Pnm Field Experience—single-Pole Trip and Reclose Near High Ibr Generation

Public Service Company of New Mexico, an energy utility, has committed to achieving zero emissions by 2040, which has prompted the growth of renewable energy resources in their electric grid, thus increasing the penetration of inverter-based resources (IBRs) into the system. IBRs provide additional load support and improve the renewable energy portfolio of the utility; however, IBRs also pose many challenges to the existing extra-high-voltage (EHV) transmission line protection system of the utility. With the goal of modernizing their line protection technology to overcome these challenges and obtain system-wide consistency, the utility standardized their EHV transmission line protection to include ultra-high-speed (UHS) line relays and presented the paper “Protecting EHV Transmission Lines Using Ultra-High-Speed Line Relays: A New Standard for PNM” at the Western Protection Relay Conference in 2021.

This paper details the utility's single-phase trip and reclose philosophy on 345 kV lines, many of which are connected to large renewal generation. Based on field experience these philosophies evolved to meet the ride-through requirements during single pole trip and reclose operations. The utility standard suggests using a neutral reactor (fourth-leg reactor) for secondary arc extinction. This paper provides field events showing the response of the differential, pilot schemes, and non-communication-based protection elements for faults on the 345 kV lines connected to high renewable generation. The utility has both type 3 and type 4 renewable generation, and fault current contributions are quite different compared to conventional generation.

The paper will discuss single-pole trip and reclose on 345 kV lines and lessons learned, single-pole trip and reclose on high IBR and series-compensated lines, the challenges associated in implementing one-line protection standards for diverse applications, secondary arc extinction and open time interval, and the use of UHS relays for breaker restrike and monitoring.