Standby power generation under utility curtailment contractagreements

Many electric utilities in the United States offer large industrial and commercial customers power sales contracts which have attractive rates under a curtailment requirement. This curtailment requirement allows the utility to require the customer to reduce its power demand to a predetermined level within a specific time period. If the required curtailment is not achieved by the customer within the allocated time period, stiff financial penalties are usually enforced by the utility. The attractiveness of the contract rates usually is proportional to the amount of curtailment required. To take advantage of these attractive rates, a customer must be able to withstand the curtailment without supplemental generation or must add standby generation to meet its needs. Obviously, the cost of the curtailments to the customer should not exceed the economic benefits of reduced rates. This paper reviews the alternatives faced by a curtailment contract customer together with potential load-shedding and standby-generation system designs. An example of implementing a curtailment contract at an existing industrial facility is presented. The example facility. Boeing Helicopters, Philadelphia, PA, USA, required both load shedding and standby generation. The load-shedding scheme is fairly complex and is controlled by a programmable logic controller (PLC). The standby-generation and load-shedding systems for the example facility are examined in detail. Also, lessons learned from implementing the required modifications to the example facility are discussed     

Classification and quantification of reserve requirements for balancing

In electrical power systems there must always be a balance between supply and demand of power. Any imbalance will result in a frequency deviation. To reduce the imbalance to zero, ancillary services for balance management are in use. Ancillary services for balance management are characterized by their deployment time and their capacity. These ancillary services as well as the requirements for balance management can be characterized in the frequency domain. Actors, that are responsible for maintaining the balance in the system, can use the characterization in the frequency domain to define their needs for reserve capacity. This paper describes a method for spectral analysis of the required and available reserve capacity.     

台山核电站二期工程消防供水设施配置分析

台山核电站二期工程正在筹建,拟采用改进型先进压水堆（EPR）核电技术。为合理配置消防供水设施,结合台山核电站一期工程及岭澳核电站二期工程消防供水设施配置情况,分析了消防供水设施对应急供水系统和燃料水池冷却与净化系统的影响,并对消防供水设施功能进行定位及分级,最终提出了台山核电站二期工程优化设计方案。该方案与台山核电站一期工程消防系统配置比较,在满足核电厂防火设计规范（核安全导则HAD102/11）、EPR机组技术要求和确保电站安全运营前提下,可节省资源和降低造价。     

地下电缆探测技术在供电生产管理中的应用

针对城市规模的不断发展、电网电缆化率的不断提高,供电生产部门对电缆相关的设备设施空间数据提出越来越高的应用要求,本文研究了地下电缆相关设施的地下位置探测、地面位置测量、电缆设施数据建模和电缆设施空间数据应用的可行方法,并提出经过广泛应用验证的公式、模型和案例,以期为电缆供电生产管理提供有价值的参考经验。     

Multiple Levels and Classifications of Emergency Electrical Power Systems

Today, designers are faced with the challenge of ensuring that all important facility functions are protected from power failures both externally and internally by providing one or more backup supply to the primary source (typically utility service). Each application has its own unique requirements of the Emergency Electrical Power Systems (EEPS) for performance, reliability, and speed to assume the load, and the length of time it must be able to provide emergency power. Lack of industry-wide definitions and standards are severely limiting the availability of equipment and services from which the users can make the best choice for his particular needs. To solve these problems, organizations such as IEEE, EMA, UL and NFPA are now, through representatives of users, the insurance industries, consulting engineers, inspectors, and manufacturers, engaged in an effort to develop definitions and guidelines. Some of the basic problems are explored, the rationale behind the present industry efforts to find a solution is given, and an approach using multiple levels and classifications of Emergency Electrical Power System is suggested.     

INFI-90和WDPF-Ⅱ分散控制系统应用比较

通过分析嵩屿电厂1、2号机组INFI 90和WDPF Ⅱ两套分散控制系统的实际应用情况,从系统网络结构、模件的备用方式、供电方式、软件系统的易用性及模件质量可靠性等方面对两套系统进行比较,从用户的角度对这两套系统作出评价。     

电磁弹射系统的脉冲功率源设计

为了解决盘形线圈弹射装置发射需要用于改变弹射体的发射方向的2个正交时变磁场,研制了由2个独立模块构成的脉冲功率源装置。每个模块的储能为300 kJ,由6个电容、改进的大功率火花隙开关、续流二极管、高频PWM整流器及用于脉冲成型网络的同轴电缆输电线组成,且每个电源模块可经光纤控制器单独触发,通过改变触发脉冲的延迟时间改变发射方向(在10 ms到几μs间)。为减小电磁干扰和电磁力的影响,使系统具有高灵活性和可靠性,改进了脉冲电源模块中元器件的位置及其结构,每个模块所能承受最大电压5 kV,放电电流峰值达200 kA。实验结果表明,研制的脉冲功率源输出电流大、安全可靠、结构紧凑、操作方便、性能满足电磁弹射研究的需要。     

Users' Needs Space Conditioning, Fire Protection, Data Processing, Life Support and Life Safety Systems, Communication Systems, and Signal Circuits

The needs for site-supplied emergency or standby backup electric power have been demonstrated many times. For some types of equipment and applications, insurors and regulatory agencies stipulate that adequate backup must be provided. In many cases, sorely needed redundant supply is not provided due to complacency because of unawareness of possible costly problems or to ignorance of requirements. The legal entanglements and costly problems arising from an unexpected power failure shutting down the following facilities and those previously discussed should be thoroughly analyzed. This paper discusses situations and systems requiring analysis in the categories of fire protection, signal circuits, communication systems, data processing, space conditioning, and critical life systems. An attempt will be made to highlight how dependent our total existence is on electrical energy from sources outside of our control. Attention being directed to problem areas will help in determining how much backup, or firm power, electrical equipment is sufficient insurance against ``the day the lights went out' and how much is pure luxury.     

高效率R78开关稳压器的设计与研究

随着现代电力电子技术的飞跃发展,直流电源的功率密度发生了质的变化,开关电源基本上全面替代线性电源,广泛应用于计算机、通信设备、办公设备、仪器仪表和照明设备等现代电子电器设备。效率可达97%的开关稳压器R78完全兼容低效率线性集成稳压器78系列。重点对线性稳压器和开关稳压器的特性进行了分析对比,给出R78开关稳压器在现代电源电路中的设计与应用,对R78系列开关稳压器电磁兼容特性和低纹波设计进行了研究。     

基于GIS的供电方案辅助决策系统的设计与应用

通过分析基于GIS的用户供电方案智能辅助决策系统的架构、功能和应用效果,利用GIS地理信息系统的二维、三维图形和数据库技术,实现了电网图形化管理和变电、输电、配电各专业的数据整合及共享,为公司生产、营销等相关专业提供电网和用户资源的编辑、查询统计、分析、专题图、供电方案辅助设计等服务,实现企业设施资源、客户关系、设计规划等业务管理的信息化与智能化,基本满足本单位实际工作的需求。     

低压供电可靠性故障模拟算法研究

针对用概率统计方法统计低压用户供电可靠性工作量超大的问题,研究如何进行电力系统设备故障模拟及其算法的实现。根据低压系统可靠性模型可建立其可靠性模拟数据库。电力系统故障服从泊松分布,根据各类设备的运行数据即平均故障率,计算出该类设备故障次数的分布曲线。采用随机取样的方法产生本次故障次数以及故障设备编号。该模拟算法简单清晰、易于实现。     

低压直流供电系统电气设备电击风险评估方法

低压直流(LVDC)供电系统的电击风险需要合适的评估方法对其进行量化.首先,文中根据电气设备安全性要素组合,结合LVDC供电系统特点,分析了LVDC的电击风险点.然后,建立了综合考虑伤害严重程度、暴露在危险中的可能性和限制伤害可能性这3个要素的LVDC供电系统电气设备5级电击风险评估模型.评估模型将输入的3个参数组合映射为5级电击风险评估结果.最后,以实际系统中的不同电压等级的设备为例,验证了所提方法的有效性.     

Dual-mode power reactor facility based on a heterophase thermionic converter reactor

The use of a heterophase thermionic converter reactor is suggested as a possible solution to the problem that relates to the development of a dual-mode power reactor facility. Two specialized subsystems of thermionic electricity-generating channels are applied in this thermionic convertor reactor to provide for its extended service life. The thermionic electricity-generating channels of the first subsystem are used to ensure a full power mode in a relatively short period of time, while the thermionic electricity-generating channels of the second subsystem are necessary to provide for a long service life. Under the full power mode, both subsystems of the thermionic converter reactor are connected in parallel to the total load, while in the mode of a durable power supply only the second subsystem acts as a source of electric power. The power reactor facility, based on such a thermionic converter reactor, is capable to ensure the power supply for an electro-propulsion system, with a maximum capacity of 150 kW operating up to 2 years, as well as for a spacecraft apparatus, with a capacity of 60–80 kW and a corresponding service life of 10 years or longer.     

火力发电厂水务管理现状及节水对策

通过对照比较国内外火电厂的耗水指标,介绍了我国火力发电厂水务管理现状。指出我国火电厂水务管理中存在的主要问题,并给出了相应的节水对策,如规范用排水收费制度、提高循环水浓缩倍率要和冲灰系统改造配套进行、干除灰技术改造必须配套干灰储存设施、将废水分类进行收集、处理、回用等,为火电厂的节水降耗和安全经济运行提供理论指导。     

Optimal frequency tracking method for phase‐shift PWM inverter

This paper proposes a new resonant frequency tracking control method for full‐bridge‐type high‐frequency inverters. Whereas the ordinary phase‐locked loop (PLL) based frequency control method uses a current sensor and a voltage sensor, the proposed technique can achieve the same purpose with a single current sensor. In high‐frequency power supply systems using a PLL, it is impossible to perform power control with an inverter. Therefore, an active converter must be used for power control, and the system grows larger. On the other hand, high‐frequency inverters using the proposed control system simultaneously enable power control and achieve the same resonant frequency tracking as a PLL, and thus high‐frequency power supply systems become extremely simple. This paper explains in detail the principle underlying the control method, and presents an example of a circuit to realize it. The theory is backed up by using a prototype high‐frequency power supply system which actually employs the proposed control system, thereby demonstrating its practical utility in industry. © 2012 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

Comparative evaluation of different power management strategies of a stand-alone PV/Wind/PEMFC hybrid power system

This study presents different power management strategies of a stand-alone hybrid power system. The system consists of three power generation systems, photovoltaic (PV) panels, a wind turbine and a proton exchange membrane fuel cell (PEMFC). PV and wind turbine is the main supply for the system, and the fuel cell performs as a backup power source. Therefore, continuous energy supply needs energy storing devices. In this proposed hybrid system, gel batteries are used. The state of charge (SOC), charge-discharge currents are affecting the battery energy efficiency. In this study, the battery energy efficiency is evaluated with three different power management strategies. The control algorithm is using Matlab-Simulink®.     

全域电网资源聚合架构的研究与应用

为满足电网企业信息系统日益增长的对完整、准确、及时、一致的电网资源信息的需求,克服传统自治系统架构模式的信息重复采集、难共享、不一致等问题,以及一体化大系统难于扩展和维护的问题,提出了涵盖电网设备配置、网络拓扑、需求侧对象等核心要素,聚合设备域、网络域、客户域3个方面的全域电网资源聚合架构。此架构以全域电网资源集成机制...     

新一代低压直流供用电系统在“新基建”中的应用技术分析及发展展望

为应对当今社会发展所面临的能源、环境、经济等压力,以5G基站、充电桩等为代表的基础设施建设成为新时期经济发展的重点。新型基础设施电力供应系统的选择和建设至关重要。该文首先概述新基建的内容演变和意义,分析普遍具有负荷直流化的特征。其次介绍新一代低压直流供用电系统(low voltage direct cur-rent supply and utilization system,LVDCSUS)及其内涵与特征,然后分析新基建不同领域电力供应系统的共性和个性需求,指出以LVDCSUS作为5G基站、数据中心、新能源汽车充电桩、直流绿色建筑、智能家居、工业互联网、农村及边远地区等7种不同领域基础设施电力供应系统的优势。进而从顶层设计、政策支持、思维方式、技术创新和核心设备、发展路线等维度探讨了新基建背景下LVDCSUS的发展方向并提出具体建议,提出关键技术和核心设备的研发方向,提出直流系统全链条、生态建设的建议。最后给出结论,在供用电领域,新一代低压直流供用电系统已经可以成为交流电源的辅助和替代,并有望成为一种新型的数字化供用电系统。     

Comparative evaluation of two models of UPQC for suitable interface to enhance power quality

Majority of the dispersed generations from renewable energy sources are connected to the grid through power electronic interface, which introduce additional harmonics in the distribution systems. Research is being carried out to integrate active filtering with specific interface such that a common power quality (PQ) platform could be achieved. For generalized solution, a unified power quality conditioner (UPQC) could be the most comprehensive PQ protecting device for sensitive non-linear loads, which require quality input supply. Also, load current harmonic isolation needs to be ensured for maintaining the quality of the supply current.     

对城市供电设施小型化的几点认识

在我国大城市城区征地费用越来越高和征地越来越困难的条件下,以如何使220kV和550 kV超高压直接供电的供电设施小型化、低噪声、防爆、环保,并最大限度减小占地面积为前提,介绍了目前电网中已投运或即将运行的小型供电设施,如组合电器、超导电缆、气体绝缘变压器及超导变压器等的研发和应用情况,可为我国在城市超高压供电方面解决现有设施体积过大等问题提供参考.