WORLD-GEN June/July 2018

WORLD-GENERATION JUNE/JULY 2018 15 If you are designing a DC-coupled solar + storage system where you are using DC-DC optimizers to connect between the PV and DC bus connected to the batter- ies and inverter, you are going to want to make sure the DC bus is protected from any harmful possible faults in the PV array such as arc faults, ground faults or light- ning strikes (among others).  If the DC-DC optimizer does not have such pro- tections built in, you are going to want to make sure to source additional balance of system (BoS) hardware that provides these protections. At Alencon, we solve this issue within our DC-DC optimizer form solar + storage, the SPOT-ES, by providing a variety of pro- tections in our device including cable arc and ground leak detection in addition to protection from lightning strikes as well as over voltage, current and temperate situ- ations.  Alencon’s DC-DC Optimizer for Energy Storage, the SPOT-ES, is able to achieve these protections in a cost effec- tive way as a result of the galvanic isolation built into the product by attaching an isola- tion transformer to each, individual PV string input. This unique feature pro- vides all the benefits of DC coupling in a protected way while simplifying system design by assuring all the protections you need between the PV array and the DC bus are included in a single device.  “The ability to isolate a troubled solar array while the rest of the solar and obvi- ously the whole solar plus storage system continues to operate is a huge benefit. Galvanic isolation of solar from the rest of the system simplifies the fundamental protection approach on a system level. Since our system is battery centric, we always have a battery on the DC bus, meaning that the fault issues are much more severe when high battery currents are taken into account,” states Aleksey Toporkov, the President of ARDA Power, a pioneer in DC-microgrids. Galvanic isolation is a unique feature of Alencon’s SPOT and it is not available from other utility scale DC-DC optimiz- er on the market today. The benefits of the electromagnetic iso- lation provided by the SPOT-ES can be summarized as follows: 1. Robustness: The SPOT-ES galvanically isolates the PV strings from one another and from the DC bus. Thus, any faults that occur in the PV array such as lightning strikes, ground leaks or arc faults will be confined only to one string and will not affect the inverter, battery or other PV strings.  2. Fail-safe: In the unlikely event of an electronic component failure (short of open), the SPOT-ES safely disconnects the failed input channel from the rest of the system. 3. Versatility The SPOT-ES’s galvanic isolation of each input channel allows complete inde- pendence of the grounding scheme of input channels and the output to the DC bus. Each PV string can have negative, positive or floating grounding while the output can be independently grounded in the mid- dle, negative or positive terminals. 4. Wide control range The SPOT-ES can be configured to map any input voltage regulation range to any output voltage range. For example a 1500 V PV string can be connected into a 600 volt storage DC bus. On the other hand, lower voltage PV can be connected to a higher voltage DC bus. 5. Interconnect Simplicity The SPOT-ES is very simple to connect into a DC-coupled Sola r + Storage system. The +/- PV cables plug directly into the input connectors and the DC bus cables plug directly into the SPOTs output connec- tors. With the SPOT-ES, there is no need to split the string in halves or use any other so-called “stretch” techniques. 6. Failure Pinpointing In the case of a PV string fault such as a ground leak of arc fault, the SPOT- ES will indicate exactly which PV string is in a fault state as well as the severity of the fault. ABOUT HANAN FISHMAN Hanan Fishman is President & CEO of Alencon Systems and a member of its Board of Directors. He oversees company operations including sales and marketing, manufacturing and finance and accounting.  Hanan has been charged with leading Alencon’s drive to commercialize the prod- ucts it has been developing over the past nine years.  Prior to joining Alencon Systems, Hanan was the President of PartMaker Inc. Hanan led PartMaker Inc. from 1998 through to 2016 when it became the global leader in specialist computer aided manufacturing, software for produc- tion machining applications. He guided the company through two acquisitions, the sec- ond of which was by Autodesk Inc., the world’s largest developer of engineering software for manufacturing and architectur- al applications. PERSPECTIVE ALENCON DEVELOPS BY HANAN FISHMAN President & CEO Alencon