L X---Cable zero-sequence current transformerD---Single-phase K---Drop type –φ80 φ240---Transformer ID Third, the structure profile The current transformer to the drop type, cast resin structures, installation of transformers can be divided into two halves, bottles and cables into one. Installation is extremely easy. Fourth, technical parameters 1, this series of zero-sequence current transformer insulation from the cable to ensure a primary, secondary windings are only examined the insulation performance of secondary winding can withstand the power frequency withstand voltage 3 kV. 2, rated current ratio, accuracy class, rated output shown in Table 1. 3, when used with the relay supporting this type a zero sequence current transformer to meet the requirements of Table 2: Table 1 Rated current ratio (A)Accuracy classRated output (VA) 60-75/110P101100/11.5150/12.5200/13.75300/1 600/15150-200/52.5300-400/55500/57.5600/510Table 2Relay ModelRelay coil connectionRelay scale value A zero sequence current (A)Rated current ratio(A)DD-11/60Series15×1 30×12 560/1In parallel15×2 30×2DD-1/60Series15×1 30×12 6In parallel15×2 30×2 v c