Large Capacity Reactive Power Compensation And Harmonic Control Technology And Equipment In35kV Substation

The injection type hybrid active power filter(IHAPF) is widely used, owing to itcan suppress the harmonics dynamically and compensate large capacity of reactivepower in the mean time. However, as the injection type hybrid active power filterreduces the active part’s fundamental voltage with fundamental resonance branch, theactive power filter is difficult to get enough energy from the grid to maintain thestability of the DC voltage, so the non-controlled rectifier is often used to supply theenergy of DC side practically. When the grid voltage fluctuates or frequency drifts,the fundamental resonance point of the injection type hybrid active power filter slips,and the fundamental resonance branch shocks, which impact the DC side of activepower filter greatly. As the injection type hybrid active power filter is supplied withnon-controlled rectifier, without the control of DC voltage, which is a security risk,and reduces the reliability of the entire device. Active power filter damaged andnon-controlled rectifier power explode are running several times, there is an urgentneed to improve the structure, to make a better application in projects.With the background of the harmonic control and reactive power compensationprojects in a substation of35kV high voltage distribution network, basing on theanalysis of the condition,the solutions are presented in this paper. The emphasis andachievement of the paper mainly manifests in the following aspects:a novel injectiontype hybrid active power filter(N-IHAPF) was proposed in this paper, aiming on theshortage of the traditional injected type hybrid active power filter. The analysis ofnovel injection type hybrid active power filter’s topology, operating mechanism,harmonic control principle, active power filter’s injectability and the stability ofcontrol system are carried out. Parameters optimization design method is also given inthis paper. With the analysis of the structure and operation mechanism, the improvedi p iqdetection algorithm is proposed,basing on the harmonic detection with limitedtimes.This method can effectively reduce the capacity of the active part, and at thesame time avoid the harmonic circulation between APF and PPF.Aiming on theshortage of the traditional method to get the fundamental voltage phase for power grid,this paper proposes a novel method, basing on the grid voltage phase directional. Thismethod has high accuracy and doesn’t rely on the accurate parameters ofcomponents.Aiming on the control strategy of the novel injection type hybrid active power filter, this paper adopts the voltage and current dual-loop control method,basing on the deadbeat control.The simulation results show that this method canmaintain the stability of the DC voltage and has good dynamic tracking performance.On this basis, we developed a novel injection type hybrid active power filter forthe power quality control of high voltage distribution network. The operation resultsof the novel injection type hybrid active power filter show that the35kV high voltagedistribution network’s power quality has been improved greatly and fully comply withdesign requirements.