Application of low voltage shunt and series reactors

The primary influence of the series reactor is to restrain the high-order harmonic and limit the switching inrush current, to avoid the risk of harmonic to the capacitor, and to prevent the connection of the capacitor assembly from excessively amplifying and harmonizing the harmonic of the power grid.

The shunt reactor is usually connected between the end of UHV transmission line and the ground to compensate reactive power. A reactor connected in parallel to a grid to compensate for capacitive current. The reactor for full load test of generator is the prototype of shunt reactor. Because of the attraction of alternating magnetic field between the segmented dead center cakes, the dead center reactor is usually more noisy than the transformer of the same capacity and quality by more than 10dB. The reactors in 220kV, 110KV, 35kV and 10kV power grids are used to receive the charging capacitive reactive power of cable lines. The operation voltage can be adjusted by adjusting the number of shunt reactors.

UHV shunt reactors have various functions related to the operation of reactive power in the improved power system, including:

1、 The reactive power in the line under light load should be balanced on the spot as much as possible to avoid reactive power bifurcation and reduce the power loss on the line.

2、 Improve voltage distribution on long transmission lines.

3、 When the large unit and the system are parallel, the power frequency steady-state voltage on the high-voltage bus will be lowered, which is convenient for the generator to be parallel in the same period.

4、 Avoid the self excitation resonance sign of generator with long line.

5、 When the neutral point of the reactor is assembled through the small reactance grounding, the small reactor can also be used to compensate the phase to phase and phase to ground capacitance of the line, so as to speed up the active extinguishing of the potential supply current and facilitate the adoption.

6、 Capacitance effect on light no-load or light load lines to reduce power frequency transient overvoltage. For EHV long distance transmission lines, the charging power of the line capacitance is very large when the shunt reactor is no-load or light load. Generally, the charging power increases sharply with the square of the voltage, and the huge charging power will not only cause the above-mentioned signs of power frequency voltage reduction, but also increase the power and power consumption of the line, cause self excitation, and the same period of difficulties. The installation of shunt reactors can compensate for the charging power of this sector.