Identification of the three-phase transformer

Three-phase transformers are widely used in various electrical devices and the AC power applications, where the high and low voltage windings there are many different ways of coupling. Different winding connection mode not only cause the circuit structure is different, but related to the amount of harmonic electromagnetic transformer parallel operation issues and other issues. To do this, you must understand the connection method and the three-phase winding mcb circuit breaker. China now the International Electrotechnical Commission (IEC) standard recommended that, according to high and low pressure line EMF phase to determine the three-phase transformer connected group label. When the three-phase transformer high and low voltage winding connection mode is not the same, and its primary and secondary sideline potential have different phase. The same with the primary and secondary threads is always the potential phase integer multiple of 30 degrees, so the international identification notation are used clock high and low voltage winding of the phase relationship. The so-called clock notation that the original clock edges as Electric energy meter, always pointing to 0:00 (or 12:00) as the clock Vice sideline potential short hand, they point to the part-time as a joint group label. Specific approach is to first transformer for each letter symbols marked on the outlet side to the A-phase, for example, the high voltage winding head-end labeled as A, end labeled X, low-voltage winding head end labeled a, end labeled x. each winding potentials are defined as from the first end point to the end, the high voltage winding of the electric potential from the A point X, the low Circuit breaker of the electric potential from a point x. electric potential relative to the amount of the head and tail with the actual winding beginning and end is the opposite, winding X, Y, Z into a common point of termination, in fact, the amount of the electric potential relative to the head end of the starting point, the electric potential relative to the common point of the amount of the arrow. Every analysis of a group, we must draw a phasor diagram. If the amount of the electric potential phase switching voltage phasors, voltage phasor and the actual beginning and end of the winding head and tail is the same, the winding X, Y, Z into a common termination point is actually the end of voltage phasors point, the voltage phasors arrow out, so that the amount of the voltage phase can be X, Y, Z connected to the common point of rotation, each time a group is determined, only the phase rotation corresponding to the amount of voltage can, without then draw phasor diagram.