The More Microgrids Project

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1 The More Microgrids Project Prof. Nikos Hatziargyriou National Technical University of Athens, Vice Chair and Deputy CEO, PPC, Greece

2 What are MICROGRIDS? Interconnection of small, modular generation to low voltage distribution systems forms a new type of power system, the Microgrid. Microgrids can be connected to the main power network or be operated islanded, in a coordinated, controlled way.

3 MORE MICROGRIDS Project Large Scale Integration of Micro-Generation to Low Voltage Grids Contract : ENK5-CT Budget: 8M

4 Objectives Sophisticated control techniques for Distributed Generators Load Controllers to implement Study of integration of several Microgrids into operation and development of the power system. Interaction with DMS. Field trials to test control strategies on actual Μicrogrids Quantification of Microgrids effects on Power system operation and planning

5 Østkraft Pilot FYROM (INCO) 5

6 Kythnos (Gaidouromandra) Microgrid Supply of 12 buildings (EC projects MORE and PV-Mode)

7 Systems added: Next generation Sunny Island inverters, to deal with islanded mode control Intelligent Load Controllers The test site is a small settlement of 12 houses Generation: 5 PV units connected via standard grid-tied inverters. A 9 kva diesel genset (for back-up). Storage: Battery (60 Volt, 52 kwh) through 3 bi-directional inverters operating in parallel. Monitoring: Data logging equipment

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9 Technical Challenges Test decentralized control in a real environment with the aim to increase energy efficiency Technical challenges of the Multi Agent System test negotiation process Test novel features in MAS implementation including communication capabilities Test of new inverters

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11 Technical Description

12 PV The main load in each is the water pump. The goal of the system is to optimise the usage of the pumps by limiting the operation of the diesel Battery Full Low

13 Step 1: The agents identify the status of the environment Step 2: The agents negotiate on how the share the available energy PV Diesel Batteries System House Wi-Fi

14 Intelligent Load Controllers In each house an ILC is installed: Windows CE 5.0 Intel XscaleTM PXA255 64MB of RAM 32MB FLASH Memory Java VM Jade LEAP

15 Measurements: V, I, P, Q, Hz, voltage dips, over current, power quality Communication cards enables access to internet via an available network (Wi-Fi, DSL, etc) Measurement Unit Internet/LAN Communication Processor Main Board Controls the switch by injecting a signal to the power cable. PLC Control Power Line 230V Filter Load

16 The shedding procedures start later In this case the frequency if almost 52Hz. This is an indication that the batteries are full and the PV inverters via the droop curves limit their production.

17 Technical Lessons learned Fully satisfactory performance of the Load Controllers with embedded processors to host the agents. Novel techniques successfully tested, such as: negotiation algorithms, wireless communication, CIM based ontology etc... Key issue the communication among the Load controllers. Problems in Wi-Fi (due to humidity) and in the PLC (system frequency near 52Hz) affected the system although this did not affect the citizens. The Java applications require a lot of memory Architecture too complex for such small systems, but offering great scalability.

18 Non-technical challenges Avoid power interruptions that could be annoying to the citizens User acceptance of the installation of Intelligent Controllers to act autonomously on their loads User acceptance of co-operative behaviour of intelligent Controllers. Agreement on energy consumption concept based on the principle of equality Results of 2008 Social Study The majority of users would prefer a connection to the public grid; they have not developed a special attachment to their PV powered microgrid system. Users do not consider taking responsibility for the system or becoming the owners of it, because they are there only during summer vacations and they lack technical knowledge. Need for local support (technician) The system operator (CRES) has tried to offer a similar energy service to the users as the public grid and this was not possible, because the conditions and expectations are very different. Ecological aspects have not been sufficiently appreciated; users do not see the advantages and the special value of receiving a green energy supply.

19 Non-technical lessons learned MAS for energy optimization provides a technical limitation and protection of the system to prevent over-use. This helps to maintain the good relationships between the neighbours. Importance of involving or at least explaining to users negotiation process to equally share the available energy - development of demonstration software Only a few of the residents of the settlement are interested. The rest expect the full benefits of the interconnected system The technical and economical aspects of system operation are evaluated positively: the system works quite reliably, users pay regularly, the maintenance and repairs of the system are well organized.

20 Potential for replication, business case Microgrids operation the way to unlock the full benefits of DER in isolated systems. The coordinated operation of several DGs and Loads (Consumers) increases the efficiency and provide opportunities for better network management. Decentralized MAS based control well suited to manage multitude of DERs and flexible loads with conflicting objectives and different ownerships Decentralized control provides cheap solutions, with low communication requirements, without need for central operator The solution provides plug and play capabilities The approach is suitable for large scale systems

21 The Bronsbergen Microgrid Holiday park, Zutphen, NL 108 cottages with PV roofs Installed solar power 315 kwp Peak load 150 kw 10 kv utility network Systems added: Dyn5 400 kva automatic islanding and reconnection switch 200 A LV feeder 1 Storage > Batteries + inverters 630 A 200 A 200 A LV feeder 2 LV feeder 3 Control > MGCC and isolating CB Monitoring > Battery mon. system inverter A battery unit A inverter B battery unit B 200 A LV feeder 4

22 Objectives 1. Demonstrate stable islanded mode 2. Demonstrate automatic isolation from and reconnection to MV network 3. Demonstrate fault level sufficient to ride through MV fault and microgrid feeder faults 4.Demonstrate reduced harmonic distortion, damping of resonances 5. Develop optimal energy management for service life optimization of battery system 6. Demonstrate stable parallel operation of inverters 7. Black start demonstration

23 Technical challenges Reduction of harmonics from PV systems Microgrid-level island detection Synchronizing the microgrid to the SMART public grid ELECTRICITY NETWORKS, Demonstration of smart distribution network

24 Non-technical challenges Obtaining civil and environmental permissions for the test site Avoiding annoyance to the residents of the park during installation and operation Scarcity of formally certified staff for supervision on safety during work and tests

25 Technical lessons learned Power Quality was the toughest problem: Resonances successfully damped, but traditional harmonics were overlooked Monitoring of as many parameters as possible is key Our strategy for island detection on microgrid level needs refinement. It works but is rather blunt Droop mode is a perfect way of operating inverters in a plug and play manner. Black start capability relies on a short-circuit proof inverter. Ours did an excellent job.

26 Non-technical lessons learned There was no space for a test shack or containers: We just purchased one of the properties in the park and converted that into a lab. Excellent choice both for staff and for avoiding inconvenience to other residents Obtaining formal permissions takes at least a year Availability of qualified staff members has to be ensured from a high level within the company Only a few of the residents in the park take interest. The rest doesn t want to be bothered A fine team is everything!

27 Potential for replication, business case Network companies are only starting to understand the technical potential of smart storage Performance of the equipment in Bronsbergen has been well received by Dutch network operators, a second project now in preparation will use a similar set-up First applications are now seen as grid-connected units for load levelling and power quality improvement. Business case follows from savings on network upgrading and reduced network losses Islanded operation is not considered as a short-term benefit in the Netherlands because of high availability of the public network. This may be viewed differently in other countries

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