Hybrid fuzzy evaluation algorithm for power system protection security assessment

Meyer, Georg Janick; Lorz, T.; Wehner, Rene; Jaeger, Johann; Dauer, Maximilian; Krebs, R.

doi:10.1016/j.epsr.2020.106555

Cited by 8 publications

(5 citation statements)

References 6 publications

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“…Besides, the polarization and ohmic effect are more significant if the battery ages severely, resulting in a more pronounced voltage drop at low SOC and voltage rise at high SOC [33][34][35][36]. us, adopting SOC as the single equalization criterion is not enough; this cannot prevent possible battery damage from overcharging and over-discharging [12,37,38].…”

Section: Equalization Control Algorithmmentioning

confidence: 99%

Active Equalization Strategy for Lithium-Ion Battery Packs Based on Multilayer Dual Interleaved Inductor Circuits in Electric Vehicles

Lei

Fan

et al. 2022

Journal of Advanced Transportation

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Lithium-ion batteries (LIBs) are widely used in electric vehicles (EVs) due to their superior power performance over other batteries. However, when connected in series, overcharged cells of LIBs face the risk of explosion, and undercharged cells decrease the life cycle of the battery. Eventually, the inconsistency phenomenon between cells resulting from manufacturing tolerance and usage process reduces the overall charging capacity of the battery and increases the risk of explosion after long-time use. Research has focused on synthesizing active material to achieve higher energy density and extended life cycle for LIBs while neglecting a comparative analysis of equalization technology on the performance of battery packs. In this paper, a nondissipative equalization structure is proposed to reconcile the inconsistency of series-connected LIB cells. In this structure, a circuit uses high-level equalization units to enable direct energy transfer between any two individual cells, and dual interleaved inductors in each equalization unit increase the equalization speed of a single cell in one equalization cycle by a factor of two. The circuit is compared with the classical inductor equalization circuit (CIEC), dual interleaved equalization circuit (DIEC), and parallel architecture equalization circuit (PAEC) in the states of standing, charging, and discharging, respectively, to validate the advantages of the proposed scheme. Considering the diversity of imbalance states, the state of charge (SOC) and terminal voltage are both chosen as the equalization criterion. The second-order RC model of the LIB and the adaptive unscented Kalman filter (AUKF) algorithm are employed for SOC estimation. For effective equalization, the adaptive fuzzy neural network (AFNN) is utilized to further reduce energy consumption and equalization time. The experiment results show that the AFNN algorithm reduces the total equalization time by approximately 37.4% and improves equalization efficiency by about 4.89% in contrast with the conventional mean-difference algorithm. Particularly, the experiment results of the equalization circuit verification certify that the proposed equalization structure can greatly accelerate the equalization progress and reduce the equalization loss compared to the other three equalization circuits.

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Section: Equalization Control Algorithmmentioning

confidence: 99%

Active Equalization Strategy for Lithium-Ion Battery Packs Based on Multilayer Dual Interleaved Inductor Circuits in Electric Vehicles

Lei

Fan

et al. 2022

Journal of Advanced Transportation

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“…The relay operating time in the forward and the reverse direction is also set to its lower and upper limits i.e., 0.1s and 2.5s respectively. It is given in (14).…”

Section: B Relay Coordination Constraintsmentioning

confidence: 99%

“…A multipopulation based GA was used in order to reduce the number of mis-coordinations and operating time [12]. An number of hybrid algorithms are developed to solve the complex and non-convex PC problem such as hybrid quadratic programming with quadratic constraints (QCQP) [13], hybrid fuzzy evaluation algorithm [14], and hybrid particle swarm optimization (H-PSO) [15]. The relay operating time can also be reduced drastically by modifying standard time-current characteristics (TCC) of OCR.…”

Section: Introductionmentioning

confidence: 99%

User-Defined Dual Setting Directional Overcurrent Relays with Hybrid Time Current-Voltage Characteristics-Based Protection Coordination for Active Distribution Network

et al. 2021

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With the penetration of renewable energy sources based distributed generation (RES-DG) in the distribution network (DN), the operating time of protection relays becomes a major concern to avoid the mis-coordination and nuisance tripping of RES-DG. It is due to the bidirectional flow of current, variance in the fault current level, i.e. high fault current in case of Squirrel cage induction generator (SCIG) based RES-DG, and low fault current for an inverter-based RES-DGs. This paper proposes a novel User-defined dual setting direction overcurrent relay with hybrid time currentvoltage (UDDOR-TCV) characteristics to intensify the proposed scheme's flexibility without any communication assistance for radial DN. The proposed model is formulated in a constrained non-linear optimization fashion and solved with the MINLP solver of general algebraic modelling system(GAMS) software to determine the optimal relay settings. The propounded protection scheme is simulated on IEEE-33 bus radial distribution system and a local 40-bus system hosting the multiple SCIG and PV based RES-DGs at optimal locations. Detailed numerical studies are carried out to show the performance of the proposed scheme. 66.848% and 68.26% reduction in relay operation time with zero mis-coordination is achieved with SCIG-WTG case and PV-units case for the IEEE-33 bus system and a similar reduction in operation time is 68.937% and 66.563% for Local-40 bus system. Moreover, the relays numbers are reduced by 32.692% and 39.7% for IEEE-33 and Local-40 bus systems, respectively, due to the forward/reverse characteristics capability of the proposed UDDOR-TCV. The performance of the proposed scheme is also evaluated on IEEE-8 bus meshed DN. The results are compared with the existing protection schemes in recent literature.INDEX TERMS Distributed Generation, dual setting directional overcurrent relay, hybrid TCV characteristics, GAMS, protection coordination, optimization, user-defined relay settings, fault currents.

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“…First, the relative importance of evaluation indicators was scored to obtain the relative importance of each indicator. Second, according to the characteristics of the collected data, the qualitative indicators in the evaluation index system were fuzzy evaluated to obtain the fuzzy membership data of each indicator [39,40].…”

Section: Subjective Datamentioning

confidence: 99%

Research on Comprehensive Evaluation of Data Source Quality in Big Data Environment

Li¹,

Xu²,

Peng³

2021

IJCIS

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Data quality is the prerequisite of big data research and the basis of all data analysis, mining, and decision support. Therefore, a comprehensive fuzzy evaluation method for big data quality evaluation is proposed. Through the analysis of big data quality characteristics, a big data quality evaluation system for the whole process of data processing is constructed. The subjective weight and objective weight of each indicator are calculated through the analytic hierarchy process and entropy method. In order to overcome the subjective and one-sided shortcomings of the single weight determination method, the subjective weight and the objective weight are organically integrated through the distance function method to determine the combined weight of each indicator. The quantified result of big data quality is obtained through fuzzy calculation of membership degree. Finally the ranking results of the proposed method are compared with those of some existing multi-attribute decision-making (MADM) methods. The obtained results indicate that the proposed method is reasonable and efficient to deal with MADM problems. It can comprehensively measure the level of big data quality, and provide users with accurate and efficient quality evaluation results.

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Hybrid fuzzy evaluation algorithm for power system protection security assessment

Cited by 8 publications

References 6 publications

Active Equalization Strategy for Lithium-Ion Battery Packs Based on Multilayer Dual Interleaved Inductor Circuits in Electric Vehicles

Active Equalization Strategy for Lithium-Ion Battery Packs Based on Multilayer Dual Interleaved Inductor Circuits in Electric Vehicles

User-Defined Dual Setting Directional Overcurrent Relays with Hybrid Time Current-Voltage Characteristics-Based Protection Coordination for Active Distribution Network

Research on Comprehensive Evaluation of Data Source Quality in Big Data Environment

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