Blind Number Theory Research Articles

Mobile power sources pre‐allocation and dispatch strategy in power‐transportation coupled network under extreme weather

AbstractThis study introduces a strategy for the pre‐allocation and dispatch of mobile power sources (MPSs) within a power‐transportation coupled network, targeting efficient distribution network fault recovery under extreme weather conditions. The strategy incorporates the Dijkstra algorithm and blind number theory to analyse the MPS driving path and generate fault scenarios respectively, considering the effects of extreme weather on traffic capacity and distribution network fault rate. The MPS pre‐allocation model, formulated to minimize the load outage loss, MPS investment, and driving fuel cost, provides a foundation for optimization of the dispatch process. The dispatch optimization model adapts to dynamic information from the power‐transportation coupled network to make decisions on load restoration sequencing and MPS driving path. The effectiveness of the proposed strategy is demonstrated through an application to the IEEE 33‐node distribution system and a corresponding 33‐node transportation network.

Reliability Investigation of Pavement Performance Evaluation Based on Blind-Number Theory: A Confidence Model

The evaluation of in-service pavements’ performance is a complex system that encompasses a variety of uncertain factors. These uncertainties include random, fuzzy, gray, and unascertained information, and their interrelationships are intricate, making comprehensive quantification unachievable. Nonetheless, current highway management organizations rely on a comprehensive indicator, namely, the Pavement Quality Index (PQI), to assess the level of pavement performance. This paper introduces a novel approach that employs blind number theory to evaluate the reliability of pavement performance test data. The proposed method aims to enhance the representativeness of PQI and is demonstrated using detection data from highway asphalt pavements in Hunan Province. The method takes into account the probability distribution characteristics of evaluation metrics and incorporates the blind number representation format of PQI. A confidence model for pavement performance evaluation is established to assess the reliability of pavement detection results. The method also integrates expert empowerment and entropy weight to consider both the subjectivity of evaluation and the objectivity of measured data. The method presented in this study has demonstrated superior performance compared to traditional evaluation index systems. This is attributed to the effective utilization of blind information to accurately characterize the discreteness of pavement performance indexes. Consequently, pavement performance can be quantitatively graded based on anticipated issues and data.

Cost Analysis of Synchronous Condenser Transformed from Thermal Unit Based on LCC Theory

With the development of large-scale renewable energy consumption and multi-infeed high voltage direct current (HVDC) systems, the demand of a system for the synchronous condensers with a strong dynamic reactive power support capacity and a strong short-time overload capacity is increasing. Meanwhile, with the reuse of a large number of retired thermal units, the most practical and economic way is to transform thermal units into synchronous condensers. The cost difference in the life-cycle of the synchronous condenser transformed from a thermal unit (SCTTU) and the newly established synchronous condenser (NESC) is a key factor that affects the decision-making and construction of the transformation from thermal unit to synchronous condenser. However, the life-cycle cost (LCC) of the synchronous condenser transformed from a thermal unit and the newly established synchronous condenser contains many uncertain factors, which affect the accuracy of the LCC estimation value. In order to quantify the impact of the blind information on the cost of the synchronous condenser station, blind number theory is introduced to establish the blind number model of the LCC of the synchronous condenser transformed from a thermal unit and the newly established synchronous condenser. Additionally, the LCC of the NESC and SCTTU with a different life-cycle under the capacity of 2 × 300 MVar are estimated. The results show that the cost of the SCTTU with a long service life of more than 15 years is significantly lower than that of the NESC and, thus, the SCTTU has better economic performance. The economic performance of the SCTTU with a life-cycle of less than 15 years is not better than that of the NESC. Compared with the traditional calculation method of a single cost value, the blind number model can obtain the possible distribution interval of LCC and the reliability of the corresponding interval, which makes the estimation results more valuable for practical engineering reference.

Power source flexibility margin quantification method for multi-energy power system based on blind number theory

The grid connection of high proportion of renewable energy generation increases the uncertainty of power system. Therefor the flexibility margin of different energy sources needs to be quantified to cope with the uncertainty change and maintain the dynamic balance of power system flexibility. In this paper, firstly, the flexibility characteristics of source, net, load and power and load community (PLC) are analyzed. The dynamic equilibrium relationship among them is briefly introduced. Secondly, taking into full consideration the complex output characteristics of different energy sources and combining their respective flexibility characteristics, a quantitative model of the power source flexibility margin for thermal power, hydro-power, gas power and concentrating solar power was established. A quantitative model of the power source flexibility margin of PV and wind power based on blind number theory was established. Furthermore, the calculation method of theoretical power generation capacity which can reflect different characteristics of output power of various energy sources is presented. The actual output power of each power source in each period is predicted. Finally, a case study shows that the model and method can consider the operating characteristics of different types of power sources, and quickly and accurately quantify the adjustable range of flexibility margins of each power source at different periods of time, which can provide an important basis for evaluating the capacity of renewable energy consumption and the optimal operation of multi-energy power system (MEPS).

Interval Multi-Objectives Optimization of Electric Wheel Dump Truck Frame Based on Blind Number Theory

With respect to heavy carrying tasks and uneven road surface in open pit mine, the mechanical performances of electric wheel dump truck frame regarded as the main bearing component are extremely important for its safe operation. For the problem of insufficient strength and stiffness, an interval multi-objectives optimization design method based on blind number theory is presented in this paper, taking into account uncertain factors caused by manufacturing process. The allowable interval strength of welding material and permissible interval bending and torsional stiffness are obtained by means of experiments and simulations, using the blind number theory. Based on Latin hypercube sampling technique, the strength and stiffness of frame under different conditions is estimated. It shows that in the case of braking interference between interval strength and interval dynamic stress appears. Strength and stiffness are considered as optimization objectives, while the thicknesses of top longitudinal beam, stiffener, lateral longitudinal beam and hanging ear in the frame are deeded as design variables, and Young’s modulus and Poisson’s ratio are taken as uncertain variables. The optimized results show that the stress and deformation of the frame due to dynamic loading decreased. This result enables to formulate the following sentence: the mechanical performance of frame is improved.

Uncertain flow calculations of a distribution network containing DG based on blind number theory

A large number of distributed generations (DG) integrated into a distribution network challenge the planning for traditional power systems making traditional deterministic power flow calculations not applicable. Based on the interval and credibility of the blind number theory, this study is about the uncertainty of DG and the correlation between DGs. The interval models for wind power and solar power are established based on the characteristics of the wind power generator output and the photovoltaic cell output. The improved analytic hierarchy process is applied to determine the credibility of the intervals. The blind number theory and Cholesky decomposition are applied to study the correlation between wind speed and light intensity. According to the result of the power flow calculation with uncertainty, the voltage operational quality index is proposed to measure the impact of the DG. Through a modified IEEE 33-bus system, the feasibility and effectiveness of the blind number model for the DG and the necessity of considering the correlation between wind speed and light intensity are verified.

Estimation of Voltage Sag Loss Based on Blind Number Theory

Serious power quality issues and huge economic loss can be caused by voltage sag. It’s helpful for grid corporation to estimate voltage sag loss. Voltage sag and influence of sensitive equipment are analyzed in the paper. An estimation method of voltage sag loss based on blind number theory is proposed, which takes the sag magnitude and duration as its main characteristic parameters. First euclid distance and relative close degree between the sag magnitude and duration of voltage sag samples and threshold values is calculated based on TOPSIS. According to relative similarity degree，probable value, credibility and mean value of voltage sag loss are then calculated and influence of uncertainty factor can be considered. Example analysis shows that loss estimation method is a feasible and applicable for most sensitive equipments.

Water Quality Evaluation Based on Entropy Coefficient and Blind Number Theory Measure Model

The blind number theory was applied to define the blind numbers of the parameters of environmental system according to the characteristics of several kinds of uncertainties coexisting in water environmental system. Entropy coefficient method was calculate indicator weight based on the differences of water evaluation indicators and effectively solve the problems of weight calculation and effect of subjective factor. On this basis, A new model for water quality evaluation that is representative of overall water quality of river stretch was established based on water quality comprehensive index evaluation model. The results of simulation case study showed that comparing with the deterministic model is feasible and reliable.

Sensitivity Analysis Method of Uncertainty Based on Conditional Entropy

In order to reduce uncertainty of maintenance support analysis result, the article puts forward a method to analysis the sensitivity of result uncertainty on input parameter. Firstly, the paper analysis the uncertainty measurement methods and uncertainty production mechanism of model output result. Secondly, the sensitivity parameter and sensitivity analysis method which based on conditional entropy thought are given. Thirdly, it briefly introduces blind number theory used in analysis data with uncertainty. Finally, combined with the mean maintenance time model case, the paper illustrates the availability of uncertainty sensitivity analysis method and proves the conclusion that uncertainty sensitivity analysis cant be equated to derivation.

Transformer Economic Life Assessment Based on Blind Number Theory

Because of lacking technical and economic theory support, running transformer life assessment work often goes to disorder, thus constructing transformer assessment new model of economic life has a certain practical significance. Because of the transformer serving for a long time and the running environment being complicated, factors that influence the assessment of transformer economic life have a certain characteristic of a variety of coexistence or cross-existence. Due to this characteristic, introduce blind number theory into transformer life assessment, use blind number express evaluation parameter uncertainties, and establish transformer economic life evaluation model. This model not only can get transformer economic life expectancy, but also can obtain economic life interval under different confidence level An example shows that blind number theory applied to the transformer economic life assessment is feasible and effective, which can provide more detailed and diversified information for decision makers and have a certain reference value.

Transformer Remaining Life Assessment Based on Blind Number Theory

Because of the transformer serving for a long time and the running environment being complicated , factors that influence the assessment of transformer remaining life have a variety of uncertainties coexistence or cross-existence. Due to this characteristic, introduce blind number theory into transformer life assessment, use blind number express evaluation parameter uncertainties, and establish transformer economic life evaluation model based on comprehensive health index .The model not only can give health status of the transformer and state level ,but also give remaining life expectancy ,remaining lifetime interval and corresponding credits, possibility of not more than a certain year.

考虑系统元件故障不确定性的电压暂降盲数评估

系统元件可靠性参数和电压暂降评估结果的不确定性刻画方式对评估结果的可信性和工程应用价值有重要影响。本文基于盲数理论提出考虑复杂不确定性的元件可靠性参数盲数刻画模型和电压暂降评估方法。在研究元件可靠性参数盲数模型及算法的基础上，结合电压暂降解析式评估法，建立了电压暂降盲数评估模型，并研究具体算法。在得到评估结果的可能取值区间和可信度的基础上，通过求取盲数均值得暂降频次定量评估结果。对IEEE-30节点测试系统进行仿真并与现有方法比较证明，所得结果准确，同时具有点值法和区间法的优点，不仅能获得暂降频次的可能区间取值，而且还能获得取值可信度，更满足工程应用需要。 The way to depict the uncertainty of components reliability parameters and voltage sag evaluation results has significant influence on the credibility of evaluation results and engineering application value. Based on the blind num-ber theory, this paper proposed a new method to depict components reliability parameters and voltage sag evaluation results. Introducing the blind number into depicting the multiple uncertainties of components reliability parameters, combining the advantage of the analytical method to assess voltage sag, this paper establish the model of evaluation voltage sag on the base of the blind number and research on the specific evaluation algorithm. Upon obtaining the possible interval of voltage sag frequency and the corresponding credible degree, this paper take the blind number ex-pectations of evaluation results as voltage sag frequency evaluation results. The proposed method had been applied to the IEEE-30 bus test system, the simulation results have shown that the evaluation results have high accuracy, including the advantage of deterministic method and interval number method, this method can not only give the possible interval results but also the corresponding credible degree, better satisfying the engineering applications.

Reliability Optimization Design Based on the Blind Number Theory

The concept and operation rules of the blind number based on Unascertained Theory are introduced. This case study demonstrates the advantage of unascertained theory described in reliability optimization, and a stress-strength reliability optimization design model is built up at same time. In addition, the corresponding practical optimization calculating program is given. Test on the validity and practicability of this model is also verified by comparing the result of reliability gained from this model with that obtained from the traditional reliability-design method.

Temporal and Spatial Simulation of Adsorbed Nitrogen and Phosphorus Nonpoint Source Pollution Load in Xiaojiang Watershed of Three Gorges Reservoir Area, China

The presence of nonpoint source (NPS) pollution due to agricultural activities at the Three Gorges Reservoir Area in China has been of concern to the public in recent years. Due to the extent of the polluted area and seasonal dispersion mode, sediments have greatly impacted the water quality in the area. Generation and formation of adsorbed NPS pollution involves great uncertainty, which makes monitoring and controlling pollution very difficult. Rainfall erosivity factors, which are calculated by surface rainfall data from watershed hydrological simulation, and sediment delivery ratios were both selected and determined as the dynamic factors, whereas blind number theory was introduced and used to describe and deal with the factors' uncertainty of the Revised Universal Soil Loss Equation (RUSLE). Through the integration among blind number theory, dynamic factors, and pollution load model, parameter uncertainty and model dynamics could be better understood in the new and comprehensive pollution load model using GIS technology. Results indicated that rainfall runoff and sediment delivery ratio had significantly affected the uncertainty of final adsorbed NPS pollution load simulation results; the magnitude of adsorbed nitrogen and phosphorus loads from different land use types in descending order in turn was glebe, grassland, paddy fields, forestland, and urban land. This work provides a theoretical basis for control and management of soil loss and NPS pollution in the Three Gorges Reservoir Area, and these data are also useful in evaluating potential soil loss and NPS pollution loads in the watershed.

Calculation Method of Mechanical Structure Complex Time-Dependent Reliability with Blind Number Theory and its Implementation

The basic ideas of expressing uncertain variables with blind number were introduced. The mechanical structure time-dependent characteristics variation in stochastic process was deduced. A time-dependent reliability calculation model was built with blind number theory. The numerical method based on blind number was applied to solve this complicated computing model. A LabVIEW program was compiled, and a frame beam’s time-dependent reliability was computed. The result shows the method based on blind number is very convenient and effective in solving the complicated reliability calculation model. In this method, the structure time-dependent reliability can be predicted quickly based on the historical data.

Research on New Numerical Calculation Method for Reliability of Mechanical Strength Based on Blind Number Theory

The uncertainty variable in mechanical design is expressed in blind number and the relation among variables is expressed in the operation rule of blind number; By combining the reliability design theory with blind number calculating method, the reliability of the mechanical elements with arbitrary distribution parameters and discrete test data is discussed; and a numerical method for mechanical reliability based on blind numbers is presented. Besides, the typical examples show that the method is reasonable and effective.

Estimation of non-point source pollution loads under uncertain information

Many kinds of uncertainties are involved, such as random, fuzzy, grey, unascertained property and so on, in soil erosion process. To exactly predict the non-point source pollution loads, some uncertainties should be taken into consideration. Aiming at the deficiency of present blind number theory being helpless for fuzziness, a novel blind number, i.e. extended-blind number, was introduced by substituting a set of triangular fuzzy numbers (TFNs), expressed as α-cuts, for interval values in present blind number, and the expected value of extended-blind number was also brought forward by referring to the current blind number theory. On the basis of denoting the parameters of Universal Soil Loss Equation (USLE) as extended-blind parameters, a novel USLE model was established for quantitatively evaluating soil erosion loss and non-point source pollution loads. As a case, the uncertain USLE was employed for predicting the soil erosion loss and non-point source pollution loads of absorbed nitrogen and phosphorus in a district in the Hangbu-Fengle River basin, in the upstream of Chaohu Lake watershed. The results show that it is feasible in theory to extend blind number into fuzzy environment and reliable on conclusion to apply extended-blind number theory for predicting non-point source pollution loads.

Risk analysis on groundwater resources carrying capacity based on blind number theory

Blind numbers of evaluation indices about groundwater resources carrying capacity are defined from the concomitancy of randomness, fuzziness, grey property and unascertainment of groundwater system. Based on fuzzy theory, a comprehensive evaluation model on groundwater resources carrying capacity is constructed with blind information. Then a risk assessment model of surcharge about groundwater resources carrying capacity is established on blind reliability theory. The probable value “*” matrix of fuzzy membership degree about carrying capacity corresponding to each judgment level can be obtained with the aid of blind algorithm as well as the subjective reliability “×” matrix. And then a graph of “groundwater carrying capacity v.s. accumulative reliability” can be gained. Based on the graph, fuzzy membership degree of groundwater resources carrying capacity to each judgment level under different risk probability can be got. Thus, a comparatively reasonable judgment to groundwater resources carrying capacity might be obtained, with comprehensive analysis to the state of society, economy technology and ecology.