Ill. Admin. Code tit. 83, § 466.75
c) The export controls identified in subsections (c)(1) through (3) are acceptable for non-exporting systems only. The export control identified in subsections (c)(4) and (c)(5) may be used for limited export systems only. The export controls in subsections (c)(6) and (7) may be used for either non-exporting or limited export systems. Inverter-based limited export systems shall use advanced inverters utilizing operating modes and settings specified by the EDC in its written technical standards for interconnection.
1) Reverse Power Protection (Device 32R)
To limit export of power across the point of interconnection, a reverse power protective function is implemented using a utility-grade protective relay. The default setting for this protective function shall be 0.1% (export) of the service transformer's nominal base nameplate rating, with a maximum 2.0 second time delay to limit inadvertent export.
2) Minimum Power Protection (Device 32F)
To limit export of power across the point of interconnection, a minimum import protective function is implemented using a utility-grade protective relay. The default setting for this protective function shall be 5% (import) of the generating unit's total nameplate capacity, with a maximum 2.0 second time delay to limit inadvertent export.
3) Relative Distributed Energy Resource Rating
This option requires the DER facility's nameplate capacity to be so small in comparison to its host facility's minimum load that the use of additional protective functions is not required to ensure that power will not be exported to the electric distribution system. This option requires the DER facility's nameplate capacity to be no greater than 50% of the interconnection customer's verifiable minimum host load over the past 12 months. For systems above 250 kVA, the EDC may require additional assurances, equipment, or agreements based upon evaluation of the stability and reliability of the minimum load data. This option is not available for interconnections to area networks or spot networks.
4) Directional Power Protection (Device 32)
To limit export of power across the point of interconnection, a directional power protective function is implemented using a utility-grade protective relay. The default setting for this protective function shall be the export capacity value, with a maximum 2.0 second time delay to limit inadvertent export.
5) Configured Power Rating
A reduced output power rating utilizing the power rating configuration setting may be used to ensure the DER does not generate power beyond a certain value lower than the nameplate capacity. The reduced power rating shall be indicated by means of a nameplate rating replacement, or by a supplemental adhesive nameplate rating tag to indicate the reduced nameplate rating. At the discretion of the EDC, the applicant may additionally be required to provide a letter from the manufacturer confirming the reduced capacity.
6) Limited Export Utilizing Power Control Systems
C) An acceptable open loop response time may need to be mutually agreed upon between the EDC and the applicant for DER facilities with a nameplate capacity greater than 1 MVA that utilize a NRTL certified power control system.
COMMISSION NOTE: NRTL testing to the UL power control system certification requirements decision shall be accepted until similar test procedures for power control systems are included in a standard.
The following are the minimum requirements for the limited export utilizing power control systems that meet the criteria specified in this subsection (c)(6). Other factors relevant to the interconnection study process may necessitate additional technical requirements that are not explicitly noted in this subsection. This option is not available for interconnections to area networks or spot networks.
7) Limited Export Using Agreed-Upon Means
DER facilities may be designed with other control systems or protective functions to limit export and inadvertent export if mutual agreement is reached with the EDC. The limits may be based on technical limitations of the interconnection customer's equipment or the electric distribution system equipment. To ensure inadvertent export remains within mutually agreed-upon limits, the interconnection customer may use an uncertified power control system, an internal transfer relay, energy management system, or other customer facility hardware or software if approved by the EDC.
The following technical specifications are intended to identify acceptable export control methods to facilitate the interconnection and parallel operation of limited-export and non-export systems with the EDC's electric distribution system.
(Source: Added at 46 Ill. Reg. 9666, effective May 26, 2022)