Half‐cycle method for exponentially DC components elimination applicable in phasor estimation

Tajdinian, Mohsen; Seifi, Ali Reza; Allahbakhshi, Mehdi

doi:10.1049/iet-smt.2017.0028

Cited by 23 publications

(44 citation statements)

References 37 publications

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“…Also, the variance for all load and generations is considered 3% of mean value. Applying fault scenario corresponding to step 1: The fault scenario corresponding to RVs generated in step 1 is applied. As mentioned in Section , the parameter estimator in the study of Tajdinian, Seifi, and Allahbakhshi only requires half‐cycle data of fault‐current signal to calculate the desired data. Calculating required parameters from fault‐current signal: Applying Equations to on half‐cycle fault‐current signal, obtained in step 2, the desired parameters I 1 , α , and τ dc are calculated. Calculating VKP: Utilizing Equations to , Y SSC , Y REM , and Y AT are determined. Also, it must be noted that in the case of autoreclosing operation, Y AT is calculated from Equations to .…”

Section: Methodsmentioning

confidence: 99%

“…According to Tajdinian, Seifi, and Allahbakhshi, Tajdinian, Jahormi, et al, and Tajdinian, Kouhsari, et al, the fault current may contain transient decaying DC component during fault occurrence in the power system. Also, as it has been mentioned in the studies of Tajdinian, Seifi, and Allahbakhshi, Tajdinian, Jahormi, et al, and Tajdinian, Kouhsari, et al, the fault current may be contaminated with high‐order unwanted harmonic components in which the level of even harmonic is negligible. According to the aforementioned assumption, the fault‐current signal can be described as follows:

i ((), t) = I_{dc} e^{- t / τ_{dc}} + \sum_{j = 1}^{n} I_{j} cos ((), ((), 2 j - 1) ω_{0} t + α_{j}) .

…”

Section: Current Transformermentioning

confidence: 99%

“…Authors in the study of Tajdinian, Seifi, and Allahbakhshi proposed a hybrid method for fundamental phasor component that utilizes a hybrid method based on the half‐cycle integration and phase shifting to calculate and remove the effect of the decaying DC component from fault‐current phasor. Also, by developing the half‐cycle DFT to deal with the off‐nominal frequency condition, the fundamental phasor component is calculated with very good accuracy in the half cycle. As proven in the study of Tajdinian, Seifi, and Allahbakhshi, τ dc , I dc , I 1 , and α 1 are estimated as follows:

τ_{dc} = \frac{1}{2} \frac{- normalΔ t}{ln ((), \frac{{(|, \overset{true¯}{I})}_{t + 2 Δ t} - {(|, \overset{true¯}{I})}_{t + Δ t}}{{(|, \overset{true¯}{I})}_{t + Δ t} - \overset{true¯}{I}})},

I_{dc} = \frac{{\overset{I}{true} - \overset{I}{true} ∣}_{t + normalΔ t}}{\frac{2}{T} τ_{dc} ((), 1 + e^{T / 2 τ_{dc}}) ((), 1 - e^{- T / 2 τ_{dc}}) ((), 1 - e^{- normalΔ t / 2 τ_{dc}})},

I_{1} = \frac{1}{Δ_{1} Δ_{4} - Δ_{2} Δ_{3}} \sqrt{[(I_{1}^{italicre} - I_{1}^{re - dc}) - {normalΔ}_{2} ((), I_{1}^{im} - I_{1}^{italicim})]}

…”

Section: Current Transformermentioning

confidence: 99%

“…In the time‐domain fault analysis, unlike the conventional fault analysis, the value of the decaying DC component corresponding to any FL and FIA can be easily separated from symmetrical value. To extract the influential factors, it is required to utilize methods that are able to extract parameters such as the magnitude of the fault current and the time constant of the decaying DC component. To such aim, a hybrid discrete Fourier‐transform (DFT)‐based method has been suggested in the study of Tajdinian, Seifi, and Allahbakhshi, which computes the decaying DC component and fundamental phasor of the fault current and requires half‐cycle data. So according to this method, in each case of the running in the Monte Carlo simulation (MCS), the first half cycle of the fault signal is required. It also must be mentioned that the effects of the noise and harmonic components, which are ignored in the conventional fault analysis methods, are taken into account in the time‐domain fault analysis. New criterion called depth of saturation (DofS) is introduced and designed based on the distance between the VKP in worst‐case condition (WCC) and the samples of VKP obtained in Monte Carlo analysis.…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Probabilistic analysis of current‐transformer dimensioning: A criterion for determining the level of exposure to saturation

Hashemi

Tajdinian

Seifi

2018

Int Trans Electr Energ Syst

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Summary Saturation of the current transformer (CT) results in maloperation of current‐dependent protective relays. While enhancing in the core area may prevent the saturation, it simultaneously increases the size, the weight, and, subsequently, the price of the CT, which is desirable for neither the CT manufactures nor the operators. This paper conducts a probabilistic analysis to investigate the impact of influential factors on CT saturation for CT dimensioning. The main aim of the probabilistic analysis is to identify the busses of the power network in which they may be highly exposed to the CT saturation phenomena. The proposed probabilistic framework is performed based on the time‐domain fault analysis. In the probabilistic time‐domain fault analysis, the effects of fault location, fault type, and fault resistance are investigated. Also, the effects of load and generation are considered probabilistically. On the basis of the selected random variables (RVs), the probability density function (PDF) of the voltage of the knee point (VKP) is obtained. Also, a new criterion so‐called depth of saturation (DofS) is introduced that shows the level of exposure to saturation phenomena for each bus. The results show that the proposed probabilistic framework helps to find a general observation to VKP of each CT from the CT‐dimensioning aspect. Also, the proposed probabilistic framework provides some useful information about the probability of saturation area in the power system.

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Section: Methodsmentioning

confidence: 99%

i ((), t) = I_{dc} e^{- t / τ_{dc}} + \sum_{j = 1}^{n} I_{j} cos ((), ((), 2 j - 1) ω_{0} t + α_{j}) .

…”

Section: Current Transformermentioning

confidence: 99%

τ_{dc} = \frac{1}{2} \frac{- normalΔ t}{ln ((), \frac{{(|, \overset{true¯}{I})}_{t + 2 Δ t} - {(|, \overset{true¯}{I})}_{t + Δ t}}{{(|, \overset{true¯}{I})}_{t + Δ t} - \overset{true¯}{I}})},

I_{dc} = \frac{{\overset{I}{true} - \overset{I}{true} ∣}_{t + normalΔ t}}{\frac{2}{T} τ_{dc} ((), 1 + e^{T / 2 τ_{dc}}) ((), 1 - e^{- T / 2 τ_{dc}}) ((), 1 - e^{- normalΔ t / 2 τ_{dc}})},

I_{1} = \frac{1}{Δ_{1} Δ_{4} - Δ_{2} Δ_{3}} \sqrt{[(I_{1}^{italicre} - I_{1}^{re - dc}) - {normalΔ}_{2} ((), I_{1}^{im} - I_{1}^{italicim})]}

…”

Section: Current Transformermentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Probabilistic analysis of current‐transformer dimensioning: A criterion for determining the level of exposure to saturation

Hashemi

Tajdinian

Seifi

2018

Int Trans Electr Energ Syst

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“…This paper attempts to minimize the unwanted effects of the transient coupling capacitor voltage transformer (CCVT) due to fault condition on the phasor estimation. It is worth to mention that the same studies have been conducted on the impact of current transformer (CT) on the phasor estimation of the fault current signal and CT saturation detection prevention. It was observed that taking dynamic behavior of CT into account will result in more accuracy and speed and robustness into estimated phasor component.…”

Section: Introductionmentioning

confidence: 99%

Minimizing the undesirable effect of coupling capacitor voltage transformer on DFT-based phasor estimation method

Tajdinian

Allahbakhshi²,

Seifi

et al. 2018

Int Trans Electr Energ Syst

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Summary This paper presents an innovative half‐cycle method to minimize the undesirable effects of coupling capacitor voltage transformer (CCVT) on the discrete Fourier transform (DFT)‐based phasor estimation methods during fault condition. The proposed method analytically calculates transient components of the CCVT by using a combination of half‐cycle phase shifting along with the modified least squares technique. The latter combination is used to obtain the transient characteristics of CCVT. Afterward, subtracting estimated transient behavior from original voltage fault signal, modified half‐cycle DFT is utilized to estimate fundamental phasor component. Half‐cycle DFT formulation is modified to cope with the instability caused by off‐nominal frequency condition. Based on some case studies conducted on MATLAB software environment, the performance of the proposed phasor estimator is investigated. The results illustrate that the proposed method estimates fundamental phasor component with an ignorable effect of CCVT transient in almost half cycle after disturbance happening under different fault conditions.

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New modified DFT-Prony-based algorithms for removal of decaying DC components from fundamental phasor estimates

Rozgić

Petrovič

2022

Electr Eng

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Half‐cycle method for exponentially DC components elimination applicable in phasor estimation

Cited by 23 publications

References 37 publications

Probabilistic analysis of current‐transformer dimensioning: A criterion for determining the level of exposure to saturation

Probabilistic analysis of current‐transformer dimensioning: A criterion for determining the level of exposure to saturation

Minimizing the undesirable effect of coupling capacitor voltage transformer on DFT-based phasor estimation method

New modified DFT-Prony-based algorithms for removal of decaying DC components from fundamental phasor estimates

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