B
BruceB
I thought you might be interested in an unusual fault I have been dealing with by telephone.
Customer phoned yesterday saying that with passing cumulus and sunshine the inverter output was oscillating wildly the inverter then cut out as the voltage was rising fast around 255V with fault code W003, more than once. He is a friend who lives 50 miles away in the sticks on the end of a long thin line with about 40m between the service head and inverter. I thought initially bugger - the first time I have been caught out undersizing a cable. He was an engineer in the past so had a meter and could do some diagnostics. Now codes on the Aurora are:
W003 - grid fail wrong grid parameters
W004 - over-voltage
W005 - under-voltage
W006 - over-frequency
W007 - under-frequency
So it was strange it was not failing with W004. He tightened things up within the installation and measured R1+Rn between service head and inverter at about .2 ohm. He then tested voltage at service head (henley block) as he switched loads on. A 1kW load caused about a 4V drop when switched on which then decayed over about 5s to around a volt. It implied initially a DNO line resistance of around 1 ohm which was strange as my records showed a Zs at the inverter of 0.47 ohms. Discussing what had been going on locally, WPD had been tidying up cables in the lane including the pole outside his property. I suspected a bad connection on the DNO side. He went outside and gave the stay on the pole a good shake and the problem disappeared.
So it looks like a bad crimp which with a bit of tugging around is now making better contact. When a high current was initially flowing there was a few volts dropped across the connection, but after a few seconds the high current made the connection better temporarily until the next time the current dropped.
The inverter never hit the 264V G83 limit, but because it detected the fast rising voltage when the sun came out it decided it was entering island mode and cut out with fault code W003.
So all Ok at the moment. He just needs to pursuade WPD they have a dodgy connection now!
Regards
Bruce
Customer phoned yesterday saying that with passing cumulus and sunshine the inverter output was oscillating wildly the inverter then cut out as the voltage was rising fast around 255V with fault code W003, more than once. He is a friend who lives 50 miles away in the sticks on the end of a long thin line with about 40m between the service head and inverter. I thought initially bugger - the first time I have been caught out undersizing a cable. He was an engineer in the past so had a meter and could do some diagnostics. Now codes on the Aurora are:
W003 - grid fail wrong grid parameters
W004 - over-voltage
W005 - under-voltage
W006 - over-frequency
W007 - under-frequency
So it was strange it was not failing with W004. He tightened things up within the installation and measured R1+Rn between service head and inverter at about .2 ohm. He then tested voltage at service head (henley block) as he switched loads on. A 1kW load caused about a 4V drop when switched on which then decayed over about 5s to around a volt. It implied initially a DNO line resistance of around 1 ohm which was strange as my records showed a Zs at the inverter of 0.47 ohms. Discussing what had been going on locally, WPD had been tidying up cables in the lane including the pole outside his property. I suspected a bad connection on the DNO side. He went outside and gave the stay on the pole a good shake and the problem disappeared.
So it looks like a bad crimp which with a bit of tugging around is now making better contact. When a high current was initially flowing there was a few volts dropped across the connection, but after a few seconds the high current made the connection better temporarily until the next time the current dropped.
The inverter never hit the 264V G83 limit, but because it detected the fast rising voltage when the sun came out it decided it was entering island mode and cut out with fault code W003.
So all Ok at the moment. He just needs to pursuade WPD they have a dodgy connection now!
Regards
Bruce
