G. Forte

Planning and Operating Combined Wind-Storage System in Electricity Market

The increasing penetration of renewable sources in power systems yields various issues in network operation. Most of them are related to uncertainties of energy production. In particular, the variability of wind source does not allow for accurate forecasting of power generation. Production plans may not be accomplished, incurring penalties for system unbalance. For this reason, the use of an energy storage system can improve integration of wind energy in production planning and dispatch. In this paper, an approach for planning and operating an energy storage system for a wind farm in the electricity market is proposed. To this purpose, electrochemical batteries are employed to compensate for generation variations in order to set up a reliable hourly delivery profile, complying with market requirements. The delivery plan can be settled according to energy prices, as well. Moreover, an economic feasibility analysis is carried out on the combined wind-storage system.

Risk-Constrained Profit Maximization in Day-Ahead Electricity Market

The deregulation of the electricity industry has caused for the generation company (Genco) the need of tools for measuring and managing the risk, beyond the classical problem of generating unit scheduling. In this paper, a probabilistic framework for the problem of managing risk faced by Gencos trading in day-ahead energy market is proposed. In particular, a stochastic forecast of electricity price and the technical features of hydrothermal units are considered. The approach is based on an optimization procedure for maximizing expected profits in the presence of risk constraints. Conditional value at risk for the distribution of daily profit is used as risk measure.

A procedure for evaluating microgrids technical and economic feasibility issues

Microgrids exploitation is one of the most useful and efficient ways of integrating Distribution Generation (DG) technologies. Microgrids allow to realize a coordinate control of different DG facilities, and to provide proper control strategies to the distribution grid. In this paper, economical involvements affecting decisions of realization of microgrids are assessed. Furthermore, a procedure for economical evaluation of microgrids is proposed, aiming to minimize costs in the presence of different constraints. The procedure is applied to a test system representing a cluster of residential final users and services, and various cases are analyzed, in order to account for different choices for energy supply.

PrInCE Lab experimental microgrid Planning and operation issues

This paper aims at describing the experimental Microgrid (μG) built at the Politecnico di Bari within a project funded by the Italian Ministry of Education, University and Research. In particular, the μG will provide a test-bed for research, development and testing devices and components for smart-grid applications. Moreover, it will give the possibility to test new control strategies for the optimal management of internal resources and the connection with the distribution company, in order to ensure the proper operation and the integration with the network in compliance with current connection rules.

Voltage compensation for wind integration in power systems

The fast growth of wind generation leads to concern about its effects on electric grid. The wind power integration needs to be ruled by specific voltage and frequency requirements. As concerns voltage support, wind farm are called to guarantee a reactive power regulation range at point of common coupling (PCC). Moreover, in the presence of voltage dips or fault conditions, wind generators should be able to respect low-voltage ride-through curves to contribute to grid regulation and avoid sudden unbalances. In this paper, different control strategies of wind farm are evaluated, in order to comply with grid code requirements for voltage support. In particular, reactive power and voltage regulation is carried out through generator power factor variation and by static compensation devices as SVCs. Simulations are performed on a wind farm connected to IEEE 14-Buses test system in the presence of grid fault condition.

PV plants for voltage regulation in distribution networks

This paper deals with the development of a centralized nonlinear auto-adaptive controller able to optimize the network voltage profile by managing the reactive power supplied by PV inverters. The control design is based on a realtime optimization procedure involving the sensitivity theory in conjunction with the Lyapunov function and produces the control laws that must be sent to local controllers of PV-inverters. The derived controller is implemented and tested on a MV distribution network.

Critical issues in large offshore wind farm design and operation

Interest in the realization of offshore wind farms is growing even in zones where exploitation was considered unprofitable so far. For this reason, studies are needed in order to design suitable methodologies aiming to investigate economic feasibility and control strategies both in steady-state and dynamic conditions. In this work, the analysis of steady-state behaviour and investment concerns of electric system for offshore wind farms is carried out. In particular, the case of a 300-MW offshore wind farm is taken as the reference case in order to investigate issues concerning both design and operation of the electrical system of offshore wind farms.

A procedure for day-ahead optimal operation planning of a MicroGrid

The integration of a Micro Grid (MG) in the distribution system requires the development of energy management procedures to provide flexibility to distribution system operators. In this paper, a tool for the day-ahead operation plan of a grid-connected MG, including distributed generators, electrical and thermal loads and storage devices, is proposed. The operation condition of the MG components is optimized by minimizing production and operational costs while satisfying electrical and thermal load demand. The procedure is applied to a test-bed of an experimental MG.

An architecture for the monitoring of microgrid operation

The operation of different energy sources in a MicroGrid (MG) has to be monitored and controlled by means of the Energy Management Systems (EMS) both in the grid-connected and islanded modes. In the first case, the MG can be seen as a single controllable unit by the grid operator whereas in the islanded mode the successful balance between internal load and planned generation is also required. In this paper, the architecture of an experimental MG is described. Modbus TCP/IP is used as the communication protocol in the MG to receive data and send commands to different components within the system, and monitoring by means of cabled signals is performed. Furthermore, in order to efficiently cater for electric and thermal demand, a central EMS is aimed to evaluate different procedures for the day-ahead scheduling of a MG. In particular, operational planning is proposed and applied to a selected configuration of a testbed facility at Politecnico di Bari. Grid-connected as well as stand-alone configurations are tested.

PrInCE lab microgrid: Early experimental results

This paper deals with the experiences of operation of the PrInCE microgrid realized at Power and Energy System Laboratory of Politecnico di Bari in the framework of a structural development project. The main peculiarities of the facility are the integration of different commercial generators, the presence of cogeneration systems, the possibility to manage mode transition and the supervision and control by means of an open SCADA/EMS system where different strategies can be tested.