A three-stage control strategy for back-to-back converter stations

A control strategy and converter station technology, applied to AC network circuits, power transmission AC networks, circuit devices, etc., can solve the problems of large difference in frequency response capabilities, low-frequency load shedding, etc., and achieve accurate power boosting capabilities, rich capabilities and means, the effect of improving stability and reliability

Active Publication Date: 2022-04-08
DALIAN UNIV OF TECH
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Problems solved by technology

[0003] For the DC asynchronous interconnection grid, the frequency response capabilities of the grids with different installed scales at both ends are very different and they operate independently. The probability of the frequency before and after the fault is at a low level increases, and low-frequency load shedding is prone to occur.

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  • A three-stage control strategy for back-to-back converter stations
  • A three-stage control strategy for back-to-back converter stations
  • A three-stage control strategy for back-to-back converter stations

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Embodiment Construction

[0040] The present invention will be further described below in conjunction with the accompanying drawings and specific implementation, but it is not intended as a limitation of the present invention.

[0041] An active control strategy for a back-to-back DC interconnection system under high power loss, the strategy includes:

[0042] Step 1: Establish a two-area three-unit model of the back-to-back DC interconnection system, and its structure diagram is as follows figure 1 As shown, the power system is divided into two research systems, research system 1 is the disturbance occurrence area, research system 2 is the non-disturbance occurrence area, research system 1 is further divided into subsystem A and subsystem B, and the disturbance occurrence area The internal subsystem A and subsystem B are connected through the AC tie line. The back-to-back converter station is used as the HVDC tie line of the research system at both ends of the weak connection. One end of the back-to-b...

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Abstract

A three-stage control strategy for back-to-back converter stations is applied to the interconnected large power grid of back-to-back DC projects. Considering the spatial distribution and geographical location of the AC system at both ends of the back-to-back converter station, a two-region three-unit model is established. Model the back-to-back DC system in the two-area three-unit model, where the back-to-back DC system includes the modeling of the back-to-back converter station and the modeling of the DC additional controller; divide the frequency response stage according to the different attribute characteristics of the frequency response stage after being disturbed Three different stages, and implement the active control strategy based on the model predictive controller, the active control strategy based on the ladder controller and the passive control strategy based on the PI controller for the three stages. Through the rapid controllability of the back-to-back direct current transmission system, the present invention quickly transmits direct current power from the non-disturbed area to the disturbed area, effectively intercepts the downward trend of the frequency, and realizes the redistribution of the power deficit.

Description

technical field [0001] The invention belongs to the field of power grid frequency stability control, and relates to a three-stage control strategy for back-to-back converter stations. Background technique [0002] In recent years, the energy interaction of the power system has become more and more close. UHV transmission projects have fast and flexible transmission, low line loss, and low land occupation costs. DC mode change. Compared with the AC interconnection grid, the DC transmission project does not have the stability problem of AC transmission, which is conducive to long-distance large-scale power transmission; realizes asynchronous networking between power systems, which is conducive to the sharing of spare capacity between regions; implements fast and accurate frequency response The control strategy is beneficial to the power support of the non-disturbed area after the disturbance to the disturbed area and the frequency adjustment capability of the opposite end. A...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H02J3/36H02J3/24
CPCH02J3/36H02J3/241H02J2003/365Y02E60/60
Inventor 李卫东吴限李梓锋
Owner DALIAN UNIV OF TECH
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