Control method for optimizing thyristor controlled transformer type controllable electric reactor

A technology of thyristor control and transformer type, applied in harmonic reduction devices, AC networks to reduce harmonics/ripples, reactive power adjustment/elimination/compensation, etc., can solve the problem of increasing investment, increasing floor area, and current Distortion and other issues

CN103683304AActive Publication Date: 2014-03-26STATE GRID CORP OF CHINA +3
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Applications(China)
Current Assignee / Owner
Publication Date
2014-03-26

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Abstract

The invention discloses a control method for optimizing a thyristor controlled transformer type controllable electric reactor. The control method comprises the following steps: 1) detecting load three-phase power, 2) calculating a current harmonic wave distortion rate, 3) judging whether harmonic waves cross the limit, 4) constructing the grading function of a power quality index, 5) utilizing the analytic hierarchy process to determine the weight of the index, and 6) determining a three-phase firing angle with the purpose of enabling the power quality to be optimum. On the condition of not increasing the number of equipment, depending on the optimizing selection of the firing angle of a controllable electric reactor thyristor, the control method lowers the harmonic waves generated by the electric reactor, and improves the power quality of a circuit.
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Description

technical field

[0001] The invention belongs to the field of reactive power compensation in electric power systems, and relates to an optimal control method for a thyristor-controlled transformer-type controllable reactor. Background technique

[0002] In recent years, with the continuous development of the national economy, asynchronous motors and power electronic devices have begun to be connected to the power grid in large quantities. These loads need to absorb a large amount of reactive power to work normally, which will increase the active power loss of the power system, reduce the utilization rate of equipment, and affect The power transmission capacity has a negative impact on the safety and stability of the power system operation. At the same time, with the increase of asymmetric loads such as electric arc furnaces and electric locomotives in the power system, the problem of three-phase imbalance in the power grid has attracted more and more attention. The three-phas...

Examples

Embodiment Construction

[0040] The technical solutions of the present invention will be specifically introduced below in conjunction with the accompanying drawings.

[0041] A thyristor-controlled transformer-type controllable reactor optimization control method of the present invention, the main wiring of the system figure 1 shown, where U a , U b , U c is the grid phase voltage, I ca , I cb , I cc is the three-phase current flowing into the reactor, I La , I Lb , I Lc is the load three-phase current, P L(ab) ,P L(bc) ,P L(ca) , Q L(ab) , Q L(bc) , Q L(ca) is the three-phase power of the load. The control flow chart of the present invention is as figure 2 shown, including the following steps:

[0042] 1) Detect the load three-phase power P when the controllable reactor is not connected L(ab) ,P L(bc) ,P L(ca) , Q L(ab) , Q L(bc) , Q L(ca) .

[0043] 2) Calculate the harmonic distortion rate of the three-phase current, the specific process is:

[0044] 21) Use the load three-...