Advanced Inverter Roll Out in Hawai’i Sandia Systems Symposium

10 May, 2016

John Berdner

Senior Director of Regulatory and Policy Strategy

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• Background

• Multi-Step Approach

• Close collaboration with Inverter industry

• Choose expediency over perfection

• Codes and Standards constraints

• Current Status and Activities

• Enphase Vision of the Future

Presentation Outline

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• Why is Hawaii the first State with mandatory requirements for

advanced Inverters ?

• The need for advanced inverter functionality are similar to those in

other high penetration areas but are magnified in Hawai’i

• Hawai’i has highest level of DER penetration of any State in the US.

• Hawai’ian grids are low inertia and inertia continues to decline as more PV

displaces conventional generation

• Voltage regulation becoming a limiting factor on some feeders

• Frequency regulation could become an issue in near to mid term.

• Modeling showed system stability and security was at risk

• AES unit trips resulted in significant frequency excursions.

• Installation of additional DER without ride through capabilities could lead to loss of

Oahu grid (tipping point)

• Political direction is for further increases in renewables

• Target of 100% RPS by 2045 set by State law

Background

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Modeling of System Stability

Graphic Courtesy of Hawai’an Electric Inc.

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Frequency Event due to AES Trip ~ 270 MW

Graphic Courtesy of Hawai’an Electric Inc.

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US Codes / Standards / Regulatory Structure

NEC Article 690.4(B) requires equipment to be Listed for PV applications

UL 1741 is an equipment certification Standard and references IEEE 1547.1 tests

IEEE 1547.1 is the equipment compliance testing Standard for IEEE 1547

IEEE 1547 is the interconnection requirements Standard

Energy Act of 2005 Mandates use of IEEE 1547 as the National Standard

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• First issued in July 2003

• Specifically prohibited DER from participation

in Voltage regulation

• IEEE 1547.a amendment published in

May 2014

• Permitted DER to participate in Voltage

Regulation

• Widened trip settings.

• Allowed other settings by mutual

agreement

• 1547.1a amendment published in

March 2015

• Test protocols to match new functionality

described in 1547.a

Regulatory Constraints – IEEE 1547

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• Second edition published in

January 2010.

• Includes references to 1547.1 for testing

and IEEE 1547 (via 1547.1)

• Contains no requirements for ride

through but does not prohibit ride

through

• Does not prohibit ramp rate control

at startup

• Allows for fixed PF operation

• Includes tests for fixed PF

• Assumed to unity but non-unity PF’s are

allowed.

• Fixed PF minimizes adverse impacts on

anti-islanding

• Does NOT include tests for V/VAr,

f/W, V/W

• Concerns over impacts on anti-islanding

Regulatory Constraints – UL 1741

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• Developed in collaboration between HEI and inverter industry

• Formed “Mai Tai” group to address Hawaiian requirements

• Step 1 - Urgently address system stability via ride through settings

• Create new frequency and voltage ride through capabilities within limits of existing

UL Listings

• A best effort approach by each manufacturer.

• Request voluntary retrofit of existing installations with new settings.

• Target was <= 40 MW of installed base with old settings.

• Enphase updated approximately 135 MW of installed base and met target (barely)

• Step 2 – Develop new ride through settings based on system need

determined by modeling

• Required new UL Listing for most inverters to address wider settings.

• Target was implementation within 9 months after agreement on new settings

• Also added TrOV requirements and ramp rate control at restart (0.33%/sec)

• Enphase completed second update to fielded fleet of ~ 800k inverters

• Step 3 – Add reactive power requirements and mandatory remote

update capabilty

• Default value is 0.95 inductive

Multi-Step Approach

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• All interconnections approved after 1 Jan, 2016 requires advanced

inverter functionality

• Voltage and frequency ride through

• Fixed PF operation (0.95 inductive/absorbing VAr)

• Ramp rate control on restart (0.33%/sec)

• Mandatory remote update capability (manufacturer specified protocol)

• NEM closed in Hawai’I for any new interconnections

• Customer Grid Supply (35 MW cap)

• Offset onsite use at retail rare, sell at near avoided cost

• Customer Self Supply (No cap)

• No export of active power at PCC

• Inadvertent export for less than 30 seconds

• Limit of 1 hr times system size montly, i.e. 5 kW system <= 5 kWh/mo.

• Inadvertent export is uncompensated

• Large backlog of older NEM applications in the queue

• Likely will carry through most of 2016

Current Status

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• Advanced inverter testing underway at NREL

• Characterization of advanced inverter functions

• Models created for several HECO feeders

• Hardware in the loop modeling of advanced inverters on HECO feeders

• Future activities will model system level interactions

• Definition of additional advanced inverter functions beginning

• New functions are allowed by UL 1741 Supplement A

• Volt/VAr (voltage droop) function and settings

• Freq./Watt (frequency droop) function and settings

• Volt/Watt function (as a backup voltage regulation function)

• Development of requirements for energy storage systems

• Similar to advanced PV inverters

• Additional capabilities due to bi-directional nature and dispatch capability

• Driven by customer self supply and customer grid supply tariffs

• New proposed TOU rates under discussion

• DER Phase 2 Docket will be opened soon to address technical,

economic and fairness issues.

Current Activities

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Network Insight

Accurate, granular, and near real-time

visibility and data

Today, Enphase has almost 50k

systems reporting in Hawaii equating

to nearly 1 million sensors reporting

every 5 minutes

Production data from distributed

resources in addition to grid telemetry

measured at secondary voltage

Enphase Vision – Data and Control

Distributed Control

Changes to advanced inverter settings

occur infrequently now but will likely

increase as penetration levels rise.

Command, control and optimization of

distributed energy resources are being

piloted now (in CA)

Advanced controls for real power,

including storage dispatch. Coordination

of real and reactive power for voltage

optimization schemes seem likely

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Capabilities:

• PV production and grid data

• Historic and near real-time data

• Multiple aggregation levels

• Revenue-grade telemetry

• Master data management

• Automated changes to advanced

inverter functions

• Storage dispatch

• Forecast/actual tracking

• Alarms and notifications

• Power quality metrics

• DR system integration

Features Available Now / Near Term

Applications

• Interconnection Studies

• DER Integration

• CVR and VVO Programs

• Customer Engagement

• System Planning

• Support DERMS Pilots