GB/T 18891-2009 Identification by hour numbers of the phase conductors of 3-phase electric systems

Scope

This standard proposes a method of identifying the conductors of three interconnected systems using clock-hour (clock dial) ordinal numbers. The clock-hour ordinal numbers used take any arbitrary origin as the starting point and are based on the phase sequence of the voltage applied to them. The identification system using clock-hour ordinal numbers takes into account the phase shift of the phase voltage vector caused by the connection mode of the windings of the power transformer, but does not consider the phase shift caused by the impedance of the conductors and transformer windings. This is because the impedance varies with the length of the conductors and windings and the connected load, and it does not play any role in the conductor identification system. Therefore, the ordinal numbers of the same conductor are the same along its entire length, and only after the conductor system passes through the transformer will the ordinal numbers change. For a given transformer, the change in clock-hour ordinal numbers is constant, indicating that the position of the voltage vector at the transformer's no-load condition has changed.

Development Information

Replace the following standards

Superseded by the following standards

Adopt standards

Related Standards