Fundamentals of Reactive Power in AC Power Systems

There is no generally accepted definition for apparent power components in circuits with non-sinusoidal conditions. The decomposition of apparent power has been the subject of many discussions and is still an open topic. Over the years, a number of apparent power decompositions have been proposed and analysed, usually in the context of compensation. These analyses were performed by means of simulations or by calculating quantities using measurements on a simple test circuit. Here, we present a unique system capable of simultaneous apparent power decompositions for non-sinusoidal conditions in real-time. The system can calculate power components related to various power decompositions. The system’s capabilities are demonstrated on non-linear load characterization.

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“…In linear circuits [26], a simple sinusoidal voltage source defined in a time domain with the equation…”

Section: Power In Circuits With Sinusoidal and Non-sinusoidal Conmentioning

confidence: 99%

Non-Linear Load Characterisation Using Orthogonal Apparent Power Decompositions

Dimitrijević

Stevanović

Litovski

2021

ELEKTRON ELEKTROTECH

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“…These deviations are often tolerated for small percentages, but if they cross certain limits, they are considered as disturbances. Considering a short line model between nodes 1 and 2, the real part of the voltage difference between the two nodes ΔV d is given by the well-known expression [11]:…”

Section: Voltage Deviationmentioning

confidence: 99%

Power Quality Improvement of a Microgrid with a Demand-Side-Based Energy Management System

D’Hoop¹,

Deblecker²,

Thomas³

2019

Micro-Grids - Applications, Operation, Control and Protection

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This chapter addresses the power quality of grid-connected microgrids in steady state. Three different power quality issues are evaluated: the voltage drop, the harmonic distortion, and the phase unbalance. A formulation for an energy management algorithm for microgrids is proposed under the form of a mixed-integer linear optimization including harmonic load flows. It handles both the optimization of the scheduling of all the generation, storage, and load assets, and the resolution of power quality issues at the tertiary level of control by adjusting the levels of certain types of loads within the system. This algorithm is simulated for different scenarios on a conceptual test-case microgrid with residential, industrial, and commercial loads. The results show that the demand-side management mechanism inside the algorithm can adapt efficiently the consumption behavior of certain loads, so that the voltage drop, the voltage total harmonic distortion, and the voltage unbalance factor meet the required standards at every node of the microgrid during the day. It is also highlighted that the microgrid can gradually reduce the purchase of power from the utility grid to which it is connected if the electricity price on the spot market increases.

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“…It is obvious that in the case of non-sinusoidal power supply of an induction motor, the reactive power can be determined only by computer simulation. Before modeling, it is necessary to consider theories of reactive power for non-sinusoidal condi-tions, the general analysis of which was carried out in [1][2][3].…”

Section: Introductionmentioning

confidence: 99%

Reactive Power of Asynchronous Electric Drives with Semiconductor Converters

Kovalova

Kovalov

Shcherbak

2021

LEPE

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The purpose of the article is to obtain a ratio for determining the reactive power of induction motors when powered by semiconductor converters. The task is to determine the dependence of reactive power on control parameters of the converters. The research method used is computer simulation of electric drive based on Fryze power theory for non-sinusoidal currents. The result is the obtained expression for the calculation of reactive power, which takes into account the rated idle current of the motor with sinusoidal power supply and the type of converter, due to introducing special coefficients. Numerical values of the latter, depending on the control parameter, are obtained on computer models with their subsequent approximation. The scientific novelty of the research is in the further development of Fryze power theory in the direction of decomposition of non-sinusoidal current components using computer models. The practical significance is the obtained expression for determining the reactive power of an asynchronous electric drive with a thyristor voltage converter, on the basis of which the capacity of compensating capacitors is calculated to increase its energy efficiency.

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Fundamentals of Reactive Power in AC Power Systems

Cited by 6 publications

References 29 publications

Non-Linear Load Characterisation Using Orthogonal Apparent Power Decompositions

Non-Linear Load Characterisation Using Orthogonal Apparent Power Decompositions

Power Quality Improvement of a Microgrid with a Demand-Side-Based Energy Management System

Reactive Power of Asynchronous Electric Drives with Semiconductor Converters

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