Impact of harmonics on tripping time of overcurrent relays

Masoum, Mohammad A. S.; Islam, Syed; Tan, K. T.; Xuan, Tu

doi:10.1109/aupec.2007.4548125

Cited by 8 publications

(5 citation statements)

References 16 publications

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“…Lastly, it is important to note that the total harmonic distortion (THD) produced by non-linear loads can also exert an additional impact on the tripping time of protective devices, particularly when THD exceeds 10% [39]. However, utilities typically comply with established directives such as the IEEE 519-2014 standard, which imposes THD limits below 5% for distribution networks ([40]; Table 1).…”

Section: Discussionmentioning

confidence: 99%

Incorporating Modern Fault Ride-Through Standards into the Short-Circuit Calculation of Distribution Networks

Pompodakis,

Katsigiannis,

Karapidakis

2023

Sensors

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Modern fault ride-through (FRT) standards in many countries require distributed generators to remain connected for a specified period during the fault by providing reactive current, to support voltage and prevent a massive renewable outage. As a result, short-circuit current is not constant, but it varies depending on the current and disconnection order of distributed generators (DGs). This time-varying short-circuit current complicates the estimation of the time it will take for an overcurrent relay or fuse to trip. The existing short-circuit calculation algorithms usually assume that the fault current is constant throughout the whole period of fault. This assumption may result in incorrect conclusions regarding the tripping time of protective devices in networks with high renewable penetration. This paper incorporates modern FRT standards into the fault analysis by considering the influence of fault current variations on the protective devices (relays, fuses), significantly increasing the accuracy of the estimated tripping time. Simulations carried out in a 13-bus and the IEEE 8500-node network indicate that the traditional short-circuit calculation approaches may miscalculate the tripping time of protective devices, with deviations up to 80 s, when applied to networks complying with modern FRT standards.

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Section: Discussionmentioning

confidence: 99%

Incorporating Modern Fault Ride-Through Standards into the Short-Circuit Calculation of Distribution Networks

Pompodakis,

Katsigiannis,

Karapidakis

2023

Sensors

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“…Therefore third harmonic magnetizing current can exist in the lines and in the phase windings of the transformer [7]. So, a contribution of 3rd harmonic currents due to star-star connection of transformer is: So the harmonic current injected by soft starter and converter transformer gives rise to the increase in current towards source side [5]. The current obtained with harmonic analysis is same as the measured current.…”

Section: Vfd Soft Start Synchronous Motor Configuration In Industrmentioning

confidence: 99%

“…Due to extensive application of nonlinear loads like VFDs the load current usually contains harmonic components that affect the operating characteristic of the overcurrent relay [5]. Current with a high crest factor can also nuisance-trip peak sensing devices.…”

Section: Effects Of Harmonics On Protection Equipmentmentioning

confidence: 99%

Differential Protection Strategies for Synchronous Motor :A Case Study

Mundkar

Suhasini²

2011

IJPSOEM

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Three-phase synchronous motors are widely used in the industrial motor driven systems. Variable frequency drives (VFDs) which allow soft-start of motors produce PWM voltage. Numerical relays are used in the protection schemes of these high voltage motors. The location of current transformer (CT) is an important criterion in the protection circuit. Impact of harmonics and the location of current transformer in the motor starting circuit is analysed considering a case study. A suitable protection strategy recommended by IEEE for synchronous motor driven by VFD is presented.

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“…This issue has notably been investigated in case of power distribution system protection conducted on static under-frequency and over-current relays [15]. Authors in [7,16] presented analytical approaches based on relay characteristics and performed theoretical and experimental analysis to derive phase angles of low-order harmonics on the tripping time of overcurrent relays. Harmonic order and amplitudes are determinant.…”

Section: Introductionmentioning

confidence: 99%

Evaluation of Moving Average Window Technique as Low-pass Filter in Microprocessor-Based Protecting Relays

Khodabakhshi‐Javinani

Abyaneh

2017

Eng. Technol. Appl. Sci. Res.

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Over the last decades, with the increase in the use of harmonic source devices, the filtering process has received more attention than ever before. Digital relays operate according to accurate thresholds and precise setting values. In signal flow graphs of relays, the low-pass filter plays a crucial role in pre-filtering and purifying waveforms performance estimating techniques to estimate the expected impedances, currents, voltage etc. The main process is conducted in the CPU through methods such as Man and Morrison, Fourier, Walsh-based techniques, least-square methods etc. To purify waveforms polluted with low-order harmonics, it is necessary to design and embed cutting frequency in a narrow band which would be costly. In this article, a technique is presented which is able to eliminate specified harmonics, noise and DC offset, attenuate whole harmonic order and hand low-pass filtered signals to CPU. The proposed method is evaluated by eight case studies and compared with first and second order low-pass filter.

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Impact of harmonics on tripping time of overcurrent relays

Cited by 8 publications

References 16 publications

Incorporating Modern Fault Ride-Through Standards into the Short-Circuit Calculation of Distribution Networks

Incorporating Modern Fault Ride-Through Standards into the Short-Circuit Calculation of Distribution Networks

Differential Protection Strategies for Synchronous Motor :A Case Study

Evaluation of Moving Average Window Technique as Low-pass Filter in Microprocessor-Based Protecting Relays

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