A reactive power compensation method to solve the problem of low load reactive power overcompensation and undercompensation

Abstract

The invention discloses a reactive power compensation algorithm for solving low-load reactive power over-compensation and under-compensation problems. When the reactive power is less than or equal tozero, capacitors are cut off from small to large until the reactive power is recovered and an over-compensation state is eliminated; and if all capacitors are not put into practice and the reactive power is still negative, a phase sequence error is determined and wiring has a problem. On the contrary, when the reactive power is greater than zero, if the power factor is in a set range, the system is determined to be normal; otherwise, the capacitors are put from large to small until the current reactive power is less than the minimum capacitance or no capacitor is put, so that a system stable state is realized. Therefore, setting of a reactive upper limit and a reactive lower limit is reduced; whether switching is carried out is determined automatically by the device based on parameters, sothat the automation degree is high; over compensation and under compensation of reactive power on the low-load condition are avoided; and whether the phase sequence is correct is determined automatically and thus a wiring error of a sampling signal is avoided.

Description

technical field [0001] The invention relates to the technical field of reactive power compensation control of electric power systems, in particular to a reactive power compensation method for solving the problem of low-load reactive power overcompensation and undercompensation. Background technique [0002] At present, most reactive power compensation controllers on the market use the power factor as the criterion for switching capacitors, and the input is lower than the set value, and the output is higher than the set value, so as to ensure that the system power factor is within the controllable range. However, when the system is in a low-load state, the power factor may be very low, and a capacitor needs to be added; if the minimum capacitor capacity is still greater than the current reactive power at this time, overcompensation will occur, and the device will cut off the capacitor again, and so on, resulting in oscillation. [0003] In addition, if there is a sampling sig...

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Problems solved by technology

However, when the system is in a low-load state, the power factor may be very low, and a capacitor needs to be added; if the minimum capacitor capacity is still greater than the current reactive power at this time, overcompensation will occur, and the device will cut off the capacitor again, and so on, resulting in oscillation

[0003] In addition, if there is a sampling signal wiring error, an alarm signal cannot be issued.

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