Selection of equipment and instruments for low-voltage reactive power compensation capacitor cabinet

issuing time:2021-05-25
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Many friends who do electrical design are not clear about the choice of switchgear for the capacitor compensation cabinet in the low-voltage power distribution system diagram. Today I will analyze with you the selection of equipment and instruments for low-voltage reactive power compensation capacitor cabinets.
 
The selection of equipment and instruments for low-voltage reactive power compensation capacitor cabinets is
 
 
based on the relevant regulations of GB50053-2013 "Code for Design of Substations of 20kV and Below":
 
1) Steady-state overcurrent of electrical appliances and conductors of the total circuit and group circuit of the shunt capacitor device It should be 1.35 times the rated current of the capacitor bank;
 
2) The allowable current of a single capacitor conductor should not be less than 1.5 times the rated current of a single capacitor.
 
Case study:
 
The compensation capacity of a 1000kVA transformer is a 30x10=300kvar compensation cabinet.
 
1) The calculated current of the main circuit is 433A. According to the requirements of the above specification, the coefficient that needs to be multiplied by 1.35 is 584A, and 630A is required. Load switch + fuse set, equipped with a 600A meter (multiplied by 1.5, the coefficient is 650A, whichever is close to the gear specification).
 
2) The calculated current of each grouping circuit is 43A, and the factor that needs to be multiplied by 1.5 is 64A, so the 63A fuse is appropriate.