Busbar parts that do not require busbar thermal and electrodynamic effects verification
(1) Adopt fuse protection and connect to the bus bar under the fuse (except current-limiting fuse).
(2) Busbar in voltage transformer circuit.
5.3 A few points to note
(1) According to the provisions of GB3906-1991, the minimum current-carrying capacity of busbars in switchgear and control equipment should have a margin of 10% relative to the rated current.
(2) Under normal circumstances, considering the heat dissipation and increasing the load capacity for the future, the main bus bar in the design drawing is generally larger. At this time, it should be manufactured in strict accordance with the drawing, and the bus bar specifications cannot be reduced at will.
(3) Choose a model with a larger bus width for the same cross-sectional area as much as possible. If you can choose TMY80×6 but not TMY60×8, it is mainly conducive to heat dissipation.
(4) When the operating environment temperature of the switchgear and control equipment is slightly higher than the specified temperature, it is necessary to fully consider whether the current carrying capacity of the bus is sufficient.
GB311.1-1997 "Insulation Coordination of High Voltage Transmission and Transformation Equipment" stipulates:
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When the temperature is higher than 40℃, the rated insulation voltage should be multiplied by the temperature correction coefficient Kt=1+0.0033(T-40);
General: Each increase in ambient temperature by 3°C increases the test voltage by 3%. When the ambient temperature increases by 1°C, the rated current should be reduced by 1.8%.