Studies On The Low-Voltage Dynamic Reactive Power Compensation Device

Due to increasing loads of electric power system, demand on reactive power was also increasing. Because transmission of reactive power in electric network can lead to network loss and step-down voltage, transmission of a great deal of reactive power necessarily resulted in reduction of using efficiency of power energy and severely effected voltage quality. It became necessary means that reactive power compensation devices were installed in proper position of electric network.A TSC reactive power compensation device which was fit for low-voltage distribution network was introduced in this paper. Based on compensation principle and connection way, this paper mainly studied switches of capacitors and criterions of the device. Zero-cross SSR(Solid State Relay) was applied in this device. Interior zero-cross detection circuit of SSR insured that Bidirectional Thyristor was triggered in the zero-voltage condition and thus greatly reduced surge current. This sort of switch circuit achieved switching of capacitors without transition course and was simple and reliable. At the same time, some sorts of criterions were compared in this paper and voltage and reactive power compound criterion was applied in the device. The compound criterion whose main criterion was reactive power and whose assistant criterion effectively overcame the defects of the power factor criterion in which switching oscillation was often resulted in under light load and compensation was insufficient under heavy load. Compared with reactive power criterion, the compound criterion gave attention to decreasing power loss and improving voltage quality.AT89C52 was a sort of cheap Single Chip Microcomputer and was applied to control system of reactive power compensation device. This device could fleetly and truly compensate reactive power and was low-cost. It processed preferably practicability and wide application foreground in low voltage city network and country network.