Tag: line reactor

One of the other manufacturing reasons for the high noise of the reactor lies in the insufficient clamp force of the iron core. The low iron core fastening force will increase the operation noise of the reactor. As the experience indicates, when the pressure intensity of the iron core clamp force is 0.8~1.2MPa, the noise of the reactor is the lowest. In addition to this, the compression screw and clamp nut of the iron core sheet should be equipped with an additional lock net, preventing from the looseness of the nut caused by the vibration of the iron core sheet in operation, so as to result in the high noise degree.

Reactor is used to maintain the current and stabilize the voltage of the electrical system. The reactor adopted in the power grid is substantially a hollow coil without the permeability magnetic material. It can be arranged in vertical, horizontal and stagger assembling forms as the demand. When the electrical system has short circuit, the short-circuit current with high values will be generated. If it is not restricted, it is very difficult to maintain the dynamic stability and thermal stability of the electrical equipment. Therefore, in order to satisfy the interrupting capacity requirement of some disconnectors, reactors are usually connected in the outgoing breaker in series, so as to increase the short-circuit impedance and limit the short-circuit current.

The main function of DC reactor is to reduce the higher harmonic components of the input current, improve the power factors of the input power source, and limit the short-circuit current. Before the DC reactor is connected with the filter capacitor, it hinders the impulse current amplitude entering the capacitor, and reduces the AC impulse of the busbar. When the power of the frequency converter is higher than 22kW, it is suggested to consider the application of DC reactor. The greater the power of the converter is, there should be a higher possibility of using the reactor. Because when there is no DC reactor, the capacitor filtering of the frequency converter will result in the serious distortion of the current wave, thus further causing the serious distortion of the network voltage waveform. In addition, it is very harmful to the service life of the rectifier bridge and filter capacitor of the frequency converter.

A conductor will produce magnetic field in a certain range of space it occupies when it's powered on, so all electric conductors carrying current are inductive on a general sense. However, a long straight conductor often generates a small inductance, the generated magnetic field is not strong, so the actual line reactor is a wire wound solenoid, which is also called air core line reactor. Sometimes an iron core would be inserted into the solenoid to generate greater inductance, which is called iron core line reactor. Reactance is divided into inductive reactance and capacitive reactance, in the more scientific division, both impedor (inductor) and reactance (capacitor) are called line reactor. However, as inductor appeared earlier and was called line reactor, the capacitor people often say only refers to the reactance, and line reactor refers specifically to the inductor. Main function of three-phase output line reactor is to compensate the influence of long line distributed capacitance, restrict the output of harmonic current and improve output high frequency impedance, thus protecting the inverter.

The vibration frequency of body is not in line with that of grading ring. Owing to the damping of transformer oil, grading ring has a low vibration frequency. And owing to single point welding and aluminum sheet welding, it has a poor mechanical strength. In the long-term operation, the vibration brought by the inconsistent vibration frequency of earth tag of line reactor (aluminum, welding) and grading ring causes metal fatigue and cracks. Solution: fix ascending flange base and body to reduce free-running vibration.

Oil replacement and drying treatment of electric reactor: if the long idle time or operation time or other nature and human factors cause insulation deterioration of line reactor, water inflow or oil deterioration, oil replacement and drying treatment should be conducted to line reactor. Oil replacement of line reactor: lift the body of line reactor out, drain sump oil, wash oil tank, and wash the greasy dirt on the body of electric reactor if any. After drying, fill electric reactor with oil and replace all grease-proof rubber seals. Theline reactor can be operated only after passing the test.
Drying treatment of line reactor: its body has many drying methods. Users can adopt zero phase sequence drying method, eddy drying method, short circuit drying method and oven drying method when they dry line reactor by themselves.

The functions of input line reactor
It can restrain harmonic current, improve power coefficient, weaken surge voltage in input circuit, the impact of current on VFD, the influences of power voltage, limit current surge caused by grid voltage change and switching surge, spike pulse or voltage defects in phase change of rectifying circuit, effectively protect VFD and improve power coefficient. Input line reactor not only can stop the disturbance from power grid but reduce the pollution of power grid by harmonic current produced by rectifying unit.