Operating Errors/PST Incidents

Question 1

SSO 2020 # Operating Errors Goal

Answer 1

<= 10

Question 2

SSO 2020 # Operating Errors

Answer 2

9

Question 3

Cherry Street

Answer 3

M PST – Cherry Street (Improper Isolation)

• While updating in-service relay settings at Cherry St., technician opened the wrong flexitest switch first (for CT instead of the trip circuit). This caused differential current to appear in the relay.
• Relay operated. This caused a feeder/breaker/transformer at E13th to trip out
• Technician flipped the wrong flexis because he was expecting them to be in a different order (based on prior experiences and in the print). But the panel with the flexis was labeled correctly.

Question 4

East River

Answer 4

M PST – East River (Tripped Wrong Relay)

• PST technicians doing trip check. Left relay panel and came back. Then applied jumper and inadvertently tripped wrong/in-service breaker
• Breaker @ East River opened automatically
• The technicians had used trip sheets to mark relay panel they were working on. While two technicians left the panel briefly, the sheets were moved due to insufficient lighting. When they came back, they tripped the wrong breaker

Question 5

West 42nd St

Answer 5

M PST – West 42nd (Improper Isolation)

• Bus section and feeder opened auto @ West 49th
• PST technicians had been performing testing at West 42nd, failed to provide isolation on relays during testing and inadvertently triggered transfer trip
• Distracted by Covid

Question 6

Cherry Street 2/7/21

Answer 6

M PST – Cherry St. (Not operating error)

The techs on site on planned to review how the lo gas trips were going to be performed prior to tripping breaker 4TR.

At this time the 43-4-11L-1/38M54 and 43-4-11L-2/38M54 “J” flexis were not isolated, however the 1st and 2nd line TSS and TSR switches were in the “OFF” position and the switch 43-63SF6 was in the ‘OFF’ Position to ensure that trips would not be sent to BRK 4TR or sent via DTT.

While performing the review, the technicians jumped points 152 to 151 which sent transfer trip to 13/36/29th St.

After investigation, we found that the 43-63SF6 switch (which was not labeled in the panel) had very faint markings which show that the Normal position was relabeled “OFF” and the Off position was relabeled “Norm” (See picture attached).

Question 7

Trade Center

Answer 7

• 5 feeders opened auto on February 4th
• CT’s arcing
• Issues with startup/shutdown panel

We feel the loss of the feeders in sections 1A and 1B are most likely attributed to the burned wiring above the CT block in position 12A. After reviewing with Engineering, we are comfortable returning the breaker controls to Remote at Operations’ convenience.