Welfare-maximizing market procurement of flexibility services for distribution network planning

With the setting up of regulatory authorities the cost pressure on the electricity distribution companies will increase further in Germany. Due to political reasons the distributed generation (DG) has increased. Therefore, nowadays many distribution network companies face two important tasks: reduction of network costs to improve the network efficiency and integration of the large-scale DG into existing systems. A long-term planning of the distribution networks can provide an optimal target network for the efficiency analysis of distribution networks and the evaluation of effects, which are caused by the DG. Planning of distribution networks without the DG is known as a non-linear mixed integer problem. Additional technical constraints (such as voltage rising effect, short-circuit current, etc.) and stochastic characteristics of the DG make the planning problem become more complex. In this paper we propose a new efficient two-stage heuristic method, which is based on large neighborhood search and guided local search, for the planning problem of distribution networks with the DG. Technical modeling and stochastic characteristics of the DG are described. Applications of the proposed method for the planning of real German distribution networks with large-scale DG show that distribution network companies can use this method, not only for planning the future optimal network structure but also for analyzing the effects, which are caused by different DG scenarios

The subject of the study is the practical experience of the functioning of the mechanism of public procurement of goods, works and services in the member states of the European Union, its reformation under the influence of the introduction of new EU legislative norms in the field of public procurement, and the harmonization of the national legislation of the participating countries with Directives 2014/23/EU, 2014/24/EU and 2014/25/EU. The purpose of the work is to establish the impact of the new legislative norms of the European Union in the field of public procurement on the mechanism of procurement of goods, works and services for budget funds in the European Union, to identify the advantages of applying these norms. The methodological basis of the article is a set of cognitive methods applied to the mechanism of public procurement. The research was based on general scientific methods, namely: dialectical, which implies objectivity, comprehensiveness and systematic knowledge; logical; special methods of scientific knowledge: historical, method of systematic analysis and generalization of normative documents. The general logic of the article is based on a complex and systematic approach using modern scientific apparatus. Results of the article. The article establishes the main directions of changes in the mechanism and tools of public procurement in the countries of the European Union, which took place after the implementation of the norms of Directives 2014/23/EU, 2014/24/EU and 2014/25/EU, an analysis of the advantages of their implementation in national legislation of member states. The evaluation of the efficiency of the public procurement market in the EU countries was carried out. The directions and sources of further research are substantiated, first of all, by taking into account the aspects of digitalization of the sphere of public administration and finance, social and environmental innovations. Field of application of results. The results can be used by state and local self-government bodies, territorial communities, and economic entities of various forms of ownership. Conclusions. The new norms of EU legislation in the field of public procurement, set out in Directives 2014/23/EU, 2014/24/EU and 2014/25/EU, are aimed at simplifying procedures for public procurement of goods, works and services for budget funds, which promotes the free movement of goods and services in the countries of the European Union. As a result, customers get better value for money. Thus, public procurement becomes a tool of EU strategic policy. Although it cannot be claimed that the EU's public procurement policy is flawless, the experience of all participating countries is always taken into account in the process of its development and implementation. The EU public sector can use the procurement of goods, works and services with budget funds to increase the number of jobs, growth and investment, as well as to create an economy that is more innovative, resource and energy efficient and socially inclusive.

The high permeability of distributed energy and the continuous expansion of distribution network demand higher requirements for distribution network planning and construction. The distribution network with distributed structure will be the development trend of smart distribution network in the future, and the control and planning of distribution network for distributed architecture will become a new direction for the research of smart distribution network. Intelligent distribution network information system is an important foundation to support the operation and planning of intelligent distribution network. From the point of view of communication network construction, power grid construction, distributed energy storage planning and grid structure, distributed distribution network planning indicators are proposed. The application of multi-agent system theory to build intelligent distribution network collaborative control system, on one hand, can reduce the cost of system construction and maintenance, and improve the flexibility and stability of the system. On the other hand, due to the high efficiency and real-time of data acquisition, the allocation of distributed storage can be achieved in the planning stage of distribution network. After distributed storage connecting to the distribution network, the system can coordinate other equipment in the distribution network for active management and control, and optimize the operation status of the distribution network.

The integration of large-scale distributed generations (DGs) in power grids has enabled the movement of the traditional distribution network toward the active distribution network. However, this transition poses new challenges to the planning of distribution network frameworks under active management mode. The proposed work addressed these challenges by proposing a bilevel planning model of active distribution network frameworks with DGs that considers demand-side management. In the bilevel model, considering the influence of DG penetration level and the installed capacity of wind turbine generator and photovoltaic generator on the planning of distribution network, the upper distribution network planning model is established by taking lowest annual comprehensive cost as the upper-level objective. Then, the lower level model optimized DG curtailment and interruptible load shedding by accounting for the uncertainty of load and the intermittent DG output of wind farms and photovoltaic generators. The above models were solved through an improved pertheno-genetic algorithm and prime-dual interior point method. Finally, case studies were conducted on a 29-bus distribution network. Simulation results showed that by considering demand-side management, the network framework scheme and node voltage of the distribution network improved and the annual comprehensive cost decreased. By adjusting the DG penetration and installment capacity proportion of the wind turbine generator , the network planning scheme can be further optimized to minimize the annual comprehensive cost.

Energy storage planning in electric power distribution networks – A state-of-the-art review

Distribution network planning is used to scientifically guide the development of distribution networks. The smart software to actualize Distribution network planning is significant for improvement of result scientificity, as well as efficiency of planning work. This paper reviews the characteristics of well-known distribution network planning softwares including IPSA, DPlan and SINCAL. The development trends of distribution network planning software are also analyzed. As a conclusion, the continuous improvement of informatization and intelligence of distribution network planning is the future trend, in the circumstance of the continuous application of new technologies such as data management, distributed processing, display and interaction, artificial intelligence, and the actualization of new functions such as accurate load forecasting, distributed power generations planning, and differentiated planning strategies. An intelligent planning software scheme of function and architecture for distribution network is proposed. The functions of intelligent planning software are attributed by eight modules: diagnosis of power distribution situation, power demand forecasting, network planning and substation allocation, mathematic calculation, investment estimation, input and output benefit analysis, planning results management, and graphic display. The functions of the above modules are designed in detail. The framework of the intelligent planning software is given. The proposed structure of the distribution network planning function is holonomic, and these functions can realize the closed-loop operation from the analysis of current distribution network problems to the proposal of the network planning scheme. The research results can provide reference for the power planning researchers to study the intelligent planning function of the distribution network and can be used as top-level guidance for the network planning software design.

Planning of electrical distribution networks is considered of highest priority at the present time in Iraq, due to the huge increase in electrical demand and expansions imposed on distribution networks as a result of the great and rapid urban development.
 Distribution system planning simulates and studies the behavior of electrical distribution networks under different operating conditions. The study provide understanding of the existing system and to prepare a short term development plan or a long term plan used to guide system expansion and future investments needed for improved network performance.
 The objective of this research is the planning of Al_Bayaa 11 kV distribution network in Baghdad city based on the powerful and efficient CYMDist software as a tool for the simulation and analysis of the network.
 The planning method proposed in this thesis is to reach the optimum operating conditions of the network by combining the network reconfiguration in sequence with the insertion of capacitors with optimal sizing and locations. The optimum performance of the network is achieved by reducing losses, improving voltage profile and alleviating overload for transformers and cables.

Consumption growth demands power system expansion, and changes in a network lead to changes in operation indices of the upstream network. Hence, to establish a reliable planning of the distribution network, simultaneous planning of the subtransmission network should also be taken into account. It is predicted that this planning impacts different technical indices; therefore, formulation of various technical indices need to be included in the planning model. Therefore, in this study, the stochastic problem model of simultaneous planning of distribution and super distribution network development considering the reliability and security indicators is presented. The aforementioned problem is in the form of an optimization problem whose objective function is to minimize the costs of construction, replacement, operation, maintenance, reliability, and security. Furthermore, the mentioned problem is bound to the equations of power distribution, reliability, and security of voltage in addition to the limitation of network indicators. It is worth mentioning that, in the proposed problem, the active and reactive loads in addition to the operating price are in the form of uncertainty. Thus, the mentioned problem is in the form of a stochastic problem in which the point estimation method is used to evaluate the scenarios. Simultaneous expansion planning of distribution and subtransmission networks along with the placement of distributed generations and capacitors, as well as modeling security and reliability indices, is the novelty of the proposed scheme. In the end, the proposed problem is applied to the test network by GAMS optimization software, and then the capabilities of the proposed problem are extracted. Accordingly, based on numerical results, the expansion of distribution networks imposes considerable cost. Moreover, expansion planning of both distribution and subtransmission networks helps voltage to be in its permissible range, lower power loss, and improve reliability and security to 100%.

The urban 35kV substation is the link between the main network and the distribution network, and the economic power supply and site selection optimization are the keys to the coordinated planning of the main network and the distribution network. A comprehensive evaluation system is established for collaborative economic planning of the main distribution network from three aspects: social benefit, construction economy, and operation economy, and the combination of scale expansion method and rough set method is applied to determine the combined weight of indicators. Based on this index system, a comprehensive evaluation model for economic coordination planning of an intelligent main distribution network is established. It is applied to the economic effect evaluation of the main distribution network planning of a power supply company and the optimal location selection of substations. The results show that the proposed method is a new evaluation method for power grid collaborative planning. Under the premise of ensuring the economy and reliability of power supply, the collaborative planning level of the main distribution network has been significantly improved, and the planning results are better than the traditional site selection results. It not only expands the evaluation system for coordinated planning of the main network and distribution network but also provides guidance for the planning and construction of the main distribution network.

To deal with the problem of How to reasonably configure different types of distributed generation (DG) and energy storage systems (ESS) in distribution network (DN) planning. This paper conducts a more detailed study on the related issues of DG-ESS's DN planning through optimization theory and professional knowledge in the research field. Combining the economic and technical characteristics of installing ESS on the grid, from the two time scales of equipment investment and system operation, a bi-level decision model for the distribution network planning including DG and ESS is proposed. Among them, the objective functions of the upper and lower optimization models are to maximize the annual revenue of the distribution operator and minimize the total wind abandonment, solar abandonment and load shedding costs in typical daily scenarios. Finally, the particle swarm algorithm is used to solve the proposed optimization model, and the effectiveness is verified by the simulation analysis of improved IEEE33-bus distribution network system.

With large scale of renewable energy access into distribution network and technologies improved gradually, the structure of distribution network become more complex and diverse, so that the traditional operation methods will be hard to meet the requirements of reliability. Reviewed about interactive coordination and planning of active distribution network, the interactive coordination among sources, grid, loads and storage system of active distribution network is discussed. For promoting comprehensive benefits of distribution network and boosting the consumption of renewable energy, demand response and demand side management are effective measures to reduce costs and increase the penetration of renewable energy by utilizing the flexibility between generation and consumer. Forecasting is important for corrdination and planning, whose results can offer essential reference about dispatching and control. Some forecasting methods are summaried. Last, the current planning on active distribution network is discussed. Based on fundamental indicator, evaluation of ditribution network planning is necessary for its development. And with the challenge of renewable energy access, some prospects are concluded for planning of active distribution network.

Robust optimization framework for dynamic distributed energy resources planning in distribution networks

The authors conducted a study aimed to identify the role of «Big Four» («Big 4») audit firms in the public procurement market in Ukraine.The purpose of the article is to answer the questions: whether Ukraine is in a general trend of most countries in the concentration of audit market; what is the share of revenues of the «Big Four» audit firms in the performance of audit services in the public procurement system in Ukraine. First of all, in order to get answers to these questions, the authors conducted a study of the main trends in the development of the «Big Four» companies in Ukraine. It was found that the characteristic competitive environment in the market of audit services, the impact on competitiveness of pricing policy and regulatory requirements, relating to the acquisition of audit services by public sector entities through a public procurement system "ProZorro". An element of price regulation and compliance with the transparent conditions of the competitive environment is the participation of audit firms in the public procurement system. As a result of processing data on procurement of audit services for the period 2008-2019, the authors calculated key indicators that characterize the concentration of the audit market. Based on the data on the amount of remuneration for various types of audit services using the public procurement system "ProZorro", aspects of pricing policy and the role of the companies of the "Big Four" in the market were established. The values indexes indicate that the companies of the «Big 4» do not have a complete monopoly in the segment of procurement of audit services, having certain dominant positions in some years, and the indexes indicate a trend towards effective competition in the audit services market in Ukraine.

ЗДІЙСНЕННЯ «ЗЕЛЕНИХ» ПУБЛІЧНИХ ЗАКУПІВЕЛЬ: ПОТЕНЦІЙНІ ПЕРЕВАГИ ТА ВИКЛИКИ ДЛЯ УКРАЇНИ

This paper identifies and explores regulatory issues that may have an impact on the use of flexibility services by distribution utilities to solve grid constraints. This can be done by flexible distributed energy resources which can be instructed, for instance, to reduce export generating capacity or increasing consumption. We want to identify how regulation can better support the development of the future distribution utility in its role as neutral market facilitator, enabling more competition in local flexibility markets and optimal use of resources. A set of questionnaires were designed to capture the insights around important aspects of the regulation of flexibility markets (utilities’ network incentives, network tariff structure, market design for flexibility markets, etc.). These were sent to distribution utilities, energy regulators, energy marketplaces, energy associations and relevant experts from seven jurisdictions. The responses suggest a collective interest in the procurement of flexibility services by distribution utilities from distributed energy resources. New regulations, the adaptation of current rules and recent consultations reflect this. However, the amount of progress with and preferences for key regulatory changes differ across jurisdictions.