Chapter PSC 119

PSC 119.04(6) (6) Upon approval of an application under sub. (4) (a), (c), or (g), the public utility shall provide the applicant with an interconnection approval memorandum that confirms the utility’s application approval and identifies any applicable conditions of approval. For Category 2 to 4 facilities, the memorandum and associated attachments shall provide:

PSC 119.04(6)(a) (a) The date of approval.

PSC 119.04(6)(b) (b) Completed application materials.

PSC 119.04(6)(c) (c) Engineering review requirements, if applicable.

PSC 119.04(6)(d) (d) Distribution system study requirements, if applicable.

PSC 119.04(6)(e) (e) Identification of the authorized tariff or program agreement applicable to the DG facility at the time the memorandum is issued.

PSC 119.04(6)(f) (f) Expiration date of the memorandum if utility requirements are not met, including identification of options for deadline extensions.

PSC 119.04(6)(g) (g) System specifications and specific requirements imposed by the utility as conditions of approval.

PSC 119.04(6)(h) (h) Estimated distribution system construction or modification costs and scope, if applicable.

PSC 119.04(6)(i) (i) Estimated completion date for the public utility to complete distribution system upgrades, if applicable.

PSC 119.04(6)(j) (j) A copy of the standard interconnection agreement that would be executed by both parties upon completion of all requirements, including any anticipated distribution system upgrades.

PSC 119.04(6)(k) (k) Acknowledgement that the public utility will interconnect the DG facility if all identified conditions are met.

PSC 119.04 History History: CR 03-003: cr. Register January 2004 No. 577, eff. 2-1-04; CR 22-077: am. (1), (2), cr. (2m), am. (3), cr. (3g), (3r), (4) (intro.), renum. (4) to (4) (a) and am., cr. (4) (b), renum. (5) to (4) (c) and am., renum. (5) (a) to (d) to be (4) (c) 1. to 4., renum. (6) to (4) (d) and am., renum. (7) (intro.) to (4) (e) (intro.) and am., renum. (7) (a) to (d) to be (4) (e) 1. to 4. and, as renumbered, am. 4., renum. (8) to (4) (f) and am., renum. (10) (a) to (4) (h) and, as renumbered, am. (intro.), 2., renum. (10) (b) to (4) (i) and am., renum. (11), (12) to (4) (j), (k), and am., cr. (5), (6) Register April 2024 No. 820, eff. 5-1-24; correction in (4) (e) (4) made under s. 35.17, Stats., Register April 2024 No. 820.

PSC 119.05 PSC 119.05 Insurance and indemnification.

PSC 119.05(1) (1) An applicant seeking to interconnect a Category 1 DG facility to the distribution system of a public utility shall maintain liability insurance equal to or greater than the amounts stipulated in Table PSC 119.05-1, per occurrence, or prove financial responsibility by another means mutually agreeable to the applicant and the public utility.

PSC 119.05(1m) (1m) An applicant seeking to interconnect a Category 2 to 4 DG facility to the distribution system of a public utility shall maintain liability insurance equal to or greater than the amounts stipulated in Table PSC 119.05-1, per occurrence, and shall name the public utility as an additional insured party in the liability insurance policy, or prove financial responsibility by another means mutually agreeable to the applicant and the public utility.

- See PDF for table

PSC 119.05(2) (2) Each party to the standard interconnection agreement shall indemnify, hold harmless and defend the other party, its officers, directors, employees and agents from and against any and all claims, suits, liabilities, damages, costs and expenses resulting from the installation, operation, modification, maintenance or removal of the DG facility. The liability of each party shall be limited to direct actual damages, and all other damages at law or in equity shall be waived.

PSC 119.05 History History: CR 03-003: cr. Register January 2004 No. 577, eff. 2-1-04; CR 22-077: am. (1), cr. (1m) Register April 2024 No. 820, eff. 4-1-24.

PSC 119.06 PSC 119.06 Modifications to the DG facility. The applicant shall notify the public utility of plans for any material modification to the DG facility by providing at least 20 working days of advance notice for a Category 1 DG facility, 40 working days for Category 2 DG facility, and 60 working days for a Category 3 or 4 DG facility. The applicant shall provide this notification by submitting a revised standard application form and such supporting materials as may be reasonably requested by the public utility. The applicant may not commence any material modification to the DG facility until the public utility has approved the revised application, including any necessary engineering review or distribution system study. The public utility shall indicate its written approval or rejection of a revised application within the number of working days shown in the table below. Upon completion of the application process, a new standard interconnection agreement shall be signed by both parties prior to parallel operation. If the public utility fails to respond in the time specified in Table 119.06-1, the completed application is deemed approved.

- See PDF for table

PSC 119.06 History History: CR 03-003: cr. Register January 2004 No. 577, eff. 2-1-04; CR 22-077: am. Table 119.06-1 Register April 2024 No. 820, eff. 5-1-24.

PSC 119.07 PSC 119.07 Easements and rights-of-way. If a public utility line extension is required to accommodate a DG interconnection, the applicant shall provide, or obtain from others, suitable easements or rights-of-way. The applicant is responsible for the cost of providing or obtaining these easements or rights of way.

PSC 119.07 History History: CR 03-003: cr. Register January 2004 No. 577, eff. 2-1-04.

PSC 119.08 PSC 119.08 Fees and distribution system costs.

PSC 119.08(1) (1) Upon receiving a standard application form, the public utility shall specify the amount of any engineering review or distribution system study fees. The applicant shall pay the fees specified in Table PSC 119.08, unless the public utility chooses to waive the fees in whole or in part. For any fees paid by the applicant per Table PSC 119.08, any unexpended funds shall be credited to subsequent interconnection steps and associated fee obligations.

- See PDF for table

PSC 119.08(2) (2) The public utility may recover from the applicant an amount up to the actual cost, for labor and parts, of any distribution system upgrades required. The utility may charge for retesting an installation that does not conform to the requirements set forth in this chapter. The fee for retesting shall be equal to the applicable commissioning fee, unless at the public utility’s discretion a lower fee amount is assessed.

PSC 119.08(3) (3) Costs for any necessary line extension shall be assessed pursuant to s. PSC 113.1005.

PSC 119.08(4) (4) For any application that is withdrawn by the applicant or deemed withdrawn by the public utility, the public utility shall provide the applicant with a reconciliation of costs from any engineering review, distribution system study, or required distribution system upgrades or modifications performed. Public utilities shall refund to the applicant any fees paid in excess of costs incurred by the utility. Applicants shall pay any additional costs incurred by the utility in excess of previous payments.

PSC 119.08(5) (5) Public utilities may assess a fee of up to $300 for preparation of a pre-application report, unless the public utility chooses to waive the fee in whole or in part.

PSC 119.08(6) (6) For each year in which a public utility assessed an engineering review fee or a distribution system study fee for a Category 1 or 2 facility, the public utility shall provide a report to the commission by March 31 of the following year which includes:

PSC 119.08(6)(a) (a) The number of Category 1 and 2 facilities in which an engineering review fee was assessed and the average engineering review fee that was charged to applicants.

PSC 119.08(6)(b) (b) The number of Category 1 and 2 facilities in which a distribution system study fee was assessed and the average distribution system study fee that was charged to applicants.

PSC 119.08 History History: CR 03-003: cr. Register January 2004 No. 577, eff. 2-1-04; CR 22-077: am. (1), Table 119.08-1, (2), cr. (4) to (6) Register April 2024 No. 820, eff. 5-1-24.

PSC 119.09 PSC 119.09 Disconnection. A public utility may refuse to connect or may disconnect a DG facility from the distribution system only under any of the following conditions:

PSC 119.09(1) (1) Lack of approved standard application form or standard interconnection agreement.

PSC 119.09(2) (2) Termination of interconnection by mutual agreement.

PSC 119.09(3) (3) Non-compliance with the technical or contractual requirements.

PSC 119.09(4) (4) Distribution system emergency.

PSC 119.09(5) (5) Routine maintenance, repairs, and modifications, but only for a reasonable length of time necessary to perform the required work and upon reasonable notice.

PSC 119.09 History History: CR 03-003: cr. Register January 2004 No. 577, eff. 2-1-04.

PSC 119.10 PSC 119.10 One-line schematic diagram.

PSC 119.10(1) (1) The applicant shall include a one-line schematic diagram with the completed standard application form. ANSI symbols shall be used in the one-line schematic diagram to show the following:

PSC 119.10(1)(a) (a) Generator or inverter.

PSC 119.10(1)(b) (b) Point where the DG facility is electrically connected to the customer’s electrical system.

PSC 119.10(1)(c) (c) Point of common coupling.

PSC 119.10(1)(d) (d) Lockable interconnection disconnect switch.

PSC 119.10(1)(e) (e) Method of grounding, including generator and transformer ground connections.

PSC 119.10(1)(f) (f) Protection functions and systems.

PSC 119.10(2) (2) The applicant shall include with the schematic diagram technical specifications of the point where the DG facility is electrically connected to the customer’s electrical system, including all unintentional islanding and power quality protective systems. The specifications regarding the unintentional islanding protective systems shall describe all automatic features provided to disconnect the DG facility from the distribution system in case of loss of grid power, including the functions for over/under voltage, over/under frequency, overcurrent, and loss of synchronism. The applicant shall also provide technical specifications for the generator, lockable interconnection disconnect switch, and grounding and shall attach the technical specification sheets for any certified equipment. The applicant shall include with the schematic diagram a statement by the manufacturer that its equipment meets or exceeds the type tested requirements for certification.

PSC 119.10 History History: CR 03-003: cr. Register January 2004 No. 577, eff. 2-1-04; CR 22-077: am. (2) Register April 2024 No. 820, eff. 5-1-24.

PSC 119.11 PSC 119.11 Control schematics. For equipment not certified under s. PSC 119.26, the applicant shall include with the application a complete set of control schematics showing all protective functions and controls for generator protection and distribution system protection.

PSC 119.11 History History: CR 03-003: cr. Register January 2004 No. 577, eff. 2-1-04.

PSC 119.12 PSC 119.12 Site plan. For all categories, the applicant shall include with the application a site plan that shows the location of the interconnection disconnect switch, adjoining street name, and the street address of the DG facility. For Category 2, 3, or 4 DG facilities, the site plan shall show the location of major equipment, electric service entrance, electric meter, interconnection disconnect switch, and interface equipment.

PSC 119.12 History History: CR 03−003: cr. Register January 2004 No. 577, eff. 2-1-04.

PSC 119.13 PSC 119.13 Pre-application report.

PSC 119.13(1) (1) Potential applicants may request a pre-application report in order to obtain information about system conditions at their proposed interconnection location, without submitting an application under s. PSC 119.04.

PSC 119.13(2) (2) To request a pre-application report, potential applicants shall complete and submit to its public utility the standard pre-application request form. A request for a pre- application report shall not be considered submitted until applicant submits the standard pre-application form and pays applicable pre-application review fees under s. PSC 119.08 (5).

PSC 119.13(3) (3) All submitted pre-application report requests shall be reviewed for completeness in the order in which they fulfill the requirements of sub. (2).

PSC 119.13(3m) (3m) Public utilities shall evaluate the submitted pre-application form for completeness within 5 business days of receipt. A complete request shall include location information that allows the public utility to clearly identify a proposed point of interconnection, and information on the proposed DG facility sufficient to identify DG type, nameplate and export capacity, and service configuration.

PSC 119.13(4) (4) All complete pre-application report requests shall receive pre-application reports in the order in which they fulfill the requirements of sub. (3). Within 15 business days of determining a pre-application report request complete, the public utility shall respond by providing the applicant with a completed standard pre- application report that provides information on the capacity, network and operating characteristics, and applicable operating constraints at the proposed point of interconnection.

PSC 119.13(4m) (4m) Completed pre-application reports shall reflect the best available information using existing data readily available to the public utility at the time of reporting. A public utility shall not be obligated to conduct additional analysis of the proposed project or location in order to complete a pre- application report. The report shall communicate to potential applicants that the information provided is subject to change and may not be applicable as of the date when a future application is submitted.

PSC 119.13 History History: CR 22-077: cr. Register April 2024 No. 820, eff. 5-1-24; renum. (3) (a), (4) (a) to be (3m) and (4m) under s. 13.92 (4) (b) 1., Stats., Register April 2024, No. 820.

subch. III of ch. PSC 119 Subchapter III — Design Requirements

PSC 119.20 PSC 119.20 General design requirements.

PSC 119.20(1) (1) The applicant shall install protection devices to ensure that the current supplied by the DG facility is interrupted if a fault or other potentially dangerous event occurs on the distribution system. If such an event occurs and the public utility’s distribution system is de-energized, any DG facility that is connected to this distribution system shall automatically disconnect. All DG facilities shall utilize protection devices that prevent electrically closing a DG facility that is out of synchronization with the distribution system.

PSC 119.20(2) (2) All installations shall include equipment circuit breakers, on the DG facility side of the point where the DG facility is electrically connected to the customer’s electrical system, that are capable of interrupting the maximum available fault current. Equipment circuit breakers shall meet all applicable UL, ANSI, and IEEE standards.

PSC 119.20(3) (3) The public utility may require that the applicant furnish and install an interconnection disconnect switch that opens, with a visual break, all ungrounded poles of the interconnection circuit. The interconnection disconnect switch shall be rated for the voltage and fault current requirements of the DG facility, and shall meet all applicable UL, ANSI, and IEEE standards. The switch enclosure shall be properly grounded. The interconnection disconnect switch shall be accessible at all times, located for ease of access to public utility personnel, and shall be capable of being locked in the open position. The applicant shall follow the public utility’s recommended switching, clearance, tagging, and locking procedures.

PSC 119.20 Note Note: Provisions of the Wisconsin Electrical Safety Code, Volume 2, ch. SPS 316 also apply to these installations.

PSC 119.20(4) (4) The applicant shall label the interconnection disconnect switch “Interconnection Disconnect Switch” by means of a permanently attached sign with clearly visible and permanent letters. The applicant shall provide and post its procedure for disconnecting the DG facility next to the switch.

PSC 119.20(5) (5) The applicant shall install an equipment grounding conductor, in addition to the ungrounded conductors, between the DG facility and the distribution system. The grounding conductors shall be available, permanent, and electrically continuous, shall be capable of safely carrying the maximum fault likely to be imposed on them by the systems to which they are connected, and shall have sufficiently low impedance to facilitate the operation of overcurrent protection devices under fault conditions. All DG transformations shall be multi-grounded. The DG facility may not be designed or implemented such that the earth becomes the sole fault current path.

PSC 119.20 Note Note: Grounding practices are also regulated by the Wisconsin Electrical Safety Code Volumes 1 and 2, as found in chs. SPS 316 and PSC 114.

PSC 119.20(6) (6) 

PSC 119.20(6)(a) (a) All inverter-based DG facilities shall be UL 1741 published September 28, 2021 listed.

PSC 119.20(6)(b) (b) All DG facilities shall meet the requirements of IEEE Std 1547-2018 and be tested in accordance with IEEE Std 1547.1.

PSC 119.20(6)(b)1. 1. Synchronous machine generation shall use the normal performance category of Category A and the abnormal performance category of Category I. Ride-through and trip settings shall meet the recommendations of the regional transmission operator guidelines.

PSC 119.20(6)(b)2. 2. Inverter-based DG facilities shall use the normal performance category of Category B and the abnormal performance category of Category II. Ride-through and trip settings shall meet the recommendations of the regional transmission operator guidelines. The public utility shall constructively work with the regional transmission operator to provide a recommendation whether abnormal performance category of Category III is the proper category assignment for inverter-based DG facilities.

PSC 119.20(6)(b)3. 3. Exceptions to these performance categories may be reviewed by the public utility on a case-by-case basis.

PSC 119.20(7) (7) 

PSC 119.20(7)(a) (a) All Category 1 and 2 DG facilities shall be operated at a power factor greater than 0.9.

PSC 119.20(7)(b) (b) All Category 3 and 4 DG facilities shall be operated at unity power factor or as mutually agreed between the public utility and applicant.

PSC 119.20(8) (8) The DG facility shall not create system voltage or current disturbances that exceed the standards listed in subch. VII of ch. PSC 113.

PSC 119.20(9) (9) The applicant shall protect and synchronize its DG facility with the distribution system.

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.