Converter Fed Microgrids : Challenges & Solutions Presenter: Charles Sao, PhD Candidate, ECE Dept., U. of Toronto Contact Info: Prof. Peter Lehn Microgrids: Power Network with Loads and DGs that operate as a Single Controllable System. Grid Connected Mode  Current Mode Control: Dynamic Current Control  Synchronized to PCC Voltage: Fast P and Q Control  Grid Provides PCC Voltage and Frequency Control

Microgrids: Challenges Intentional Islanding Mode  Identical Topology and Control as Grid Connected Mode  Lose Control of PCC Voltage and Frequency  PQ Supply does NOT equal Demand Operate Like Conventional Gen?  Voltage Source with Regulated Voltage & Frequency  Frequency & Voltage Droop to Share Real & Reactive Power  No Dynamic Control of Current– Risk Burn-out (or)  Conventional P & Q Control - Slow

Solution & Results  Identical Topology as Grid Connected Mode  Regulates PCC Voltage and Frequency  Fast Control of Current and Power to meet Demand

Load Sharing of 2 Converters

Grid Connection Transient

Islanding Transient

Summary Project Summary:  Identical Controls in Island & Grid Connected Modes  Regulate V & Freq., Manage P and Q  Dynamic Current Control to Protect Converters Other Research Projects:  Autonomous Load Sharing of Voltage Source Converters  Computing Lightning Exposure of Wind Turbines (with Dale Dolan)  Benchmark System for Time Domain Simulation of D-STATCOMs Selected Industrial Projects (at BC Hydro):  Stability study of the North Coast 500 kV Line  Effect of non-linear loads on reactive power metering  CEA Power Quality Survey Coordination in BC