HV switching advice for the mechanically mindedà 2

[AshleyK]

Obviously unaware of the more blatant forms of trade blasphemy, my management team have seen fit to let me (a mechanical engineer) loose within a HV switching role. A recent promotion has left me as an area supervisor whereby any mechanical/electrical bias is basically disposed of and this role oversees both areas of engineering, plus some instrumentation work. Of my new roles and responsibilities, the most daunting by far is the HV switching course I will be attending soon, and the subsequent switching I will be performing afterwards.

Anyway, that's the situation and I'm throwing myself upon your mercy for any advice, tips, honest criticism of this appalling managerial decision, etc. I'm confident that that course will be fairly encompassing when compared to the limited amount of switching on our simple circuits, and a highly experienced HV engineer friend of mine has told me that I'll be amazed how simple it all is. That aside, any tips for manuals, books, documents, etc, that should be read to boost my confidence with regards to the HV switching world would be much appreciated, and I have plenty of time to get back into some serious reading now that my role has seen me live my life in various Premier Inns.

Any tips and abusive language involving the terms 'spanner-wielding grease monkey' are more than welcome.

Yours mechanically,
Ashley.

 

[waross]

A couple of details may help.
Are you designing, manufacturing, operating or specifying HV switches?
What specific voltage, frequency and current are you concerned with?

'spanner-wielding grease monkey'

That may be more than one of us when changing the rotating diodes on an old, greasy and poorly designed gen-set. Grin

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[AshleyK]

Apologies for the vagueness, but I won't actually be 100% certain of the circuit until I've been given further details. I was only promoted on Tuesday.

The incoming circuit is 32kV, and the substations convert that to 1000V for our equipment.

Is this a decent place to start…

http://www.amazon.co.uk/High-Voltag...8&qid=1393533670&sr=8-1&keywords=hv+switching

 

[dpc]

Wear your PPE and keep your head turned.

 

[ScottyUK]

What equipment are you being asked to look after? If you don't know the specific type and manufacturer, do you know if it is vacuum / SF6 technology or older bulk oil gear? What is the operating voltage, and under what rules / legislation are you working?

FWIW I think your management is making a decision which is bordering on reckless and dangerous if the only experience you have of HV plant is what you'll gain on a three or four day course.

From company names above I have a feeling you're UK-based. Have a read of the HSE's book HSG230: Keeping Switchgear Safe. The closing sentence says everything that needs saying about the position which you are in. Your management might care to consider that this book is written by the organisation that will be prosecuting them if you get something badly wrong through lack of knowledge, confidence, experience or understanding.

Lack of knowledge
Switchgear should be operated by trained staff, who are often known as
‘authorised persons’. In the past these were generally works’ electrical engineers
and senior supervisors but due to changing employment patterns this is no
longer the case. Some users may not have any ‘authorised persons’ on their staff
and may have chosen to contract out all operational work and maintenance of
their switchgear. As a result, there may be no one within the organisation who
understands the equipment, its safe operation or the need for maintenance. This
should be treated as unacceptable and steps should be taken to remedy the
situation.

Staff responsible for care, operation and maintenance of switchgear should
receive training (or refresher courses) relevant to the duties that are required of
them. This is particularly relevant to staff called upon to operate switchgear and
such staff should have competency at the ‘authorised person’ level. Even where
all operational and maintenance work is contracted out, it is preferable that there
is sufficient technical knowledge within the company to audit the practices of
the contractors and to handle abnormal (including emergency) situations that will
inevitably arise on the premises. If this is not the case, this role should be given to
an independent organisation.

 

[crshears]

Love the quote, ScottyUK! Excellent stuff!

And AshleyK, kudos to you for readily admitting to being a 'spanner-wielding grease monkey', as it save us the trouble of pushing your nose into it

I don't envy you your position at all, and I strongly concur with dpc's advice.

In my world anything < 50 kV isn't high voltage, it's only medium voltage; but in many situations things are relative, I suppose...

By all means make every effort to exercise due diligence, and don't let them toss you into the deep end either with or without a lifejacket.

And, if you get really, really desperate, there's always here...

CR

 

[davidbeach]

Given the amazon domain referenced, I'd agree with Scotty that you're probably UK, but even in the US, tasking unqualified personnel to perform certain tasks is a good way to bring the wrath of OSHA down upon the employer.

Two rules about MV and above (>1000V) work:
1. If you're totally comfortable about what you're doing, you don't understand what you're doing.
2. If you're totally apprehensive about what you're doing, you haven't been sufficiently trained.

Qualified, trained, experienced personnel get much closer to comfort than apprehension, but there's always a process of double and triple checking each step of the process. All it takes is one small slip up in the process to totally ruin your day. Even (especially?) in the utility business, there's always the ability to have help with any switching procedure for which a single operator (switchman) isn't assured of safe completion of the switching sequence.

Another thing to consider is that in the utility business, nobody writes and implements a switching sequence by themselves; there's always multiple sets of eyes looking at it, and generally the people doing the switching weren't the people putting the sequence together and if the operators don't understand or accept the process they can get it revised. I've seen switching instructions for some projects go through multiple revisions; each revision removing some amount of risk and I've never hesitated to add multiple steps to a switching process to reduce risk. My personal view is toward keeping the protection system as sensitive as possible during switching, so that if something goes wrong the fault will be completely cleared as quickly as possible. Others bring other viewpoints; and eventually the sequence gets hammered out. I've seen substation maintenance projects have 30-40 step switching sequences to move load and sources from one end of the station to the other end while being prepared for the worst to happen at any step of the process.

 

[collies99]

Send us you operating one line and associated rating.

 

[jghrist]

NFPA 70E, Standard for Electrical Safety in the Workplace, would be a good read. You can read it free at

http://www.nfpa.org/codes-and-standards/document-information-pages?mode=code&code=70e

but not print or save it.

 

[stevenal]

Switching for mechanical spanner-wielders? Think of switching trains. Bad things happen if the new path isn't clear to travel. Congratulations on the promotion, even if the decision was appallingly bad. I expect your apprehension will subside with training and experience, just be careful to never get complacent about it.