BLOG: Power Perspectives

[#1]

Too many times people are maintaining the mechanical portions of their power system but they forget or don't understand the electrical side. Most people understand the mechanical side because we drive our cars, trucks, or perhaps motorcycles to work and we maintain those vehicles. We change the engine oil, ensure proper tire inflation, keep the brakes in order, etc.

I've often seen instances where a facility manager has a maintenance contract on the generator set/s but either doesn't ask or get offered a maintenance program on the electrical portion of the system... thus it doesn't always receive proper attention. Sure, if you've got a UPS, you need to be concerned about things like:

• batteries
• corrosion on terminals
• temperature of the room

If flywheel or mechanical energy storage:

• keeping track of bearing temperatures
• vacuum pressure
• vibration figures

 
When called to duty most people either see the light flicker (or not) depending on the transfer scheme and the overall system responds. This happens maybe a few times each year and over time people become complacent. So after a few years, people have the generator set and/or UPS under a maintenance contract but are not getting their ATS, Switchgear, and Circuit Breakers serviced, what I like to call, "the quiet and forgotten portion of your power system."

There are some key things to consider when maintaining your electrical equipment:

What's Required

• What does the manufacturer recommend? What's in the Operation and Maintenance Manual? What's in NETA? Depending on your industry you might be required to prove you've maintained your entire system…i.e. Joint Commission. Insurance companies might increase rates if equipment is not maintained or might reduce rates if you can provide/prove stellar maintenance records.

 
Environment Considerations

• Adverse conditions are known to negatively impact useful service life of electromechanical equipment.
• Pay attention to application environment and any changes to the surrounds.

 
Record Keeping

• People change and employees retire so it is important to setup a good process for detailed record keeping.
• Records should be kept with equipment, including any modifications.

 
Inspection Cycle

• Depending on other equipment you have under contact, consider sole-source to get the benefits associated with working with only one company.
• Cycle also depends on how critical is your system to overall operation of the business. It's also a function of the age. Older electrical equipment needs to be maintained more often.

 
Training

• Facility managers have local staff trained, which is great to understand the system and possibly be the first responder in case of emergency. But this does not necessarily mean they are fully qualified to perform system maintenance. Consider the specialized tools, diagnostics equipment or computer software required… which may be better applied by field experts.

 
Repair Parts

• Consider having some common failure parts on the shelf. You can't ever consider everything that would fail – but work with your service provider to understand common items.

 
Ask yourself these two questions:
1. Who is maintaining the electrical portion of your system?
2. If the system doesn't respond, what will the economic impact be?

All these items are incorporated into a good maintenance program for your electrical equipment. Challenge your service providers to incorporate all of your power systems maintenance requirements in the beginning to ensure maximum performance throughout the lifecycle.

Questions

• Are there any other key maintenance considerations you would add that are not mentioned above?
• Do you have a service contract for your ATS, Switchgear and Circuit Breakers?
• What does that contract include?
• What doesn't it include that you wish it would?
• If you don't have a contract, are you performing maintenance? Monthly? Yearly?
• Can you think of any additional "quiet" and/or "forgotten" components of an electric power system?

Please share your thoughts by posting below.

[#2]

Nice start to the discussion, I worked a few years for a NETA testing company, a few additional points I'd like to make.

Good electrical system maintenance starts at the design phase, way too many facilites can't perform the needed maintenenace simply because the power distribution design and site operational requirements don't allow for it.  If an ATS needs work, especially in the current NFPA 70E compliance environment, it will need to be de-energized, many facilities, even critical ones don't have bypass arrangements because it was too expensive.  And the site operations folks also can be a big part of not getting things done, the IT folks want their computers up no matter what, and most think the power at work is like at home, why maintain something that never breaks?

NETA is pretty much the standard for industrial power systems in the US, they have a free publication on maintenance testing recommendations, http://www.netaworld.org/

How important is your facility, in defining the level of importance your help define the needed levels and intervals of electrical maintenance.  Your system voltage levels also will drive many of your decisions as well.  480 VAC systems are much easier to deal with than 12kV systems, but all need some form of regular inspection, testing and documentation.

Along with environment also consider impact of infestation.  Spider webs by themselves are usually non-conductive, but they hold dust, moisture and debris that can lead to some pretty exciting flashovers.  Regular cleaning is important.  Rodents are also a huge contributor to system problems and faults.  Installation practises can have a large impact on how critters can get into you equipment.  They chew, piss and poop, all bad for your equipment and they need to be dealt with quickly.  They also attract other creatures, I get many service calls each year from damage by snakes in electrical switchgear.  Why do they go into the swithgear? It's usually warm and there is usually a good supply of food.

Larger systems also have loadshare and VAR/PR controls, protective relays, and plant controls, these also need regular service, from things like cleaning cabinets to checking wire connections, to regular tests performed by competent field engineers to assure the protective elements and controls are working as intended.

One of the questions I here most is "what kind of maintenance do I need?"  My first answer is "depends", it depends on how important you facility is, what kind of equipment yo have, your ability to take all or part of the system out of service to perform work and the level of expertise your in house staff has.  If you go to multiple testing companies and ask them for  quotes, you'll likely get all kinds of different prices and scopes of work.  The best way is to have a competent electrical engineer, preferably one familiar with your facility, generate a maintenance and testing specification for your facility.  This way you know the quotes you recieve address the needs of your facility, not some boiler plate proposal that may or may not include all you need.

Safety is a key element, proper LOTO procedures, up to date prints and arc flash studies, and proper work procedures for your facilites electrical system will assure work can be carried out safely and in a timely manner, remember one seemingly minor mishap can make a planned 4 hour outage a real mess.

Mike L.

[#3]

The majority of the bigger sites today (>2.0-mW) are typically MV Distribution, with complex software and design parameters that are not completely understood by either the Operations Staff, and the service technician. It would be much more reliable if the trend in engineering design was to move back to a simplier approach to reliability and reduce the risk across the board.

High Voltage (above 600-Volts) need to be done by qualified service technicians and not the facility staffing other then shut-down or safe-off of the problem, because typically there is sufficient redundant backup (N+1) to continue the operation without concern to the facility.

BIM/SCADA system have just complicated our life and forcing users to properly not understand the system one-lines and sequence of operations for the Mechanical & Electrical one-line systems 

[#4]

Mike L, All great comments. We discuss and reference NETA regularly. I also like your approach to incorporate maintenance into the design, that is very smart. "Local" people also help ensure you're covered or including what needs to be included in the maintenance/inspection program. I would also suggest safety.cat.com Another way for customers to mitigate their risk is Extended Service Coverage (ESC). This provides protection on the Caterpillar equipment and a tool to budget unplanned/unscheduled repairs. Robb

[#5]

Mike G. Designs are driven by customers needs and yes the larger systems are typically MV. Understanding the complete system design and customer expectations are critical. You're correct Sequence of Ops and system one-lines are all part of the puzzle. Many times customers don't understand that a Caterpillar system can incorporate/aggregated desired information to be communicated with the bim/scada system. Robb

[#6]

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[#7]

Electrical maintenance [which is mostly conducted by trained eletricians] is very important in making sure that every power generated appliance, or device within an area, building or home is working the way it should be at all times. 

Also, having this kind of routine helps regulate an ensure the safety of the device.

[#8]

I'M THE POWER PLANT SUPERVISOR AT THE US EMBASSY IN KABUL, AFGHANISTAN. WE HAVE SEVERAL 3516 GENERATORS (EXAMPLE - ZAR00573 - 256-0760)  AND ARE PLANNING ANOTHER 8 UNIT 3516 POWER PLANT THIS YEAR. AT THIS TIME WE ARE HAVING THE LOCAL CAT DEALER IN KABUL (ALLIED) DO OUR SCHEDULED REBUILDS.

MY QUESTION IS: WHERE OR HOW CAN I GET CATERPILLAR DOCUMENTATION STATING SUGESTED TIMES NEWLY REBUILT ENGINES / GEN UNITS BE LOAD TESTED. I HAVE SPENT AN EXTREME AMOUNT OF TIME ON SIS TRYING TO FIND ANYTHING RELATED TO THIS DOCUMENT WITH NO RESULTS. ANY HELP WOULD BE APPRECIATED.

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Wattsup wrote:

Too many times people are maintaining the mechanical portions of their power system but they forget or don't understand the electrical side. Most people understand the mechanical side because we drive our cars, trucks, or perhaps motorcycles to work and we maintain those vehicles. We change the engine oil, ensure proper tire inflation, keep the brakes in order, etc.

I've often seen instances where a facility manager has a maintenance contract on the generator set/s but either doesn't ask or get offered a maintenance program on the electrical portion of the system... thus it doesn't always receive proper attention. Sure, if you've got a UPS, you need to be concerned about things like:

• batteries
• corrosion on terminals
• temperature of the room

If flywheel or mechanical energy storage:

• keeping track of bearing temperatures
• vacuum pressure
• vibration figures

 
When called to duty most people either see the light flicker (or not) depending on the transfer scheme and the overall system responds. This happens maybe a few times each year and over time people become complacent. So after a few years, people have the generator set and/or UPS under a maintenance contract but are not getting their ATS, Switchgear, and Circuit Breakers serviced, what I like to call, "the quiet and forgotten portion of your power system."

There are some key things to consider when maintaining your electrical equipment:

What's Required

• What does the manufacturer recommend? What's in the Operation and Maintenance Manual? What's in NETA? Depending on your industry you might be required to prove you've maintained your entire system…i.e. Joint Commission. Insurance companies might increase rates if equipment is not maintained or might reduce rates if you can provide/prove stellar maintenance records.

 
Environment Considerations

• Adverse conditions are known to negatively impact useful service life of electromechanical equipment.
• Pay attention to application environment and any changes to the surrounds.

 
Record Keeping

• People change and employees retire so it is important to setup a good process for detailed record keeping.
• Records should be kept with equipment, including any modifications.

 
Inspection Cycle

• Depending on other equipment you have under contact, consider sole-source to get the benefits associated with working with only one company.
• Cycle also depends on how critical is your system to overall operation of the business. It's also a function of the age. Older electrical equipment needs to be maintained more often.

 
Training

• Facility managers have local staff trained, which is great to understand the system and possibly be the first responder in case of emergency. But this does not necessarily mean they are fully qualified to perform system maintenance. Consider the specialized tools, diagnostics equipment or computer software required… which may be better applied by field experts.

 
Repair Parts

• Consider having some common failure parts on the shelf. You can't ever consider everything that would fail – but work with your service provider to understand common items.

 
Ask yourself these two questions:
1. Who is maintaining the electrical portion of your system?
2. If the system doesn't respond, what will the economic impact be?

All these items are incorporated into a good maintenance program for your electrical equipment. Challenge your service providers to incorporate all of your power systems maintenance requirements in the beginning to ensure maximum performance throughout the lifecycle.

Questions

• Are there any other key maintenance considerations you would add that are not mentioned above?
• Do you have a service contract for your ATS, Switchgear and Circuit Breakers?
• What does that contract include?
• What doesn't it include that you wish it would?
• If you don't have a contract, are you performing maintenance? Monthly? Yearly?
• Can you think of any additional "quiet" and/or "forgotten" components of an electric power system?

Please share your thoughts by posting below.

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