Improved Unsustained Pressure Rejuvenation (iUPR)

Our iUPR process is a good choice for segments in outage-adverse areas where splices are flowable, difficult to access, or cost prohibitive to replace. The process requires only one switching event and is backed by up to a 25-year warranty.

Improved Unsustained Pressure Rejuvenation uses low pressure (15–30 psi) to flow fluid through splices while the circuit is energized, making it the choice for injecting hard-to-reach splices or radial segments.

Benefits

  • Saves time because it doesn’t require two switching events.
  • Allows for complete injection in a single day.
  • Extends cable life up to 25 years.
  • Is value conscious—the choice when it’s not economical to replace a cable splice.
  • Eliminate the risk of injection port flashover, with our reticular flash-prevention (RFP) technology.
  • Employ more robust and redundant seal designs that reduce fluid leaks and the probability of transformer fires.
  • Eliminate the need for postmanufacture air-pressure testing to identify flashing from molding defects.
  • Reduce the oozing of treatment fluid from the elbow by 30 percent during and after injection. Fluid secretion can compromise elbow reliability under hot conditions and lowers the post-injection reliability of the cable in all cases.

Process

iUPR
  1. Isolate, test, and ground the cable.
  2. Use a TDR device to check every segment for splices, neutral corrosion, and length.
  3. Perform an airflow test and, if a splice is present, a pressure test. Confirm the fluid will flow and the splice is suitable for injection.
  4. Install new connectors and injection elbows.
  5. Connect the feed tank to the injection elbow at one end of the cable.
  6. An injection technician installs a receiver tank at the other end of the cable.
  7. Re-energize the segment with the injection equipment attached, start the injection process, and close the transformer. The segment is typically de-energized for 30 minutes or less.
  8. We inject the cable at 25 psi or less. The injection process typically takes 24 hours or less to complete.
  9. Our technician returns after the injection is complete to collect the equipment, which is designed to allow safe removal while the cable is energized.