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TUV Rheinland of N.A.Renewables Energy Division

Topic: Green Power Compliance

Speaker: Robert Holt, SFr

Regional Sales Manager

Renewable Energies Division

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Situation: Utility demand has increased 2.5% per year over the last 35 years and will by at least 1.07% till 2030*.

A core of President Obama’s energy policy will be to improve

energy efficiency…including tougher appliance standards.

Smart Grid Background

Mandate: Grid 2030 (GridWise, Intelligrid, EPRI, DOE, FERC)

Goal: Revolutionize the current (aging) electrical infrastructure with a “Smart” electric grid allowing utilities to “fine-tune” energy use*.

Key words: Measurement and Control

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Mandate: Energy Independence and Security Act 2007 title XII, section 1305

That language on the metalevel is IEC 62559: IntelliGrid Methodology for Developing Requirements for Energy Systems,applications for communications, control, and data management

Smart Grid = Green =Energy independence +

Reduction of CO2 +Grid stability

Effect…Bringing together:Generation – Transmission – Distribution - Consumption …in a common secure information infrastructure using a common language

The KEY words are: Interoperability and Efficiency

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Rise in “Intelligent” Power Products =

Rise in “Green Standards“ =

More compliance requirements from Power Generation manufactures

(…for consultants and third party labs/certifiers)

Solar Wind GeoThermal Biomass

New Standards driven by new advancements in Renewable Energy “Generation”

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Different Categories of Solar

CPV Concentrating Solar Photovoltaic

Solar Thermal

CSP Concentrating Solar Thermal

Photovoltaic

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Rise in New Panels =

Rise in “Green Supply chain“ Support Products =

More compliance requirements from Power Distribution manufactures

(…for consultants and third party labs/certifiers)

Optimizers

Inverters

Controllers Servo Moters

J-Boxes

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Greater need for “Intelligent” Power Products = Rise in “Green Standards“ =

Broader & tougher standards throughout the Green Power Industry

2004: The DOE established the Gridwise "Architecture Council“to bolster support for their emerging interoperability requirements.

• Apply IT ingenuity to “reinvent” existing energy systems.• Collaborate & create Technology Solutions that transcend corporate or regulatory boundaries.• Ensure ruggedness and security through an intelligent power grid.• Ensuring a “shareholder” mentality with the consumers.

2003: The Pacific Northwest National Laboratory (a US Department of Energy (DOE) government research laboratory) was founded and became the“GridWise

Alliance” (www.gridwise.org) a public-private forum.

OBJECTIVES:

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Smart (as in SmartGrid) = Measuring & Control =

2004 The Electric Power Research Institute (EPRI) founded “Intelligrid”.

2004 EPRI published the “Intelligrid Architecture”(SmartGrid framework for linking communications).

~Automatic Meter reading (AMR)~Supervisory Control And Data Acquisition (SCADA)~Remotely Controlled Distribution devices

Sensors and Control Elements have to be integrated throughout the entire power generation & distribution chain…all of it.

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ModernGrid strategy =

AMI “ Milestone “ Approach =

AMI allows the consumer to “Invest” in the SmartGrid & and enables communication to the loads

Milestone 1 – AMI lead to AMR (Advanced Meter Reading)

Milestone 2 – ADO "Advanced Distribution Operations" allows for Self-Healing.

Milestone 3 – ATO: substation automation, control, protection, modeling simulation

Milestone 4 – AAM (Advanced Asset Management) Raises the bar in power products asset programs

AMI >AMR >ADO >ATO > AAM

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SmartGrid =

Control & Measure Communications =

Integrated 2-way Communications & Power infrastructure consisting of “Demand Response” (control of loads) through a customer interface.

Advanced Metering – measures, collects & analyses energy usage, while communicating “BACK” to the utility and consumer

Remote Access and Control – For both Consumer & Utility

Intelligent Appliances – Thermostats, Refrigerator, HVAC…

HAN (Home Area Networks) are customer portals linking Smart meters to Controllable loads.

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“Smart Grid” Objectives

(1)

Distribution Reliability Outage Duration (SAIDI), Outage Frequency (SAIFI)

Grid Reliability Loss of Load Probability (LOLP), Number of MajorEvents as Defined in Section 311 of the Federal Power Act

Power Quality Momentary Interruption (MAIFI), Voltage Sags (SARFI), Harmonics, Unbalance

Utilization Load Factor (Average to Peak), Asset Utilization \Factor

Sustainability “Self-Healing”, Delivery System Losses, Information Enabled End-Use Energy Efficiency; reduced CO2 footprint

Market Efficiency Extent of participation of distributed resources in the energy market

Safety Public and worker safety

Security Protection for Cyber and Physical Treat

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Sample: solar residential microgrid

Single point of connection with grid with a disconnect switch (and active controller)Islanded operation with local generation, storage and microgrid controller

Semi-autonomous power system, Active and reactive power support to grid

Significant reduction in required infrastructure (high PV capacity value)

(2)

submetering and control on the local A/C grid

Utility ask and bid offers;Negotiation vrs rigid control

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The central role of the inverter:Universal power management system (UPMS)

interactive, multi-functional, power management systemGrid support with real time communication

Power flow control based on real time pricingEnhanced power quality, power factor correction

Demand management and load controlAdvanced grid and islanding algorithms

Multi-port DC-DC converter

Grid

Super cap

Battery

DC-AC PWMconverter

DC link

Digital,supervisorycoordinatedcontroller

PV panels

Sensors

Utility command

Microgrid controller

Intelligent loads

A/C interop

Communication Interop

(2)

Off-grid DC loads

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Types of Photovoltaic Inverters

DC from Solar Cells, Wind turbine, Hydrogen Fuel Cells, DC Generator, etc

Grid-Tied from a Distributed Energy System

Stand Alone or Grid Tied

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US Norms, standards and requirements

Operational ConstraintsIEEE Std 929-2000: IEEE Recommended Practice for designing inverters for utility-interconnected PV systems ANSI/UL 1741:2005 - Inverters, Converters, Controllers & Interconnection System Equipment for use with Distributed Energy SystemsIEEE 1547 - Standards for Interconnecting Distributed Resources with Electrical Power SystemsNational Electric Code - Section 690: Solar Photovoltaic SystemsPower quality (PQ): The quality of power provided by the PV system for the on-site ac loads and for delivery to the interconnected utility is governed by practices and standards addressing voltage, flicker, frequency, and distortion.Additional safety and protection functions: Proper and safe operation of the PV systemsInverter reliability is a major concern. A number of institutions work on measurable standards and methods to achieve verifiable improvements

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Canadian, standards and requirements

CSA C22.2 No. 107.1 Power SuppliesCSA C22.2 No. 257Interconnecting Inverter-Based Micro-Distributed Resources to Distribution SystemsCSA C22.3 No. 9Interconnection of distributed resources and electrical supply systemCanadian Electrical Code (CEC)Section 50 Solar Photovoltaic SystemsSection 84-Interconnection of Electrical Power Production Sources

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PQ – Normal Voltage Operating Range

Utility-interconnected PV systems do not regulate voltage, they inject current into the utility. Therefore, the voltage operating range for PV inverters is selected as a protection function that responds to abnormal utility conditions, not as a voltage regulation function.Small system (< 10 kW)The operating window for these small PV systems is 106-132 V on a 120 V base, that is, 88-110% of nominal voltage. This range results in trip points at 105 V and at 133 V.Intermediate (>10kW, < 500kW) and large (>500 kW) systemsUtilities may have specific operating voltage ranges. If not, operating between 88% and 110% of the appropriate voltage shouldbe followed.

(3)

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PQ – Power Factor, DC Current InjectionThe PV system should operate at a power factor > 0.85 (lagging or leading) when output is > 10% of rating.Most PV inverters designed for utility-interconnected service operate close to unity power factor.Specially designed systems that provide reactive power compensation may operate outside of this limit with utility approval.The PV system should not inject dc current > 0.5% of rated inverter output current into the ac interface under either normal or abnormal operating conditions.The PV system should include DC disconnect safety switching and sub-metering on the SE networkUPMS is responsible for all power and load management (i.e. outside of SE)

(3)

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Protection – Response to Voltage DisturbancesVoltage (at PCC) Maximum Trip Time

V<60 (V<50%) 6 cycles

60V<106 (50% V <88%) 120 cycles

106V<132 (88% V <110%) Normal operation

132V<165 (110% V <137%) 120 cycles

V165 (V 137%) 2 cycles

“Sense to reconnect” required, minimum 5 min stand-by for utility out-of-bound events

When the utility frequency is outside the range of 59.3 - 60.5 Hz, the inverter should cease to energize the utility line within six cycles.

(3)

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European Norms and standards

• EN 50160/DIN 50160 „Voltage Characteristics of Public Distribution Systems”• IEC 61000-4-30, “Power quality measurement standard”• IEC 62053 “electricity metering requirements”• IEEE Standard 1159-1995, “Recommended practice on monitoring power quality”• VDEW_1, 2 und 3 (Verband der EnergieWirtschaft - Voltage Dips, harmonic & interharmonic

disturbances) and “„Eigenerzeugungsanlagen am Niederspannungsnetz“• The “VDEW-Richtlinie für den Parallelbetrieb von Eigenerzeugungsanlagen mit dem

Mittelspannungsnetz“• VDN Transmission code 2003 VDN_4 (Verband der Netzbetreiber)• VDN Metering Code 2006 (metering minimum requirements)• “Merkmale der Spannung in öffentlichen Elektrizitätsnetzen“• DIN VDE 0101 “ Starkstromanlagen mit Nennspannungen über 1 kV“ (safety requirements > 1kV)• DIN 50110 “ Betrieb von elektrischen Anlagen < 1kV“

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EN 50160 short overviewPower frequency measured over 10 s, ±1% (49.5 - 50.5 Hz) for 99.5% of week, -

6%/+4% (47- 52 Hz) for 100% of weekVoltage magnitude Variations ±10% for 95% of week, mean 10 minutes rms values

Rapid voltage changes LV: 5% normal, 10% infrequently, Plt ≤ 1 for 95% of week, MV: 4% normal, 6% Infrequently,Plt ≤ 1 for 95% of week

Supply voltage dips Majority: duration <1s, depth <60%.Locally limited dips caused by loadswitching on: LV: 10 - 50%, MV: 10 - 15%

Short interruptions ofsupply voltage

(up to 3 minutes), few tens - few hundreds/year, Duration 70% of them < 1 s

Long interruption of supply voltage

longer than 3 minutes, <10 - 50/year

Temporary, power frequency overvoltages

LV: <1.5 kV rms, MV: 1.7 Uc (solid or impedance earth), 2.0 Uc (unearthed or resonant earth)

Transient overvoltages LV: generally < 6kV, occasionally higher; rise time: ms - μs., MV: not defined

Supply voltage unbalance LV, MV: up to 2% for 95% of week, mean10 minutes rms values, up to 3% in some locations

Harmonic voltage Order/%, 5/6, 7/5, 11/3.5, 13/3, 17/2, 19/1.5, 23/1.5, 25/1.5, 3/5, 9/1.5, 15/0.5, 21/0.5, 2/2, 4/1, 6-24/0.5

Note: this is a minimum standard local standards e.g. VDE 100 are stricter

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Upcoming Inverter Meter Test Procedure• Addresses current SAF concerns (i.e., ANSI/UL1741) as well as EMC and PERFORMANCE

• Collaboration of KEMA, Sandia, PV Metering Subc., & various Stakeholders

• Main goal is verifying integral metering devices to +/- 5% accuracy

• Every effort made to provide synchronicity with ANSI 1741 & IEEE 1547.1 & these tests are meant to supplement them (and when in conflict 1741 & 1547.1 take precedence)

• EMC is typical: RE/CE, RI/CI, ESD, Surge, EFT, VDI (+ Oscillatory Surge withstand Capabilities)

• There also is one test performed in conjunction with California’s weighted efficiency standard

• Performance tests include:

* Stability of Performance* Operating Temperature* Humidity* Weather Simulation * Raintightness

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Upcoming Inverter Meter Test Procedure (RMS)• RMS requirements apply to all test procedures.

Parameter True RMS (V,I,P) Allowable Maximum Uncertainty Preferred Maximum Uncertainty

DC Voltage* Plus or Minus 1% of reading Plus or Minus .25% of reading

AC Voltage Plus or Minus 1% of reading Plus or Minus .25% of reading

DC Current* Plus or Minus 1% of reading Plus or Minus .5% of reading

AC Current Plus or Minus 1% of reading Plus or Minus .5% of reading

DC Power* Plus or Minus 1% of reading Plus or Minus .5% of reading

AC Power** Plus or Minus 1% of reading Plus or Minus .5% of reading

AC Frequency Plus or Minus 0.05 Hz Plus or Minus 0.01Hz

Temperature Plus or Minus 1 degree C Plus or Minus 0.5 degree C

DC Current Ripple Plus or Minus 5% of reading Plus or Minus 1% of reading

• *“True RMS” measurements must be made for voltage & Current (including contribution of the ac ripple on dc values.

• **The ac power measurement should only include the usable 60Hz power.

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Conclusion

In the US technical requirements are generally utility specific and consortia driven, safety requirements are central and clearIn Europe the EN and ISO standards are applicable with added requirements by local utilitiesSolar and wind add instabilities to the networks that require specific and sophisticated control strategies and changes to network topologies Manufacturers of devices for these markets can orient themselves on European AC requirementsSpecifically inverters will play a critical role as control and measurement nodes for distributed generation and within green large scale plants. demand management implemented over UPMS is essential for the “Smart Grid”

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References

(1) NIST Smart Grid workshop 2008(2) Prof. Raja Ayyanar, PV ASU/PTL meeting Febr. 2008(3) Prof Bingsen Wang, PV ASU/PTL meeting Febr. 2008(4) Jerry Raime, TUV Newsletter Article, March 2009(5) Intech Article, Feb 1, 2009