This paper presents a new unified power-quality conditioning system (MC-UPQC), capable of simultaneous compensation for voltage and current in multibus/multifeeder systems. In this configuration, one shunt voltage-source converter (shunt VSC) and two or more series VSCs exist. The system can be applied to adjacent feeders to compensate for supply-voltage and load current imperfections on the main feeder and full compensation of supply voltage imperfections on the other feeders. In the proposed configuration, all converters are connected back to back on the dc side and share a common dc-link capacitor. Therefore, power can be transferred from one feeder to adjacent feeders to compensate for sag/swell and interruption. The performance of the MC-UPQC as well as the adopted control algorithm is illustrated by simulation. The present work study the compensation principle and different control strategies used here are based on PI & ANN Controller of the MC-UPQC in detail. The results obtained in MATLAB/PSCAD on a two-bus/two-feeder system show the effectiveness of the proposed configuration.
- power quality (PQ) unified power-quality conditioner (UPQC)
- voltage-source converter (VSC)
- Aritifical neural network- ANN
Fig.1.Block diagram of MC_UPQC with STATCOM
EXPECTED SIMULATION RESULTS:
Fig2. BUS1 voltage,series compensating voltage, and load voltage in feeder1
Fig3.BUS2 voltage,series compensating voltage, and load voltage in feeder2
Fig4.nonlinear load current,compensating current,feeder1 current and capacitor voltage
Fig5.Bus1 loadcurrent,Bus2 load current,Bus1 load voltage,Bus2 load voltage wave forms using ANN controller in Mc- UPQC
Fig 6. Three phase source voltage(Va,Vb,Vc) wave form
Fig.7. load current with ANN controller
Fig.8 Load Voltage with ANN Controller
The present topology illustrates the operation and control of Multi Converter Unified Power Quality Conditioner (MCUPQC). The system is extended by adding a series VSC in an adjacent feeder. A suitable mathematical have been described which establishes the fact that in both the cases the compensation is done but the response of ANN controller is faster and the THD is minimum for the both the voltage and current in sensitive/critical load. The device is connected between two or more feeders coming from different substations. A non-linear/sensitive load L-1 is supplied by Feeder-1 while a sensitive/critical load L-2 is supplied through Feeder-2. The performance of the MC-UPQC has been evaluated under various disturbance conditions such as voltage sag/swell in either feeder, fault and load change in one of the feeders. In case of voltage sag, the phase angle of the bus voltage in which the shunt VSC (VSC2) is connected plays an important role as it gives the measure of the real power required by the load. The MC-UPQC can mitigate voltage sag in Feeder-1 and in Feeder-2 for long duration.
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