November 1, 2008

JCP&L's SCADA-controlled adaptive relay scheme saves 25 SAIDI impact minutes

Richard R. King, PE

Successful installations

JCP&L started the systemwide project implementation in July 2007. It was completed and fully functional in December 2007. Installations were completed at 275 locations, which are able to control all 1,100 circuits in JCP&L’s 13 districts. The installations included the Electroswitch Series 31 TRs, wiring, testing, upgrading of the RDO SCADA software, commissioning, and training of management and operations personnel on the adaptive relay solution (Figure 6).

6.    Rewire the cabinets. A typical JCP&L three-phase breaker cabinet shown after the upgrade was completed. The Electroswitch Tagging Relay at the upper right controls storm settings for the three overcurrent relays to the left. Courtesy: Jersey Central Power & Light

Over the first 46 days of operation from December 16, 2007, to January 30, 2008, there were five wind-related instances when the system operated proactively, switching to prepare for inclement weather. During these five storm mode periods, 100% of the 275 adaptive relay sites confirmed proper operation, 64 breaker operations were recorded, and an estimated 7,546 customers were saved from sustained outages.

The conservatively calculated savings during the period were 2.695 SAIDI minutes — an annualized run rate of 21.4 SAIDI minutes. Results through March 2008 also exceeded the annual SAIDI savings forecast of 25.1 minutes. With one SAIDI minute saved per $30,000 invested, the six-month project is recognized by JCP&L as a very cost-effective SAIDI improvement project.

JCP&L anticipates enjoying additional benefits from this protection timing strategy. Operating in instantaneous mode during storm periods will limit the system’s exposure to extended fault current, improving the life of station transformers, in-line equipment, and distribution lines. That, in turn, will reduce exposure to conductor burndown.

— Contributed by Richard R. King, PE, supervisor of engineering for Jersey Central Power and Light.