The dynamic voltage restorer (DVR) is one of the modern devices used in distribution systems to protect consumers against sudden changes in voltage amplitude. In this paper, emergency control in distribution systems is analysed by using the proposed multi functional DVR control strategy. Also, the multiloop controller using the Posicast and P+Resonant controllers is proposed in order to improve the transient response and eliminate the steady-state error in DVR response, respectively. The proposed algorithm is applied to some disturbances in load voltage caused by induction motors starting, and a three-phase short circuit fault. Also, the capability of the proposed DVR has been tested to limit the downstream fault current. The current limitation will restore the point of common coupling (PCC) ( (the bus to which all feeders under study are connected) voltage and protect the DVR itself. The idea here is that the DVR acts as a virtual impedance with the main aim of protecting the pee voltage during downstream fault without any problem in real power injection into the DVR. Simulation results obtained using MATLAB software show the capability of the DVR to control the emergency conditions of the distribution systems.
- Power System
- Resonant controllers
- Closed loop control.
Fig.1. Representation of DVR system Injection/booster transformer
EXPECTED SIMULATION RESULTS:
Fig.2. Simulation showing the sag in the closed loop system
Fig.3. Simulation showing the swell in closed loop system
Fig .4. Simulation showing the output after DVR is connected
Fig.5. Output for real and reactive power control
Fig.6. Waveform for the fault analysis
Fig.7. output of FFT analysis for input
The main purpose of using DVR in industries is to maximize efficiency in production. We choose the proposed an improved progressive phase changing scheme of post fault voltage. For any fault situation of voltage sag this method is effective which is proved from the analysis and MATLAB simulation results. We chose MATLAB programming because it is easy and can be easily fed in any microprocessor chip. The sag transients can be easily mitigated and pre fault voltage can be established. For real time applications, this may necessitate the application of the microcontroller/processor with fast speed. The analysis done in this paper is detection and compensation of the voltage sag with DVR active power injection.
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