Simulation and the monte carlo method

This paper proposes a new heuristic approach for distributed generation (DG) capacity investment planning from the perspective of a distribution company (disco). Optimal sizing and siting decisions for DG capacity is obtained through a cost-benefit analysis approach based on a new optimization model. The model aims to minimize the disco's investment and operating costs as well as payment toward loss compensation. Bus-wise cost-benefit analysis is carried out on an hourly basis for different forecasted peak demand and market price scenarios. This approach arrives at the optimal feasible DG capacity investment plan under competitive electricity market auction as well as fixed bilateral contract scenarios. The proposed heuristic method helps alleviate the use of binary variables in the optimization model thus easing the computational burden substantially.

Optimal investment planning for distributed generation in a competitive electricity market

It is difficult to estimate how much distributed generation (DG) capacity will be connected to distribution systems in the coming years; however, it is certain that increasing penetration levels require robust tools that help assess the capabilities and requirements of the networks in order to produce the best planning and control strategies. The work of this Task Force is focused on the numerous strategies and methods that have been developed in recent years to address DG integration and planning. This paper contains a critical review of the work in this field. Although there have been numerous publications in this area, widespread implementation of the methods has not taken place. The barriers to implementation of the advanced techniques are outlined, highlighting why network operators have been slow to pick up on the research to date. Furthermore, key challenges ahead which remain to be tackled are also described, many of which have come into clear focus with the current drive towards smarter distribution networks.

/pdf/state-of-the-art-techniques-and-challenges-ahead-for-33qpynfhmy.pdf

State-of-the-Art Techniques and Challenges Ahead for Distributed Generation Planning and Optimization

Climate change concerns due to the rising amounts of the carbon gas in the atmosphere have in the last decade or so initiated a fast pace of technological advances in the renewable energy industry. Such developments in technology and the move towards cleaner sources of energy have made distributed generation (DG) from renewable resources more desirable. However, it is a known fact that rising penetrations of DG can have adverse impacts on the grid structure and its operation. The microgrid concept is a solution proposed to control the impact of DG and make conventional grids more suitable for large scale deployments of DG. Covering many aspects of the power systems and power electronics fields, microgrids have become a very popular research field. This paper reviews the background and the concept of a microgrid, the current status of the literature, on-going research projects, and the relevant standards. It also presents a review of the microgrid pilot projects around the world in further detail and discusses the potential avenues for further research.

Recent developments in microgrids and example cases around the world—A review

Active Network Management is a philosophy for the operation of distribution networks with high penetrations of renewable distributed generation. Technologies such as energy storage and flexible demand are now beginning to be included in Active Network Management (ANM) schemes. Optimizing the operation of these schemes requires consideration of inter-temporal linkages as well as network power flow effects. Network effects are included in optimal power flow (OPF) solutions but this only optimizes for a single point in time. Dynamic optimal power flow (DOPF) is an extension of OPF to cover multiple time periods. This paper reviews the generic formulation of DOPF before developing a framework for modeling energy technologies with inter-temporal characteristics in an ANM context. The framework includes the optimization of nonfirm connected generation, principles of access for nonfirm generators, energy storage, and flexible demand. Two objectives based on maximizing export and revenue are developed and a case study is used to illustrate the technique. Results show that DOPF is able to successfully schedule these energy technologies. DOPF schedules energy storage and flexible demand to reduce generator curtailment significantly in the case study. Finally, the role of DOPF in analyzing ANM schemes is discussed with reference to extending the optimization framework to include other technologies and objectives.

/pdf/dynamic-optimal-power-flow-for-active-distribution-networks-1oey063vs7.pdf

Dynamic Optimal Power Flow for Active Distribution Networks

Active management provides a method to extend capacity for generation connections to distribution networks through the coordinated control of multiple network components in real-time. Identifying principles and strategies for active network management that hold for all situations will provide support to network operators and planners and form the basis for a new paradigm in utility strategy concerning the connection of distributed generation. The authors build upon previous work regarding the initial specification and economic evaluation of an active power- flow management (APFM) scheme concerned with facilitating increased generator connections. Operating margins have been identified as an essential element of the APFM scheme for the provision of network security and play a significant role in determining the economic viability of generation connected under the APFM scheme. An approach to the definition of the operating margins required to trigger generator output regulation (trimming) and tripping is introduced. These concepts are demonstrated through a case study using one of the UK generic distribution system models. The analysis considers technical, regulatory and economic factors, resulting in practical recommendations for future work and the identification of the factors that affect the implementation of such a scheme.

Active power-flow management utilising operating margins for the increased connection of distributed generation

The problem of exchanging data between two or more organizations in a format that is accessible and understandable by each is a universal problem. Furthermore, the problem of translating or accessing data in the correct format for applications using proprietary data formats is challenging. Legacy software applications may endure, for some time given, regulatory expenditure pressures on electricity system operators and these require data translators (importer/exporter) and access facilities. The basis of this paper is that the Electric Power Research Institute (EPRI) common information model (CIM) in eXtensible Markup Language (XML) represents the first stage in a revolution of data exchange and manipulation for power systems. This paper explores the problem of translating data in the CIM XML format to the required format for such legacy power system analysis applications. This paper discusses solutions to some of the challenges in data translation, and illustrates how these solutions can be implemented.

Translating CIM XML power system data to a proprietary format for system simulation

The problem of exchanging data between two or more organizations in a format that is accessible and understandable by each is a universal problem. Furthermore, the problem of translating or accessing data in the correct format for applications using proprietary data formats is challenging. Legacy software applications may endure for some time given regulatory expenditure pressures on electricity system operators and these require data translators (importer/exporter) and access facilities. The basis of this paper is that the EPRI common information model (CIM) in extensible markup language (XML) represents the first stage in a revolution of data exchange and manipulation for power systems. This paper explores the problem of translating data in the CIM XML format to the required format for such legacy power system analysis applications. This paper discusses solutions to some of the challenges in data translation, and illustrates how these solutions can be implemented.

As a result of many factors, including the European Union's aim to increase the share of electrical energy from renewable sources, the number of distributed-generation (DG) devices in Europe is significantly increasing. Increasing numbers of DG units may cause problems with power quality (PQ). In this paper, a PQ-management algorithm is presented that reduces or even solves this problem in low-voltage grids. This algorithm will be implemented as one of several software modules in a system for distributed power operation and PQ management in low-voltage grids. PQ management in this context means maintaining PQ within prescribed limits by optimizing the control of generators, storage units, and controllable loads. Significant advantages of the presented approach are that the algorithm is universal and that it adapts its control variables automatically. Therefore, a detailed analysis of the grid in advance is not necessary. Furthermore, local PQ control of distributed resources can work autonomously and continuously without triggering by external signals, which is advantageous in the case of loss of communications. Various simulations to validate the effectiveness and stable operation of the algorithm were performed and results presented that show a marked improvement in PQ.

A Power-Quality Management Algorithm for Low-Voltage Grids With Distributed Resources

Our interest in the theory and practicalities of distribution system planning have been aroused by recent discussions with distribution network operators in the U.K. and by more general work on the requirements for power system planning methodologies for the twenty-first century. Specific note is made of distributed generation, which presents substantial challenges for distribution system planners and has been the focus for a study of the changing needs of distribution planning.

C.E.T. Foote

Papers

Active power-flow management utilising operating margins for the increased connection of distributed generation

Translating CIM XML power system data to a proprietary format for system simulation

Translating CIM XML power system data to a proprietary format for system simulation

A Power-Quality Management Algorithm for Low-Voltage Grids With Distributed Resources

Distribution System Planning in Focus