Frequency dependent grid-impedance determination with pulse-width-modulation-signals

Jordan, Michael Guilherme; Langkowski, H.; Thanh, Trung Do; Schulz, Detlef

doi:10.1109/cpe.2011.5942220

Cited by 31 publications

(19 citation statements)

References 13 publications

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“…The similar instrumentation, named Complex Harmonic Impedance Measurement (CHIME) system was developed by Heskes [9], but there are no reports on its measuring implementations (simulation results only are given). The other reports from Germany show that similar quality impedance can be obtained with a classical method of swept sinusoidal excitation tests ([10], Figure 5), or with the use of random excitations [11].…”

Section: Current State Of Grid Impedance Measuring Instrumentation Ansupporting

confidence: 56%

Smart grids instrumentation-obtaining subgrid impedance information

Staroszczyk

2015

Int. Trans. Electr. Energ. Syst.

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Summary The paper deals with impedance measurements in smart grids. It presents the current state of the research in the field, with the information on methods and assured accuracy of grid impedance determination with the use of invasive methods. Associated problems and propositions for impedance observation infrastructure, which can be embedded in smart grid, are presented. Copyright © 2015 John Wiley & Sons, Ltd.

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Section: Current State Of Grid Impedance Measuring Instrumentation Ansupporting

confidence: 56%

Smart grids instrumentation-obtaining subgrid impedance information

Staroszczyk

2015

Int. Trans. Electr. Energ. Syst.

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“…The devices generate pulse-width-modulated (PWM) current signals at specific discrete frequencies or wide spectral regions to determine the frequency characteristic of the network impedance including resonance points with high accuracy [3]- [6]. However, most of these stated methods fail to exactly identify the resistive and reactive components of the network impedance in the lower frequency range around the fundamental.…”

Section: Tllli Venin Impedance Identificationmentioning

confidence: 98%

“…The amplitude spectrum of the current signal has a number of mint components. It can be easily derived from system theory that, beside the fundamental network frequency, significant components at odds of the pulse frequency fp plus/minus the network frequency fN are included in the spectrum [6]:…”

Section: Basic Measurement Principlementioning

confidence: 99%

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Online network impedance identification with wave-package and inter-harmonic signals

Jordan

Grumm

Langkowski

et al. 2015

2015 International School on Nonsinusoidal Currents and Compensation (ISNCC)

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In power system analysis the main supply at a point of common coupling (PCC) is often presented by its Thevenin or Norton equivalent. In most cases these models adequately define the electrical characteristics of a PCC and are commonly used for power flow evaluations, fault estimations, as well as stability and power quality assessments. To determine the equivalent impedance of a PCC through analytical calculation or simulation precisely may be challenging due to the complexity and time varying nature of power supply systems. Especially in medium-and low-voltage distribution networks with a high share of fluctuating consumers and generators a measurement may be required to exactly capture the equivalent impedance over time. This contribution presents a method, which can be used to identify varying equivalent parameters of an AC power system with high accuracy and time resolution. To identify the network impedance the system is excited with short sequences of current signals while measuring the corresponding voltage and current characteristics. The method is evaluated in a simulation model. Further on, impedance measurements on the low-voltage level are presented and discussed.

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“…Random pulse-width modulation signals were applied in [7] to obtain the grid impedance over a wide spectral range. The method was however affected by the characteristics of aperiodic excitation such as leakage and uncontrollable spectral energy distribution.…”

Section: Introductionmentioning

confidence: 99%

Online grid impedance measurement using discrete-interval binary sequence injection

Roinila

Vilkko

Sun

2013

2013 IEEE 14th Workshop on Control and Modeling for Power Electronics (COMPEL)

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Grid impedance affects the stability and control performance of grid-connected power electronic devices such as inverters used to integrate wind and solar energy. Adaptive control of such inverters to guarantee stability under different grid conditions requires real-time measurement of the grid impedance performed online by the inverters themselves. Existing online measurement methods based on broadband excitations such as maximum-length binary sequence (MLBS) require relatively high injection that may interfere with normal grid control functions, or degrade inverter output current quality, especially when the grid impedance is low and a high current needs to be injected in order to produce sufficient voltage perturbation. This paper proposes the use of a discrete-interval binary sequence (DIBS) for such cases. The DIBS is a computer-optimized binary sequence where the energy is maximized at specified harmonic frequencies to minimize the required level of signal injection. Experimental results based on a three-phase grid-connected inverter are presented to demonstrate the effectiveness of the proposed methods.

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Frequency dependent grid-impedance determination with pulse-width-modulation-signals

Cited by 31 publications

References 13 publications

Smart grids instrumentation-obtaining subgrid impedance information

Smart grids instrumentation-obtaining subgrid impedance information

Online network impedance identification with wave-package and inter-harmonic signals

Online grid impedance measurement using discrete-interval binary sequence injection

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