A method and device for calculating the overvoltage phase of the DC blocking sending end power grid considering the influence of the condenser

Abstract

The present invention provides a method and device for calculating the overvoltage stage of a DC blocking sending-end power grid considering the influence of the regulator. The method includes: Step 1. According to the DC control and protection information, it is judged that the fault of the power grid is a fault of the AC system of the receiving end or a fault of the DC system , if the AC system at the receiving end is faulty, go to step 2, and if the DC system is faulty, go to step 3; step 2, determine whether the safety device is shut down according to the time of the safety device shutdown, and determine whether the safety device is cut off after the DC block due to the fault of the receiving end AC system The overvoltage calculation model before the machine and the overvoltage calculation model after the shutdown; step 3, determine whether the safety device is cut off according to the shutdown time of the safety device, and determine the overvoltage calculation model and the Calculation model of overvoltage after shutdown. The invention realizes the theoretical analysis of the overvoltage at the sending end under the DC blocking working condition, and provides guidance for the structure optimization and operation mode adjustment of the sending end power grid.

Description

technical field [0001] The invention relates to the technical field of power systems, in particular to a method and device for calculating the overvoltage stage of a DC blocking sending end power grid considering the influence of a condenser. Background technique [0002] With the continuous completion and commissioning of DC projects in my country, the problem of "strong DC and weak AC" of power grid companies has become increasingly prominent, and higher demands have been put forward for dynamic reactive power support of power grids. To this end, the State Grid Corporation of China has built a batch of large-scale condensers in the UHV converter station to improve the system voltage stability. For the sending-end power grid, the UHV large-capacity DC block may cause the transient overvoltage problem of the sending-end AC power grid, which may lead to large-scale off-grid of the sending-end wind turbines in severe cases. The access of a new generation of condensers may eff...

AI Technical Summary

Problems solved by technology

For the sending-end power grid, the UHV large-capacity DC block may cause the transient overvoltage problem of the sending-end AC power grid, which may lead to large-scale off-grid of sending-end wind turbines

The access of a new generation of condensers may effectively suppress the overvoltage level at the sending end, but the existing research on its impact on the overvoltage at the sending end lacks relevant analysis, especially when the safety control system cut-off and DC blocking at the sending end occur at the same time, the Multiple overvoltage phenomena may occur, and it is urgent to evaluate the research of the regulator on the stable overvoltage level of the sending end, so as to provide guidance for the configuration of the reactive power compensation device of the sending end power grid and the calculation of the system operation mode.

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