Computer algorithm for selection of frequency relays for load shedding

Jones, Joel; Kirkland, W.D.

doi:10.1109/67.899

Cited by 53 publications

(42 citation statements)

References 1 publication

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“…Operation below 49.5 Hz should be limited to very short durations. Hence it is very important to co-ordinate the settling frequency of the PS and the relay tripping frequency in use to control generator shut-down [9], [11], [16].…”

Section: A Identifying Setting Frequencymentioning

confidence: 99%

“…of stages in its LSS.  In [11]and [22]it has been mentioned that " [3][4][5] steps" is the most adequate selection based on experience.  In [23] a comparison of several UFLSSs has been carried out which were with different number of stages (e.g.…”

Section: B Deciding the Number Of Steps In The Lssmentioning

confidence: 99%

“…All of them are to shed a proper amount of load to decrease the overall power consumption and restore the power balance between generated and absorbed power. The problem of optimal LS has been extensively investigated and many publications on the utility implementation are presented in the literature over the past [5], [9]- [11].Selection of a suitable LS strategy depends on the application scenario.…”

Section: Introductionmentioning

confidence: 99%

“…Therefore the load is shed in blocks until the frequency stabilizes. Different methodologies have been introduced to implement LS actions based on frequency [5], [10], [11], [13]- [14]. With reference to them, it is possible to understand that an intelligent & adaptive control and protection system for wide-area disturbance is needed to make full utilization of the power network possible, which will be less vulnerable to a major disturbance.…”

Section: Introductionmentioning

confidence: 99%

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Comparison of three Under-Frequency Load Shedding Schemes referring to the Power System of Sri Lanka

2016

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Abstract:To cater the consumers with high quality electricity, a reliable Power System (PS) is a must. Recently several major changes have been taken place in the PS of Sri Lanka. Today the PS of Sri Lanka, that operates under Ceylon Electricity Board (CEB) is comprised with 3 numbers of coal Power Plants (PPs), each having a generation capacity of 300 MW, a combined cycle PP (Yugadanavi) and considerably extended transmission network[1], [2]. To maintain the stability of a PS, the balance between power generation and consumption (demand) is a must. In any event, the first few seconds of frequency degradation and recovery after a major generator trip is essentially be accomplished by governor control. When the PS"s self-regulation is insufficient to establish a stable state, the system frequency (SF) will continue to drop until it is arrested by automatic under-frequency load shedding (UFLS) to re-establish the load-generation balance within the time constraints necessary to avoid system collapse [3], [4]. Therefore it has become necessary to review the performance of the present CEB LS Scheme (LSS) and suggest amendments where necessary. This paper proposes two LSSs which can address the recent changes taken place in the Sri Lanka PS while maintaining stability. Having simulated the PS of Sri Lanka, performance comparison of the CEB LSS which is being implemented in Sri Lanka and the proposed LSSs (PLSSs) are presented. Results show that the LSS should exclusively be specific for a particular PS. It depends on factors such as electrical PS practice, regulations, largest generator capacity, electricity consumption pattern etc.

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Section: A Identifying Setting Frequencymentioning

confidence: 99%

Section: B Deciding the Number Of Steps In The Lssmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Comparison of three Under-Frequency Load Shedding Schemes referring to the Power System of Sri Lanka

2016

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“…This lack of adaptability may result in either overshedding or undershedding in different situations. Several conventional and adaptive UFLS schemes have been proposed in the literature [13][14][15][16][17][18][19][20][21] . However, most of them have not proposed an effective method to prevent system blackout in the case of cascading outages.…”

Section: Introductionmentioning

confidence: 99%

Design of New Load Shedding Special Protection Schemes for a Double Area Power System

Seyedi¹,

Sanaye-Pas²

2009

American J. of Applied Sciences

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Abstract:In this paper several Under Frequency Load Shedding (UFLS) schemes are designed as special protection schemes to preserve the integrity of islands, formed following the outage of tie lines connecting two areas in a double area power system. For the purpose of analysis, the Iranian interconnected grid is simulated in a suitable power system analysis software. The grid is connected to the Khorasan province network, the greatest province of the country, through a double circuit tie line. Following the outage of tie lines in a double area power system the area with great import of power may face large deficiency of energy and consequently blackout may occur in the island. The purpose of this research work is to propose a special protection scheme, being capable of preserving the balance of generation and consumption in order to prevent major outage. Special types of adaptive UFLS scheme are proposed in this work.

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Toward a wide-area load shedding scheme: Adaptive determination of frequency threshold and shed load values

Mehrabi

Afsharnia

Golshannavaz

2017

Int Trans Electr Energ Syst

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Summary Conventional under frequency and under voltage load shedding (UFLS and UVLS) schemes are generally independent than each other. Besides, in these schemes, the operating thresholds, amounts, and location of shed loads are settled in constant values for different disturbances. Due to these technical flaws, the conventional load shedding schemes fail to retrieve power system stability which outlines the necessity of devising improved adaptive mechanisms. To this end, the ongoing study proposes an adaptive UFLS scheme based on wide area measurement systems (WAMS). In contradiction to the existing methods, the proposed approach is featured with an adaptive manner. In other words, the frequency threshold of load shedding relays is adaptively tuned at each disturbance. Furthermore, a wide‐area index is proposed to select the amount of required shed loads. Extensive numerical studies conducted on a real‐world case study are involved to evaluate performance of the proposed approach.

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Computer algorithm for selection of frequency relays for load shedding

Cited by 53 publications

References 1 publication

Comparison of three Under-Frequency Load Shedding Schemes referring to the Power System of Sri Lanka

Comparison of three Under-Frequency Load Shedding Schemes referring to the Power System of Sri Lanka

Design of New Load Shedding Special Protection Schemes for a Double Area Power System

Toward a wide-area load shedding scheme: Adaptive determination of frequency threshold and shed load values

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