Current through Register Vol. 63, No. 12, December 1, 2024
(1) A public
utility must use the Tier 2 interconnection review procedures when an applicant
submits an application requesting Tier 2 review to interconnect a small
generator facility that meets the following requirements:
(a) The small generator facility does not
qualify for the Tier 1 interconnection review requirements;
(b) If the small generator facility is
inverter-based, the small generator facility's export capacity does not exceed
the limits identified in Table 1 attached, which vary according to the voltage
of the line at the proposed point of interconnection;
(c) Inverter-based small generator facilities
located within 2.5 line miles of a substation and on a main distribution line
with minimum 600-amp capacity are eligible for Tier 2 interconnection under
higher thresholds;
(d) If the small
generator facility is not inverter-based, the small generator facility's export
capacity is two megawatts or less;
(e) The small generator facility must not
interconnect to a transmission line, or area network; and
(f) The small generator facility must use
interconnection equipment that is either lab-tested equipment or field-tested
equipment. For equipment to gain status as field-tested equipment, the
applicant must provide all the documentation from the prior public utility
approval including any interconnection studies and the certificate of
completion.
(2) Tier 2
Approval Criteria. A public utility must approve an application to interconnect
a small generator facility under the Tier 2 interconnection review procedures
if the facility meets the approval criteria in subsections (a) through (l). A
public utility may not impose different or additional approval criteria.
(a) Substation transformer backfeed screen.
Where existing protective devices and equipment cannot adequately support
backfeed, the aggregated export capacity on the substation transformer must be
less than 80 percent of the relevant minimum load for the substation
transformer.
(b) Penetration Screen
for interconnection to a radial distribution circuit.
(A) If 12 months of minimum load data
(including onsite load, but not station service load served by the proposed
small generator facility) are available for the line section, the aggregated
export capacity on the line section is less than 90 percent of the relevant
minimum load for all line sections bounded by automatic sectionalizing devices
upstream of the proposed small generator facility;
(B) If 12 months of minimum load data
(including onsite load but not station service load served by the proposed
small generator facility) are not available for line section, the aggregated
export capacity on the circuit is less than 90 percent of the relevant minimum
load for the feeder;
(C) If minimum
load data are not available for the line section or the circuit, the aggregated
export capacity on the circuit must not exceed 15 percent of the line section
annual peak load as most recently measured at the substation or calculated for
the line section.
(c)
Network Screen. For interconnection of a small generator facility within a spot
network, the aggregate nameplate rating may not exceed 20 percent of the spot
network's anticipated relevant minimum load. The public utility may select any
of the following methods to determine anticipated minimum load:
(A) The spot network's measured minimum load
in the previous year, if available;
(B) Five percent of the spot network's
maximum load in the previous year;
(C) The applicant's good faith estimate, if
provided; or
(D) The public
utility's good faith estimate if provided in writing to the applicant along
with the reasons why the public utility considered the other methods to
estimate minimum load inadequate.
(d) Fault Current Screen. The small generator
facility, aggregated with other generation on the distribution circuit, will
not contribute more than 10 percent to the distribution circuit's maximum fault
current at the point on the primary voltage distribution line nearest the point
of interconnection.
(e)
Short-Circuit Interrupting Capability Screen. The aggregated nameplate rating
on the distribution circuit must not cause any distribution protective devices
and equipment (including substation breakers, fuse cutouts, and line reclosers)
or other public utility equipment on the transmission or distribution system to
be exposed to fault currents exceeding 90 percent of the short circuit
interrupting capability. The small generator facility's point of
interconnection must not be located on a circuit that already exceeds 90
percent of the short circuit interrupting capability.
(f) Transient Stability Screen. The small
generator facility's nameplate rating, in aggregate with other small generator
facilities interconnected to the distribution side of a substation transformer
feeding the circuit where the small generator facility proposes to interconnect
must not exceed 10 megawatts in an area where there are known or posted
transient stability limitations to generating units located in the general
electrical vicinity (for example, three or four distribution busses from the
point of interconnection).
(g) Line
Configuration Screen. Using Table 2 attached, determine the type of
interconnection to a primary distribution line. This screen includes a review
of the type of electrical service provided to the project, including line
configuration and the transformer connection to limit the potential for
creating over-voltages on the interconnecting public utility's electric power
system due to a loss of ground during the operating time of any anti-islanding
function.
(h) Single-Phase Shared
Secondary Screen. For interconnection of a small generator facility to a
single-phase shared service line on the transmission or distribution system,
the aggregated export capacity on the shared secondary must not exceed 65
percent of the transformer nameplate power rating.
(i) Service Imbalance Screen. For
interconnection of a single-phase small generator facility to the center tap
neutral of a 240-volt service line, the addition of the small generator
facility must not create a current imbalance between the two sides of the
240-volt service line of more than 20 percent of the nameplate power rating of
the service transformer.
(j) Except
as provided in section (4), the interconnection of the small generator facility
must not require system upgrades or interconnection facilities different from
or in addition to the applicant's proposed interconnection equipment.
(k) If the public utility's distribution
circuit uses high speed reclosing with less than two seconds of interruption,
then the small generator facility must not be a synchronous machine. If the
small generator facility is a synchronous machine, then the applicant must
submit a Tier 4 application.
(l)
Inadvertent Export Screen. For interconnection of a proposed small generator
facility that can introduce inadvertent export, where the nameplate rating
minus the export capacity is greater than 250 kilowatts, the following
inadvertent export screen is required. With a power change equal to the
nameplate rating minus the export capacity, the change in voltage at the point
on the medium voltage (primary) level nearest the point of interconnection does
not exceed three percent. Voltage change will be estimated applying the formula
shown in Figure 1 attached.
(3) Timelines. In addition to the timelines
and requirements in OAR 860-082-0025 and if a net metering facility, OAR
860-039, within 20 business days after a public utility notifies an applicant
that is application is complete, the public utility must:
(a) Evaluate the application using the Tier 2
approval criteria in section (2);
(b) Review any independent analysis of the
proposed interconnection provided by the applicant that was performed using the
Tier 2 approval criteria; and
(c)
Provide written notice to the applicant stating whether the public utility
approved the application. If the proposed interconnection passes the screens,
the public utility must follow the requirements in OAR 860-082-0025(7)(f). If
applicable, the public utility must include a comparison of its evaluation to
the applicant's independent analysis.
(4) Approval despite screen failure. Despite
the failure of one or more screens, the public utility, at its sole option, may
approve the interconnection provided such approval is consistent with safety
and reliability. If the public utility determines that the small generator
facility could be interconnected safely if minor modifications to the
transmission or distribution system were made (for example, changing meters,
fuses, or relay settings), then the public utility must offer the applicant a
good-faith, non-binding estimate of the costs of such proposed minor
modifications. Modifications are not considered minor under this subsection if
the total cost of the modifications exceeds $10,000. If the applicant
authorizes the public utility to proceed with the minor modifications and
agrees to pay the entire cost of the modifications, then the public utility
must approve the application.
(5)
Process after screen failure. If the public utility cannot determine that the
small generator facility may nevertheless be interconnected consistent with
safety and reliability standards, at the time the public utility notifies the
applicant of the Tier 2 review results, the public utility must provide the
applicant with:
(a) The screen results,
including specific information on the reason(s) for failure in writing, using a
standard format approved by the Commission; and
(b) An executable Supplemental Review
Agreement.
(c) In addition, the
public utility must allow the applicant to select one of the following, at the
applicant's option. The applicant must notify the public utility of its
selection within 10 business days, or the application will be deemed withdrawn.
(A) Request an applicant options
meeting;
(B) Undergo supplemental
review in accordance with OAR 860-082-0063; or
(C) Continue evaluating the application under
Tier 4.
(6)
Applicant options meeting. If the applicant requests an applicant options
meeting, the public utility shall offer to convene a meeting at a mutually
agreeable time within 15 business days of the applicant's request. At the
applicant options meeting the public utility shall provide the applicant the
opportunity to review the screen analysis and related results, to designate a
different RPA, to review possible customers-generator modifications, and to
discuss what further steps are needed to permit the small generator facility to
connect safely and reliably.
(7)
The interconnection process is not complete until:
(a) The public utility approves the
application;
(b) Any minor
modifications to the transmission or distribution system required under section
(4) are complete;
(c) The witness
test, if conducted by the public utility, is successful; and
(d) The applicant and public utility execute
a certificate of completion. The certificate of completion must follow the
standard form certificate developed by the public utility and approved by the
Commission.
To view attachments referenced in rule text,
click here to view
rule.
Statutory/Other Authority: ORS 183, ORS 756 & ORS
757
Statutes/Other Implemented: ORS
756.040 & ORS
756.060
