267
Event Reports
Maintenance (134)
Safety (76)
Operations (39)
Environmental (18)
Latest Event Reports
Maintenance
Equipment
Overhead Door Malfunction & Subsequent Vehicle Damage
A powered overhead roll-up door operator malfunctioned and unexpectedly began closing the door, contacting the rear of a vehicle that was backing into the building at the time.
OpEx
Safety
Employee
Powerhouse Roll Up Door Incident
On Tuesday, October 18, 2022, at approximately 1315 hours, a contract employee was engaged in manually operating the chain hoist to open the roll-up door when the assembly sheared at its mechanical drive shaft connection to the roll up door.
OpEx
Safety
Public
Powerhouse Weir Injury and Near Miss Event
On June 14, 2021, at approximately 12:13 pm, three individuals in a small boat with an outboard motor became trapped immediately downstream of the powerhouse tailrace weir at the Alpha Hydropower Project.
OpEx
Operations
Human Performance
Failure to respond to FERC Requests
On 11/24/2020, a letter was received from FERC identifying 68 follow up items and correspondence pertaining to dam safety inspections, spillway assessments, and ongoing engineering studies that are overdue or have not been responded to by Company.
OpEx
Safety
Structural
Sloughing and Erosion in Power Canal
During an operator inspection, a hydro operations employee noticed turbidity in the tailrace of Beta Plant’s powerhouse. The employee proceeded to the power canal forebay where he noticed sloughing and erosion of the canal in progress.
OpEx
Maintenance
Equipment
Repetitive Forced Outages Due to Relay Operations
Alpha Hydro Plant Unit 1 tripped by protective relay action on July 17, 2022, and tripped again on August 6, 2022, under identical circumstances.
OpEx
Safety
Employee
Close Call with Use of a Spillway Hoist to Lower a Worker
Inspecting spillway gate rails. The work was done using the main blocks of a spillway crane using boatswain chair. To get a missed set of measurements, the aux blocks were used. When employee was lowered, the hoist began to back spool.
OpEx
Safety
Employee
Injury removing rotor pole keys
While driving out a rotor pole key using a hammer, the hammer glanced off of the key and struck the employees hand causing minor injury.
OpEx
Maintenance
Equipment
Protective Relay Inadvertently Operates While Unit is Online and Causes Unit Wicket Gates to Close
At Beta Hydropower Plant, the “4” relay dropped out and the hydro controller went to a failsafe position of closed. This caused the wicket gates to go closed which called for an open on the 52 G relay and the unit overspeed with vibration.
OpEx
Maintenance
Equipment
Surge Tank to Penstock Deflector Plate Failure
While swapping units at Beta Hydropower Plant (Beta), (shutting down U1 for brake work) the operator heard a noise under the head cover area-possibly in the runner. Investigation found a metal plate on the runner which was a gate deflector plate.
OpEx
Maintenance
Equipment
Headwater Level Exceedance
On Friday January 31, 2020, @15:26, the headwater elevation as shown on the Beta Hydro Plant project control screen at the Remote Operation Center facility registered a static value due to the headwater elevation point being put in "Test".
OpEx
Safety
Employee
LOTO Issue, Live Crane Bus
Contractor was installing a new bridge crane in the powerhouse. Utility inspectors observed that the crane bus was energized with the main breaker open and workers terminating power wiring without proper LOTO tagging or locks.
OpEx
Operations
Grid
Failure of Spillway Gate to Operate as Intended
On Friday January 21, 2022, at approximately 03:40 hours there was a power outage on the 46 kV transmission line system feeding Beta Hydro. The outage caused the loss of all station power including the Tainter spillway gate.
OpEx
Safety
Employee
Runner Repair Contractor Fall
A contractor who was working on repairing the runner vanes fell through an open hatch which led to a 7 foot drop. This work was being done on a temporary work platform (TMP).
OpEx
Safety
Employee
Highway Guardrail Motor Vehicle Incident
During snowy conditions, an employee lost traction on a slight curve and slid off the Highway (HWY) into a nearby guardrail. The accident occurred on December 14, 2021, on HWY 222.
OpEx
Operations
Procedural
Generator Operation w/o Permit
A Notice of Violation was issued on January 13, 2021 for an engine operating without a permit.
OpEx
Maintenance
Human Performance
Monthly Alarm Testing Not Executed
Monthly EAP (Emergency Action Plan) instrument alarm testing at Alpha Reservoir was not completed per company procedure.
OpEx
Operations
Human Performance
Unit Trip After Human Error
The plant’s lead operator failed to follow the blow down procedure for the Governor Oil Tank when the air valve was left open, and the operator left the site to perform other duties. This event has been classified as an Operator Error.
OpEx
Safety
Employee
Fatigued Driver Motor Vehicle Incident
On July 3, 2020 at 0103 an employee was returning home in a company vehicle about 19 hours after leaving home for work the prior day. The employee was traveling at approximately 24 MPH when the employee fell asleep.
OpEx