07
2022
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02
Using SVR line automatic voltage regulator to solve the low voltage problem of 10kV line
Author:
In view of the "low voltage" problem of rural power grid lines, the current countermeasures are mainly as follows: new conductor cross-sectional area; Adjust the substation main transformer tap to change the system voltage; Reasonable distribution of reactive power compensation equipment in the system to improve the reactive power flow distribution of the power grid; Transform the line to increase the load of the pumping station; Increase the number of outgoing lines in the substation to share the load of the original line. The above-mentioned measures have the following problems.
The construction period of new substation is long, and the investment cost is huge and the effect is slow. Adjust the tap of the main transformer of the substation to limit the voltage of 10kV bus within a certain range to meet the requirements of voltage deviation within the radius. As the bus of the substation has multiple outgoing lines, the load curve of each outgoing line is different, and the voltage drop is also different, which cannot guarantee that the voltage of all lines meets the requirements. Therefore, the flexibility and pertinence of this voltage regulation method are poor. When the lines are complicated, the voltage near the substation is often high, low voltage far away from the substation.
The use of reactive power compensation is mainly to improve the power factor of the line, and the effect of voltage regulation is limited. Only relying on capacitor compensation can not solve the problem of voltage reduction caused by long line, thin line diameter and resistance.
Measures such as increasing substation transformers and new lines are used as a permanent cure, but the investment is large and the construction period is long.
In the case of limited funds for rural power network transformation, in order to better and faster solve the problem of low voltage at the end of 10kV long line in rural power network, in order to improve the voltage quality of long line.
The SVR line automatic voltage regulator can automatically adjust the gear of the on-load tap changer according to the condition of the line voltage to realize the change of the node ratio, so as to ensure that the output voltage is stable within a certain range. It can be widely used in the power supply distance is relatively far, the power supply load is large, the voltage fluctuation is large, the power quality is not up to the use of the standard power supply line.
SVR line automatic voltage regulator consists of three parts: autotransformer, on-load tap-changer and automatic controller.
The whole coil of autotransformer is divided into three parts: series coil, shunt coil and control coil. The series coil is a winding with multiple taps. These taps are connected in series between the input and output through different wires of the on-load tap changer to change the tap position, thereby changing the ratio of the autotransformer to achieve the purpose of adjusting the voltage; The shunt coil is the common winding of the autotransformer and generates a magnetic field that transfers energy; the control coil provides working power and sampling signals for the controller.
An on-load tap changer is a switch that can switch nodes under load. In the automatic voltage regulator, the taps of the series windings are connected to different nodes of the on-load tap changer, and the output voltage can be changed by adjusting the transformer ratio through the conversion node. Considering the service life of the on-load tap-changer and the user's voltage regulation accuracy requirements, the gears of the commonly used on-load tap-changer are 7 and 9 gears.
The automatic controller is the core part of the whole device, which is mainly composed of single-chip microcomputer control chip, display circuit, key circuit, voltage sampling, current sampling, state input, communication port, control output circuit, data storage and other circuits. By collecting the load side voltage and current signals and comparing with the set value, the automatic controller sends out instructions to control the load tap for voltage regulation operation.
For rural areas where there is no room for load growth and there is no power distribution of 35kV and above, the SVR line automatic voltage regulator has a more significant effect on the "low voltage" problem caused by the long power supply radius and small wire diameter of the line. Compared with the new substation and the transformation of the line, it saves a lot of money and has good economic and social benefits. For some rural areas with large capacitive load (with rural structure), with the addition of reactive power compensation device on the column, the "low voltage" treatment effect is better.
Low voltage,Wire,Substation
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