Urban Grid Monitoring and Distributed Energy Resource Integration - Approach using Analytics

Abstract

In metropolitan and sub urban business districts of Boston, New York city, Los Angeles, Philadelphia and other major load centers, utilities have installed an electrical distribution system known as a secondary area network grid for that provides operational flexibility and the highest level of reliability. In secondary network grids, integration of distributed energy resources (DER) such as inverter based solar photovoltaic (PV) installations and through DG. The new power landscape is a mix of grid scale and distributed power resources with an increasing share of the later. This creates a constellation which distributed networks were never designed of. Hence the management of distributed generation becomes more complex than that of the current transmission grid. The distributed generation offers the flexibility adds supply wherever needed at lower infrastructure and provides more reliability. But with the addition of more of them to the grid, there evolves unintended consequences and inherent operating challenges. The secondary network grid is designed for directional power flow, from multiple transformers all connected in parallel (secondary connected), providing power “into the load”. In a secondary network grid scenario, utilities need to understand the dynamics as the integration of DER can render existing protective schemes inadequate and can create an unsafe condition as monitoring involves a high number of components, substations and nodes in comparison to that of the high voltage grids. In such environments, interconnection of renewable generation to the grid is critical for smart grid programs. To understand the dynamics of the secondary area network and the impacts of DER, under a Department of Energy (DOE) Grant, Eversource Energy (previously NSTAR Energy) have implemented a project called “Urban Grid Monitoring and Distributed Resources Integration Program” in the City of Boston, Massachusetts on one of the secondary network grids.