Stand-by Power – Generators

One of the most critical capabilities for businesses is electrical power – something many take for granted until the Mains Power Grid fails.

I am going to examine the provision of stand-by power by means of emergency generators – future articles will address UPSs and Surge Suppression etc.

Following the ravages of Hurricane Ivan and subsequent “brushes”, “near misses” and “false alarms” many companies that did not previously have generators, have now had them installed – this is only the first step.

Obviously, any company that own a generator expect it to start automatically when Mains Power fails; however, like most electrical and mechanical equipment, regular maintenance and testing is required to ensure prime performance as and when required. This maintenance and testing applies to not only the electrical and mechanical components of the generator and associated Automatic Transfer Switch (ATS), but also to the Fuel Supply.

It is absolutely vital that any generator provided for the provision of stand-by power, is maintained in accordance with the Manufacturer’s guidance – ideally, on at least a monthly basis by either, a professional agency with qualified personnel or, suitably qualified personnel from within your own company. Such maintenance will essentially check:

Fuel, Lubricants & Coolant levels
Fuel & Coolant hoses, valves & connections
Fuel, Oil, Air & Coolant filters
Belts
Engine & ATS settings
Batteries & Battery Charger
All Start up & Shut Down functions
Engine, Fuel Tank & ATS Alarm functions
Fuel Heater
Integrity of Fuel Tank & associated Safety devices such as Gauges, Alarms & Vents
Cleanliness of Diesel Fuel

Additionally, the generator should be run on a regular basis. During “non-Hurricane Season” months, the stand-by power generator at BIC is tested on a weekly “exercise run” for 1-2 hours – every second week for 2 hours “under load” i.e. providing power to your company infrastructure and the other 2 weeks “not under load” for 1 hour. During Hurricane Season, this frequency “under load” is increased to 4 per month. Also, in the event of a suspected Tropical Storm or Hurricane approaching the Cayman Islands, we do a 4 hour run “under load” 2-3 days prior to forecast landfall of the storm. Sadly, I have both seen and heard of companies who singularly failed to “exercise” their generators – especially “under load” and then seemed to be somewhat surprised when the system did not work as designed. Bottom line – you have to test run your generator “under load” on a regular basis otherwise there is a high likelihood that failures will occur when you actually need your generator for what may be extended periods.

In the event of extended generator running in emergencies, I would recommend at least a daily check of systems, liquid levels and components – DO NOT LET YOUR GENERATOR RUN OUT OF FUEL!

I would also recommend holding a stock of spares for the Generator – these should include all Filters, critical Hoses and Belts.  The most likely “high use” spares in the event of extended generator use are Fuel and Oil Filters and you would not be remiss in holding extra stocks of these items during Hurricane Season.  Remember, however, to store perishable items such as Hoses and belts in suitable conditions i.e. essentially not exposed to direct sunlight or high heat levels.

Finally, I will turn to the subject of Diesel fuel.  One of the most common causes of generator failures is “dirty” fuel – more specifically the presence of water or particles/sludge in the Diesel fuel and, therefore, regular maintenance and checks of Diesel fuel and the fuel tank are essential to ensure effective generator operation. In the Cayman Islands, the most significant risk to Diesel fuel is from the prevalent temperature and humidity levels. Simply put, any moist air inside the Diesel tank will result in some accumulation of water. The interface layer of the Diesel fuel and any water present provides an ideal “breeding ground” for the formation of certain types of microbes, especially in warm conditions. These microbes can eventually clog Fuel Feed Hoses and Engine Injectors to the extent that the generator may either, fail to start or, will not run smoothly.

The best way to combat water in Diesel fuel is to minimize the entry of any water into the fuel tank – Water Detection Paste is readily available and, at BIC, we insist of carrying out a Water Detection check of a Delivery Truck sample before any Diesel fuel is transferred into the Fuel Tank. Additionally, we carry out regular Water Detection checks of fuel tank contents as part of our maintenance cycle. The last in place defence mechanism is the use of high quality Water Separation Filters (Racor) to eliminate any water in the fuel prior to entering the Engine Injector system. Ideally, you should have 2 such Filters installed in parallel isolated lines, to enable cleaning of one filter without the need to shut down the generator.

It is always advisable to try and turn over (consume) and replenish your Diesel fuel regularly; however, if this is not economically feasible, there are companies on the Cayman Islands who have the appropriate mobile equipment to “scrub” your fuel supply i.e. circulate it through an external Water Separator Filter trolley. Additionally, it is recommended that you keep Diesel fuel tanks topped up at all times to minimize the presence of moist air in the fuel tank.

There are Biocides available that will kill any microbe colonies in Diesel fuel; however, be advised that the dead microbes form a sludge at the bottom of the fuel tank which will require removal at some stage and, microbes can build up a resistance to a particular biocide so you will have to try a different brand – personally, I try to avoid the use of such Diesel fuel treatment biocides unless there is not other alternative.

In conclusion and simply put – if you maintain, check and run your generator, ATS and fuel supply on a regular basis and in accordance with manufacturer’s guidance, performance will be as advertised and you will have that critical stand-by power supply in the event of Mains Power failures.

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May 2019
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