Wisconsin Administrative Code › Public Service Commission › Chapter PSC 119 - Rules For Interconnecting Distributed Generation Facilities › Subchapter III - Design Requirements › Section PSC 119.20 - General design requirements

Current through June 24, 2024
(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.
(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.
(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.
Note:
Provisions of the Wisconsin Electrical
				  Safety Code, Volume 2, ch. SPS 316 also apply to these installations.
(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.
(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.
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.
(6)
(a) All inverter-based DG facilities shall be
				UL 1741 published September 28, 2021 listed.
(b) All DG facilities shall meet the
				requirements of IEEE Std 1547-2018 and be tested in accordance with IEEE Std
				1547.1.
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.
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.
3. Exceptions to these performance categories
				may be reviewed by the public utility on a case-by-case basis.
Note:
The UL standards are available at
http://ulstandards.ul.com
, and
				  IEEE standards are available at
http://ieee.org
. They may also be viewed at the
				  PSCW Library, 4822 Madison Yards Way, Madison, WI.