PREVENTIVE MANAGEMENT AND CONTROL OF A MICROGRID SYSTEM USING FLEXIBILITY OF DISTRIBUTED STORAGE

Distributed Electrical Energy Storage (EES) is a key element of the MicroGrid (MG). When associated with accurate load and generation forecasts, the management of EES can avoid potential technical problems and at the same time ensure adequate reserve capacity to ensure the autonomous operation of the MG. This paper presents a preventive management and control framework for the operation of the MG both interconnected and islanded from the main grid. The main results obtained in an experimental MG test setup at INESC TEC Smart Grid and Electric Vehicle Laboratory are also presented. INTRODUCTION When deployed as an extension of a Distributed Management System (DMS), the MicroGrid (MG) concept divides the distribution system into small controllable MV and LV clusters, which can be operated both grid-connected and islanded from the main grid [1]. This new distribution network operation philosophy can potentially increase the system reliability and resilience against not only component failures but also extreme events such as natural disasters. One of the key elements of the MG is Distributed Electrical Energy Storage (EES). Its flexibility helps balancing renewable energy generation and load and enables the autonomous operation of the MG. However, in order to be effective, it requires an adequate management of its energy capacity as this is crucial to ensure the survival of the MG in islanded mode. This paper presents a preventive management and control strategy for the operation of the MG in both interconnected and islanded operation modes. The main objective is to promote a coordinated management of both DSO controlled EES and flexibility services provided by the Low Voltage (LV) consumers for improving system efficiency, avoid technical limits violation and improve the system resilience in islanded operation. MG ARCHITECTURE AS AN EXTENSION OF DMS/SCADA The MG architecture adopted was defined in the context of SENSIBLE project [2] and is represented Figure 1. The observability of the LV network is ensured by the Automated Metering Infrastructure (AMI) consisting of two layers: the smart meter and the Distribution Transformer Controller – DTC) Together with the EES controller this system provides relevant information from the LV network, which is then used in the Analytics layer, where the MG tools are housed. Also, through a market platform, the DSO is able to subscribe flexibility services provided by LV clients. In this case, residential storage capacity is exploited for self-consumption purposes while the remaining capacity can be used by the DSO for voltage and congestion management through the Home Energy Management System (HEMS). Figure 1. SENSIBLE Distribution Management and control architecture [2]. MG PREVENTIVE MANAGEMENT AND CONTROL TOOLS A multi-temporal approach is proposed for an effective management strategy of DSO-owned electrical storage devices and for mobilizing flexibility services from the LV consumers. Based on load and generation forecasts, the algorithms are able to plan the operation of the MG and prevent probable technical problems. Distribution Transformer Controller DTC D SO A n al yt ic s