Zero sequence current transformer

Power industry used items. Zero sequence current transformer is single-turn feedthrough current transformers, and power protection devices for general use, such as: small current grounding line selection device, harmonic elimination equipment and other ancillary uses.
Outline
Zero sequence current transformer in the power transformers system to produce zero sequence ground current protection devices or signals with the use of the device element action to achieve protection or monitoring.
HS-LJK, HS-LXK series of zero-sequence current transformer is the cable type, using ABS plastic shell, resin pouring sake of sealing; using insulating oil cooling cutting process, effectively avoiding the transformer in the long-term use in the process of corrosion. Good insulation, beautiful appearance.

High sensitivity, good linearity, reliable operation, convenient installation. Its performance is superior to the general zero-sequence current transformer, using a wide range, not only for electromagnetic relay, but also apply to electronic and computer protection device. Users can according to the system

Operation mode, effectively earthed neutral or non-effectively grounded neutral point difference, the choice to adapt to zero-sequence current transformer.
Action
When the circuit breakers in an electric shock or leakage fault, the transformer secondary side output zero-sequence current, so that the connected devices on the secondary circuit protection action (cut off the power, alarms, etc.).
Zero-sequence protection principles
Principle Overview
Zero sequence current protection specific applications can be installed one each on the three-phase line current transformer (CT), or let the three phase wires together through a zero sequence CT, can also be installed on a neutral line N zero sequence CT, the use of These CT to detect the phase current vector and that the zero-sequence current

Io, IA + IB + IC = Io, when the line is connected to the three-phase load on the full balance (without ground fault, and does not consider the lines, electrical equipment leakage current), Io = 0; when the line is connected on the three phase load imbalance, then Io = IN, this time for the zero-sequence current unbalance

Current IN; when one phase ground fault occurs, inevitably produce a single-phase ground fault current Id, at this time the detected zero-sequence current IO = IN + Id, is a three-phase and single-phase unbalanced current vector sum of currents .