Coordinated voltage control method and device for multiple reactive power compensation devices in DC transmission system

Abstract

The invention discloses a coordinated voltage control method and device of multiple reactive power compensation devices in a direct current transmission system, including: if the current AC bus voltage is greater than the AC bus voltage threshold, then according to the U-I characteristic slope of each reactive power compensation device Ratio, current AC bus voltage and AC bus voltage threshold, assign corresponding first reactive power compensation capacity to each reactive power compensation device; if the sum of all first reactive power compensation capacities is greater than the compensation capacity threshold, and the current input When the cut filter bank is the minimum filter bank and the current AC bus voltage is greater than the AC bus voltage threshold, assign the corresponding second reactive power compensation capacity to each reactive power compensation device; if all the second reactive power compensation capacity If the sum is greater than the compensation capacity threshold, the minimum reactive power control method is used; the invention controls the cooperative voltage of various reactive power compensation devices, maintains the AC bus voltage within a certain range, and improves the stability of the system.

Description

technical field [0001] The invention relates to the technical field of power transmission and distribution, in particular to a method and device for coordinated voltage control of multiple reactive power compensation devices in a DC power transmission system. Background technique [0002] The HVDC transmission system needs to consume a large amount of reactive power while transmitting active power. Therefore, the conventional DC system needs to be equipped with a certain number of AC filters, high-voltage capacitors, low-voltage capacitors or reactors to compensate the system while filtering out system harmonics. However, the above-mentioned reactive power compensation device adopts the method of mechanical switching, and the action time is s level. When the system has low load, overload or fault, the mechanical switch is too late to act, and the change of active power will inevitably cause The reactive power fluctuation of the system is likely to lead to voltage instability...

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Problems solved by technology

[0002] The HVDC transmission system needs to consume a large amount of reactive power while transmitting active power. Therefore, the conventional DC system needs to be equipped with a certain number of AC filters, high-voltage capacitors, low-voltage capacitors or reactors to compensate the system while filtering out system harmonics. However, the above-mentioned reactive power compensation device adopts the method of mechanical switching, and the action time is s level. When the system has low load, overload or fault, the mechanical switch is too late to act, and the change of active power will inevitably cause The reactive power fluctuation of the system may lead to voltage instability, which seriously restricts the safe and stable operation of the AC and DC system

[0003] In the prior art, the reactive power compensation device of the switched virtual circuit (SVC) or static synchronous compensator (STATCOM) is used in the DC transmission system to compensate the reactive power required by the system. Due to the corresponding regulation of the switched virtual circuit and the static synchronous compensator The means are different, and there is a lack of mutual coordinated control between the exchange virtual circuit and the static synchronous compensator, so that the DC transmission system can only use a single reactive power compensation device, so that the compensation effect of the reactive power required by the system is not good, resulting in Voltage fluctuations, thereby reducing the stability of the DC transmission system

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