Crowbar/Chopper Resistor
█ Application
Crowbar resistor is mainly used in low voltage ride through technology of wind power inverter. It is used at the rotor side of wind turbine generator to bypass the rotor side converter. In case of low voltage disturbance in the power grid, the DC bus voltage and rotor current shall be prevented from being too high. It mainly works in fault state to damp stator flux linkage. Crowbar resistors can dissipate huge amounts of energy instantaneously.
It is mainly used in the frequency conversion / converter system of doubly fed variable speed constant frequency generator units to improve the low voltage ride through capability of generator units, which is limited by the power grid
Large current impact caused by voltage drop protects excitation converter and limits rotor winding over voltage.
█ Feature：
The resistance material is imported alloy steel, which can absorb large energy impact in a short time, and can meet different power requirements.
█ structures：
Mica sandwich structure, traditional metal carrier grid structure and block carrier structure:
1. mica sandwich structure, with small volume, low cost and large heat capacity, is suitable for absorbing large energy in a short time and for single impact at long intervals (once a week).
2. with the traditional metal grid structure, the product has relatively moderate volume, relatively moderate cost and good heat dissipation performance. It is suitable for multiple impacts in a short time (once every 30 minutes). It can be used in crowbar resistor, chopper resistor and braking resistor circuits.
3. block carrier structure, the product has strong impact resistance and good heat dissipation performance. High structural strength and moderate price. Suitable for short-time multiple impact. It can be applied to crowbar resistor, chopper resistor, braking resistor and other circuits.
█ Life Time of Crowbar Resistor
| 200J | 1 times/second | |
| 220KJ | 1 times/30mins | 35000 times（20 years of life） |
| 640KJ | 1 times/week | 1000 times（20 years of life） |
| 1360KJ | 1 times/month | 260 times（20 years of life） |
| Take 1.5MW windmill generator as an example, environment temperature ≤ 60℃ | ||
█ Resistor Material Comparison
|
Material |
（g/mm3） |
（Ω·mm2/m） |
J/(g·K) |
W/(m·K) |
ppm/℃ |
|
SUS304 |
7.9 |
0.72 |
0.5 |
13.2 |
≤1400 |
|
SUS316 |
7.93 |
0.78 |
0.45 |
13.23 |
≤900 |
|
SUS310S |
7.98 |
0.88 |
0.46 |
13.2 |
≤600 |
|
Cr20Ni80 |
8.4 |
1.09 |
0.441 |
16 |
≤100 |
█ Selection Table
|
Energy |
Resistance |
Time |
Dimension（mm） |
||
|
（L）mm |
(W)mm |
(H)mm |
|||
|
50KJ |
3R |
30mS |
420 |
160 |
95 |
|
200KJ |
2R |
3.8S |
285 |
178 |
150 |
|
500KJ |
3.3R |
3.8S |
670 |
150 |
150 |
|
1.0MJ |
0.36R |
0.1S |
395 |
190 |
153 |
|
1.5MJ |
0.45R |
3S |
520 |
292 |
100 |
|
2.0MJ |
0.4R |
30mS |
868 |
175 |
130 |
|
2.0MJ |
0.5R |
30mS |
943 |
195 |
135 |
|
2.2MJ |
0.7R |
1S |
446 |
240 |
153 |
|
2.5MJ |
0.95R |
3S |
597 |
400 |
200 |
|
3.0MJ |
0.7R |
1S |
432 |
240 |
153 |
Note: For other technical parameters & requirements， please contact with our company's business man.
