Electricity

Electric vehicles (EVs) have emerged as the best alternative to conventional fossil fuel-based vehicles due to their lower emission rate and operating cost. The escalating growth of EVs has increased the necessity for distributed charging stations. On the other hand, the fast charging of EVs can be improved by the use of efficient converters. Hence, the fractional order proportional resonant (FOPR) controller-based current-fed bidirectional DC-DC converter is proposed in this work for EV charging applications. The output capacitance of the switches is utilized to achieve the resonance condition for zero voltage switching (ZVS) and zero current switching (ZCS). The proposed converter topology is implemented using the MATLAB Simulink tool. The result analysis verified that the proposed converter topology provides better switching characteristics for different operating modes, which is necessary for a high-voltage EV charger. Hence, it is proved that the proposed converter is more efficient for battery charging in EVs.

Piyush Sharma

Dheeraj Kumar Palwalia

Ashok Kumar Sharma

Yatindra Gopal

Julio C. Rosas-Caro

Novel Current-Fed Bidirectional DC-DC Converter for Battery Charging in Electric Vehicle Applications with Reduced Spikes

电动汽车应用中用于电池充电的新型电流馈电双向DC-DC变换器，具有减少尖峰的特点

The research and development of hybrid electric vehicles has become a significant goal for large automotive manufacturers. The hybrid electric vehicle integrates a conventional engine and one or more electric motors powered by a battery, offering better fuel economy and lowering exhaust emissions. This paper develops an optimal energy management algorithm based on Model Predictive Control that can produce optimal control parameters for power distribution between the battery unit and generator. The energy management strategy adapts this optimal power distribution by adjusting the objective function equivalent parameter of the controller according to changes in driving conditions. Dynamic programming is utilized offline to find the reference state of charge of the battery and used as the reference trajectory of our proposed strategy. Simulation results using different driving cycles show that the proposed method has better power distribution compared with two other strategies. The final state of charge reached a higher level, and the energy-saving percentage rose compared to the conventional algorithm.

Farah Mahdi Ali

Nizar Hadi Abbas

Energy Management Strategy for Hybrid Electric Vehicles Based on Adaptive Equivalent Ratio-Model Predictive Control

基于自适应等效系数-模型预测控制的混合动力电动汽车能量管理策略

This paper presents the application of quantitative and qualitative methods to assess reliability and security in urban electrical substations. The method is a visual technique based on a conceptual analysis of the different substation configurations. We also performed a sensitivity analysis considering the effects of connecting and disconnecting various elements of a power system. The procedure considers evaluating the loadability levels of transformers, buses, and lines, as well as the current state of the individual elements and the number of connected elements. A new index was proposed for urban electrical substations, evaluating the non-attended demand risk. The technique was tested in a power system case study with a meshed subtransmission network and distribution circuits to supply power to the loads. The results showed that the proposed method is a useful qualitative method to obtain a quantitative description of the system during operation in critical cases and the non-attended demand risk. In addition, 30% of the electrical substations showed low reliability indicators for critical cases such as failures in transformers that connect different internal configurations. These findings could be of interest for utilities and operators, as this document provides a simplified and graphic method that can integrate components such as configurations, non-attended demand risk, and loadability indicators as key parameters to identify critical points that affect the reliability and security of power systems. The case study showed that the electrical substations with the highest non-attention demand risk, around 50%, were those with single- and double-bar configurations in their respective switchyards. On the other hand, the substations with the lowest risk of unmet demand, equal to or less than 20%, were electrical substations with a double-bar + bypass switch configuration, a double-bar and ring configuration in the 110 kV switchyard, and a single-bar configuration in the 13.8 kV switchyard. This study showed that those substations that had couplings had a higher probability of withstanding contingencies.

Jorge Silva-Ortega

Jesús Ortíz

John E. Candelo-Becerra

A New Method to Assess the Reliability and Security of Urban Electrical Substations

评估城市变电站可靠性与安全性的一种新方法

To enhance stability and reliability, multi-microgrid systems have been developed as replacements for conventional distribution networks. Traditionally, switches have been used to interconnect these microgrids, but this approach often results in uncoordinated power sharing, leading to economic inefficiencies and technical challenges such as voltage fluctuations, delay in response, etc. This research, in turn, introduces a novel multi-microgrid system that utilizes advanced electronic devices known as soft open points (SOPs) to enable effective voltage management and controllable power sharing between microgrids while also providing reactive power support. To account for uncertainties in the system, the two-point estimate method (2PEM) is applied. Simulation results on an IEEE 33-bus network with high renewable energy penetration reveal that the proposed SOP-based system significantly outperforms the traditional switch-based method, with a minimum voltage level of 0.98 p.u., compared to 0.93 p.u. in the conventional approach. These findings demonstrate the advantages of using SOPs for voltage management in forming multi-microgrid systems.

Ali Azizivahed

Khalil Gholami

Ali Arefi

Mohammad Taufiqul Arif

Md Enamul Haque

Utilizing Soft Open Points for Effective Voltage Management in Multi-Microgrid Distribution Systems

利用软开放点实现多微电网配电系统有效电压管理

Combining wind and hydropower facilities makes it possible to solve the problems caused by power supply shortages in areas that are remote from the central energy system. Hydropower plants and highly manoeuvrable hydroelectric units successfully compensate for the uneven power outputs from wind power plants, and the limitations associated with them are significantly reduced when they are integrated into the regional energy system. Such an integration contributes to increasing the efficiency of renewable energy sources, which in turn reduces our dependence on fossil resources and decreases their harmful impact on the environment, increasing the stability of the power supply to consumers. The results of optimisation calculations show that a consumer load security of 95% allows the set capacity of RESs to be used in the energy complex up to 700 MW. It is shown here that the joint operation of HPPs and WPPs as part of a power complex and hydraulic energy storage allows for the creation of a stable power supply system that can operate even in conditions of variable wind force or uneven water flow. The conclusions obtained allow us to say that the combination of hydro- and wind power facilities makes it possible to solve the problem of power supply deficits in the regions of Kazakhstan that are remote from the central power station. At the same time, hydroelectric power plants and highly manoeuvrable hydroelectric units successfully compensate for the uneven power output from wind power plants and significantly reduce the limitations associated with them during their integration into the regional energy system.

Rollan Nussipali

Nikita V. Martyushev

Boris V. Malozyomov

Vladimir Yu. Konyukhov

Tatiana A. Oparina

Victoria V. Romanova

Roman V. Kononenko

Combined Power Generating Complex and Energy Storage System

联合发电综合体与储能系统

Today’s power systems are operated closer to their stability limits due to the continuously growing load demands, interface to open markets, and integration of more renewable energies. In order to provide operators with clear insight on the current system situation, near real-time power systems dynamic security assessment tools are required. One of the core elements of near real-time dynamic security assessment tools is contingency screening and ranking. Most of the commercially available tools screen and rank contingencies by using the traditional numerical integration or Transient Energy Functions (TEFs) or hybrid methods. The traditional numerical integration method is accurate but computationally intensive and has a slow assessment speed which makes it difficult to identify any insecure contingency before it happens. Despite the TEF method of transient stability analysis being relatively fast, it develops less accurate results due to models simplification and assumptions. This paper introduces transient stability based on fast and robust contingency screening and ranking using an Adaptive step-size Differential Transformation (AsDTM) method. Based on the most current snapshot from Supervisory Control and Data Accusation (SCADA) data, the proposed method triggers AsDTM-based transient stability simulation for each credible contingency and evaluates Transient Stability Indices (TSI) as the normalized weighted sum of squares of errors derived from state variables and complex bus voltages at every simulation time step. Finally, contingencies are ranked based on these TSI and the worst contingency is identified for the next detail assessment. The method is tested on IEEE 9 bus and 39 bus test systems. Test results reveal that the proposed method is faster, robust, and can be used in near real-time dynamic security assessment sessions.

Teshome Lindi Kumissa

Fekadu Shewarega

Transient Stability-Based Fast Power System Contingency Screening and Ranking

基于暂态稳定性的快速电力系统故障筛选与排序

ISSN	2673-4826
h-index	10

Publication Information	Publisher: Multidisciplinary Digital Publishing Institute (MDPI)，Publishing cycle: ，Journal Type: journal，Open Access Journals: Yes
Basic data	Year of publication: 2020，Proportion of original research papers: 0.00%，Self Citation Rate:N.A.， Gold OA Rate: 0.00%
Journal Fees	$Details
Average review cycle	网友分享经验：7 Weeks

Electricity

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Novel Current-Fed Bidirectional DC-DC Converter for Battery Charging in Electric Vehicle Applications with Reduced Spikes

Energy Management Strategy for Hybrid Electric Vehicles Based on Adaptive Equivalent Ratio-Model Predictive Control

A New Method to Assess the Reliability and Security of Urban Electrical Substations

Utilizing Soft Open Points for Effective Voltage Management in Multi-Microgrid Distribution Systems

Combined Power Generating Complex and Energy Storage System

Novel Current-Fed Bidirectional DC-DC Converter for Battery Charging in Electric Vehicle Applications with Reduced Spikes

Utilizing Soft Open Points for Effective Voltage Management in Multi-Microgrid Distribution Systems

A New Method to Assess the Reliability and Security of Urban Electrical Substations

Energy Management Strategy for Hybrid Electric Vehicles Based on Adaptive Equivalent Ratio-Model Predictive Control

Transient Stability-Based Fast Power System Contingency Screening and Ranking