Safety Scenarios And Rules Flashcards
You arrive at a typical customer point of delivery substation where a 13.8 KV PCB has been bypassed and cleared to remove and install a new PCB in its place. The clearance limits are on the disconnects on both sides of this PCB. The construction Foreman in charge of the breaker replacement informs you that his crew needs to install ‘cover-ups’ on energized 13.8 KV bus work above the PCB to allow an electrician safe access to the top of the PCB bushings to disconnect them from the bus.
- Describe what your response would be given this information from the construction Foreman.
- Is there any switching or tagging procedures required?
- Yes, cover-ups can be installed as long as they are using approved barriers Per APM rule B-1.
- Concerns will be, do they need to get off the ground, can it be installed with hot sticks, and will the MAD be violated. I would want to review the barrier installation plan.
- If able to be installed with hot sticks from the ground no additional switching or procedures required.
- If needing to get off the ground, on a ladder or in a bucket, but installed with hot sticks without violating the MAD then it can be done energized with hold order.
- If barriers cannot be installed with Hotline tools or they are going to violate the MAD they must have a clearance in place so we would need to back up the clearance
A substation maintenance Foreman arrives with for electricians at your station to perform mechanism services on to 2:30kV PCBs at opposite ends of the yard that you have cleared for him on a work clearance. He has been issued these 2 work clearances by the dispatcher. Following the walk around, the foreman mentions that he needs to finish his work as soon as possible in order for him and his crew to attend a required meeting that afternoon. Thus, he will split his crew of four and complete the mechanism Services concurrently.
- Explain, if any, your concerns with the Foreman’s work plan.
- What procedure might you suggest to allow this work to be accomplished in the time allotted
My concern would would be that the clearance Holder will not be able to be ‘at the job site’ of both PCBs at the same time. The foreman can hold two clearances at the same time but cannot work them concurrently, because he would not be able to be at both pcbs. My suggestion would be to have one of the crew members hold the clearance of one of the pcbs so they could work both jobs concurrently
BPA has hired a contractor to raise 2 Towers on a 500 KV transmission line at a railroad crossing the BPA Line inspector is a certified restricted electrical worker. There are no BPA qualified Electrical Workers that can be made available to hold the clearance for several weeks needed to complete this work.
-Explain in detail the procedure that would allow this work to be accomplished
Per OB-2 sect VI, a clearance is not required if the equipment is Returned to Construction. This requires a letter of request to release the equipment from operations to another entity and is approved by the Manager of the Dispatching Office. The letter must define the equipment requested; circuit parts that will be remove to separate it from the power system, the employee that will receive the release and the organization represented, date of release, duration of work, and an outline of how the work will be accomplished safetly. Under a clearance separate the equipment from the system by removing transmission line jumpers. Visual inspection by a substation operator to assure the dispatcher of appropriate separation and guards and barriers in place if needed. the dispatcher will then release them to the requesting organization. Work standard BPA-WS-3-3 work on equipment separated from the power system should be consulted
BPA has hired a contractor to raise Two Towers on a BPA 500 KV transmission line at a railroad crossing. The BPA line inspector is certified restricted electrical worker. Attached is an under built to one of the two 500kv towers it is it is an energized 115 KV transmission line owned by a foreign utility. It has been determined by the inspector that for 8 hours during the process of raising the structures the 115 kV line would be contacted by the contractor workers were their equipment. Explain how this safety concern can be resolved so that the work can be accomplished safety
A Clarence will be required and portable protective grounds will need to be installed on the 115 KV transmission line. The clearance will need to be held by a BPA qualified electrical employee, the BPA line inspector would not be able to hold this clearance. We will need to work with the foreign utility 2 clear and tag their transmission line.
APM rule C-1
Conductive Devices, restrictions of
Portable metal ladders are not permitted in energized substation yards or for use in any situation where there is danger of contact with energized line or equipment.
Conductive objects such as metal tapes, surveyor chains, fish capes, and center-line wire may be used only when restrained by adequate methods, as determined by a Qualified Electrical Employee, to prevent electrical contact in event time slippage or breakage at any point
APM rule C-2
Coupling capacitors and bushing potential devices.
Work in the base units of this equipment, other than tuning or voltage adjustment shall be performed under the protection of a clearance as outlined in BPA work standard BPA–WS-9-7, Bushing PD’s, Coupling Caps and Line Tuning Units
A 500 KV transmission line terminates between two breakers on a breaker and a half bus. the tie BKR on this line terminal is cleared on a test clearance for substation maintenance work. a hold order has been requested for the line for hotline work. explain in detail the switching and tagging requirements for the hold order.
OB-2 provisions of a hold order State “all control points have been properly tag of the Line or equipment included in the hold order if they are de-energized by terminal relay action”. In this case, the tie BKR PCB is not capable of energizing the line and it is not considered a control point, so cut out reclosing on the bus side PCB and tag the RECL SW and control point with a hold order tag. If the clearance is released it is up to the dispatcher to decide what they want there are two options. 1) dispatcher calls hold order holder into the clear accepts the release of the clearance and switches to restore, leave the reclosing cutout switch cut out and tagged both reclosing and the control point with the hold order notified a hold order they may resume work or, 2) leave the PC be cleared and restore after the hold order is released
During an inspection you see sub maintenance working on a bushing on a spare Transformer that has had the bus work removed, you tell them they need a clearance and they say you are mistaken, who is right you or them?
They are right work standard 3-3 allows for work on spare Transformer when it has been physically separated from the power system and there are no means to energize it. This equipment is considered under the control of the maintenance Foreman that is on the spare Transformer/reactor removed from service form. They do not need any type of clearance hold order or work permit for their work.
