When zero sequence current transformer produces zero sequence ground current in the power system, it can cooperate with the relay protection device or signal to make the device components act and realize protection or monitoring.
The zero-sequence current transformer is a single-turn through-core current transformer, which is generally used for supporting power protection equipment such as: small current grounding line selection device, computer harmonic elimination device, etc.
When an electric shock or leakage fault occurs in the circuit, the secondary side of the transformer outputs a zero-sequence current to make the equipment protection action on the connected secondary line (cut off the power supply, alarm, etc.).
Use environment
Ambient temperature: -10ºC ~ 40ºC · Atmospheric pressure: 80 ~ 110KPa
Air relative humidity: 90% (25ºC), 50% (40ºC)
Protection principle
The specific application of zero-sequence current protection can install a current transformer (CT) on each of the three-phase lines, or let the three-phase wires pass through a zero-sequence CT together, or install a zero-sequence CT on the neutral line N, using These C.T are used to detect the three-phase current vector sum, that is, the zero-sequence current Io, IA+IB+IC=Io, when the three-phase load connected to the line is completely balanced (no ground fault, and regardless of the line and electrical equipment) Leakage current), Io=0; when the three-phase load connected to the line is unbalanced, then Io=IN, the zero-sequence current at this time is the unbalanced current IN; when a ground fault occurs in a certain phase, a single The phase-to-ground fault current Id, the zero-sequence current IO=IN+Id detected at this time is the vector sum of the three-phase unbalanced current and the single-phase ground current.
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