Introducing custom power
ABSTRACT Changes in customers' needs require improvements in the reliability and quality of the electricity supply. This paper describes how the concept of custom power is now becoming familiar. The term describes the value-added power that electric utilities and other service providers will offer their customers in the future. The improved level of reliability of this power, in terms of reduced interruptions and less variation, will stem from an integrated solution to present problems, of which a prominent feature will be the application of power electronic controllers to utility distribution systems and/or at the supply end of many industrial and commercial customers and industrial parks.< >
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ABSTRACT: This paper presents a single stage transformer-less grid-connected solar photovoltaic (PV) system with an active and reactive power control. In the absence of active input power, the grid-tied voltage source converter (VSC) is operated in a reactive power generation mode, which powers the control circuitry, and maintains a regulated DC voltage to the VSC. A data-based maximum power point tracking (MPPT) control scheme which performs power quality control at a maximum power by reducing the total harmonic distortion (THD) in grid injected current as per IEEE-519/1547 standards is implemented. A proportional-integral (PI) controller based dynamic voltage restorer (DVR) control scheme is implemented which controls the grid side converter during single-phase to ground fault. The analysis includes the grid current THD along with the corresponding variation of the active and reactive power during the fault condition. The MPPT tracks the actual variable DC link voltage while deriving the maximum power from the solar PV array, and maintains the DC link voltage constant by changing the modulation index of the VSC. Simulation results using Matlab/Simulink are presented to demonstrate the feasibility and validations of the proposed novel MPPT and DVR control systems under different environmental conditions.Frontiers in Energy. 06/2014; 8(2):240-253.
- Frontiers in Energy. 12/2014; 8(4):464-479.
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ABSTRACT: The robustness of parameter variations and external disturbances is the major property of sliding mode control system. The aim of this paper is to present a decentralized adaptive sliding mode controller (DASMC) with a nonlinear sliding surface for nonlinear multi-machine power systems model. The combination of adaptive approach and sliding mode controller is used to achieve the decentralization of the control and to exploit the advantage of the sliding mode control. The feedback linearization technique is used in order to handle the nonlinearities of power systems model. Each machine is modeled as an independent uncertain dynamic subsystem where the uncertainty is a disturbance that represents the effects of the rest of the system on that particular machine. This disturbance is expressed as a polynomial function of transient EMF deviation and its parameters are estimated by an adaptive control. A local adaptive sliding mode stabilizer is designed to regulate the machine angle and to stabilize the terminal voltage of each generating unit in the global system under high level external disturbances. This method is illustrated with a three machines-infinite bus power systems. Simulations show that the proposed (DASMEC) provides high-performance in dynamic characteristics and its robustness with regard to external disturbance.International Review of Automatic Control. 11/2012; V. 5(n.6):790-797.