Zero phase current transformer

When the power system generates zero-sequence grounding current, the zero-sequence current transformer is used in conjunction with the relay protection device or signal to activate the device components to achieve protection or monitoring.   The specific application of zero-sequence current protection can be to install a current transformer (CT) on each of the three-phase lines, or to let the three-phase conductors pass through a zero-sequence CT together, or to install a zero-sequence CT on the neutral line N, and use these CTs to detect the current vector sum of the three phases, that is, the zero-sequence current Io, IA+IB+IC=Io. When the three-phase load connected to the line is completely balanced (no grounding fault, and the leakage current of the line and electrical equipment is not considered), Io=0; when the three-phase load connected to the line is unbalanced, Io=IN, and the zero-sequence current at this time is the unbalanced current IN; when a grounding fault occurs in one phase, a single-phase grounding fault current Id will inevitably be generated. At this time, the zero-sequence current IO=IN+Id detected is the vector sum of the three-phase unbalanced current and the single-phase grounding current.   The installation of the integral transformer should be carried out before laying the cable, and the cable should pass through the transformer during laying.   The split core current transformer is not restricted by whether the cable is laid or not. The specific method is as follows: (1) Remove the connecting pressure plates of the transformer "K1ˊ" and "K2ˊ" (this requirement is not applicable to circular transformers).   (2) Loosen and remove the two hexagon socket bolts on the top of the transformer (loosen and remove the fastening screws on both sides of the circular transformer), and the transformer will be divided into two parts.   (3) Put the transformer on the cable, wipe the contact surface clean, apply a thin layer of anti-rust oil, align the two parts of the transformer, and tighten the hexagon socket bolts (fastening screws on both sides). The two parts of the transformer should be aligned to avoid affecting the performance.   (4) Fix the connecting plate on "K1ˊ" and "K2ˊ" (this requirement is not applicable to circular transformers).   (5) When installing a transformer with an inner hole > 120 mm horizontally, please add a non-magnetic bracket.