Interconnection Equipment, Metering, and Technical Requirements

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Distribution Interconnection Handbook

This information is intended to help guide you through the process of interconnecting distributed energy resources (DERs) to the PGE system. Refer to our complete Distribution Interconnection Handbook for more detailed information.

Customer equipment requirements

Small generator applicants must meet all requirements in OAR 860-082 (small generator). Net Metering applicants must meet all requirements in OAR 860-039 (Net Metering). Community Solar Program (CSP) applicants must meet all requirements in OAR 860-088 (CSP). DER and related customer equipment must also meet standards as designated by PGE and local electrical and building codes. Descriptions of certain equipment requirements are summarized below. 

Inverters must be UL 1741-tested and compliant. Non-UL 1741 inverters will not be considered. Any material modifications to the inverter’s standard settings must be noted with the interconnection application materials. These may include, but are not limited to, static or dynamic power factor adjustments, use of smart inverter functionality, and permanent curtailment of the maximum inverter output compared to its AC nameplate capacity provided by the inverter manufacturer. 

PGE offers direction to applicants on Supervisory Control and Data Acquisition (SCADA) requirements for their DER on an individual project basis.

Grounding and bonding are critical for safety and electrical reliability. You are responsible for ensuring that your DER’s electrical wiring and service equipment are grounded and bonded in accordance with applicable National Electrical Code requirements.

The DER must also provide the same level of effective grounding as the PGE system to avoid an adverse impact on the PGE system. Maintaining effective grounding is critical to protecting equipment of PGE and its customers. PGE system grounding is designed to provide a path of least resistance for potentially damaging electrical current following a surge or fault on the PGE system.

PGE’s Electric Service Requirements (ESR) are to be followed in full. Within the ESR, guidance on customer-owned transformers beyond the point of delivery must be followed, if applicable. 

PGE requires solidly-grounded facilities and uses wye-wye transformers on the PGE system to achieve this condition. An applicant can have a wye or delta connection on its side of the point of delivery, but it must connect to PGE with a grounded wye connection. 

For secondary voltage connections of parallel operations, a lockable AC disconnect switch is required. This switch must be within 10 feet of the interconnection meter unless another location has been approved by PGE. 

For primary voltage connections, lockable switching equipment (disconnect switch, breaker, or recloser) with a visible break to isolate the DER from the PGE system is required. 

You are responsible for the protection of your DER. For primary voltage interconnections, you are required to have overcurrent protection to isolate PGE from a disturbance on the DER. For proposed three-phase DER interconnections, overvoltage and undervoltage relaying must be included on each phase, and overfrequency and underfrequency must be included on at least one phase. Three-phase systems must also be gang operated if any single phase of the protection devices detect a power quality violation. 

If you are installing relays incapable of sending/receiving Mirrored Bits, then an ancillary device can be used to translate Mirrored Bits to the relay. This device will have hard-wired inputs and outputs as well as a fiber connection for the Mirrored Bits. Typical devices are the SEL-2505 and SEL-2506. Check with PGE on Fiber Type needed. 

Voltage surges and transients are considered temporary overvoltages of various levels, durations, frequencies, and repetition. Such occurrences can overheat arresters and cause failure. If the voltage surges and transients as a result of the proposed DER cannot be mitigated through other means, your installation of additional surge arresters or surge arresters with higher maximum continuous operating voltage ratings may be required.

When a DER is generating for a duration of 100 milliseconds (ms) or more while connected to the PGE system, the DER is considered to be in parallel operation. Refer to the Distribution Interconnection Handbook for more detailed information.

If you are seeking to interconnect to a feeder with limited capacity for new DERs, you may be required to install an additional utility meter base to accommodate a second, non-revenue utility meter. The second utility meter will allow for temporary remote disconnection of the DER from the PGE system by PGE during times of high DER generation and low customer energy load on feeder. Temporary disconnection will be performed by PGE without notice to you during times disconnection is deemed appropriate. You are responsible for the cost of the additional utility meter base. 

We may require a Two-Meter Solution based on capacity of the feeder to avoid significant interconnection costs for system upgrades or new facilities to accommodate new DER. 

Metering Requirements

You and PGE must have unrestricted access to metering and data acquisition equipment to conduct routine business or respond to an emergency. The below provides a high-level summary of PGE’s interconnection service voltages and associated metering equipment.

PGE’s ESR provides interconnection and equipment requirements for relocated, rewired, and new services. For single-phase services over 320 A or three-phase services over 200 A, you must submit a drawing package for PGE review. The package must contain a site plan, electrical one-line, electrical room layout (if applicable), working clearances, and manufacturer drawings with EUSERC references. You must receive confirmation that equipment meets PGE requirements from PGE Meter Engineering prior to installation.  

You must consult with PGE regarding services greater than 600 V prior to construction. Switchboard must meet EUSERC Section 400 requirements for service voltage of 12.47 kV. Consult with PGE regarding equipment requirements for service voltage of 34.5 kV.

You must consult PGE for specifications on instrument transformers, the meter test switch, and secondary wiring of instrument transformers prior to ordering the meter enclosure. Enclosure drawings with a site plan and electrical room detail must be provided to PGE for approval prior to installation.  

PGE will specify and purchase all revenue metering instrument transformers (CTs and PTs). PGE will provide the instrument transformers to you for applicable switchboard and primary services for you to install. PGE will install the test switch and all secondary meter wiring. All instrument transformers must meet IEEE C57.13-2016 revenue metering requirements and will only be used for PGE revenue metering devices. 

All commercial, industrial, and large residential electricity customers of PGE must coordinate their service requirements with PGE. You must provide factory-produced submittal drawings of metering equipment before purchase and installation. Single residential services over 320-amp continuous and all three-phase residential services are considered large residential services. 

Appropriate revenue-grade metering shall be installed and owned by PGE. Additional behind-the-meter telemetry may be required at the discretion of PGE to distinguish between net and gross electricity consumption at the customer premises for PGE operational or planning purposes. 

We require monitoring of connection status, real power output, reactive power output, and voltage at the point of connection for interconnections of small generator DER with capacity of 3 MW and larger.  

For SCADA-connected DERs, the metering will be consistent with the schematic in Figure 3 of the Distribution Interconnection Handbook. That schematic represents a general wall-mounted, remote meter base design. Your individual site requirements may alter the design, and you must coordinate with PGE on any changes to the design. 

Additional technical requirements for parallel operations on secondary networks

When a DER is serving as a source of electric power for greater than 100 ms while connected to the PGE system, the DER is in parallel operations. Interconnection to a secondary network system for parallel operations is limited due to PGE system risks related to cycling network protectors and potential islanding of customers. Although common rules exist for the general network system, there are additional interconnection rules when addressing grid or spot networks. 

For interconnection to a secondary grid network (also called an area network), PGE can accommodate new or modified DERs up to an aggregate DER capacity not exceeding the lesser of 5% of the associated network system’s peak load, or 50 kilowatts (kW). If either of these thresholds are met, no additional DER can be added to the network system. There are no additional provisions for connecting to secondary grid networks. 

For interconnection to a spot network, PGE can accommodate new or modified DERs if aggregate DER capacity does not exceed the lesser of 5% of the spot network’s peak load or 50 kW. If either of these thresholds are met, no additional DER can be added to the network system. Additional rules, per IEEE 1547-2003, are: 

  • Network protectors shall not be used to separate, switch, perform breaker failure back up, or isolate a network or network primary feeder to which the DER is connected from the remainder of the spot network. 

  • The DER shall not cause operation or prevent reclosing of any network protectors on the spot network. This coordination shall be accomplished without requiring any changes to prevailing network protector clearing time practice at PGE. 

  • Connection of the DER to the spot network is only allowed if the network bus is already energized by more than 50% of the installed network protectors. 

  • The DER output shall not cause any cycling of network protectors.

  • The network equipment loading and fault interrupting capacity shall not be exceeded with the addition or modification of the DER. 

  • DER installations on a spot network, using an automatic transfer scheme in which load is transferred between the DER and PGE in a momentary make-before-break (closed transition) operation, shall meet the above requirements regardless of the duration of paralleling.