Sensitivity-based locational marginal value calculations in distribution grids

Electric utilities are experiencing a rapid growth of distributed energy resource (DER) deployment in their distribution grids. DERs can result in operational challenges in distribution grids, while at the same time can be viable assets in helping electric utilities better plan and manage grid design, operation, and planning. The DER valuation becomes an extremely important factor in this situation to ensure that DERs are fairly and accurately valued for the services they provide. This paper investigates the idea of spatiotemporal valuation of DERs and develops a sensitivity-based locational marginal value (LMV) calculation method that can be solved without the need for solving the network power flow problem. Furthermore, the impact of cost allocation to various upgrades in the system on LMV calculation is investigated, with the goal of demonstrating the fairness of the proposed LMV calculation method. The proposed model is applied to a standard test system for evaluation and validation.     

Risk Assessment at the Edge: Applying NERC CIP to Aggregated Grid-Edge Resources

Distributed energy resources (DERs) promise to deliver benefits for both utilities and consumers by dynamically interoperating utility systems with customer-owned grid-edge technologies. These small energy-consuming devices are increasingly being aggregated for participation in grid markets, planning and operations. A cyber attack penetrating the control system of aggregated DERs could negatively impact the operation of the grid. In the worst case, the power grid could be severely damaged and physical safety compromised.In this paper we analyze cybersecurity risks associated with the aggregation of DERs and develop an approach to mitigating that risk. The approaches to both cyber risk analysis and mitigation were developed during a recent research project that serves as an example of how the approaches could be applied. However, both the risk analysis and mitigation are applicable to the broader domain of all DERs. An important conclusion is that the successful cyber compromise of aggregated DERs could have a significant impact on the bulk power system. This is the case even if each individual DER falls below the threshold of compliance with bulk-grid cybersecurity standards.For this reason, we specifically investigate how National Electricity Reliability Corporation’s Critical Infrastructure Protection requirements could flow down to interactions between DER aggregators and the DERs themselves in order to protect the grid from these bulk-scale cyber attack impacts.     

Controlling and optimizing resilient distributed energy resources and microgrids with a demand-side operation platform

Moving to true grid resiliency requires multiple distributed energy resources, but these DERs must be properly controlled for each installation’s needs. This article answers these DER and microgrid resiliency questions and suggests some best practices for optimal financial and operational control in our New Energy Landscape.     

一种分布式电源并网监控通信适应性评价方法

分布式电源(DER)与配电网之间以及DER之间的通信不畅,会导致DER并网后对电网的电能质量、继电保护、孤岛问题产生不利影响,进一步影响整个电网的经济性和安全性。文中综合考虑技术性、经济性、适应性、扩展性和对DER的支撑性,设计了一种DER并网监控的解决方案,并提出了含DER的配电网通信方式适应性评价指标体系。根据DER并网监控通信需求,提出一种模糊一致的层次分析评价方法,并选择多种通信方式进行适应性评价。该评价方法结合了主客观需求,为含DER并网的配电网通信平台建设提供了可行性依据。     

Resolving the conflict between new and old: A comparison of New York,California and other state DER proceedings

Distributed energy resources present opportunities to serve grid and customer need through two-way power flow. New values, methods, and planning are required to efficiently interconnect and utilize DERs. This paper analyzes New York’s and California’s DER proceedings to provide a comparison of the similarities and differences between these and other states that will result in different levels of deployments and valuations of DERs.     

Valuation of distributed energy resources in active distribution networks

In concert with the transformation of conventional passive power distribution system, distributed energy resources (DERs) have progressively become participants in the provision of electricity services in active distribution networks (ADNs). In this paper, we propose a systematic valuation process to quantify the value of DERs in the ADN context. The paper first provides comprehensive insights into the impacts of DERs on ADN and the society as a whole. Given the technological, locational, and temporal diversity of DERs, a two-part scheme is developed to value and compensate DER portfolios proposed by customers and independent third parties. In particular, DERs are valued for their benefits and costs in both short and long terms. An integrated resource planning model is formulated to quantify the value of a given DER portfolio to be installed, where bi-level optimization techniques are applied to coordinate decisions on ADN planning and operations. In order to determine the short-term operation benefits of the DER portfolio on a continuous basis, a retail market operation model is developed based on peer-to-peer energy transactions among prosumers, when the impacts of DERs on ADN operations are monetized by distribution locational marginal prices. It is finally concluded in the paper that the proposed valuation scheme will not only contribute to the proactive investment of DERs in ADN but also help enhance the role of DERs in offering affordable, reliable, resilient and sustainable electricity services to customers.     

Economic framework for compensating distributed energy resources: Theory and practice

We offer an economic framework for analyzing the compensation that DERs should receive for energy exported to the grid. This economic framework requires that the prices paid to DER owners be based upon the forward-looking, economic costs that their utility avoids when it buys the energy from the customer. We explain why this results in efficient ‘build or buy’ and ‘purchase and install’ decisions of the utility and DER customer, respectively.     

分布式能源提供未来辅助服务的技术能力

近年来,分布式能源技术（Distributed Energy Resource）得到了快速发展。分布式能源（DER）系统具有可靠、高效、清洁、环保、配置灵活等优势,有着巨大的发展潜力,因此研究分布式能源技术具有重要的理论意义和重大的应用价值。概述了国内外分布式能源的发展现状及应用前景,简要介绍了分布式能源的概念、技术和特点,分析了DER提供当前和未来的辅助性服务（频率控制、电压控制、拥塞管理、电能质量提高、网络恢复、孤岛操作和电网损耗优化）的控制能力（分布式发电机DGs,存储和加载）。主要重点是对技术能力的评估。此外,通过DER系统的电网连接技术分析了这种技术方法,因为不同类型的电网连接技术可以应用在同样的DER系统中,而且电网连接技术决定了整个DER系统的许多功能。     

Peer-to-peer (P2P) electricity trading in distribution systems of the future

Recent years distribution systems have been witnessed a rapid interconnection of distributed energy resources (DER), solar energy generation and electric vehicles (EV) in particular. To this end, residential and commercial electricity customers equipped with DERs are transforming their roles from pure electricity consumers to prosumers that can switch between electricity consumers and producers. Indeed, if properly managed, DERs of prosumers could bring significant benefits to distribution system operations. Peer-to-peer (P2P) electricity trading in distribution systems has been recently explored, in order to properly manage existing prosumers and to continually promote a deeper penetration of prosumers. This article discusses two types of P2P mechanisms, namely auction-based and bilateral contract-based P2P electricity trading mechanisms, and analyze their effectiveness in properly managing electricity trading among prosumers in distribution systems of the future.     

Increasing DER integration through discrete intraday settlements

Deployment of distributed energy resources (DERs) is accelerating across the United States. These assets have the potential to provide cost-effective grid services and bulk power while supporting a low-cost energy transition to carbon-free electricity. Full integration of these resources into the bulk power system remains a barrier to unlocking the potential value of these assets. The regional wholesale energy markets, originally designed to integrate centralized, dispatchable power plants, must be reformed to adapt to the changing potential resource mix. The current day-ahead and real-time system is poorly designed for DERs. Day-ahead DER forecast errors create exposure to real-time price variations, as resources committed in the day-ahead market are required to rebalance in real-time, challenging the business model for DERs. New intraday markets with multiple discrete intermediate auctions between the day-ahead market and real-time market are needed to enable proper integration of DERs and efficient mitigation of forecast uncertainty risk. These markets must incorporate financially-binding commitments, closer-to-dispatch price signals, and adequate liquidity to ensure competition. Intermediate auctions should be built on top of existing intraday processes in each regional market, incorporating the principles of the existing market structures and leveraging the benefits of the centralized dispatch systems. Regional transmission organization (RTOs) and Independent System Operators (ISOs) should pursue and implement intermediate auctions to support fair, open, and efficient markets in the U.S.     

Distributed machine learning for energy trading in electric distribution system of the future

Machine Learning (ML) has seen a great potential to solve many power system problems along with its transition into Smart Grid. Specifically, electric distribution systems have witnessed a rapid integration of distributed energy resources (DERs), including photovoltaic (PV) panels, electric vehicles (EV), and smart appliances, etc. Electricity consumers, equipped with such DERs and advanced metering/sensing/computing devices, are becoming self-interested prosumers who can behave more actively for their electric energy consumption. In this paper, the potential of distributed ML in solving the energy trading problem among prosumers of a future electric distribution system - building DC grid cell, is explored, while considering the limited computation, communication, and data privacy issues of the edge entities. A fully distributed energy trading framework based on ML is proposed to optimize the load and price prediction accuracy and energy trading efficiency. Computation resource allocation, communication schemes, ML task scheduling, as well as user sensitive data preserving issues in the distributed ML framework are addressed with consideration of all the economic and physical constraints of the electric distribution systems.     

含分布式能源直流配电网的优化调度

直流配电网对促进分布式可再生能源消纳、解决传统交流配电网发展瓶颈等方面具有巨大优势。基于直流配电网现有讨论和研究,针对含多种分布式能源（distributed energy resource,DER）的直流配电网,讨论其组网方式与系统结构,重点研究适用于接有多种分布式能源的直流配电网的优化调度方法,设计各并网单元运行策略及直流配电网多时段优化调度策略,并建立了综合考虑运行成本、环境效益以及系统损耗的多目标优化调度模型。通过算例的计算和分析,表明所提优化调度方法在促进接入多种分布式能源后直流配电网的优化运行以及接入分布式能源前后配电网优化目标的改善方面具有良好作用,验证了该方法的有效性。     

采用基于市场控制的微网分布式能量优化方法

为了控制微网内各类分布式能源的协调运行,同时适应能源互联网的核心理念,提出了采用基于市场控制的微网分布式能量优化方法。首先,从理论上论证了该方法与集中式能量优化方法的等价性,并建立了分布式能量优化的通用流程。然后,基于启发式规则,系统地提出了分布式电源、可平移负荷、储能、联络线等资源的投标策略。最后,通过仿真计算,验证了该方法在削峰填谷、经济性以及提高可再生能源消纳率等方面的效果。所提出的方法利用各分布式能源的分布式决策代替传统的集中式优化,能够更好地保护用户隐私,并能够适应各种类型的分布式能源以标准化方式接入不同规模微网的要求。     

Optimization of Lebanon's power generation scenarios to meet the electricity demand by 2030

Presently, Lebanon provides 95 % of the primary energy electricity power generation by using fuel-oil used in thermal power plants. To meet the population needs, private generators are also used in all the country and they represent the third of total electricity production. The challenges over the future development of the Lebanese electric sector are economic and environmental. This is why currently, the energy policy makers aim to diversify the national electricity generation mix in the energy planning strategy and to introduce low-carbon technologies. The complexity of these challenges in the particular Lebanese context has motivated our study which aims to recommend policies to develop the optimal electricity generation scenario by 2030. This paper presents a methodology to evaluate different scenarios reflecting different combinations of technologies by 2030. This is achieved by using an excel tool “Excel Solver Optimization Calculator” which makes possible the interaction of various inputs to produce a least-cost generation mix. The main results focus on the least-cost electricity generation portfolio, total investment required to generate electricity, level of energy independence and carbon emissions. Many policy choices could be feasible and very advantageous for Lebanon if renewable energies are deployed massively. However, this requires policies that support the massive use of renewable energy technologies in the mix.     

The value of the grid and the role of the utility in managing it

Distributed energy resources and electrification are countervailing trends in the electricity business. DER challenges the traditional electric utility business model, while electrification presents new opportunities for the economy, for the environment, and for utilities. Both of these new developments highlight the importance of the electric grid, and the critical need for utilities to manage this integrated grid of the future.     

A dynamic model for distributed energy resource expansion planning considering multi-resource support schemes

In this paper, a system dynamics based model is developed to investigate the impacts of multi-resource regulatory policies on distributed energy resource (DER) expansion planning. DERs usually include a variety of renewable and fossil based generation technologies such as wind and gas engine resources, combined heat and power (CHP), demand response (DR) and energy storage. The intermittent nature and uncertainty in power generation of some of these resources and other uncertainties that exist in the market environment would cause investors to encounter risk in their investment decisions. Implementation of any supporting policy affects any investor’s behavior and investment level of other investors. Regulators should properly identify long-term impacts of their support policies in the energy resource expansion in order to choose a proper support scheme. These support schemes should ensure the long-term market stability. It is important for a DER investor to properly identify his/her long-term investment behavior to select an appropriate strategy. In this paper, the system dynamics method is used to investigate these issues. The impacts of various multi-resource regulatory policies on market dynamics are modeled and compared with the single-resource support schemes ones. In this study, support schemes are considered for supporting DR, wind resources, CHPs and photovoltaic resources.     

Measuring “Reasonably Reliable” access to electricity services

While the electricity access rate is regularly measured in most countries, there are no routinely tracked metrics that measure reliability. This paper presents a new approach that: (1) aggregates all available country data on reliability; (2) defines a minimum threshold metric for ‘reasonable reliability’; and (3) estimates the number of people without ‘reasonably reliable’ electricity services. We estimate the number of people without access to reliable electricity is approximately 3.5 billion. This new metric provides a more granular view of the enormous energy access gap globally, and insights for future investment and policy decisions.     

基于均衡理论的虚拟电厂市场参与模式及方法

随着化石能源的枯竭与其对环境的污染，分布式发电这种经济、环保、灵活的新型发电方式逐渐得到广泛的应用。但分布式电源大量并入电网将带来电能质量问题，影响电网安全稳定运行。虚拟电厂的出现有效解决了这些问题，它通过对分布式电源进行协调优化，减小了分布式电源并网对电网产生的冲击，提高了电网运行稳定性。然而目前虚拟电厂与主网之间的协调研究仍有待深入，因此提出了虚拟电厂与主网之间交互迭代的市场均衡方法，对虚拟电厂的出力与主网的电价迭代求解从而实现收敛。首先，对虚拟电厂的定义与内部主体进行分析，进而将虚拟电厂与主网之间的协调优化表述为两个层次之间的市场均衡问题，提出虚拟电厂与主网交互的双层模型，分别构建以自身成本最小化为目标，计及分布式能源运行约束与电网安全约束的虚拟电厂与主网数学模型，并采用迭代算法对模型进行求解。算例分析表明提出的市场均衡方法在考虑虚拟电厂对主网影响的同时能够有效降低虚拟电厂与主网协调的复杂程度，同时减小运行总成本，提升经济效益。     

智能配电网建设中的继电保护问题 讲座二 配电网故障分析计算问题及其发展

传统短路电流的计算方法已难以适应分布式电源接入后配电网短路电流的计算。介绍了配电网短路电流的近似计算公式。分析配电网故障时分布式电源(DER)短路电流输出的特点,给出了用于短路电流输出计算的DER等效电路。指出传统短路故障计算机算法用于配电网存在的问题,介绍了一种高效率的基于端口补偿原理的配电网短路故障计算方法。利用模变换法推导出小电流接地故障暂态分析等效电路,更正了目前普遍使用的等效电路的错误。     

Viable transformation of an electric utility? The case of the Puerto Rico electric power authority

There are similarities that Puerto Rico’s electric grid transformation has with other jurisdictions in terms of integration of distributed energy resources (DERs), net energy metering (NEM) and a diversified energy mix. However, it is important to first evaluate the impacts of Puerto Rico’s debt restructuring in view of federal emergency funds to be deployed. This paper aims to analyze expected impacts of the restructuring agreement and related plans on Puerto Rico’s economy and on its electric utility, PREPA. A restructuring agreement, and related plans, that considers a charge that starts at 2.768 cents per Kwh; that its length is 47 years; that comprises a nonbypassable and unavoidable charge, including on energy generated by consumers; and that excludes the regulator from the evaluation and implementation of debt restructuring charges, it is worth to analyze.