Distribution Automation

[CPOPE]

I got you on the differance between Hot-Line-Tag and non-reclose. Understand that only newer equipment has the hotline tag feature.

Your situation needs a code based argument to your management engineers and accountants. Goes like this. We have a feeder breaker and three normal open points. Automatic restoration scheeme is enables such that we have 4 possible sources to be disabled non-auto and tagged via scada by the way I read NESC.

NESC 442F requires for the protection of the field worker the circuits or equipment shall be left open until reclosing has been authorized.

Refer to rule 442E for the tagging requirement. If I'm working on a line and there are 4 possible divices that can auto reclose back into my work area I need to tag up all 4 devices by code. Take note on the exception as to this is how the hotline tag protocal via SCADA fits in.

442. Switching control procedures
E. Tagging electric supply circuits associated with work activities

1. Equipment or circuits that are to be treated as de-energized and grounded per Rule 444D shall have suitable tags attached to all points where such equipment or circuits can be energized.
2. When the automatic reclosing feature of a reclosing device is disabled during the course of work on energized equipment or circuits, a tag shall be placed at the reclosing device location.

EXCEPTION: If the automatic reclosing feature of a reclosing device is disabled by a Supervisory Control and Data Acquisition System (SCADA), the system shall provide for the following:
(a) At the SCADA operating point
(1) A signal is received by the SCADA operator confirming that the disabling operation has occurred at the reclosing device location, and
(2) A readily visible tag or electronic display is used to inform any potential SCADA operator that a disabling operation has been initiated, and
(3) The tag or electronic display is removed before action is taken to re-enable the automatic reclosing feature.

(b) At the reclosing device location
(1) The reclosing feature is disabled in such a manner as to prevent manual override of the normal control by any potential on-site operator, or
(2) A signal, flag, or other display is used in such a manner as to alert any potential on-site operator that the reclosing feature has been disabled.

3. The required tags shall be placed to clearly identify the equipment or circuits on which work is being performed.

[lewy]

We all have different work protection codes , In Ontario 90% of the province uses the same code, but I am sure they are different from province to province & state to state maybe even company to company. Anytime we are working live line the operator knows what circuit we are on & if there are any other circuits at that location & again they would be under hold off protection. Obviously if that feeder tripped the operator is going to get in touch with the person or persons who are holding the protection, they are not going to start closing the breaker or the open points, that is why I do not see the point of having all of the other feeders at the open points under hold off. Would you go around & tag all of the open points that are not under scada control?
A little different angle do you have all of the feeders at the open points under hold off protection when working on a de-energized line, we do not ,but I think it would make sence no use testing your grounds more than 1 time.

[mainline]

I see as usual that Maine is way behind the curve on some things. All SCADA at my uitility is controlled by operators. We do not currently (as far as I know) have any distribution automation that will perform switching to close n/o. Most of that is still done manually using gang operated switches or operator switches. If I am understanding the way it works where you are, I too would be very leery of working on a system where a computer could switch and close n/o to restore power. That could lead to some nasty incidents.

[1007Control]

CPOPE

Thank you for the regulation, I am not sure that there is a similar Canadian reg., I have been looking.

LEWY

In our transmission system manual disconnects are "Opend Locked & Tagged" our motorized disconnects are Opend via SCADA then "Locked & Tagged in the Local Position & the DC fuses pulled" to isolate a de-energized line.

Like most other places at our utility most of the really experienced people have retired and the few that are left have one foot out the door. The systems are getting more complicated every day, Anything that can be done to prevent a system malfunction or an operator error (we are human) from becoming a Mistake with Consequences must be done.

I will have to leave this discussion for a while, I start my night shifts in a few hours.

[lewy]

CPOPE

Thank you for the regulation, I am not sure that there is a similar Canadian reg., I have been looking.

LEWY

In our transmission system manual disconnects are "Opend Locked & Tagged" our motorized disconnects are Opend via SCADA then "Locked & Tagged in the Local Position & the DC fuses pulled" to isolate a de-energized line.

Like most other places at our utility most of the really experienced people have retired and the few that are left have one foot out the door. The systems are getting more complicated every day, Anything that can be done to prevent a system malfunction or an operator error (we are human) from becoming a Mistake with Consequences must be done.

I will have to leave this discussion for a while, I start my night shifts in a few hours.

We do the same on our motorized switches, but not when working on energized lines.& again we would not have hold offs on the other sides of the open points

[1007Control]

LEWY

In our distribution system we Hot Line Tag the breaker via SCADA the normal open points up until now have been manually operated and not an issue. Now that in this one area we have a DA system the N/O points in that area are an issue.

We operate 138 / 240 & 500kv switch yards that are tie points with the Provincial Grid. When the transmission utility needs to isolate a line to do Dead & Grounded work on a line between our switch yard and theirs we provide them with isolation from the disconnects and block & tag the re closure at the switch yard (not by SCADA) , tag the local control handles of the associated breakers at the yard and apply "NO CLOSE" tags to the breakers in SCADA. I don't know if this is to comply with a Utility Regulation or just their own standard. They ask, we do it for them.

[Stinger]

I know that NSTAR is using the SCDA now. We as contractors have been putting them up. The one thing that bothers me about them it is hard to see if it closed or open at night because the colors are hard to see from the GRD. At least the old GOAB's you can visibly see if the are open or not. As one of our brothers stated nothing takes the place of good safe line work and job planning. Some systems are so old or overloaded you can not get DNR.

Also, MAINLINE if you read this I feel very safe with CMP lock out/tag out hold and the DNR procedures you have in place.

[lewy]

LEWY

In our distribution system we Hot Line Tag the breaker via SCADA the normal open points up until now have been manually operated and not an issue. Now that in this one area we have a DA system the N/O points in that area are an issue.

We operate 138 / 240 & 500kv switch yards that are tie points with the Provincial Grid. When the transmission utility needs to isolate a line to do Dead & Grounded work on a line between our switch yard and theirs we provide them with isolation from the disconnects and block & tag the re closure at the switch yard (not by SCADA) , tag the local control handles of the associated breakers at the yard and apply "NO CLOSE" tags to the breakers in SCADA. I don't know if this is to comply with a Utility Regulation or just their own standard. They ask, we do it for them.

I am going by your original post which was 25 kv . I have only worked distribution so I cannot really comment on the transmission side, but again as far as distribution I do not see the need for hold offs on the other side of the open point when doing live line work.

[1007Control]

I am going by your original post which was 25 kv . I have only worked distribution so I cannot really comment on the transmission side, but again as far as distribution I do not see the need for hold offs on the other side of the open point when doing live line work.

LEWY

I am not suggesting that we put "hold offs" on the other side of the open points. I am saying that the N/O points (PME / VISTA cubicles & ScadaMate sws) that have the ability to "auto close" and or be closed by a SCADA command need to be properly disabled & tagged in SCADA.

I'm off to work, will try to check in tomorrow.