Alexandre Oudalov

Optimizing a Battery Energy Storage System for Primary Frequency Control

This paper presents a method for the dimensioning of a battery energy storage system (BESS) to provide a primary frequency reserve. Numerical simulations based on historic frequency measurements are used to determine the minimum possible capacity, i.e., the lowest possible cost, which fulfills the technical requirements of the grid code. We implement a novel control algorithm with adjustable state of charge limits and the application of emergency resistors. At current European market prices, an optimized lead-acid BESS can be a profitable utility solution for the primary frequency control.

Optimizing a Battery Energy Storage System for Frequency Control Application in an Isolated Power System

This paper presents a method for optimal sizing and operation of a battery energy storage system (BESS) used for spinning reserve in a small isolated power system. Numerical simulations are performed on a load-frequency control (LFC) dynamic simulator of the isolated network. A novel control algorithm using adjustable state of charge limits is implemented and tested on a BESS dynamic model. An optimal sizing procedure of the BESS is developed for an isolated power system in order to achieve highest expected profitability of the device. The BESS can increase significantly the power system stability, the grid security, and the planning flexibility for a small isolated power system with low grid inertia. Meanwhile, it fulfills the frequency control requirements with a high expected economic profitability.

Sizing and Optimal Operation of Battery Energy Storage System for Peak Shaving Application

This paper presents a sizing methodology and optimal operating strategy for a battery energy storage system (BESS) to provide a peak load shaving. The sizing methodology is used to maximize a customers economic benefit by reducing the power demand payment with a BESS of a minimum capacity, i.e. a system with a lowest cost. The BESS optimal operating strategy is based on dynamic programming and is aimed to minimize the energy cost while satisfying battery physical constraints.

The Provision of Frequency Control Reserves From Multiple Microgrids

The concept of microgrid is invented to harmonize local electricity production and consumption. The increasing interest on microgrids is caused by the considerable growth of renewable energy sources (RES) and distributed generation (DG). In a large geographical region, there can exist multiple microgrids. Many academic articles have reported the technicalities of microgrids operating in islanded mode, and few have analyzed their aggregated technical/economic impacts or benefits on the network in a larger region. Deregulation encourages RES to participate in energy markets to facilitate competition among different energy providers. Apart from participating in energy markets, an alternative way of making use of and making profit out of multiple microgrids is to take part in the ancillary-service market. This paper investigates the technical aspects of providing frequency control reserves (FCRs) and the potential economic profitability of participating in FCR markets based on a setup of multiple microgrids. In particular, it has a focus on the communication aspects under different market scenarios, i.e., decentralized or centralized coordination approach, for FCRs with the assumption of the possible aggregation of reserve provision from multiple microgrids (microsources and flexible loads).

Islanding detection in smart grids

All distributed generators (DG), especially those connected to low voltage distribution grids are required to detect islanding conditions. The methods for detecting islanding are classified in three main categories: passive, active and communication based. Passive methods are based on grid monitoring, are easy to implement but have a large non-detection zone in the case local generation meets the load demand. Active methods, which are commonly used today, may reduce the non-detection zone but in the case of large amount of DGs installed, power quality problems are foreseen. The communication based methods are seldom used today mainly because of high cost of communication.

Adaptive Protection and Microgrid Control Design for Hailuoto Island

Microgrids can provide various economic and environmental benefits but their implementation poses great technical challenges in control, protection and energy management. One of the most important technical aspects in microgrids is distribution system protection. This paper first demonstrates a need for and then focuses on the design aspects of the adaptive protection system addressing issues such as: selection of alternative setting groups, components and system architecture; system configuration and programmed logic. The system is based on a centralized controller running the real-time analysis of the data received from the field Intelligent Electronic Devices and communicating with them by means of IEC 61850 communications. The adaptive protection and microgrid control system has been developed and currently being installed at Hailuoto island in Finland.

Utility Scale Applications of Energy Storage

Power system operating conditions that are on the verge of being unsafe have encouraged utilities and power consumers to look for bulk energy storage systems. Various energy storage systems (ESSs) have excellent records and have been used for decades. This paper provides an overview of different energy storage technologies and their possible applications in power systems. The purpose of this analysis is to highlight combinations of technologies and applications with the highest benefit for the owner of the ESS. The analysis shows that frequency regulation and integration of renewables are the applications that most likely will be asked for by utilities in the future. Technologies which are most suitable for these applications include thermo-electric energy storage and batteries. These are technologies which are not restricted by their geographic footprint and offer payback times of five to ten years.

The Feasibility and Profitability of Ancillary Services Provision from Multi-MicroGrids

Because of the ever-increasing energy demand and petrol shortage one resorts to renewable energy supplies. Together with the advantages of having the generation sources physically close to the energy demand Microgrid has become a topical research area in recent years. A microgrid is capable of operating in parallel to the main power network or in intentional islanded mode. Such microgrids usually consist of several small coordinated generation units located closely together in the distribution network. The units can be solar, wind, CHP (Combined Heat and Power), fuel cells, etc. and are small in capacity. In a big physical region there can exist multiple micro- grids. Apart from participating in energy markets, an alternative of making profit is to take part in the Ancillary Services (AS) market. This study investigates the technical feasibility and difficulties of providing such services as well as the potential profitability of participating in the AS markets based on a setup of multiple microgrids.

Application of fuzzy logic techniques for the coordinated power flow control by multiple series FACTS devices

This work describes the development of a fuzzy logic based control system capable of governing multiple thyristor-controlled series capacitors (TCSCs). The main purpose of the presented coordinated control system is the improvement of active power flow control in a power system. The proposed control strategy is quite simple; therefore it does not require intensive computations on on-line computers. The control system has been designed as a real time tool constantly monitoring power flows and generating appropriate control signals to each TCSC to maintain acceptable power flow levels in the normal and N-1 steady-state modes. The prototype control system has been interfaced with power system simulation software to test its effectiveness through nonlinear simulations using the Central European-CIS interconnected power system as the study case. The results obtained are presented.

Coordinated power flow control by multiple FACTS devices

This work describes a development of a control system and control strategies capable of governing multiple flexible AC transmission system (FACTS) devices. The main purposes of the presented coordinated control system are to remove overloads and to achieve specified power flows in transmission lines of a power system in the normal and N-1 steady-state operational modes. Proposed control strategies are based on heuristic rules; therefore they do not require intensive computations. A prototype of a control system has been designed as a real time tool constantly monitoring power flows and generating appropriate control signals to each FACTS device in order to maintain acceptable power flow levels. It has been interfaced with load flow software to test its effectiveness through non-linear simulations using the 380/220 kV Swiss power system as the study case. The results obtained are presented.