Alternative 3VO Ground Fault Overvoltage Protection with DER Interconnected on Distribution Side

With the increasing application of renewables and other distributed energy resources, ground fault overvoltage and the protection become a concerned issue for Photovoltaic and other distributed energy resources interconnection. Generally, utilities require a protective relaying package 3V0 installed on the transformer high-voltage side to detect the ground fault overvoltage. This type of installation is costly in terms of money and construction timeline, which has become one of the main barriers to renewables and other distributed energy resources installation in NY State and other territories with similar grid circuit architecture. Applied Power Systems will work with Rensselaer Polytechnic Institute and Island Technology to develop a low-cost alternative ground fault overvoltage protection device. It is a microprocessor based smart protection device to complete the ground fault overvoltage detection. Because it is installed on the low voltage side, the cost and construction timeline of the alternative ground fault overvoltage can be reduced greatly. In phase I the feasibility study of the alternative ground fault overvoltage protection will be completed. Applied Power Systems will be responsible for the feasibility study and conceptual design of the smart protection device hardware technology. Rensselaer Polytechnic Institute will complete the alternative ground fault overvoltage methodology and verification. The protection methodology and hardware development will be conducted under consulting with utility protection engineers from Island Technology. The typical application of the proposed the smart protection device is ground fault overvoltage protection for a delta/wye (ground) substation transformer with distributed energy resources installed on the transformer wye (ground) side. It can reduce the cost of required ground fault overvoltage protection greatly, therefore facilitating renewables and other distributed energy resources interconnection and application. It is also potential to develop an alternative temporary overvoltage protection of modern power system, based on the methodology proposed in the document.