Reliability and quality of heat supply as priorities of SNiP (Construction Code and Regulations) 41-02-2003: Heat supply networks

The difference between the new Construction Code and Regulations and the SNiP (Construction Code and Regulations) 2.04.07-86*: Heat Supply Networks is shown. The set of new codes for the design of heat supply networks is presented, and the regulations are pointed out deviating from which may inflict damage to the health and safety of population, and to the environment. Criteria of heat-supply network reliability are considered in detail.     

基于弃风消纳的热网主动储热优化

为解决由热电联产机组热电耦合特性所引起的弃风现象,基于热负荷可调性,提出基于热网主动储热的综合能源系统运行优化策略。通过分析不同场景下机组输出功率、热网储热效果及等效热负荷变化情况,分别探究了热网被动储热和热负荷可调性对风电消纳和系统运行性能的影响。结果表明：热网被动储热和柔性热负荷都可以提高风电消纳水平,但后者要优于前者。此外,热负荷可调性在一定程度上可以实现热网储热的主动性。     

国家电网供电可靠性管理实践与思考

供电可靠性是指配电网向用户持续供电的能力,是对电力用户服务水平的综合体现。介绍了国家电网有限公司经营区域的供电可靠性指标现状,并对供电可靠性指标的变化趋势、停电原因进行了分析;总结了近年来配电网供电可靠性提升成效,分析了“十四五”期间供电可靠性管理工作面临的形势与挑战;最后,对提升“十四五”供电可靠性工作进行了展望。     

风热冲突下热电厂供热问题研究

将热电联产机组的成本分为发电成本和供热成本,实现了两者的分离独立计算。剖析了风热冲突问题的机理和热电机组2种灵活性改造方式(配置储热设备和配置电锅炉)的原理和有效性。以电热综合能源系统整体综合能耗最小为目标建立了供热问题分析模型。研究了热电厂在灵活性改造前后的供热策略,并讨论了配置蓄热设备和电锅炉的有效性以及最佳热负荷水平问题。算例结果验证了理论分析的有效性,相关结论可为热电厂决策提供参考。     

Geothermal Power Supply Systems around the World and in Russia: State of the Art and Future Prospects

Solar and geothermal energy systems are shown to have received the widest use among all kinds of renewable sources of energy for heat supply purposes around the world. The power capacities and amounts of thermal energy generated by solar and geothermal heat supply systems around the world are presented by way of comparison. The thermal power capacity of solar heat supply systems installed around the world as of 2015 totaled 268.1 GW, and the thermal energy generated by them amounted to 225 TW h/year. The thermal power capacity of geothermal heat supply systems installed around the world totaled 70.3 GW, and the thermal energy generated by them amounted to 163 TW h/year. Information on the geothermal heat supply systems in the leading countries around the world based on the data reported at the World Geothermal Congress held in 2015 is presented. It is shown that China, with the installed thermal power capacities of its geothermal heat supply stations totaling 17.87 GW and the amount of thermal energy generated per annum equal to 48.435 TW h/year, is the world’s leader in this respect. The structures of geothermal heat supply systems by the kinds of heat consumption used around the world are presented. The systems equipped with geothermal heat pumps accounted for 70.95% in the total installed capacity and for 55.3% in the total amount of generated heat. For systems that do not use heat pumps, those serving for pools account for the largest share amounting to 44.74% in installed capacity and to 45.43% in generated heat. A total of 2218 geothermal wells with the total length equal to 9534 km (with 38.7% of them for heat supply purposes) were drilled in 42 countries in the period from 2010 to 2014. In Russia, geothermal heat supply systems are in operation mainly in Dagestan, in Krasnodar krai, and in Kamchatka. The majority of these systems have been made without breaking the stream after the well outlet. A cyclic control arrangement is also used. The combined geothermal and solar heat supply system with an installed thermal power capacity of 5 MW that is in operation in the Rozovyi settlement, Krasnodar krai, is described. In the summer time, the solar installation with a capacity of 115 kW is used for supplying hot water to residential houses and for restoring the geothermal well pore pressure. The basic process circuit and characteristics of the geothermal heat supply system with the installed thermal power capacity of 8.7 MW operating in the Khankala settlement, the city of Groznyi, are given. The specific feature of this system is that the spent geothermal heat carrier is reinjected into a specially drilled inclined well. Advanced geothermal heat supply technologies involving reinjection of the spent geothermal heat carrier, combination with binary power units, use of heat pumps for recovering the spent heat carrier, and protection of equipment from corrosion and deposits are proposed.     

Analysis of Animal-Related Outages in Overhead Distribution Systems With Wavelet Decomposition and Immune Systems-Based Neural Networks

Outages in overhead distribution systems caused by different factors significantly impact their reliability. Since animals cause large number of outages in overhead distribution systems, analysis of these outages has a practical value as it allows utilities to keep track of historical trends. This paper presents a methodology for yearend analysis of animal-caused outages in the past year. Models to estimate weekly animal-caused outages in overhead distribution systems using combination of wavelet transform techniques and neural networks are presented. Discrete wavelet transform is applied to decompose the time series of weekly animal-caused outages into two components and separate neural networks are constructed for each decomposed coefficient series. The outputs of neural networks are combined according to wavelet reconstruction techniques to get estimated results for the weekly animal-caused outages. Artificial immune system (AIS) is used to overcome the overtraining problem associated with neural networks. Results obtained for four districts in Kansas of different sizes are compared with observed outages to evaluate performance of three different models for estimating these outages.     

架空线路监测系统的使用和效益

Overhead lines are the backbone of the electrical power transmission.Contrary to the distributions networks,the transmission system consists only in exceptional cases of longer cable lines.Typical exceptions are connections of cavern power plants,approaches to airports or bird sanctuaries and lines in urban centres.In the majority of cases,an overhead line is the most economic and practicable solution for the energy transmission.In tourism regions,an overhead line will be seen as impairment of nature or landscape and so the approval chain and procedure is in most countries long-winded and circumstantial.At the other hand,the energy consumption in Europe is growing and the volatility of transmitted power is also increasing during the last decade caused by the opening of the electric energy market.This opening process leads to a stopping of the enlargement of the interoperation network and to a minimisation of the maintenance of existing lines.Today the network operates more often at the limit of the equipment and the small and large-areas disturbances and blackouts are increasing.The operators of transmission lines are forced to ensure the electrical power supply and so they have to improve the reliability of the network.One solution is to monitor the critical(heavy loaded)overhead lines.For example,with the knowledge of the thermal condition,the risk of unexpected outages can be reduced.Today several monitoring systems are available on the market.They differ in the principle and techniques of the condition evaluation.The three most interesting output variables are the line temperature,the capable transmission power and the actual sag of the investigated section.In this paper an overview of existing overhead line monitoring system and also an outline over the usage and benefit for the application will be given.Thermal monitoring is one technique to improve the reliability of the network and for increasing or optimising the capable transmission power.     

基于用户需求精确建模的乡村清洁供能系统可靠性评估

乡村电采暖设备的普及使得用电负荷峰值增加，为使系统可靠性水平得到保证，需要综合考虑室内建筑热平衡特性和用户柔性舒适需求。为此，文章提出了一种基于用户需求精确建模的乡村清洁供能系统可靠性评估方法。首先，构建了乡村清洁供能系统架构，包括系统侧设备模型和用户侧建筑热平衡模型。其次，对用户柔性舒适需求进行建模，并引申出考虑柔性舒适需求的供能可靠性指标。再次，提出了乡村清洁供能系统故障影响分析的方法，制定了故障时的负荷削减策略和进行可靠性评估的流程。最后，通过实际算例比较了是否考虑用户柔性舒适需求与建筑热平衡特性下的可靠性指标，从而证明了所提方法对系统整体供能可靠性的提升作用。     

CHP Plants in Russia: the Necessity for Technological Renovation

The role of combined heat and power (CHP) plants in the electric power industry of Russia is shown. The operational efficiency analysis of public service CHP plants and the fuel, power, and age structure of the existing CHP plants are carried out. Their main problems, such as underuse of generating equipment, excessive production in the condensing mode, high degree of equipment wear, and technological heterogeneity, are identified. The necessity of technological renovation of the CHP plants is shown. The energy efficiency of the combined production of electric and thermal energy by the existing CHP plants is compared to modern technologies for their separate gas and coal production. It is shown that the thermal capacity of the CHP plants in Russia exceeds the required capacity by almost two times. Estimates of the CHP plant thermal capacity necessary to cover the current heat loads are obtained for Russian regions. Main directions of the CHP plants' renewal based on the use of competitive domestic equipment and operation according to the heat load schedule are determined. Systemic impacts achieved by technological renewal are determined for gas-fired CHP plants with allowance for the climatic and load features of the Russian regions. It is shown that the technological renewal of gas-fired CHP plants will allow saving up to 16% of today’s fuel consumption, reducing the total CHP thermal capacity by 47.5% with the same volume and heat supply mode. The operation of a CHP plant according to the heat load schedule leads to a reduction in the electric capacity of the CHP plant by 20% with an increase in electricity generation by 11%. As a result, the consumption of the installed electric and thermal capacity of the CHP plant increases dramatically as does the fuel efficiency and the annual loading balance of external gas-fired condensing power plants. The needs for GTPs and CCGTs required for the technological renovation of the CHP plants is assessed. The necessity for developing competitive domestic medium and high power GTPs is considered.     

2004年全国电力可靠性统计分析

通过对2004年全国220kV及以上电压等级输变电设施可靠性、城市用户供电可靠性和发电主辅设备可靠性指标的统计，对影响各类输变电设施可靠性、用户供电可靠性、各类发电机组和5种火电机组辅助设备可靠性的计划停运、非计划停运的主要因素进行分析与评估。特别是通过对近几年的指标分析比较，提出影响可靠性的主要因素的变化趋势，为提高发电、输变电设施及用户供电可靠性提供了依据。     

考虑可靠性成本的配电网多阶段扩展规划方法

传统的配电网可靠性评估通过模拟组件中断来量化一组事件对供电可靠性的影响,这种基于模拟的可靠性评估方法使得其纳入到配电网扩展规划中需要采用启发式或元启发式方法求解。为了克服启发式或元启发式方法收敛性和局部最优的缺点,文中提出了考虑可靠性成本的配电网多阶段扩展规划的混合整数线性优化模型。该模型建立了配电网可靠性指标(即系统平均停电持续时间指标、系统平均停电频率指标和系统缺供电量)的显式评估表达式,并将其相关的可靠性成本纳入到配电网多级扩展规划目标函数中,以系统运行约束等为约束条件。在24节点、54节点、86节点和138节点四个算例系统上验证了所提出的方法的有效性和适用性。     

火电机组吸收式热泵的余热回收加热凝补水经济性分析

因具有从低品质热量中提取高品质热量的特性,吸收式热泵可应用于节能改造方面。但该装置应用于火电厂时,热力系统、驱动热源和余热回收利用引入系统位置等差异,会导致应用效果完全不同。通过分析2种类型机组的余热回收用于本机组凝补水加热的经济性,阐明冷端损失、驱动热源热量品质高低等因素,可能导致余热回收并不能达到节能目的。应用热泵从冷却水的废热中回收部分热量完全用于对外供热,能够提高机组经济性,若用于本机热力系统中,不一定能达到节能的效果。     

Analysis of the state of production and change in the pattern of consumption of heat energy in Russia and the Sverdlovsk oblast

The analysis of statistical data on heat energy consumption in Russia and the Sverdlovsk oblast for 1990–2010 and the comparative investigation of report data of the regional (Sverdlovskstat), federal (Federal State Statistics Service), and international (International Energy Agency) statistical organization are given. The causes of a decrease in heat energy production are analyzed. The problem areas in the operation of communal-general service, heat supplying organizations, and schemes of their collaboration are revealed. Legis-lative acts and methods for their realization are represented and weak points are determined. Variants for solving the problems of heat supply, namely, the development of the united economic-organizing mechanism of the heat supply system management, are proposed. General principles of such a mechanism are described.     

The Development of a Method for Calculating the Nodal Prices of the Thermal Energy by Modeling the Thermal and Hydraulic Regimes of the Heat Supply Systems for Solving Control and Optimization Problems

The article deals with the issues of energy saving and increasing the efficiency of thermal energy. Energy saving issues are inextricably linked to the cost of heat for consumers. The costs of thermal energy transfer depend directly on thermal and hydraulic regimes of the heat supply system. A mathematical model and a method for calculating differential heat energy prices for all nodes and consumers of a heat supply system are discussed considering various heat production costs, the actual heat flow distribution, the location of the consumers in the network (the distance from the source), the structure and parameters of the network, and numerous internal and external disturbances of both a systematic and an accidental character. The above factors are taken into account by means of a thermo-hydraulic model for calculating the regimes of the heat supply system with intermediate temporal control nodes that serve as a basis for determination of the heat amount in every node at every time point. The proposed approach to the calculation of nodal prices can be interpreted as a method for solving the problem of distribution of the “price field” over the network for a given distribution of heat flows. The approach is based on three main principles, viz., the nodal balance of the heat cost, the equality of prices for the flows from the common node, and a differentiated increment of prices due to the variable component for the transfer of thermal energy for each of the sections of the calculation scheme. The proposed method for calculating the nodal prices of thermal energy can be used for multicriteria optimization of thermal and hydraulic regimes. The maximum utilization of the cheapest energy in the system or the minimum price of thermal energy for consumers can be the optimization criteria. The proposed approach makes it possible to differentiate prices within the regulatory period currently adopted in accordance with the process conditions of the heat supply system, namely, summer, autumn–spring, and winter conditions, including using peak-load sources. The operating modes have significant differences in the parameters of the heat-transfer medium, such as the flow rate and temperature of the network water.     

Current practices and customer value-based distribution system reliability planning

Among the major issues facing utilities in today's competitive electricity market is the pressure to hold the line on rates and provide electricity with adequate quality and reliability. Utilities are increasingly recognizing that the level of supply reliability planned and designed into a system has to evolve away from levels determined basically on a technical framework using deterministic criteria, and toward a balance between minimizing costs and achieving a sustainable level of customer complaints. Assessment of the cost of maintaining a certain level of supply reliability or making incremental changes therein must include not only the utility's cost of providing such reliability and the potential revenue losses during outages, but also the interruption costs incurred by the affected customers during utility power outages. Such a cost-benefit analysis constitutes the focal point of the value-based reliability planning. Value-based reliability planning provides a rational and consistent framework for answering the fundamental economic question of how much reliability is adequate from the customer perspective and where a utility should spend its reliability dollars to optimize efficiency and satisfy customers' electricity requirements at the lowest cost. Costs to customers associated with varying levels of service reliability are significant factors that cannot be ignored. Explicit considerations of these customer interruption costs in developing supply reliability targets and in evaluating alternate proposals for network upgrade, maintenance, and system design must, therefore, be included in system planning and design process. The paper provides a brief overview of current deterministic planning practices in utility distribution system planning, and introduces a probabilistic customer value-based approach to alternate feed requirements planning for overhead distribution networks.     

考虑储能的工业园区综合能源系统日前优化调度

城市能源互联网系统通过互补和能量梯级利用,实现能源资源的有效整合,在能源生产和消费革命中起着重要作用.城市能源互联网建设的关键之一是建立城市工业园区综合能源系统.因此,围绕一个存在电、热、冷、天然气等多种能流并服务于生产生活负荷统筹的工业园区综合能源系统开展了建模,结合系统储能特性,提出了日前运行优化调度模型.该模型综...     

直接空冷热电联产机组供热优化分析

通过对直接空冷传统抽汽供热热电联产机组及热网供回水温度存在的问题进行分析,提出了抽汽-乏汽联合供热系统,并经全面性能耗计算分析了抽汽-乏汽供热与传统抽汽供热的经济性。通过技术改造后数据得出,抽汽-乏汽供热系统较抽汽供热方式节约发电煤耗约26 g/kWh、发电机功率可增加20.36 MW、可增加供热面积约70万m2,有很大的节能潜力。     

供热系统的"垃圾改造"

为解决目前供热锅炉对环境造成的污染问题,改善空气质量,国家已经决定逐年快速取缔区域性锅炉和分散锅炉.我国面临着工业用热、民用采暖和生活用热量迅速增长的需求,为减少新建供热机组的投资,充分利用原有设备,节约能源,采用垃圾焚烧技术对现有锅炉进行改造,必将具有广阔的发展前景和市场需求.     

Methods for analyzing operational controllability and their application for estimating the quality of heat supply systems

The paper presents methods for quantitatively estimating indicators characterizing the performance of heat supply systems with the use of a dynamic thermal-hydraulic model of a heat supply system. Formulas for calculating average shortage (excess) of thermal energy for each consumer with a specified scenario of disturbing inputs and control outputs, as well as mathematical expectation and variance of average shortage (excess) with different scenarios are proposed. A method for calculating the coefficient characterizing useful utilization of energy at consumers and in the heat supply system as a whole for estimating the economic efficiency of an operating mode is presented.     

Evaluating the reliability cost of computer system interruptionsdue to power system disturbances

The authors present a general modeling and simulation approach for estimating the cost of interruptions to a computer center caused by power system disturbances and outages. The major variables (e.g loss of revenue, equipment damage, renewal of lost records, costing data, user profiles, power system reliability characteristics, etc.) were included in the costing method. The simulation model was applied to the University of Alberta's computer center, which does not have an uninterruptable power system. Actual historical databases (i.e. 11 years) were used in the case studies presented. The advantages and limitations of the reliability-costing methodology are discussed in some detail with reference to existing methods. It is concluded that estimating the cost of computer system interruptions is a complex and difficult task requiring large databases