PSC 119.20(10)(10) Each DG facility shall include an automatic interrupting device that is listed with a nationally recognized testing laboratory and is rated to interrupt available fault current. The interrupting device shall be tripped by any of the required protective functions.

PSC 119.20(11)(11) An applicant for interconnection of a Category 3 or Category 4 facility shall provide test switches as specified by the public utility, to allow for testing the operation of the protective functions without unwiring or disassembling the equipment.

PSC 119.20(12)(12) The public utility may require a DG facility to be isolated from other customers by installation of a separate power transformer. When a separate transformer is required, the utility may include its actual cost in the distribution system upgrade costs. The applicant is responsible for supplying and paying for any custom transformer. This requirement does not apply to an induction-type generator with a capacity of 5 kW or less, or to other generating units of 10 kW or less that utilize a line-commutated inverter.

PSC 119.20(13)(13) The owner of a DG facility designed to operate in parallel with a spot or secondary network service shall provide relaying or control equipment that is rated and listed for the application and is acceptable to the public utility.

PSC 119.20(14)(14) For a Category 3 or Category 4 DG facility, the public utility may require that the facility owner provide telemetry equipment whose monitoring functions include transfer-trip functionality, voltage, current, real power (watts), reactive power (vars), and breaker status.

PSC 119.20(15)(15) When the public utility requires two-way communication or control functionality of the DG facility, the applicant shall work with the public utility to establish the minimum standard technical and communication requirements.

PSC 119.20(16)(16) For interconnection purposes, energy storage systems shall be treated as distributed generation facilities and shall meet the following requirements and standards:

PSC 119.20(16)(a)(a) Provide operational mode programming that controls the charging, discharging, and bypass (export or non-export) of an energy storage system. Operational mode programming shall be stated in an interconnection agreement.

PSC 119.20 NoteNote: The UL standards are available at http://ulstandards.ul.com. They may also be viewed at the PSCW Library, 4822 Madison Yards Way, Madison, WI.

PSC 119.20 HistoryHistory: CR 03-003: cr. Register January 2004 No. 577, eff. 2-1-04; CR 22-077: am. (6) (a), renum. (6) (b) to (6) (b) (intro.) and am., cr. (6) (b) 1. to 3., (15), (16) Register April 2024 No. 820, eff. 5-1-24; correction in (16) (b) made under s. 35.17, Stats., Register April 2024 No. 820.

PSC 119.25(1)(1) Each DG facility shall include protection and unintentional islanding equipment to prevent the facility from adversely affecting the reliability or capability of the distribution system. The applicant shall contact the public utility to determine any specific protection requirements.

PSC 119.25(2)(2) The protective system functions, which may be met with microprocessor-based multifunction protection systems or discrete relays, are required. Protective relay activation shall not only alarm but shall also trip the generator breaker/contactor.

PSC 119.25(3)(3) In addition to unintentional islanding protection, a DG facility shall meet the following minimum protection requirements:

PSC 119.25(3)(b)6.6. Other equipment, such as other protective devices, supervisory control and alarms, telemetry and associated communications channel, that the public utility determines to be necessary and is compliant with applicable codes and standards. The public utility shall advise the applicant of any communications requirements after a preliminary review of the proposed installation.

PSC 119.25(4)(4) A DG facility certified pursuant to s. PSC 119.26 shall be deemed to meet the requirements of this section.