Approved Customer Point of Contact and Generator Intertie Protective Devices

Posted Aug. 30, 2017

Customer Point Of Contact (POC) protection for high voltage service and Intertie Protective Relaying (IPR) for generator installations are required to protect the PPL power system and the customer power system from an electrical fault on either the customer’s or the utility’s faulted equipment. This document provides the up to date list of PPL pre-approved device for use as POC or generator IPR protection.

In addition to this list of devices a short list of general requirements is provided to help facilitate the process of choosing the appropriate protective devices. This short list of requirements is not exhaustive and is only intended to be used as a quick reference for the customer.

All installations must comply with:

In addition all installations must be reviewed and accepted by PPL.  It is recommended that the customer receives acceptance prior to purchasing any equipment to help avoid connection delays and incurred cost of field revisions.

Submission of equipment drawings should include the following:

A complete facility one-line with:

  • Point of utility/customer demarcation shown.
  • All customer owned transformers with nominal data shown.
  • All customer owned generation with nominal data shown.
  • All POC/IPR protection with Manufacturer and Model shown.
  • All Current Transformers (CTs) and Potential Transformers (PTs) shown
  • All lightning arrestors, disconnects and interlocks shown.
  • All equipment designations shown.

A three line diagram with:

  • All power transformer connections shown
  • All CT and PT connections shown

All pertinent current, potential and control elementary diagrams

The exact make and model of all POC and IPR devices

General Requirements for POC and IPR installations:

  1. The customer POC and IPR protective devices must be independent and used only for isolation of the customer’s facilities from the PPL power system. The POC and IPR protective devices and their respective CTs and PTs may not be used for any other protection or energy metering of customer equipment.
  2. Simplicity and ease of maintenance/testing is a primary goal. The POC and IPR protective device installations must include facilities (sliding links or FT test switches) to isolate the relays for testing. AC currents, AC potentials, and all input and output contacts must be fully isolated by these facilities. AC current isolation must include current circuit shorting provisions.
  3. When microprocessor based multi-element phase and ground relays are used for POC protection it is preferable that a second backup relay be installed in case the first relay fails. If a second relay is not installed the failure alarm of the installed relay will need to be connected in the trip path.
  4. When single element relays are used three separated phase relays and one ground relay will be sufficient.
  5. All CTs must be multi-ratio with a class rating of C200 or higher. Installation of a lower class CT will require a CT saturation study to be provided by the customer.
  6. All installations which require a POC protective device or IPR relay must be fully comply with the REMSI document, the Point of Contact Requirement for High Voltage Customers document and the Customer Owned Generator Interconnection requirements. In addition each installation must be reviewed accepted by PPL.

POC Relays

Electronic POC Relays

Vendor Model Submodel(s)
SEL 501  
SEL 551 C
SEL 351 A, C, L
SEL 751* A, C
ABB Micro-51  
ABB Microshield  
GE 350  
GE 750  

Electro-Mechanical POC Relays

Vendor Model Submodel(s)
Westinghouse CO-7 Phase
Westinghouse CO-9 Ground
General Electric IAC-51 Phase
General Electric IAC-51 Ground

IPR Relays for Generator Interconnection

Vendor Model Submodel(s)
SEL 351  
SEL 751  
Beckwith M-3410  
Beckwith M-3520  
Beckwith M-3425  

Note: This list will change as circumstances dictate. Availability, manufacturer’s support, software/firmware issues or new technology may dictate removals or replacements on this list. Please allow an additional 3 months to review any devices not on this list.