Coordinated Voltage Control for Efficient Utilization of Distributed Generation

  • Khaled Abdulkareem Alobeidli

Student thesis: Master's Thesis

Abstract

Nowadays, governmental organizations are more committed towards renewable energy generation. The Abu-Dhabi government has committed to incorporate 7% of the total electrical energy generation from renewable sources by 2020. Many of renewable energy resources are inverter-based, which are able to play a vital role with instant response. This thesis introduces novel control strategies for efficient utilization of the reactive power compensation in smart distribution system connecting Distributed Energy Resources (DERs), based on Coordinated Voltage Control (CVC) and Reactive Power Management Schemes (RPMS) without/with RTU communications. The proposed schemes impose different control responses and bandwidths on devices to coordinate the reactive power among DERs, Diesel Generator (Diesel), Mechanically Switched Capacitor bank (CAP) and On Load Tap Changer (OLTC). The main objective of the proposed method is twofold: 1) maximize the reactive power reserve of DERs, hence facilitating reaction during contingency situations and 2) provide voltage regulation during normal operating conditions. The Line Drop Secondary Voltage Control (LDSVC) based on RTU communication is implemented for achieving better voltage profile. The control is designed to provide slow and medium speed response, using low pass filters and fast response for DERs. Therefore, it achieves different bandwidth control dedicated by the decentralized voltage controllers and RPMS. The simulated distribution system includes inverter-based DERs (PV and wind turbine), Diesel generator, OLTC and CAP, the potential of the CVC scheme in view of improving voltage profile, maximizing reactive power reserve, enhancing Fault Ride Through (FRT) and improving transient stability margin. The control algorithms are examined under steady state, load excursion and three phases to ground fault conditions. Moreover, the CVC implemented in Hybrid Microgrid and tested for grid connected and islanded mode of operation in adherence to grid codes requirements. A comprehensive simulation study demonstrates the operation and performance of the proposed control scheme for Hybrid Microgrid with islanding capability. The results demonstrate the ability of the proposed CVC scheme in satisfying the targeted objectives. The proposed schemes are independent of real time measurements and widely adaptive to the dynamics of power system, thus making it quite suitable for utility implementation.
Date of AwardJun 2013
Original languageAmerican English
SupervisorMohamed Shawky (Supervisor)

Keywords

  • Renewable Energy Sources; Voltage Control; Distribution Networks; Reactive Power Control.

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