Novel power quality control system with fault current-limiting function and control method thereof

Abstract

The invention discloses a novel power quality control system with a fault current-limiting function and a control method thereof. The novel power quality control system with the fault current-limiting function comprises a three-phase H-leg PWM rectifier, a three-phase four-leg series converter, a thyristor controlled short-circuit branch, a thyristor controlled bypass reactance branch and a corresponding control method. The PWM rectifier and the three-phase four-leg series converter share one direct current side to achieve bidirectional energy conversion, the series converter compensates the fall, the raising and three-phase imbalance of the grid voltage and solves the quality problem of the harmonic voltage, at the same time, the system controls the series converter, the thyristor controlled short-circuit branch and the thyristor controlled bypass reactance branch to limit the current when various short-circuit faults occur on the grid, and thus the purposes of stabilizing the loaded supply voltage, improving power supply quality, protecting the grid and load equipment when short-circuit faults occur and improving the safety and stability of the electric power system are achieved.

Description

technical field [0001] The invention belongs to the technical field of electric power, and relates to a novel power quality control system and a control method thereof with a fault current limiting function. Background technique [0002] The basic requirements for power system operation are safety and reliability, high power quality, and good economy. Factors that affect the safe and stable operation of power systems are mainly various forms of short-circuit faults and various power quality problems. When a short-circuit fault occurs, the system current suddenly increases and the voltage decreases, which not only makes the electrical equipment unable to work normally, causing a power outage, but also destroys the electrical insulation, burns the electrical equipment, causes a fire, and even causes the system to break down and destroy the safe and stable operation of the system. . On the other hand, in recent years, various nonlinear, impulsive and unbalanced loads have been...

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Problems solved by technology

[0004] 1. The busbar series reactance can only realize the function of fault current limiting, and cannot solve the impact of power quality problems on the power grid and users

[0005] 2. The series reactance of the busbar will consume a lot of active and reactive energy

[0006] 3. The utilization rate of the bus series reactance is low, and it only works when there is a fault

[0007] 4. Due to the long-term series connection in the power grid, the series reactance should not be too large, so that the current limiting effect is not good enough

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