Oregon Public Utility Commission

Rule Rule 860-082-0050
Tier 2 Interconnection Review


(1)

A public utility must use the Tier 2 interconnection review procedures for an application to interconnect a small generator facility that meets the following requirements:

(a)

The small generator facility does not qualify for or failed to meet the Tier 1 interconnection review requirements;

(b)

The small generator facility must have a nameplate capacity of two megawatts or less;

(c)

The small generator facility must be interconnected to either a radial distribution circuit or a spot network distribution circuit limited to serving one customer;

(d)

The small generator facility must not be interconnected to a transmission line; and

(e)

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 Tier 4 study, review, and 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)

For interconnection of a small generator facility to a radial distribution circuit, the aggregated nameplate 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.

(b)

For interconnection of a small generator facility to the load side of spot network protectors, the aggregated nameplate capacity on the load side of the spot network protectors must not exceed the lesser of five percent of a spot network’s maximum load or 50 kilowatts.

(c)

The aggregated nameplate capacity must 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.

(d)

The aggregated nameplate capacity 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.

(e)

The aggregated nameplate capacity on 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).

(f)

If the small generator facility interconnection is to a primary line on the distribution system, then the interconnection must meet the following criteria:

(A)

If the small generator facility is three-phase or single-phase and will be connected to a three-phase, three-wire primary line, then the small generator facility must be connected phase-to-phase.

(B)

If the small generator facility is three-phase or single-phase and will be connected to a three-phase, four-wire primary line, then the small generator facility must be connected line-to-neutral and effectively grounded.

(g)

For interconnection of a small generator facility to a single-phase shared service line on the transmission or distribution system, the aggregated nameplate capacity on the shared secondary line must not exceed 20 kilowatts.

(h)

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 rating of the service transformer.

(i)

Except as provided in subsection (2)(l), 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.

(j)

The aggregated nameplate capacity, in combination with exiting transmission loads, must not cause the transmission system circuit directly connected to the distribution circuit where the small generator facility interconnection is proposed to exceed its design capacity.

(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)

If the small generator facility fails to meet one or more of the criteria in subsections (2)(a) through (k), but 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 under Tier 2.

(3)

In addition to the timelines and requirements in OAR 860-082-0025 (Applications to Interconnect a Small Generator Facility), the following timelines and requirements apply to Tier 2 interconnection reviews:

(a)

A public utility must schedule a scoping meeting within 10 business days after notifying an applicant that its application is complete. The public utility and the applicant may agree to waive the scoping meeting requirement.

(b)

Within 20 business days after a public utility notifies an applicant that its application is complete or a scoping meeting is held, whichever is later, 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 applicable, the public utility must include a comparison of its evaluation to the applicant’s independent analysis.

(4)

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 subsection (2)(l) 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.

(5)

If a small generator facility is not approved under the Tier 2 interconnection review procedure, then the applicant may submit a new application under the Tier 3 or Tier 4 review procedures. At the applicant’s request, the public utility must provide a written explanation of the reasons for denial within five business days of the request.
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Last accessed
Jun. 8, 2021