电网物资品控工作的应用实践

伴随我国电网系统的不断发展,对于新建电网的性能要求不断提升,这就要求做好电网物资品控工作通过对电网设备、物资等实施有效的管理,以确保电网系统安全、高效运转。本文在对于电网物资品控工作系统化分析的基础上,对于电网物资品控工作存在的技术标准、招标采购、监造以及保管安装问题进行了研究,并探讨了提高电网物资品控工作效率的策略。     

浅谈配网设计与建设研究

文章的中心就是对存在于国内现阶段设计规划配网,与建设中的一些技术与管理上的不到位的地方,以及根据相关的配网建设要求,把一些看法提出来。阐述电网建设,重点从设计规划配网的思路、影响的重点因素,与布置电源点等方面进行,对如何把电网规划设计做好,以及优选配电网架结构,把一些建议提出来。     

配网规划改造对提升供电可靠性分析

配电网是电网的重要组成部分,在整个电网中发挥着极为重要的作用,所以就对配电网的可靠性有着很高的要求。但是在实际的情况下,影响配网供电可靠性的因素诸多,在管理中又有着许多问题。本文主要阐述了影响配网供电可靠性的因素,并对管理中的一些措施进行了描述,对配网规划改造和提升供电可靠性的影响以及意义进行了分析。     

基于持续抽检的电力物资多阶段动态采购模型及系统

针对电力物资集中采购模式中由于采购批量大、合同周期长而导致的不稳定供应问题,提出一种多阶段迭代修正式的电力物资动态采购模型,运用持续质量抽检进行供应商动态调整。首先根据经济订购批量模型确定最佳招标批次、划分标包,并设定多阶段招标模式及供应商评价指标体系;同时依托供应商绩效评价系统,获取历史抽检数据并迭代预测各供应商物资质量,通过建立标包份额动态分配模型动态修正供应商供应量。通过具体案例对模型进行了示例和验证,并对产品质量与供货量的关联性进行了敏感性分析,为采购方有效控制物资质量、供应商提高中标率提供了指导。最后,介绍了项目组开发的一个基于移动物联网的电力物资送检系统,为本文所提的评价模型提供了可行的实施环境。     

配电网线损管理与在线分析方法研究

配电网损耗在整个电网损耗中所占比重较大,为加强配网线损的管理,需要统计配网实际线损,并将所得的统计线损与理论线损相比较,进行详细分析,寻找薄弱环节,辅助制定降损措施,提高线损管理水平,分析配网损耗的影响因素,提出配网理论损耗与统计损耗相结合进行管理与分析的实现方案。     

10kV配网电力工程的技术问题分析与解决对策

10kV配网在我国电网中占据主要地位,其工程建设技术问题也是电力企业急需解决的重点工作。尤其是在电网迅速发展的今天,这些10kV配网电力工程的技术问题已经成为了10kV配网发展的绊脚石,很大程度上制约了电网的建设与发展。本文从10kV配网电力工程技术常见的几点问题分析入手,针对性提出解决这些问题的科学合理措施,希望能为电力企业提升配网供电能力及质量提供一定的帮助。     

配网技改修理项目管理中存在的问题及其解决措施

配网技改修理项目每年的支出占电网企业开支很重要的一部分,做好项目管理精益化管理对电网的发展有积极的作用。本文在阐述目前配网技改修理项目管理现状的基础上,具体分析其存在的问题,结合配网的实际运行情况提出整改措施和建议,以提高配网技改修改项目管理水平,保证电网安全可靠运行。     

在用计量器具抽样检定方案优化设计

本文探讨了我国现行抽样检定方法存在的缺陷，发现周检合格率相同时，随着计量器具拥有量的不断增大，按现行抽检方案得到的抽检合格率将逐渐下降，它不能正确反映计量器具的实际质量状况。本文设计的抽样检定方案，彻底消除了现行抽样检定方法的缺陷，对于企业贯彻ＧＢ／Ｔ１９０２２．１，完善计量确认体系有重要指导意义     

如何做好配网调控安全工作

经济水平的持续发展和提高增加了我国对电力的需求量,这就向供电企业的生产能力提出了更高的要求。配网调控是电网的构成中不可或缺的一部分。配网调控在电网中的作用主要表现在对电网的运行进行组织和协调,最终为电网的安全使用提供有力的保障。对此,本文阐述了配网调控工作的主要内容,并从多个方面分析了如何做好配网调控安全工作,以此来促进我国电力企业的发展。     

配网自动化建设若干问题及其优化措施

随着社会经济的发展和人们生活水平的提高,对电网的安全稳定运行提出了更高的要求,而配网自动化建设对完善电网结构、保障电网安全稳定运行发挥了重要的作用。本文首先分析了配网自动化建设,然后提出当前配网自动化建设存在的问题,然后就如何加强配网自动化建设,保障电网安全稳定运行提出了几点措施。     

Designing two mixed quick switching sampling plans for linear profiles

This study compares two proposed mixed quick switching sampling (QSS) plans for linear profiles as the quality characteristic. For the QSS plans, we recommend a binomial attribute plan for normal inspection and then a variable sampling plan for tightened inspection based on capability index C_puA of linear profiles with one-sided specifications. The difference between the two proposed QSS plans is in the tightened inspection. Tightened inspection of the first proposed plan is a single sampling using C_puA index, but tightened inspection of the second plan is a multiple dependent state repetitive (MDSR) plan based on C_puA index. The optimal parameters are obtained by nonlinear optimization. Simulation study for selecting parameters is conducted with various combinations of specified acceptable quality level (AQL), limited quality level (LQL), producer's risk, and consumer's risk. Simulation results confirm that the second proposed QSS plan which applies variable MDSR at tightened inspection performs better than another proposed plan. Hence, the approach of the second proposed plan is demonstrated in an illustrative example.     

A resubmitted sampling scheme by variables inspection for controlling lot fraction nonconforming

The paper attempts to develop a resubmitted sampling scheme by variables inspection for controlling lot fraction nonconforming when the quality characteristic follows a normal distribution and has two-sided specification limits. In this paper, the plan parameters are determined by the classical two-point condition on the operating characteristic curve, which will satisfy the quality requirements and allowable risks by the producer and the consumer simultaneously. The behaviour of the proposed sampling plan is discussed and compared with the conventional single sampling plan by variables. The proposed plan requires smaller sample size for inspection with the same protection to the producer and the consumer especially when the quality of the submitted lot is good enough. Tables of the plan parameters under several selected quality requirements and risks are provided for practical applications, and the operating procedure is also presented and illustrated with an example.     

Process-capability-qualified adjustable multiple-dependent-state sampling plan for a long-term supplier–buyer relationship

Acceptance sampling plan is widely used for the inspections of incoming or outgoing products to provide the producer and the consumer a general benchmark for lot sentencing. To reduce the inspection cost, the multiple-dependent-state (MDS) plan that takes account of the preceding lots' quality history into the current lot disposition has been proposed. However, recent studies overlook the fact that the MDS plan's performance needed to reach target compliance decreases with an increase in the number of preceding lots considered. This unawareness makes the MDS plan fall into a conflictive situation. To overcome the drawback of the MDS plan, in this paper, we introduce a modified MDS plan to accommodate an adjustable mechanism, called adjustable MDS (AMDS) sampling plans. The presented AMDS plans are designed on the basis of the advanced process capability index, which is cognizant of both the process yield and the process loss. This established process-capability-qualified AMDS plan efficiently solves the conflictive situation of the MDS plan when encompassing more preceding lots in the lot-disposition decision. Notably, its efficacy has been shown on high improvements in terms of the required sample size for the inspection, the discriminatory power, and the average run length for lot sentencing.     

Developing a variables multiple dependent state sampling plan with simultaneous consideration of process yield and quality loss

Acceptance sampling plans have been utilised predominantly for the inspection of outgoing and incoming lots; these plans provide effective rules to vendors and buyers for making decisions on product acceptance or rejection. Multiple dependent state (MDS) sampling plans have been developed for lot sentencing and are shown to be more efficient than traditional single sampling plans. The decision criteria of MDS sampling plans are based on sample information not only from the current lot but also from preceding lots. In this study, we develop a variables MDS sampling plan for lot sentencing based on the advanced process capability index, which was developed by combining the merits of the yield-based index and loss-based index. The operating characteristic function of the developed plan is derived based on the exact sampling distribution. The determination of plan parameters is formulated as an optimisation model with non-linear constraints, where the objective is to minimise the sample size required for inspection and the constraints are set by the vendor and the buyer to satisfy the desired quality levels and allowable risks. The performance of the developed plan is examined and compared with traditional sampling plans. A step-by-step procedure is provided, and the parameters of the plan under various conditions are tabulated for practical applications.     

Developing a variables repetitive group sampling scheme by considering process yield and quality loss

Acceptance sampling is a useful tool for determining whether submitted lots should be accepted or rejected. With the current increase in outsourcing production processes and the high-quality levels required, it is very desirable to have an efficient and economic sampling scheme. This paper develops a variables repetitive group sampling (RGS) plan that accounts for the process yield (meeting the manufacturing specifications) and the quality loss (variation from the target). The plan parameters are determined by solving a nonlinear optimisation problem. This implies that the plan parameters minimise the average sample number required for inspection and fulfil the classical two-point conditions on the operating characteristic (OC) curve. Besides, this paper investigates the efficiency of the proposed plan and compares it with the existing variables single sampling plan. Tables of the plan parameters for the proposed variables RGS plan are provided and an application example is presented for illustration.     

Variables Sampling Plan for Resubmitted Lots in a Process with Linear Profiles

Acceptance sampling plans include a sampling scheme and a set of rules for determining whether an inspection lot from a supplier should be accepted or rejected. In some circumstances, the supplier is allowed to resubmit lots for further inspection when the original inspection result is unacceptable. In this study, two variables sampling plans based on the process‐yield index for a process with linear profiles are proposed to deal with lot sentencing. The single sampling plan is a special case of the resubmitted lots sampling plan. The plan parameters are determined using a nonlinear optimization method under the given values of producer's risk, consumer's risk, acceptable quality level, and lot tolerance percent defective. Numerous tables are provided to determine the plan parameters. One real example is used to illustrate our proposed method. Copyright © 2015 John Wiley & Sons, Ltd.     

A quick switching sampling system by variables for controlling lot fraction nonconforming

This article develops a new sampling scheme by variables inspection, namely a quick switching sampling (QSS) system based on the process yield index for lot determination when the quality characteristic is normally distributed with two specification limits. The QSS system can provide a flexible sampling procedure by switching decision policies, normal inspection and tightened inspection. The operating characteristic curve of the proposed QSS system is derived and required to pass through two designed points, acceptable quality level and limiting quality level for satisfying risks simultaneously suffered by the producer and the consumer. The proposed sampling system’s performance is investigated and a comparison with the conventional variables single sampling (VSS) plan is also examined. The results indicate that the proposed system outperforms the VSS plan by requiring a smaller sample size for inspection while retaining the same protection. For practical purposes, the plan parameters’ tables are provided on the basis of various selected quality requirements and risks. Finally, we demonstrate the proposed sampling system using an example taken from a silicone LED lens industry.     

Dependent Mixed and Mixed Repetitive Sampling Plans for Linear Profiles

In this paper, we present two new dependent mixed sampling plans and a mixed repetitive sampling plan based on the process yield index for linear profiles. A mixed sampling plan includes two stages; the first stage is a combined test by variables and by attributes, and the second stage is tested by attributes only. The first plan is based on the traditional mixed sampling scheme without marginal quality, and the second plan is based on the modified mixed sampling scheme with marginal quality. If a lot is very bad, the probability it can be rejected with the small initial sample is higher for dependent mixed sampling with marginal quality. We compare dependent mixed plans with other types of double sampling plans; the former outperforms the others with respect to average sample number. Additionally, the number of profiles required in the first stage is much smaller than in the second stage. When the inspection is costly and destructive, a mixed repetitive sampling plan includes one stage that combines the inspection by attributes and by variables and allows resampling in some conditions. We compare the mixed repetitive sampling plan with the repetitive sampling plans by attributes and by variables. The probability of acceptance using the mixed repetitive sampling plan performs better than the repetitive sampling plans by attributes and by variables. Three examples are used to illustrate the proposed methods. Copyright © 2017 John Wiley & Sons, Ltd.     

A Novel Lot Sentencing Method by Variables Inspection Considering Multiple Dependent State

A good acceptance sampling plan is necessary for quality control, and different acceptance sampling plans have been developed to meet different purposes. Under a multiple dependent state (MDS) sampling plan, the lot disposition is not only based on the current sample from the lot but also on the sample results from preceding lots. This paper aims to develop a variables MDS sampling plan for normally distributed processes with two‐sided specification limits. In the proposed MDS sampling plan, the operating characteristic curve is derived based on the exact sampling distribution. The performance of the proposed plan is investigated and compared with the existing variables single sampling plan. Copyright © 2015 John Wiley & Sons, Ltd.     

Variable stage-independent double sampling plan with screening for acceptance quality loss limit inspection scheme

The quality loss suggested by Taguchi has been recognised as a new quality evaluation based on variable property instead of the quality evaluation based on traditional attribute property such as the proportion of nonconforming items. Some variable sampling inspection plans in order to assure the quality have been considered. As one of those sampling inspection plans, the single sampling plan with screening (SSPS) has been constructed for acceptance quality loss limit inspection scheme. Further, the repetitive group sampling plan with screening (RGSPS) has been developed for reducing the average total inspection (ATI). Although ATI by RGSPS has successfully been reduced in comparison with ATI by SSPS, RGSPS may sometimes increase the average sampling frequency (ASF) in return for reducing ATI. In this study, the stage-independent double sampling plan with screening (SIDSPS) based on the concept of the acceptance quality loss limit inspection scheme is proposed under the consideration of the trade-off between ATI and ASF. Through some numerical comparisons about ATI and ASF in SSPS, RGSPS, and SIDSPS, the usefulness of SIDSPS proposed in this study is confirmed.