Zero-sequence current transformers are used in conjunction with relay protection devices or signals when zero-sequence ground currents are generated in the power system, so that the device components act to achieve protection or monitoring.
Model Meaning
Protection Principle
The specific application of zero sequence current protection can be installed in each of the three phase lines a current transformer (CT), or let the three phase conductors together through a zero sequence CT, can also be installed on the neutral N a zero sequence CT, the use of these C.T to detect the three phase current vector and, that is, zero sequence current Io, IA + IB + IC = Io, when the three phase load connected to the line is completely balanced (no ground fault, and do not consider Line, electrical equipment leakage current), Io = 0; when the line connected to the three-phase load is unbalanced, then Io = IN, when the zero sequence current for the unbalance current IN; when a phase ground fault occurs, must produce a single-phase ground fault current Id, when the detected zero sequence current IO = IN + Id, is a three-phase unbalance current and single-phase ground current vector sum.
LXK-φ(80, 120, 140, 160, 180, 200, 240, 300)type technical data 1: for residual protection
Transformation ratio (A) | Relay type | Connection type of relay coil | Relay scale value | Primary residual current of relay acting (A) | Weight(kg) |
60/1 | DD-11/60 | Series connection | 15×1 | 2.4-4.5 | 4.5 |
30×1 | |||||
Parallel connection | 15×2 | 3-5 | |||
30×2 | |||||
DD-1/60 | Series connection | 15×1 | 3-5 | ||
30×1 | |||||
Parallel connection | 15×2 | 3-6 | |||
30×2 |
LXK-φ(80, 120, 140, 160, 180, 200, 240, 300) type technical data 2: mating with microcomputer protection
Transformation ratio (A) | Accuracy class | Ratde output (VA) |
60/1 | 5P10 | 1.0 |
75/1 | 1.5 | |
100/1 | 2.5 | |
150/1 | 2.5 | |
200/1 | 3.75 | |
300/1 | 7.5 | |
150/1 | 2.0 | |
200/1 | 2.5 | |
300/1 | 5.0 | |
400/1 | 10.0 | |
500/1 | 12.5 | |
600/1 | 15.0 |
Drawing
Type | ΦD | ΦD1 | H | H1 | L | Φ |
LXK-Φ80 | 165 | 80 | 185 | 85 | 150 | 7 |
LXK-Φ120 | 205 | 120 | 224 | 104 | 150 | 7 |
LXK-Φ140 | 225 | 140 | 244 | 114 | 160 | 9 |
LXK-Φ160 | 243 | 160 | 262 | 123 | 160 | 9 |
LXK-Φ180 | 285 | 180 | 310 | 147 | ||
LXK-Φ200 | 320 | 200 | 339 | 162 | ||
LXK-Φ240 | 383 | 245 | 460 | 248 | 280 | |
LXK-Φ300 | 430 | 305 | 520 | 293 | 350 |