1. www.smart-microgrid.ca Project 1.4 Operational Strategies and Storage Technologies to Address Barriers for Very High Penetration of DG Units in Intelligent Microgrids Dr. Géza Joós Student: Michael Ross

2. www.smart-microgrid.ca Purpose and Challenges Create a general framework for energy management of Microgrids with large amounts of renewables – Controlling a Microgrid with a high level of uncertainty and variability (e.g., stochastic nature of renewable generation). The methodology will be implemented for different renewable energy portfolios and power system configurations – Developing an operation strategy that maximizes economic considerations – Incorporating various DER

3. www.smart-microgrid.ca 2011 Identify barriers associated for large number of renewable DGs & research energy management strategies 2012 Establish performance metrics considering cost optimization 2013 Evaluate Storage technologies, modes of operation, ancillary service functions and values 2014 Research and develop controlling strategies and algorithms 2015 Evaluate performance of strategies

4. www.smart-microgrid.ca Enhancement for Canada’s future power system Industrial experience Cutting edge research

5. www.smart-microgrid.ca Project 1.4 Operational Strategies & Storage Technologies for a large penetration of renewable DGs Projects 1.1 & 1.2 Control, operation and power management Projects 2.2 & 2.4 Energy & supply security and Integration design Projects 3.1 & 3.2 Communication infrastructure and Grid integration

6. www.smart-microgrid.ca Barriers for Large Number of Renewable DGs Bi-Directional Power Flow Protection Coordination System Grounding Issues Unintentional Islanding Power Balancing Ancillary Services

7. www.smart-microgrid.ca Bi-directional power flow There may be times of high input power and low consumption, and other times of high demand but low generation. – This is a problem since the voltage regulation is difficult to control (voltage rise effect). Power can be exported as well as imported A fault on a lateral feeder can be “seen” on a healthy feeder, causing it to trip Source: NRCan

8. www.smart-microgrid.ca Protection Coordination Loss of coordination (fault currents can be larger, which means that some protective equipment can trip simultaneously) Loss of sensitivity (if the fault is located downstream of the DG, the utility might not be able to detect that a fault occurred). Nuisance fuse blowing

9. www.smart-microgrid.ca Protection Coordination Fault currents can vary widely based on whether microgrids are connected to the grid, or disconnected – Protection equipment must know when the microgrid is isolated or grid-connected

10. www.smart-microgrid.ca System Grounding Issues Grounding issues of the DG and interconnecting transformer can cause either overvoltages in a line-single to- ground fault, or it can increase the short circuit current by allowing a path for zero- sequence currents to flow

11. www.smart-microgrid.ca Unintentional Islanding The DG can reconnect out of phase with the utility The DG can be damaged in a fault condition There is a risk to personnel who may operate on an energized feeder DGs may not have voltage or frequency support

12. www.smart-microgrid.ca Power Balancing Load following controls must be in place when the DG is large enough such that many loads on the feeder are supplied with power from the DG, or when operating as a microgrid. This is particularly difficult with renewable DGs since the input power is intermittent.

13. www.smart-microgrid.ca Ancillary Services The feeder cannot rely on generator inertia (if interfaced through power-electronics) with dynamic changes in load – Must rely on other sources (energy storage, for example) to ensure inertial frequency response for the initial energy balance when a new load comes online/offline

14. www.smart-microgrid.ca Current Interconnection Standards IEEE 1547 Requirements for the Interconnection of Distributed Generation to the Hydro-Quebec Medium-Voltage Distribution System BC Hydro Interconnection Requirements for Power Generators Hydro One Distributed Generation Technical Interconnection Requirements

15. www.smart-microgrid.ca Energy Management Strategies Load curtailment – Demand response – Direct load control Generation curtailment – Including dump loads Energy Storage Systems – Batteries – Flywheels – Supercapacitors – Etc.

16. www.smart-microgrid.ca Gaps: - Other barriers for high penetration renewable DGs? - Other interconnection standards? - Energy management strategies?

17. www.smart-microgrid.ca Project 1.4 Operational Strategies and Storage Technologies to Address Barriers for Very High Penetration of DG Units in Intelligent Microgrids For further information contact: Michael Ross michael.ross2@mail.mcgill.ca