Since Electronic / SMPS Ballasts for HID Lighting are relatively new to the Industry, I would expect some early failure issues.
The Ballasts _SHOULD_ have some sort of Factory Installed TVSS Protection on the Line Input side of the Ballast. The level of TVSS may not be as beefy as needed, or might be built too sensitive to TVS/S.
Just before the Line "PI" Filter - if installed, there should be - at the least - two MOVs.
Just out of curiousity, where any discrete components visually "fried"?
If so, what components lost smoke, or where are their locations on the Ballast's PCB?
The source of the Spikes / Surges would be from something generating trash back into the system, at "Off Hours" - i.e., when it is dark, and the Site Lighting is active.
Could be late night, could be early AM (pre-dawn).
Things to consider:
1: Are there any other Customers fed from the same Transformer's Secondary, besides the ones fed from this Service Section?
Other Customers may be creating issues with their equipment, and doing so during off hours.
2: Are there any Customers fed from this Service Section, which might be working late night (dusk to maybe 12:00 AM), or early morning (2:00 AM to dawn)?
They might be running noisy equipment, causing the TVS/S issues.
3: Might be some Tenants on this Service Section with noisy HVAC equipment, which automatically starts in pre-dawn hours.
4: Utility may have a Power factor Correcting Capacitor bank, which "Cuts-Out" at an off peak time (like 8:00 PM), or "Cuts-In" prior to peak time (like 4:00 AM), and when the Cap's are Cut-In or Cut-Out, creates TVS/S issues, or an overvoltage scenario.
5: May be heavy use, 24 Hour shift Customers on the same Primary Circuit, which are creating noise issues during night time hours.
Verify the time frame & duration of the noise (Spikes / Surges) with the Datalogger, to determine if there is an issue with TVS/S (Transient Voltage Spikes/Surges).
If there is an issue with TVS/S, may need to fit the House Panelboard with an SPD Panel, or query the Ballast Manufacturer for Point-Of-Use TVSS devices.
BTW, who made the Ballasts, and what are the ratings?
If the costs and maintenance factor prohibit an extensive TVSS application, the Fixtures may need to be "Retro Engineered" back to Reactor based Ballasts (Magnetic Ballasts).
Could use the "F-Can" enclosure types, or the "Pole-Based" round ones.
Will see what arises from your next reply(s).
Scott
