Reduction of Residual Current in Distributed Solar Photovoltaic Systems

Challenge details

Name: Reduction of Residual Current in Distributed Solar Photovoltaic Systems
Challenge type: Reduction to Practice (RTP)
Award: $35000
Deadline: 14th Feb 2022

Challenge overview


Over the past two decades, there has been a tremendous increase in the penetration of renewables within the global energy mix particularly for solar photovoltaic (PV) systems. Solar PV systems are renewable energy based technologies which generate electricity by harnessing energy from the sun. Although there have been several improvements in the technology itself, the presence of residual current particularly within distributed scale PV systems is a safety issue which is yet to be fully resolved. Hence, distributed PV systems currently mandate installation within confined electrical operating spaces to ensure end user safety. The Seeker for this Challenge, Dubai Electricity & Water Authority (DEWA), is looking for solutions that reduce or eliminate residual current in PV systems to allow installation without specialized protective cabinets, structures or enclosures.

This is a Reduction-to-Practice Challenge that requires written documentation and experimental proof-of-concept data.



Solar photovoltaic (PV) systems are renewable energy based technologies which generate electricity using energy from the sun. The global installed capacity for solar PV has grown from a little over 1 GW in 2000 to over 630 GW in 2019. This rapid growth continues to accelerate with utility and distributed PV installations across the globe. Many of these systems utilize transformerless inverters to convert the direct current (DC) electricity generated by the PV system to alternating current (AC) electricity for input to the power grid and use in everyday electric items. One issue that has arisen due to the overall design of solar PV systems and the use of inverters is the presence of residual currents in the systems. Current standards (IEC62109-2) allow for a continuous residual current of 10mA per kVA, resulting in potentially dangerous current levels. Protection is provided by sensing any sudden change in residual current on the inverter side however, any residual current that may arise on the load side may go undetected due to a higher residual current setting in the external residual current device (RCD) and if the inverter protection is governed by certain conditions, that necessitate the installation of PV equipment  in confined areas such as safety cabinets or specialty structures. DEWA, the Seeker for this Challenge, is looking for solutions that reduce or eliminate residual currents in solar PV systems. Ideally, the solution will be generally applicable to all inverters and PV systems but solutions that modify specific inverter types are also welcome.

The submission to the Challenge should include the following:

  1. The detailed description of the proposed Solution addressing specific Technical Requirements presented in the Detailed Description of the Challenge. This description should be accompanied by a well-articulated rationale supported by literature/patent precedents.
  2. Experimental proof-of-concept data obtained as outlined in the Detailed Description of the Challenge (and/or delivery of a prototype if requested by the Seeker).  

The Challenge award is contingent upon theoretical evaluation and experimental validation of the submitted solutions by the Seeker.

To receive an award, the Solvers will have to transfer to the Seeker their exclusive Intellectual Property (IP) rights to the solution. 

Submissions to this Challenge must be received by 11:59 PM (US Eastern Time) on 14-Feb-2022.
Late submissions will not be considered.



Employees of DEWA and their immediate families are ineligible to receive awards for this Challenge.



Dubai Electricity & Water Authority (DEWA) is the exclusive provider of electricity and water services in Dubai. DEWA was formed in 1992 following the merger of the Dubai Electricity Company and the Dubai Water Department which had been operational independently since 1959. DEWA is responsible for the generation, transmission and distribution of electricity and water across the emirate of Dubai. For more information, please visit


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InnoCentive is the global innovation marketplace where creative minds solve some of the world's most important problems for cash awards up to $1 million. Commercial, governmental and humanitarian organizations engage with InnoCentive to solve problems that can impact humankind in areas ranging from the environment to medical advancements.

What is an RTP Challenge?

An InnoCentive RTP (Reduction to Practice) Challenge is a prototype that proves an idea, and is similar to an InnoCentive Theoretical Challenge in its high level of detail. However, an RTP requires the Solver to submit a validated solution, either in the form of original data or a physical sample. Also, the Seeker is allowed to test the proposed solution. For details about treatment of Intellectual Property (IP) rights, please see the Challenge Specific Agreement.