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Method for island starting of flexible direct current power transmission system

A power transmission system, flexible DC technology, applied in AC network circuits, output power conversion devices, electrical components, etc., can solve problems such as passive start-up of flexible DC systems, to avoid high-frequency components and distortion, and avoid shocks and disturbances Effect

Active Publication Date: 2017-07-14
NR ELECTRIC CO LTD +1
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Problems solved by technology

[0004] Therefore, it is necessary to find a start-up method suitable for island control without disturbance and impact, so as to solve the problem of passive start-up of the flexible DC system when the island AC power grid loses power

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  • Method for island starting of flexible direct current power transmission system
  • Method for island starting of flexible direct current power transmission system
  • Method for island starting of flexible direct current power transmission system

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Embodiment Construction

[0020] The technical solutions of the present invention will be described in detail below in conjunction with the accompanying drawings and specific embodiments. The schematic diagram of the flexible DC transmission system is as follows: figure 1 shown in figure 2 The steps shown are for island start-up, and the reference wave output for island start-up is divided into two stages of output, that is, N=2.

[0021] (1) When the converter station is unlocked in island mode, the voltage reference wave starts from 0kv, and at the same time, assume that the rated voltage is 119.5kV; to avoid excessive sampling voltage and current errors and harmonic content when the output voltage reference wave is small adverse effects on the control system;

[0022] (2) Start the first stage, the rising rate of the voltage reference wave amplitude is set to 1195kV / s, α=1195;

[0023] (3) When the effective value of the voltage output is 23.9kV, start the second stage, the rising rate is change...

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Abstract

The present invention discloses a method for island starting of a flexible direct current power transmission system. When there is no alternating power supply in an alternating current network area connected with a flexible direct current convertor station, the flexible direct current convertor station needs to be started for operation in the island mode. The island mode employs double closed loop control, an outer ring controls to output voltage amplitude and frequency, and an inner ring controls to output current. When island starting, the size of the voltage reference wave output amplitude generated by a flexible direct current transmission control and protection system employs a section mode, a first reference wave amplitude starts from zero or a certain value Ux and is rapidly increased to UakV according to a rate of [Alpha] kV / s to avoid the unfavorable influences of too big sampling voltage and current errors and harmonic content on the control system when the output voltage reference wave is small; and a second reference wave amplitude increases to UbkV according to a rate of [Beta]kV / s, and a third reference wave amplitude increases to UckV according to a rate of [Gamma] kV / s, ..., a Nth reference wave amplitude increases to UNkV according to a rate of [Epsilon]kV / s so as to realize that the flexible direct current transmission system island can perform no disturbance and no impact starting.

Description

technical field [0001] The invention relates to the technical field of flexible direct current transmission in electric power systems, in particular to a method for island start-up of a flexible direct current transmission system. Background technique [0002] Flexible DC transmission uses voltage source converters, which can independently and quickly control the active power and reactive power of the control system, thereby improving system stability, suppressing system frequency and voltage fluctuations, and improving the steady-state performance of grid-connected AC systems . [0003] There are many coastal islands in my country, and most of the AC power grids inside the islands are weak, and the power output is unstable. Flexible DC transmission has great advantages in the fields of distributed generation grid connection, island power supply, new energy grid connection, and urban distribution network power supply. For this reason, the State Grid Corporation of China an...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H02J3/36
CPCH02J3/36Y02E60/60H02M1/36H02J3/388
Inventor 王柯随顺科卢宇董云龙胡兆庆李钢
Owner NR ELECTRIC CO LTD
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