Hawaii Utility Scale Solar Projects: TMEIC PV Outdoor Inverters with Salt Damage Prevention
CONFIDENTIAL
Donn Samsa
TMEIC CONFIDENTIAL
TMEIC CONFIDENTIAL TOSHIBA MITSUBISHI-ELECTRIC INDUSTRIAL SYSTEMS CORPORATION Page 1
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Who is TMEIC? Petroleum & Chemicals
Steel Non-ferrous Metals
Material Handling
Renewables
US$3 BILLION
Oil & Gas
Semiconductor
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Where are TMEIC PV Inverters Installed?
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China 240MW 10MW Jordan Kuwait
USA
Italy
JPN
Senegal 10MW
2838MW
3.78MW Suriname
1060MW India
6564MW
More than 10GW inverters shipped Globally. Page 3
OK, so what about PV Inverters in Hawaii?
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It’s not just about Salt!
In fact, all Utility Scale PV Inverters must operate in harsh outdoor environments Extreme Temperatures: Freezing to Extreme Heat
Sand/Dust/Dirt/Mud High Humidity Sun, Rain, Wind, Snow, Ice
Projects in Hawaii have most of these same requirements Must also deal with Corrosive Salt Atmosphere Island Grid Concerns
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First, Let’s explore basic enclosure protection for PV Inverters
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Outdoor Packaging – Two Designs
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1. Indoor Inverter in an “E-house” Pro’s: - Provides indoor working space at site - Easy to “localize” the enclosure - Fairly easy to add standard air conditioning products for very severe environments Con’s - Can be difficult to manage air flow and thermal requirements - Codes & standards for enclosed space vary by location - Difficult to “stick” build at site - Quality is dependent on house design
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Outdoor Packaging – Two Designs 2. Outdoor rated Inverter
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Pro’s: - Ships from Factory ready to install outdoors - Easy to skid mount or “stick build” at site - Manufacturer has total control over quality - Adaptable to “Anti-Salt” Design
Con’s - Product design must account for local codes. - Service work is done in varying weather conditions TMEIC chose this design for our salt atmosphere projects in Hawaii Page 7
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Before we get to thatâ&#x20AC;¦. Inverter design is about more than just enclosures!
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The real challenge: How to design an inverter to operate in harsh environments for 20, 25 or even more than 30 years?
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Design for Exceptional Reliability Usage rating of TMEIC IGBT design
IGBT rating
Usage
Usage/Rati ng
Current
300A
1035A/8= 129.4A
43.13%
Voltage
1700V
1300V/2= 475V
38.24％
Temperature
150℃
102.1℃ （at：50℃）
68.07%
TMEIC Utility-scale PV inverter IGBT stack
Extremely low usage rating – enhanced reliability in all environments ! Page 10
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But the real key to Inverter lifetime: Cooling! Introducing TMEICâ&#x20AC;&#x2122;s Advanced Hybrid Cooling Technology < Confidential to TMEIC Corporation>
Traditional Inverter cooling systems
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Forced Air Cooling
Liquid Cooling
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Advanced Hybrid Cooling Technology
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Dual cabinet design â&#x20AC;&#x201C; protecting the critical components Heat Pipe Technology
Out-door rated inductors IGBT heat-pipe radiator fins
Sealed electrical cabinet
Out-door rated Fans Page 13
Advanced Cooling Technology
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Adapting to TMEICâ&#x20AC;&#x2122;s Cooling Technology to Salt Atmosphere
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Testing for Reliabilty
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Proven performance through IEC reliability test
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-25C to 75C cycle test Thermal cycling test
Humidity freeze test Cycle Test Procedure
SAMURAI in environmental chamber
Results showing no damages to the internal components
IEC－62093(2005) 「Balance-of system components for photovoltaic systems Design qualification natural environments」 IEC-60068-2-30(2005)「Environmental testing - Part 2-30: Tests - Test Db: Damp heat, cyclic (12 + 12h)cycle」 IEC-60068-2-78「Environmental testing - Part 2-78: Tests - Test Cab: Damp heat, steady state」
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Proven performance through IEC sand test
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Sand & Dust test in a chamber MIL-STD-810G / IEC 60068-2-68 Test 1: 400g of sand @ 50% fan speed Test 2: 100% FAN speed
MIL std. 400g (50% fan)
100% FAN speed
RESULT
No penetration of sand in the airflow section at 50% fan-speed
High-sand penetration at 100% air-speed Page 17
TMEIC PV Inverter Test Lab
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Environmental/EMC Chamber
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TMEIC PV Inverter Test Lab
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PV Inverter installed in Chamber
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Inverter Field Test: Operation: after 6 months
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After 6 months of operation on-site No trace of dust or sand in the critical component cabinet
Inverter Appearance
Internal Condition (front/bottom)
Internal Condition (DC-Switch)
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What is the Result of this effort?
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Exceptional Reliability
10133MW Installed
16066 PV Inverter units 48198 IGBT stacks
2 STACKS
150+ million operational hours 0.00415% IGBT Failure Rate
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Hawaii Utility Scale Solar Projects
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Marine/Island PV Issues Physical design changes when applying inverters in high salt environments/island installations: • Enhance enclosure paint coating thickness or use corrosion resistant material (or both) • Seal electrical cabinet to protect critical components and add heat exchanger • Additional conformal coating to control boards • Heat pipe and other power components rated for high salt environment. • Conduct salt water spray tests and life cycle tests
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Marine/Island PV Issues Potential Interconnection issues when looking at island grids: • When grid tied generation (wind and/or solar) is significant, then solar assets may adversely affect the voltage and frequency of the interconnection. • If a large percentage of the generation trips off at the same time due to a grid event and then restarts at the same time, instability becomes a major concern. • Frequency ride through requirements can range from mid-50Hz up to 67Hz (for a 60Hz system).
• Others: Rapid fault detection, rapid disconnect, and Temporary Overvoltage (TOV) must be addressed for weaker grids as load rejection may cause issues Page 25
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Marine/Island PV Issues Control considerations to mitigate issues on island grids: • First: Make control adjustments. • Adjust the voltage and frequency trip levels • Generator restart times • Slew rates
• Next: Explore Inverter Grid management features • Reactive current injection • Voltage control and frequency control • More Advanced: • Add storage to help weak grids • Add control system which can control both the PV plant and storage facility from the same controller (PV+Storage).
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Hawaii: Waianae Solar Project
• • • • •
Developer: Eurus Energy Americas, Contractor: REC Solar Site is two adjacent parcels which combine for a total of 198 acres System size (AC) = 27.6 megawatts System size (DC) = 40.392 megawatts Inverters: a total of 17 TMEIC 1,667-kilowatt units used in a 1,000-volt system with “Anti-Salt Feature” • Modules: Canadian Solar 315-watt and 320-watt modules Page 27
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Hawaii: KIUC Solar
• System size (AC) = 13 megawatts • Inverters: a total of qty 8 TMEIC 1,667-kilowatt units used in a 1,000-volt system with “Anti-Salt Feature” • Grid connection risk mitigation • Commissioning: end of Feb 2017 Page 28
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Obrigado!
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