Distributed energy resource subsystem effective neutral grounding

A method of designing grounding equipment to account for interconnection of a distributed energy resource (DER) subsystem to an area electric power system (EPS), the method comprising:

• obtaining values of area EPS parameters describing an area electric power system (EPS);
• obtaining values of DER subsystem parameters describing a distributed energy resource (DER) subsystem;
• for each of multiple possible modes of operation of the DER subsystem and/or for each of multiple possible sets of one or more values for one or more unknown parameters, calculating, based on the values of the area EPS parameters and the values of the DER subsystem parameters, a temporary overvoltage (TOV) level and/or a coefficient of grounding (COG) that would be associated with different possible designs of grounding equipment for neutral grounding of the DER subsystem, wherein the different possible designs of grounding equipment comprise different possible types of grounding equipment and/or different possible sizing configurations of grounding equipment, wherein the multiple possible modes include an area EPS connected mode in which the DER subsystem is connected to the area EPS and an island mode in which the DER subsystem is islanded from the area EPS, and wherein each of the one or more unknown parameters is associated with a negative-sequence impedance of the DER subsystem;
• and
• determining, based on the calculated TOV levels and/or coefficients of grounding that would be associated with the different possible designs of grounding equipment, a design of grounding equipment, if any, that would meet a requirement on effectiveness of the grounding equipment for neutral grounding of the DER subsystem across the multiple possible modes of operation of the DER subsystem and/or across the multiple possible sets of one or more values for the one or more unknown parameters.

A method for distributing a computer program over a network, comprising:

• providing a downloadable computer program accessible via an Internet website;
• receiving a request for the downloadable computer program from a user device connected to the Internet;
• and
• transmitting the downloadable computer program from a server to the user device in response to the request, wherein the downloadable computer program comprises executable instructions for:
• obtaining values of area EPS parameters describing an area electric power system (EPS);
• obtaining values of DER subsystem parameters describing a distributed energy resource (DER) subsystem;
• for each of multiple possible modes of operation of the DER subsystem and/or for each of multiple possible sets of one or more values for one or more unknown parameters, calculating, based on the values of the area EPS parameters and the values of the DER subsystem parameters, a temporary overvoltage (TOV) level and/or a coefficient of grounding (COG) that would be associated with different possible designs of grounding equipment for neutral grounding of the DER subsystem, wherein the different possible designs of grounding equipment comprise different possible types of grounding equipment and/or different possible sizing configurations of grounding equipment, wherein the multiple possible modes include an area EPS connected mode in which the DER subsystem is connected to the area EPS and an island mode in which the DER subsystem is islanded from the area EPS, and wherein each of the one or more unknown parameters is associated with a negative-sequence impedance of the DER subsystem;
• and
• determining, based on the calculated TOV levels and/or coefficients of grounding that would be associated with the different possible designs of grounding equipment, a design of grounding equipment, if any, that would meet a requirement on effectiveness of the grounding equipment for neutral grounding of the DER subsystem across the multiple possible modes of operation of the DER subsystem and/or across the multiple possible sets of one or more values for the one or more unknown parameters.