Online input and withdrawal control method of converter in UHV DC transmission project

An ultra-high voltage DC and DC current technology, which is applied in the direction of converting AC power input to DC power output, output power conversion devices, electrical components, etc. and other problems, to achieve the effect of small reactive power impact, simple control logic and smooth change process

CN103647300BActive Publication Date: 2016-06-15STATE GRID CORP OF CHINA +2
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Patents(China)
Current Assignee / Owner
Publication Date
2016-06-15

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Abstract

The invention relates to an online input and withdrawal control method for a converter in a UHV DC transmission project. Through the trigger angle control of the SCA shielding pole layer, the self-calculated trigger angle is output to make the voltage at both ends of the valve group zero; at the same time, a PI regulator is used to track Valve group current, after the current in the bypass circuit breaker BPS drops to the breaking capacity, it will be opened to complete the online input process of the valve group. During the exit process, the trigger angle of the current control amplifier output is limited, and then bypassed and blocked to complete the transfer of DC current and realize the online exit of the valve group. The present invention is relatively fast for switching on and off, the transient state (overvoltage, overcurrent) during the starting process is relatively small, the reactive power impact on the AC system is small, and the change process of voltage, current, active power and reactive power during the switching on and off process is smoother. , the control logic is relatively simple.
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Description

technical field

[0001] The invention relates to a strategy for switching on and off of a converter in an UHVDC power transmission project. Background technique

[0002] figure 1 It is the existing ±800kv UHV DC transmission project converter series bipolar wiring mode, each pole can run two converters in series, or a single converter can run independently, and put in or out of a certain pole in the operating state converter without affecting the normal operation of the other converter on the same pole.

[0003] At present, domestic UHVDC power transmission projects all use the connection mode of double 12-pulse valve group connected in series, and there are various operation modes. Therefore, it is necessary to study the online switch-on / off strategy of a single converter, and the time for the existing converter switch-on / off strategy It is very long, and the start-up sequence control logic is relatively complicated, which requires high reactive power support of the system...

Examples

Embodiment Construction

[0029] The present invention will be described in further detail below in conjunction with the accompanying drawings.

[0030] Firstly, a brief description will be given of the prior art means related to the converter valve control involved in the following description. SCA, start control amplifier, CV_START, valve group start module, CV_IFO, valve group input module, their ports and connections are as follows figure 2 , 3 As shown, these modules are all existing products, and are manufactured by electrical manufacturers such as ABB.

[0031] exist figure 2 Among them, the port IDIFF_SCA indicates that the difference between the bridge arm current of the converter valve to be input and the neutral line current is used as the differential input of the SCA; O_START_SCA is the SCA start command; O_RETARD_SCA is the SCA phase shift command; ALPHA_ORD_POLE is the pole power control layer send ALPHA_ORD_SCA outputs the firing angle calculated by SCA; ALPHA_ORD is the firing ang...