Future grid infrastructure Field tests of LVDC distribution

Transcription

1

2 Future grid infrastructure Field tests of LVDC distribution LUT LVDC Research Group: Andrey Lana, Pasi Nuutinen, Antti Pinomaa, Tero Kaipia, Pasi Peltoniemi, Aleksi Mattsson, Jarmo Partanen

3 Introduction to utility grid LVDC Background Even though the Smart Grids is mainly development of intelligent applications and related ICT, the largest investments will be made to the primary electric infrastructure LVDC solution Renaissance of Edison's direct current electric system based on modern power electronics Basic property Improved technical performance compared to existing low voltage grid solutions more power transfer with higher control in the same power lines Special feature High penetration rate of intelligent hardware; thanks to power electronic converter technology ready to use hardware for implementing smart applications Main philosophy Replacing existing AC low voltage networks and parts of medium voltage grid with LVDC reduces the total costs of electricity distribution

4 = Concentric PE conductor 20 kv MV supply Capacitors Outgoing DC cable Capacitors Hypothesis of LVDC Research Power electronics and DC networks can reduce costs of power distribution, improve power quality and provide opportunity to integrate novel smart grid functionalities to power system and to support improvement of energy efficiency. Power line signals 20 kv 20 kv DSO TSO Aggregators Retailers etc. Mains Protection external control signals r +750 VDC = rectifiers N = -750 VDC r = = r BMS = = = = = 230/400 VAC Load Load Load Load Load Load Pad-mounted rectifier substation 3 I> circuit Double-tier breakers 3 I>> transformer 20.5/0.53/0.53 kv Rectifier AC DC AC DC Auxiliary power Coupling supply 230 VAC device Control and communications electronics PE Substation earth I > coupling I DC U DC+ U DC- Insulation monitor surge arresters +750 N -750 Local communications internal control signals

5 Concept of LVDC Electricity Distribution Rated voltage range VDC (LVD 2006/95/EC) VDC (IEC) An LVDC distribution system comprises power electronic converters and DC connection between the converters The entire low-voltage network is realised with DC system End-customers have either a direct DC connection, or an AC connection through a DC/AC inverter, or a DC connection through a step-down DC/DC converter System comprises an integrated control and communications system LVDC system provides Safe and reliable electric energy transmission from the MV network to the LV customers Constantly good-quality voltage supply for customers An easy-to-control connection point for small-scale generation units and storages A ready-to-use platform for smart metering, demand management and network control NOP LVDC supply area 20 kv main line AC/DC AC/DC DC/AC Bipolar LVDC system DC/AC DC/AC DC/AC Unipolar customer connection 110/20 kv Substation

6 LVDC in Rural and Urban Environments Urban district L 0.4 kv 0.4 kv 20/0.4 kv AC 20 kv 20/0.4 kv AC 0.4 kv 0.4 kv AC LVDC DC/AC AC 20/1/0.4 kv AC AC P AC AC DC DC 20/PJ AC DC LVDC DC DC/AC AC DC Indoor DC Public lighting AC 20 kv Backup connection Suburban district

7 Highlights Research Platforms Laboratory prototype Test environment for technical solutions, functionalities and design methods of LVDC technology Study implementation of developed solutions in practical environment Provide feedback for equipment development Impact of environmental conditions Requirements of installation and maintenance on equipment structures Compatibility with interconnected systems and devices Verification and development of system design, control algorithms and management systems Real-life network environment Durability and reliability of electronic components in demanding distribution network environment Inspections of installations and authorised approvals of structures Verification of electrical safety Equipment ratings Documentation Experiences from electricity end-users and from installations and operations personnel Practical experiences to support LVDC system standardisation

8 Field tests of LVDC distribution by LUT and SSS Oy 1.7 km bipolar LVDC network with three three-phase customer-end inverters supplying four residential houses installed in Suomenniemi Objective to test converter technology and collect experiences from LVDC distribution Continuous 24/7 operation during June 2012 May 2013 CEI #3 Connected to +DC CEI #2 ±750 VDC Connected to +DC 200 m CEI #1 Connected to DC

9 Field Installations by LUT and SSS Oy Fully customisable hardware and software platform for research purposes. Comply with national and IEC electrical safety requirements Half-controlled thyristor rectifier V side moulded-case circuit breaker V side moulded-case circuit breaker 4. DC network surge protectors 5. DC network capacitors 6. Thyristor control, insulation monitoring, and measurements 7. Rectifier control, embedded PC, and communications Rectifying substation DC supply bus 2. Common-mode choke 3. DC network surge protector 4. Electronics power supply 5. DC circuit breaker 6. Capacitor 7. Power electronics (IGBT) 8. Output filter 9. Output isolation transformer 10. Output bus Inverter substation

10 System Management Web portal for monitoring and control Rectifier Fiber/Ethernet Switch Server Backhaul NW VPN Web-browser controllable Backup remote access with 3G modem Backhaul NW M99131 Inverter 1 ADSL modem Ethernet switch Fiber/Ethernet converter Client1 VPN Web-browser controllable VS Artila Control board Artila Control board Single mode Fiber Inverter 3 Inverter 2 Fiber/Ethernet converter Client3 Fiber/Ethernet converter Client2 Artila Control board Artila Control board Local ICT-system Examples of measurements and warnings (fault codes) during July 2012 thunderstorm.

11 System Management Control functions Rectifier control, i.e. DC network start-up and shutdown Remote emergency shutdown of the system Customer-end inverter (CEI) control (start-up, shutdown, reset) Real-time monitoring, rectifier DC network voltages and currents Rectifier power electronics temperature DC network isolation resistance Real-time monitoring, customer-end inverter DC voltage and current Customer-end phase voltages and currents Control electronics supply voltage and system temperatures (cabinet and power electronics) Customer-end frequency Fault situations Fault code display and reset Alarm reporting Recording of high-resolution waveforms before and after fault ( black box operation) Logging 1 minute resolution data (maximum, minimum and mean values for powerflow, voltages and currents) Customer power quality data (currently with 16 seconds interval) Customer voltage and current harmonic content (1 minute interval snapshots) Network insulation measurements Faults and system events

12 Embedded ICT system Remote supervision and management system providing web-based portal with highresolution measurements, logging, fault identification and event recorder Power quality analyser functions (IEEE Std ) System Management

13 Conclusions on field tests of LVDC distribution First implementation of modern LVDC distribution and CEI based supply in continuous use by a DSO Very reliable, though it is a research setup Special situations have been managed as planned Quality of supply has been high, but there is still room for improving the control algorithms Platform for further development of smart grid functionalities

14 Field Installations - Next steps Continuous collection of user experiences Updates to converter hardware and system controls Connection of energy storages and local generation Integration of microgrid controls Island mode control Market oriented control Standardization issues F F DC/DC 440 VDC F Medium voltage network F F VDC DC/AC DC/DC F

15

16 Rectifying Substation 16

17 Double-Tier Transformer and Rectifier 17

18 CEI #3 and CEI Control Electronics 18

19 Rectifier Testing 19

20 First System Start-Up and CEI Tests 20

21 First System Start-Up and CEI Tests 21

22 RF EMI Measurements 22

23 PLC Communications Measurements 23

24 Winter

25 Researcher Exercising in February 2013 Thank you! 25