high voltage levels affecting equipment

[IronLiver]

Has anyone had any experience with increased voltage levels caused by PV systems affecting any of the installed equipment on site? Had to reset an SB 4000TL to G83/1 on a domestic install recently as the voltage levels were to high for the G59 settings particularly on sunny days. There seem to be a few PV installs in the area, which may be pushing up the voltage at the transfomer?

Voltage at the AC isolator for the PV system (with inverter switched off) was 244V at last measurement, which is within the +10% tolerance that the DNO is allowed. When the PV system is on the voltage rises to around 249V, but must have gone higher on occasions as the inverter was cutting out under G59 stating an error code of 103 - Grid overvoltage slow. Anyway after a lenghty exchange with SMA got the necessary code and reset to G83.

During the visit the customer told me that he has had 5 Honeywell motorised zone valves die in the last month (all now manually opened). I took a look and these motors are rated at 230-240V, could they have been damaged by the high voltage levels in the installation? Has anyone experienced this before? I stopped short of measuring the voltage at the motor/boiler spur.

Customer is not keen to replace the motors if there is a chance they will be damaged by high voltage levels. That said I have frequently recorded voltage levels in excess of 240V at CU despite being 230V nominal.

Any advice gratefully received.

Cheers

Monty

 

[Earthstore]

To cure his problems, sell him a voltage optimiser, but make sure that you wire the PV in correctly, IE before unit not after.

 

[Gavin A]

all equipment sold in the UK should be capable of handling the full uk voltage range that the inverters are set to.

were you told to set them to G59?

We've never been told to use G59 settings on a 4kW system.

 

[danesol]

It more likely an under voltage at somepoint has damaged them or he has "boiler over-run" set at 30mins and has a room stat which keeps the valve head live, even when the valve closes ........ I'm replacing mine every 2yrs because of this with cheaper Tower units as you can just buy the heads which are supplied with a 3yr warranty - lol

 

[IronLiver]

Thanks for your responses.

The DNO did not specify that the inverters should be set to G59, in fact they issued a letter stating that the inverters could be connected under G83/1 parameters. However, the inverters were shipped factory set to G59 and were not changed during install. At the time it was not seen as a problem because if anything the settings are more sensitive. The problems mentioned above changed our opinion, hence the need to reset to G83.

Back to the zone valve problem, it just seems a bit too coincidental that 5 valve motors have died around the same time. From what he told me the system does operate from room stats as there are no TRVs on the ground floor, but I don't quite follow the bit about the boiler over-run or why having the head live would have a negative impact on the motor. Sorry but my knowledge of boiler systems is patchy at best.

I'm not keen on selling him a voltage optimiser that he doesn't need.

Thanks

Monty