ISIS™ Integrated Solar Inversion Systems

Why AETI?
American Electric Technologies, Inc. (AETI) is the global market leader for Power Delivery Solutions. Founded in 1946, we have delivered over 1000 MWs of power delivery systems into the world’s harshest environments, and have proven product designs deployed in the deserts in the Middle East, high humidity/jungle environments in South America, frigid environments such as Siberia and Northern Canada, and offshore/marine environments such as the North Sea.

In the past three years alone, AETI has delivered more than 760 MWs in 340 multi-watt power conversion systems.  After supplying multi-megawatt power conversion, distribution & control systems for over 65 years to over 150+ customers with significantly larger sales revenues, demanding turnaround times, and unwillingness to accept lack in performance, AETI’s long term company financial success and hence solar financier bankability is based upon the use of global & USA codes, practices & standards to deliver high quality products on time and within budget.

AETI’s Integrated Solar Inversion Station, ISIS™, is designed for utility grade solar projects 1 MW and above, using a modular suite of 1.0 and 1.5 MW solar inversion platforms and 15 and 38 kV utility interconnection platforms.  We work with solar project developers, financers, Engineering, Procurement and Construction (EPC) firms and utilities to successfully achieve their utility scale solar project requirements with the highest performance and maximum reliability.  ISIS’ product bankability is based upon using best in class design & manufacturing codes, practices & standards to obtain high-performance, significant reliability and greater safety built-in throughout. 

AETI leveraged our multi-megawatt experience to develop the solar industry’s first 1000 Volt UL 1741 witness-tested 1.0 and 1.5 MW utility grade & scale Integrated Solar Inversion System in the industry, which is designed & manufactured in America and compliant to Made-in-America solar farm project requirements.  The solar inversion platforms of ISIS can be used with a customer-supplied transformer & switchgear for NFPA 70E PPE Level 3 protective clothing requirements, or AETI can optionally supply 15 or 38 kV ANSI C.37 witnessed-tested transformer & switchgear for NFPA 70E PPE Level 1 protective clothing requirements.

When the inversion system platform and the utility interconnection system platforms are supplied together, ISIS is the only UL 1741 and ANSI C.37 witness-tested complete and integrated solution with solar inverter, step-up transformer and interconnection switchgear that includes:

Solar Inversion System

• 1000 Volt unipolar PV array input system, witness-tested to UL 1741 Year 2010, yielding up to 15% more watts per string, while saving 5 cents per watt in cabling costs versus bipolar PV array systems.  ISIS’ PV input section is rated to 1200 open circuit Volts.
• Integrated built-in configurable multi-circuit two-pole-fused 1.0 or 1.5 MW master re-combiner system, with industry-leading CPUC compliant PV+ and PV- detecting GFCI.
• Integrated built-in 1.0 or 1.5 MW DC & AC NPFA 70E PPE Level 1 clothing two-pole DC and three-phase AC disconnect switching system, manually and remotely controlled. 
• Integrated built-in and industry-leading two-tier-fused (separate combiner & inverter fusing) for enabling DC PV to AC Output hot-run-ratios greater than 1.35 times.
• Integrated built-in dual or triple UL 508C listed 500 kW liquid cooled power modules with 98% efficiency, soft-start up of power, and the solar industry’s widest on-demand dynamic power factor range from 1.0 to 0.0 pf, leading or lagging, VAR compensation.
• Integrated and built-in master SCADA control & automation system with utility DNP3 network communication systems, along with an IT accessory and service technician bay.
• Industry’s lowest heating & cooling tare loss from 100 to 3,500 watts, using liquid pump and redundant fan cooling system, resulting in industry’s widest temperature range from  -40°C to 60°C, with no de-rating of output power until 50°C, even in peak solar sunshine.
• System pre-commissioned with heat-rejecting and NFPA 70E PPE Level 1 dead-fronting doors, as part of a NEMA 4 enclosure and fork-lift mounting skid that requires no crane.

Utility Interconnection System

• ANSI C.37 99.0% efficient, environmentally friendly (oil-less and sump-less) dry-type & air self-cooled and inverter-duty K class, 15 or 38 kV step-up transformer, with dual or triple wound secondary for higher inverter availability or single wound secondary for lower cost per watt. Secondary configurations are wye-ungrounded for floating PV array configurations, primary configuration includes delta, wye-grounded and wye-ungrounded.
• Project-specific ANSI C.37 15 or 38 kV NFPA 70E PPE Level 1 switchgear with the specific medium voltage disconnects, breakers, multi-function relays, interconnect relays, revenue meters/CTs/PTs, etc. required by AHJs & utilities to meet USA & local codes.
• System pre-commissioned with NFPA 70E PPE Level 1 dead-fronting doors, as part of on NEMA 3R enclosure and fork-lift mounting skid that requires no crane.

By delivering an integrated solar inversion system or a completely integrated solar inversion station, AETI reduces PV array design, site construction and commissioning costs.  The NEMA 4/3R pre-integrated pre-tested package means no containerized building design with separate tare-lossy HVAC systems that must conform to NEC requirements and pay additional building taxes.  In addition, ISIS’ design replaces problematic inter-section field construction wiring, testing and commissioning with guaranteed ISO 9001 factory wiring, testing and pre-commissioning.

ISIS is the world’s first 1.0 and 1.5 MW 1000 Volt Solar Inverter approved to UL 1741.
As an NRTL, TUV Rheinland validated compliance of AETI’s 1.0 and 1.5 MW ISIS to all appropriate UL 1741 Year 2010 criteria.  Witness-testing significantly increases Utility and Authorities Having Jurisdiction (AHJs) acceptance of 1000 Volt solar farm project equipment. In addition, ISIS is designed to NEMA, NEC, UL, ANSI, IEEE, NFPA and OSHA codes, practices & standards, among others, that ensure the utility, AHJ, developer and EPC of national & local code design conformance, operating site conformance and avoidance of electrical accidents and fires.

ISIS is the highest performance solar inversion system on the market.
ISIS’s 1000 Volt unipolar PV array design increases watts per string up to 15%, while saving the project up to 5 cents per watt in DC cabling costs alone when compared to 600 Volt bipolar PV array designs.  ISIS is designed to 1200 volts open circuit, allowing interconnection with higher voltage PV panels to be fully utilized.  ISIS also provides maximum power point tracking up to 1100 Volts, and has the industry’s highest input current of 1700 Amps per 1 MW.  Because of ISIS’ unique two-tier fusing system, PV DC to output AC hot-run-ratios of greater than 1.35 are possible when coordinating the PV array combiner fusing with ISIS master re-combiner fusing.
ISIS also delivers the industry’s lowest tare losses due its proprietary liquid and air cooling system, typically 100 watts when offline at night and up to only 3,500 watts when under full sun at full output power – as opposed to tare losses of up to 20,000 watts when using a conventional HVAC systems.  In addition, ISIS’ harsh-environment-duty NEMA 4 system package includes an air intake system that results in dirt & debris-less operation, and uses sunlight heat-rejecting external doors that deliver the industry’s widest ambient operating temperature range of -40 to 60C with no de-rating of output power up to 50C, even in direct solar noon sunshine.
In addition, ISIS also provides on-demand four-quadrant output power factor control from 1.0 to 0.0 pf leading or lagging, regardless of real solar power input, for controlling short-term droop by dynamically injecting VARs to shore up the grid voltage at that point, along with soft-start-up of power in the morning and after significant solar cloud fades.  All of ISIS’ features are controllable though its on-board master SCADA control & automation and cyber-secure communications.

ISIS is the most reliable and safe solar inversion system on the market.
ISIS’ design leverages AETI’s experience in deploying 1000s of MW of proven power delivery solutions into the world’s harshest energy environments. This reliability is demonstrated in both the interconnection and disconnection systems.  Regarding ISIS interconnection, for customers to quickly obtain utility interconnect and AHJ acceptance, AETI uses a three tier UL approval design & manufacturing test approach: UL 508C listed power conversion modules for demonstrated power conversion reliability of the IGBT system on the grid, UL listed IEEE 1547.1 interconnect relay for demonstrated interconnection safety when connecting to the grid, and NRTL witness testing to UL 1741 for demonstrated performance, reliability and safety at 1000 Volts.  ISIS DC & AC disconnection is done simultaneously for all DC poles & all AC phases to provide complete power circuit load break and reduce the arc flash through the DC disconnect switch, resulting in NPFA 70E PPE Level 1 clothing that requires no special suit to take the inverter off the grid. 

ISIS utility interconnect system assures safe and successful utility integration.
AETI engineers work directly with the solar farm designer and utility to incorporate project specific disconnect switches, circuit breakers, multi-function protective relays, interconnect relays, and revenue meters and their utility specific CTs and PTs, into NFPA 70E PPE Level 1 clothing compliant 15 or 38 kV custom collection or substation switchgear.  AETI is the only inverter company with this in-factory capability, which significantly reduces project risks and costs to the developer and financier alike. 

ISIS significantly reduces project schedules & costs and operations & maintenance costs.
ISIS’ solar inversion systems and project-specific utility interconnect systems are all integrated on a pre-tested, skidded NEMA 4/3R outdoor packages, resulting in less design engineering, field construction installation and field system integration, test, and start-up commissioning work, providing the financier, developer and EPC with project work, cost and schedule reductions.  By designing, manufacturing and testing the systems to NEMA, NEC, UL, ANSI, IEEE, NFPA and OSHA codes, practices and standards, among others, significant regulatory design conformance, operating site conformance, and avoidance of electrical accidents and fires is obtained to the level of quality utilities expect from their switchgear built to these national electrical standards.