The National Renewable Energy Laboratory (NREL), Southern California Edison (SCE), Quanta Technology, Satcon, Electrical Distribution Design (EDD), and Clean Power Research (CPR) have teamed together to analyze the impacts of high-penetration levels of photovoltaic (PV) resources interconnected onto the SCE distribution system.

Specifically, SCE will be interconnecting a total of 500 MW of commercial scale PV by 2015 within their service territory through a program approved by the California Public Utility Commission (CPUC). Research efforts under this project include:

  • Development of distribution and PV system models required to evaluate the impacts of high- penetration PV
  • Identification and development of the necessary distribution system studies and analysis appropriate for determining the impacts of high-penetration PV
  • Data collection on study distribution circuits to quantify the impacts of high-penetration PV
  • Development of high-penetration PV impact mitigation strategies in the form of advanced inverter functions to enable high-penetration PV interconnection
  • Lab testing of advanced PV inverter functions
  • Field testing of advanced PV inverter functions.

In the first year of the project, research efforts have focused on (1) identifying the needed PV system models and distribution system analysis tool capability, (2) identifying prospective distribution circuits within the SCE service territory to be studied, (3) understanding the challenges of integrating high-penetration PV levels onto the SCE distribution system, (4) identifying appropriate data acquisition equipment, and (5) investigating the capability of PV inverters to realize advanced inverter functions that may be useful for mitigating high- penetration PV impacts on the SCE distribution system.

Section 2 of this report describes the need for investigating high-penetration PV scenarios on the SCE distribution system. A few of the expected impacts of high-penetration PV are described, and typical distribution system operation is explained. Two study distribution circuits are also identified in this chapter and discussed in terms of the expected PV penetration levels attained as SCE builds out the 500 MW of installed PV within their service territory.

The necessary PV system modeling and distribution system simulation advances are discussed in Section 3. To properly simulate high-penetration PV operation on a distribution circuit, the expected solar resource of a given PV installation needs to be determined. The first part of Section 3 outlines how solar resource data, collected through remote sensing satellites, can be processed and formatted for inclusion in a distribution system modeling tool such as Distributed Engineering Workstation (DEW), CYMDIST, or Synergee. The second part of Section 3 describes the additional functionality required of the distribution system modeling software package itself to properly and effectively evaluate high-penetration PV scenarios....(Read more...)