Capacity Assessment Method Research Articles

WITHDRAWN: Fast Assessment of Distributed Photovoltaic Hosting Capacity of Distribution Networks Based on Photovoltaic Barycenter Theory

• The concepts of moment and barycenter of PV and load distributions are given. • The PV Barycenter Theory with three metrics is proposed for the first time. • A quick PV maximum hosting capacity assessment method is established. • The rapidity, accuracy, practicability and universality of the method are verified. High penetration distributed PV deployment will lead to serious power quality problems and a significant active power return, posing a serious threat to the safe and stable operation of distribution networks. This paper proposes an innovative fast assessment method of distributed PV maximum H osting C apacity (HC) of distribution networks based on P V B arycenter T heory (PBT). The new concepts of moment and barycenter are proposed, and the global metric GM of PV barycenter is achieved. The non-iterative formulas of HC that meet the node voltage upper limit and the conductor ampacity upper limit are derived, and the local metric LM1 of voltage upper limit and the local metric LM2 of ampacity upper limit are obtained. Together with the global metric GM, a complete PV Barycenter Theory is constituted. A new quick assessment method for HC of distributed PV in distribution networks is proposed. This method is applied to four 10kV distribution feeders in Chengde, Hebei Electric Power Company. The calculation results in all scenarios show that, compared to the classical Monte Carlo method, the new method boosts the average calculation efficiency by 4856 times while maintaining a 0.83% average error. The proposed method can also take into account the real-world constraints such as the existing PV capacity of the distribution networks and the exploitable PV capacity of the deploying point, making the deployment scheme more practical and feasible. The comprehensive analysis results on load rate sensitivity and PV penetration all verify the rapidity, accuracy, practicability and universality of this method.

Improving single-track railway line capacity using extended station switch point area

The paper focuses on the possible capacity improvement of a segment between two stations of a single-track railway line by using of extended station switch point area and on methods assessing the capacity of such railway infrastructure, where a part of a single-track line segment being not equipped itself with e.g. line blocks becomes partially double-tracked. These methods can extend state-or-art general capacity assessment methods and allow more detailed assessment in this specific case. The research was conducted on three levels. The first is only analytic, the second is based on the developed own mesoscopic stochastic simulation model and the third is based on a stochastic microsimulation model elaborated by using the OpenTrack software. Divided solutions on each level can provide assessments with different demands on computation and model development. Stepwise solutions at the individual level may rationalize capacity assessment.

Research on the Characterization of Electric Vehicle Energy Storage Capacity and Coordination Mechanism with Distribution Network Based on Two-stage Method

This paper firstly analysed the characteristics of electric vehicle movement behaviour in multiple dimensions, extracts the correlation among electric vehicle energy storage characteristics and driving behaviour, state of charge (SOC), and charging behaviour, establishes a regional vehicle state transfer machine model, and dynamically adjusts the parking status of electric vehicles. Based on the measured data of electric vehicle charging, the probability distribution of charging behaviour parameters and their correlations were modelled in detail, the electric vehicle load was predicted, and the electric vehicle charging load model was established, and the available capacity assessment method was proposed.

A Hierarchical Framework for CO2 Storage Capacity in Deep Saline Aquifer Formations

Carbon dioxide (CO2) storage in deep saline aquifers is a vital option for CO2 mitigation at a large scale. Determining storage capacity is one of the crucial steps toward large-scale deployment of CO2 storage. Results of capacity assessments tend toward a consensus that sufficient resources are available in saline aquifers in many parts of the world. However, current CO2 capacity assessments involve significant inconsistencies and uncertainties caused by various technical assumptions, storage mechanisms considered, algorithms, and data types and resolutions. Furthermore, other constraint factors (such as techno-economic features, site suitability, risk, regulation, social-economic situation, and policies) significantly affect the storage capacity assessment results. Consequently, a consensus capacity classification system and assessment method should be capable of classifying the capacity type or even more related uncertainties. We present a hierarchical framework of CO2 capacity to define the capacity types based on the various factors, algorithms, and datasets. Finally, a review of onshore CO2 aquifer storage capacity assessments in China is presented as examples to illustrate the feasibility of the proposed hierarchical framework.

Equivalent Firm Capacity Assessment of HDR-PV Hybrid Power System: A Distributionally Robust Approach

Aiming at the reliable grid connection of photovoltaic (PV) systems in frigid plateau regions, this work first designs a flexible hot dry rock (HDR) hybrid power system (HPS), making full use of the potential of HDR for energy storage and power generation. Based on the operation of HPS, a comprehensive energy system credible capacity assessment method considering the overall economy of the system and the reliability of the grid is established. In this method, the power allowable fluctuation rate of the grid as the equivalent firm capacity (EFC) constraint is considered. Then, the constraint is converted into a set of linear chance conditions through the distributionally robust method so that the capacity assessment of the HDR-PV HPS can be converted into a mixed-integer linear optimization problem for a solution. The proposed assessment method is verified by real HDR-PV HPS in the Gonghe Basin of Qinghai Province. The results show that the flexible HDR plant increases the credible capacity of the HPS by 113.38%. The profit of the flexible HDR plant was increased by 3.02% at the same time. The parameter analysis shows that the HDR-PV HPS obtains the most profit when the allowable fluctuation rate is 7%, but 10% can fully utilize the geothermal. The assessment method can effectively assess the credible capacity of the system under the premise of ensuring the overall economy of the HPS, thereby guiding power grid dispatching.

Study on Renewable Energy Accommodation Capacity Assessment Method Based on Time Series Production Simulation

In order to solve the problem of low accommodation rate of renewable energy in a single region, considering the output characteristics of wind power and photovoltaic, grid constraints and cross regional power exchange, an optimization model of renewable energy accommodation capacity in a cross regional power grid year is established. This paper analyzes the factors restricting the accommodation capacity of renewable energy, and determines the access scale of renewable energy units according to the characteristics of different power grid scale, load and power supply structure. And then taking the annual maximum accommodation capacity of renewable energy as the goal, the time series production simulation model is established, considering the constraints such as regional load balancing, power transmission and output of the network cable, unit output, unit optimization power ramp rate and renewable energy output. To improve the renewable energy accommodation capacity, the three factors of power system interconnection level, power regulation performance and load characteristics can be considered.

Analysis of the suitability of existing methods for an objective assessment of the working capacity and desirable working qualities of horses of useful breeds

Analysis of the suitability of existing methods for an objective assessment of the working capacity and desirable working qualities of horses of useful breeds

Determination of the Spatial Resolution of Radar Images in Remote Sensing of the Earth

Introduction. The analysis of the current state and prospects of space-based radar surveillance tools is important for determining their functions in global aerospace information systems, which aim to monitor air and space, as well as the Earth's surface. Radar surveillance information is used for the purposes of economic analysis, environmental monitoring, mineral search, emergency monitoring, detection and recognition of specified object s at sea and on land, as well as for ensuring national security. In this regard, it is of relevance to develop methods for preliminary assessment of the resolution capacity of novel high-precision onboard radar systems installed on a spacecraft, considering their main technical characteristics, the parameters of the spacecraft movement and the influence of the atmosphere. A priori estimation of spatial resolution values requires a method for calculating the corresponding indicators meeting the required quality of the synthesized radio holograms.Aim. To derive mathematical dependencies and logical rules allowing a priori estimation of the spatial resolution of radar images obtained by the onboard equipment of a radar complex.Materials and methods. Analytical methods were used to determine the resolution error of onboard radar systems with a synthesized aperture in the lateral (azimuthal) direction and range, as well as the theory of radar signal processing.Results. A comparison of the experimental and analytical data on the resolution capacity of an actual radar system confirmed the validity on the proposed method. The developed methodology was used to determine the procedure of calculating the error when estimating the resolution capacity in terms of azimuth and range. Conclusion. The proposed method can be used for both designing novel radar systems and comparing existing radar complexes, depending on the resolution requirements.

Research on new transmission network planning considering adjustable comprehensive resources

With the large-scale renewable energy grid integration, the problems of traditional transmission network planning methods, such as high investment, low utilization rate and difficulty in implementation, have gradually emerged. Therefore, in order to improve the level of new energy consumption, effectively improve the operation efficiency of power grid and optimize the investment benefit, this paper proposes a new mode of power grid planning based on adjustable integrated resources. This paper focuses on two key planning methods: new energy confidence capacity assessment methods and load forecasting methods considering demand side resources.Then the paper takes a city-level 220 KV power grid as an example, applies a new power grid planning method to carry out planning, and verifies the effectiveness of the proposed planning model and method.

Potential Assessment of Spatial Correlation to Improve Maximum Distributed PV Hosting Capacity of Distribution Networks

Successful distributed photovoltaic (PV) planning now requires a hosting capacity assessment process that accounts for an appropriate model of PV output and its uncertainty. This paper explores how the PV hosting capacity of distribution networks can be increased by means of spatial correlation among distributed PV outputs. To achieve this, a novel PV hosting capacity assessment method is proposed to account for arbitrary geographically dispersed distributed PVs. In this method, the empirical relation between the spatial correlation coefficient and distance is fitted by historical data in one place and then applied to model the joint probability distribution of PV outputs at a neighboring location. To derive the PV hosting capacity at candidate locations, a stochastic PV hosting capacity assessment model that aims to maximize the PV hosting capacity under thermal and voltage constraints is proposed. Benders decomposition algorithm is also employed to reduce the computational cost associated with the numerous sampling scenarios. Finally, a rural 59-bus distribution network in Suzhou, China, is used to demonstrate the effectiveness of the proposed PV hosting capacity assessment methodology and the significant benefits obtained by increasing geographical distance.

Development tendency analysis for the water resource carrying capacity based on system dynamics model and the improved fuzzy comprehensive evaluation method in the Changchun city, China

Water resource carrying capacity describes the relationship between different systems such as the socio-economic, water environment, and water resources systems. Recent studies tend to focus on the qualitative description of water resource carrying capacity, with a lack of quantitative research on the topic. This study proposes an improved water resource carrying capacity assessment method based on combining the improved fuzzy comprehensive evaluation and the system dynamics model, enabling the quantitative and qualitative measurement of water resource carrying capacity. This method can dynamically compute the water resource carrying capacity under different social development scenarios through the feedback regulation and system simulation of social economy–water resources and the water environment interactions. A comprehensive assessment of trends from six scenarios between 2018 and 2025 was conducted, based on scenarios designed for different purposes. The results indicate that if the current development model is adopted, the water resource carrying capacity will continue to decline and remain at a low level of “normal carrying” (0.431 in 2025). However, the water resource carrying capacity in Changchun may improve by changing the production mode of the national economy and adjusting the proportion of the economy. Rationally allocating water resources and strengthening water ecological protections can significantly increase the water resource carrying capacity and maintain it at “positive carrying”, while maintaining steady economic and social growth.

Soil parameters’ numerical back analysis for comparison of driven pile’s capacity assessment methods

The paper shows several methods of driven piles capacity assessment. The piling work consisted of driving around 10 000 prefabricated concrete piles for the indirect foundation of National Stadium’s located in Warsaw city center. A total number of 68 investigated piles was divided into three groups, depending on their length, because longer piles tend to be weaker, what is shown in the paper. Results of dynamic load test, CASE and CAPWAP limit capacity and piling reports provided by AARSLEFF company stood the basis for further analysis in this work. The given results of dynamic test were taken as the most reliable data to compare with other methods, as they gave surprisingly close values, while being nondependent. Large amount of displacement piles happened to impact existing soils’ mechanical properties. The difference in maximum resistance force was estimated, by carrying out a numerical back analysis with GEO5 software. The computation shows significant growth of internal friction angle, and compaction index which led to three times higher limit pile capacity. The extra compaction effect during pile driving should be considered, during the design process, both as positive for soil stiffness, and potential impediment for the contractor.

Study on Capacity Assessment Method of Terminal Area Under the Influence of Military Activities

Study on Capacity Assessment Method of Terminal Area Under the Influence of Military Activities

Positive Sequence Current Phase-Based Improved Reverse-Power Protection and a PV Hosting Capacity Assessment Method for Spot Networks

A spot network is a special low-voltage distribution network with multiple sources supplying it in parallel. It can significantly enhance supply reliability and is beneficial for integrating a distributed energy resource (DER). However, because traditional reverse power protection in spot networks cannot identify the reverse power cause, DERs, especially photovoltaic (PV) hosting capacity, are limited. Meanwhile, no uniform method exists for assessing the PV injection capacity in spot networks. Based on comparing the positive sequence current phase, this article presents an improved reverse power protection and PV hosting capacity assessment method for spot networks. Current variation is adopted to identify the reverse power cause, and a spot network equivalent model with PV is built. The positive sequence current phase relationship at the reverse power protection location is analysed when different types of short circuit faults occur. A short circuit fault section can be determined by comparing the positive sequence current phase. The influence of the PV output current on the improved reverse power protection performance is analysed. Then, a PV hosting capacity assessment method with improved reverse power is presented based on the PV influence on protection instead of on node voltage. A simulation model based on an actual project is constructed using PSCAD software. The simulation results show that the improved reverse power protection significantly enhances the ability to inject PV into the spot network and operates correctly under faults. The theoretical PV hosting capacity agrees with the simulation results.

Capacity assessment for wind power integration considering transmission line electro-thermal inertia

Considering differences in planning and construction period, there may exist a mismatch of between effective wind farms capacity and dedicated transmission line ampacity. Then, conflict appears while increasing wind power integrates into main system through limited transmission utilities. Once excessive wind power integration (WPI) causes transmission overload, wind power generation is preferably curtailed with certain scheme. However, transmission conductor electro-thermal characteristic in case of wind power fluctuation makes static thermal rating inaccurate for overload confirmation. Then this study centers on analyzing WPI considering wind power curtailment scheme which allows for overhead conductor dynamic electro-thermal inertia involving various time-varying ambient factors. Accordingly, this study presents a WPI capacity assessment method, which captures the dynamic features of WPI by synchronously simulating wind power generation as well as curtailment regulation, transmission line electro-thermal behaviors and ambient changes. The sequences of wind power and ambient factors with fixed time span given in advance are approximately treated as piecewise linear functions of time and incorporated into differential-algebra equations for WPI. Performances of power curtailment and network loss are explored by taking either static or dynamic thermal rating as transmission overload standard to adjust wind farm output.

Vulnerability assessment due to the climate change in Vinh Long province

This work aimed to assess the vulnerability to the climate change (CC) in Vinh Long province till 2020. Inundation, saltwater intrusion (SI), drought, riverbank landslide, storm, temperature and precipitation were taken into consideration. In addition to the socialogical investigation, risk assessment matrix, adaptive capacity assessment methods, etc. the vulnerability to CC was evaluated via index method. Results showed that among 8 districts in the province, Long Ho, Vung Liem, Vinh Long city, and Tam Binh were the most vulnerable. Besides, sectors interested in the relationship to CC include agriculture, infrastructure, and landuse. Indicated vulnerable sectors and areas in the province were important factor for planning suitable coping measures, especially in the context of CC seriously increasing.

How do health and social care professionals in England and Wales assess mental capacity? A literature review

Purpose: To review evidence describing how health and social care professionals in England and Wales assess mental capacity, in order to identify ways to improve practice.Methods: A systematised literature review was completed. Electronic databases of published medical, health and social care research and gray literature were searched. Journal articles and research reports published between 2007 and 2018 were included if they met predefined eligibility criteria. Evidence from included studies was synthesized using thematic analysis.Results: 20 studies of variable methodological quality were included. The studies described assessments carried out by a range of multidisciplinary professionals working with different groups of service users in diverse care contexts. Four main themes were identified: preparation for assessment; capacity assessment processes; supported decision-making; interventions to facilitate or improve practice. There was a lack of detailed information describing how professionals provided information to service users and tested their decision-making abilities. Practice reported in studies varied in terms of its conformity to legal requirements.Conclusions: This review synthesized evidence about mental capacity assessment methods and quality in England and Wales and analyzed it to suggest ways in which practice might be improved.Implications for rehabilitationMental capacity assessment practice in England and Wales varies and is not always consistent with legal requirements, risking inconsistent and inaccurate judgements about capacity and exposure to legal action.Interventions have been developed to help professionals to engage in supported decision-making, and improve their mental capacity assessments and documentation in line with legal standards.These interventions include training and practical resources, such as assessment flowcharts, checklists and documentation aids. Such interventions would benefit from robust evaluation before they are implemented more widely.

Optimizing Nanoparticle Design for Gene Therapy: Protection of Oligonucleotides from Degradation Without Impeding Release of Cargo.

Gene therapy delivery systems that rely on synthetic nanocarriers can be optimized by assays of nucleic acid protection and kinetic studies of nucleic acid release. These empirical measurements ensure nanoparticle stability and predict potential in vivo efficacy. Quantitative methods for assessment of the capacity of nanoparticles to protect oligonucleotide cargo and to measure the rate of release of the cargo were developed and tested based on six commercial cationic matrices. in vitro study of drug release kinetics provides predictable release rates under a variety of conditions which can be adapted to appropriate physiological factors that affect release in vivo. In brief, in vitro DNA release and DNase I degradation assays described here will be useful for optimization of nanocarrier-mediated gene therapy administration by various routes.

Carrageenan-based colorimetric sensor for total antioxidant capacity measurement

As antioxidant consumption is an important way to combat oxidative stress-related diseases, there is a continued interest in developing sensitive, simple and low cost antioxidant capacity assessment methods. In this regard, a novel biopolymer-based colorimetric sensor was designed for total antioxidant capacity (TAC) assessment. Carrageenan polysaccharide was chosen as a building brick of the prepared biopolymeric film. Owing to the anionic sulfate groups of the carrageenan biopolymer, the film exhibited cation exchange properties. The proposed optical sensor was shown to immobilize copper(II)-neocuproine (Cu(II)-Nc) chromogenic reagent cation onto a carrageenan film via sulfate groups. When the Cu(II)-Nc reagent immobilized on the biopolymer film was reduced with antioxidants, a Cu(I)-Nc colored chelate complex would form on the film showing a high absorbance at 450 nm. A number of antioxidants were tested by the proposed sensor so as to compare their trolox-equivalent antioxidant capacities with those found by the original solution-based cupric reducing antioxidant capacity assay, revealing that the biopolymer-immobilized Cu(II)-Nc reagent was still effective in oxidizing antioxidants. The proposed sensor was validated to measure the TAC values of synthetic mixtures, fruit juices and medicinal plant extracts. As opposed to the solution-based method, the sensor worked well in turbid solutions without pretreating samples.

Research on Downhole Risk Assessment Method for Production Wells

At present, because of long offshore oil exploitation time, a large amount of adjusting wells and large offshore oil-gas production, downhole risks are difficult to be evaluated, and safety of offshore oil exploitation faces a great challenge. Aiming at the difficulties, reservoir energy is calculated through PHAST software, and overflow capacity of oil wells is analysed. Based on analysis of factors influencing downhole risks of offshore oilfield wells and analysis of reservoir energy and overflow capacity, a qualitative and quantitative assessment method is proposed for downhole risks of production wells. Downhole risk grades are divided according to the method, and corresponding control measures are proposed. This method is applicable to an offshore oilfield, risk grades of more than one hundred wells are divided, and corresponding control measures are proposed for different risk grades, so that downhole risks are reduced, and safety exploration of the oilfield is guaranteed.