A direct method for frequency stability assessment of power systems

Cai, Zexiang; Ni, Yu

doi:10.1049/cp:20000408

Cited by 12 publications

(7 citation statements)

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“…Smaller and shorter discrepancies of the frequency can be assessed directly [10], [32] and can be used in perturbation calculus to estimate the scope of the fundamental frequency excursion and its influence on the accuracy of harmonic measurements.…”

Section: Discussion On the Range Of Applicability Of The Proposed Methodsmentioning

confidence: 99%

A Method for Harmonic Measurement of Real Power Grid Signals with Frequency Drift using Instruments with Internally Generated Reference Frequency

Antić¹,

Mitrovic²,

Vujičić³

2012

Measurement Science Review

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The authors have recently developed a number of instruments for measuring harmonic composition of power grid signals. These instruments have a simple, predominantly digital architecture and they are based on an assumption that the frequency of the measured signals equals its nominal value (50 Hz, 60 Hz or 400 Hz). This approach has enabled the measurement of a high number of harmonics within a single period. However, the internal oscillator in the instrument generates the nominal frequency and cannot adapt to frequency changes in the input signal. This paper presents a method for the improvement of the operation of the developed instruments in cases when the fundamental frequency drifts from its nominal value as is the case with real power grid signals. Based on this method, modified versions of the harmonic measurement instruments have been developed. A comparison of the measurement error with and without the application of the proposed method is presented in the paper.

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Section: Discussion On the Range Of Applicability Of The Proposed Methodsmentioning

confidence: 99%

A Method for Harmonic Measurement of Real Power Grid Signals with Frequency Drift using Instruments with Internally Generated Reference Frequency

Antić¹,

Mitrovic²,

Vujičić³

2012

Measurement Science Review

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“…According to H Gi , K Gi , and Δf, P acc is shared by all the SGs participating to the primary frequency regulation (7), 19 where the subscript 0 denotes pre-disturbance, P Gi0 -K Gi Δf shows the static frequency characteristic of the SG, H Gi /H ∑ P acc shows the shared accelerated power, and P Li f T pi U i k pi and Q Li f T Qi U i k Qi describe the voltage/frequency-dependent load.…”

Section: Dpf Model Including Dfigsmentioning

confidence: 99%

Improved dynamic power flow model with DFIGs participating in frequency regulation

Zhang

Wang

2017

Int Trans Electr Energ Syst

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Summary The primary frequency regulation of the DFIGs is newly introduced to dynamic power flow to analyze the post‐disturbance power flow and system frequency. Based on the overspeed/pitch angle control, the equivalent inertia of the DFIGs is quantified by their inherent inertia and the adjustable range of the rotor speed, which together with the inertia of the SGs determines the system frequency. With simultaneous solution to the constraints of the DFIGs and power system, the captured power by the wind turbine, the rotor speed, and the slip of the DFIGs are adjusted in dynamic power flow, thus to quantify power loss and active output of the DFIGs, and avoid optimistic judgment to the frequency regulation capability of the DFIGs. With increasing wind power, the wind turbine generators are expected to participate in the frequency regulation to save the burden of synchronous generators (SGs). The primary frequency regulation of doubly fed induction generator (DFIG) using the dynamic power flow is proposed. The equivalent inertia of the DFIG is decided by the inherent inertia and the rotor speed. Its captured power and rotor speed respond to the change of the system frequency. The constraints of the DFIG and power system are solved simultaneously to quantify the active loss of the DFIG. Then, the power flow is solved alternatively with the dynamic equation describing system frequency. The numerical results validate the feasibility of the proposed model and quantify the frequency‐support capability of the DFIG. The proposed model helps to balance the utilization of wind power with the stability of system frequency, while reducing the reserve requirement to the SGs.

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“…There has been proposed many approaches to study system's load margin such as direct method [7]- [9], continuation method [7], [10], eigen analysis [11], energy functions [12]- [13], etc.…”

Section: System Securitymentioning

confidence: 99%

Identifying reactive market areas

Almeida

Leme

Albuquerque

et al. 2011

2011 4th International Conference on Electric Utility Deregulation and Restructuring and Power Technologies (DRPT)

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This paper discusses the problem of loss reduction by the means of reactive power redispatch. The idea is to keep the system security following a transaction. In this sense, identifying the generators most likely to play redispatch is crucial. A sensitivity-based methodology is proposed, so the generators are identified and their reactive power equations are incorporated into the ordinary power flow Jacobian, which yields a suboptimal solution. The tests are obtained with the help of the IEEE-14 bus test system with all limits taken into consideration.

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A direct method for frequency stability assessment of power systems

Cited by 12 publications

References 0 publications

A Method for Harmonic Measurement of Real Power Grid Signals with Frequency Drift using Instruments with Internally Generated Reference Frequency

A Method for Harmonic Measurement of Real Power Grid Signals with Frequency Drift using Instruments with Internally Generated Reference Frequency

Improved dynamic power flow model with DFIGs participating in frequency regulation

Identifying reactive market areas

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