On-line connection/disconnection control method for extra-high voltage engineering converter

A UHV DC and control method technology, applied in the direction of converting AC power input to DC power output, output power conversion devices, electrical components, etc., can solve the problem of large reactive power impact, long switching time, and complex control logic in AC systems and other problems, to achieve the effect of small reactive power impact, simple control logic, and smooth change process

CN103647300AActive Publication Date: 2014-03-19STATE GRID CORP OF CHINA +2
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Patent Information

Authority / Receiving Office
CN · China
Current Assignee / Owner
Publication Date
2014-03-19

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Abstract

The invention relates to an on-line connection / disconnection control method for an extra-high voltage engineering converter. Through control of a trigger angle of an SCA shielding pole layer, a self-calculation trigger angle is outputted, a voltage at two ends of a valve group is made to be zero; current of the valve group is tracked by utilizing a PI adjuster simultaneously, a bypass breaker BPS is opened to accomplish an on-line connection process of the valve group when current of the bypass breaker BPS decreases to a cut-off capacity. In a disconnection process, by limiting a trigger angle outputted by a current control amplifier, then bypass pair transfer and latching are carried out to accomplish transfer of a direct current to realize on-line disconnection of the valve group. According to the method, connection / disconnection are relatively rapid, a transient state such as overvoltage and overcurrent in a start process is small, wattless impact on an alternating current system is small, a voltage, current, active and wattless change process is smoother in the connection / disconnection process, and 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...