the cold curve during frequency variations <\/td>\n<\/tr>\n | ||||||
| 25<\/td>\n | 6.7 Performance during different ambient temperatures <\/td>\n<\/tr>\n | ||||||
| 26<\/td>\n | 7 Documentation requirements 7.1 Type test report 7.2 Other user documentation <\/td>\n<\/tr>\n | ||||||
| 28<\/td>\n | Annex A (informative) Simple first-order thermal model of electrical equipment Figure\u00a0A.1 \u2013 An electrical equipment to be thermally protected represented as a simple first-order thermal system <\/td>\n<\/tr>\n | ||||||
| 32<\/td>\n | Figure A.2 \u2013 Equivalence between a first-order thermal systemand an electric parallel RC circuit Table A.1 \u2013 Thermal and electrical models <\/td>\n<\/tr>\n | ||||||
| 33<\/td>\n | Figure\u00a0A.3\u00a0\u2013\u00a0Analogue thermal circuit representationof a simple first-order thermal system Figure\u00a0A.4\u00a0\u2013\u00a0Analogue thermal circuit representation of a simple first-orderthermal system \u2013 motor starting condition Figure\u00a0A.5\u00a0\u2013\u00a0Analogue thermal circuit representation of a simple first-orderthermal system \u2013 motor stopped condition <\/td>\n<\/tr>\n | ||||||
| 35<\/td>\n | Figure\u00a0A.6 \u2013 Dynamic step response of a simple first-order thermalsystem algorithm to a current below pickup <\/td>\n<\/tr>\n | ||||||
| 36<\/td>\n | Figure\u00a0A.7 \u2013 Dynamic step response of a first-order thermal system (cold initial state) Figure\u00a0A.8 \u2013 Dynamic step response of a first-order thermal system (hot initial state) <\/td>\n<\/tr>\n | ||||||
| 37<\/td>\n | Figure\u00a0A.9 \u2013 Dynamic step response of a first-order thermal system to a load current followed by an overload current (initial state: cold) Figure\u00a0A.10 \u2013 Dynamic step response of a first-order thermal system to a load current followed by an overload current (initial state: hot) <\/td>\n<\/tr>\n | ||||||
| 42<\/td>\n | Table A.2 \u2013 Thermal insulation classes and maximum temperatures,according to IEC\u00a060085 Table A.3 \u2013 Example of correction factor values (Fa) for class F equipment according to the ambient temperature (Ta) <\/td>\n<\/tr>\n | ||||||
| 43<\/td>\n | Annex B (informative) Thermal electrical relays which use temperature as setting parameters <\/td>\n<\/tr>\n | ||||||
| 48<\/td>\n | Bibliography <\/td>\n<\/tr>\n<\/table>\n","protected":false},"excerpt":{"rendered":" Measuring relays and protection equipment – Functional requirements for thermal electrical relays<\/b><\/p>\n |