A system and method for unbalanced voltage regulation based on flexible current source

Abstract

The invention discloses an unbalanced voltage adjustment system and method based on a flexible current source, comprising a three-phase unbalanced adjustment device and a flexible current source; The current and gear information of the arc suppression coil, the three-phase unbalance adjustment device calculates the adjustment current by measuring the current and gear information before and after the adjustment of the arc suppression coil, and sends a control signal to the flexible current source through the output terminal; the flexible current source receives The control signal outputs a specific current vector. The invention controls the unbalanced neutral point voltage to ground to zero, which can reduce the problem of excessive grounding short-circuit current caused by excessive compensation of the arc suppression coil caused by the unbalanced three-phase voltage, and greatly improve the reliability of the power grid. sex and safety. In the adjustment process, the arc-suppression coil is used to adjust the gear to change the current of the arc-suppression coil, which has a very low impact on the operation of the power grid.

Description

technical field [0001] The invention relates to an unbalanced voltage regulation system and method based on a flexible current source, which is applied to a low-current grounding system and belongs to the field of relay protection of power systems. Background technique [0002] In the 3kV-66kV low-current grounding system, some lines do not have reasonable phase commutation in the early stage of construction, resulting in inconsistent three-phase-to-ground capacitance values, resulting in three-phase unbalanced voltage. The three-phase unbalanced voltage requires a high compensation degree for the arc suppression coil, but this will lead to an excessively large regulated current when a single-phase ground fault occurs, endangering the safety of the power grid. If the device is used for adjustment to eliminate the three-phase unbalanced voltage during normal operation, the neutral point arc suppression coil can adopt a smaller compensation degree, thereby improving the stabil...

AI Technical Summary

Problems solved by technology

[0002] In the 3kV-66kV low-current grounding system, there are some lines because there is no reasonable commutation in the early stage of construction, resulting in inconsistent capacitance values ​​of the three phases and grounding, thereby generating unbalanced voltage of the three phases

The three-phase unbalanced voltage requires a high compensation degree of the arc suppression coil, but this will cause the regulation current to be too large when a single-phase ground fault occurs, endangering the safety of the power grid

The size of the injected current needs to be calculated according to the network parameters. In actual operation, the operation mode changes in real time as the line is switched on. The controller cannot accurately obtain the change of the grid parameters. Therefore, the calculation of this method is complicated, and it cannot adapt to the change of the operation mode to achieve a complete compensation effect.

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