Voltage Regulation Equipment - Supplied By The Pea!

[Marvo]

Hi all,

Got a problem with the voltage in the house intermittently dropping (and repeatedly tripping the UPS's on the computers) whenever the welding shop up the road are working with powerful gear.

The PEA came round to the house and just told the Mrs that they could fit a voltage regulator (240V output) on the top of our pole (before the meter) for 4,500 baht.

We only have 220/240V cable running down our Soi, no 3 phase BTW.

Anybody had one of these PEA regulators before, or know what piece of kit they are talking about fitting?

Cheers,

[electau]

It would appear that your problem is with excessive voltage drop due to the cyclic nature of the welder use.

Transformer type welding equipment operate at low power factor unless corrected by installing capacitors.

The load from the transformer may not be balanced over 3 phases and your single phase supply is the one that has the welders connected to it.

It is really a PEA problem and they are the ones responsible to rectify it

The low voltage causes the UPS to switch to batteries and alarm, which of course that is what it is designed to do in the event of sensing a low voltage.

Does the low voltage affect any other of your electrical equipment in any way?

[Marvo]

It would appear that your problem is with excessive voltage drop due to the cyclic nature of the welder use.

Transformer type welding equipment operate at low power factor unless corrected by installing capacitors.

The load from the transformer may not be balanced over 3 phases and your single phase supply is the one that has the welders connected to it.

It is really a PEA problem and they are the ones responsible to rectify it

The low voltage causes the UPS to switch to batteries and alarm, which of course that is what it is designed to do in the event of sensing a low voltage.

Does the low voltage affect any other of your electrical equipment in any way?

The (halogen) lights dim for 1/4 sec every second (when they are welding I presume), and the hairdryer motor changes pitch a little, matching the lights dimming cycle.

The PEA told us that the weld shop uses all 3 of the phases. They (the PEA) ran a new cable down from the main road to our house ( for 4,000 baht tea money), connected to another phase which improved things slightly but not completely.

It's also on my mind that we just had a 13 month old 50" LG plasma TV go south, but have no proof that an unstable voltage supply was to blame.

Normal (good) voltage now is 215v but my (insensitive) meter shows this drops to at least 195v when the shop is welding. According to my AVO meter, the (APC) UPS's on all four computers seem to kick in at around 198v.

The PEA guy who suggested the voltage regulation box, seemed concerned that supplying the house with electricity at 240v may cause a problem for some of our household electrical equipment.

As for the PEA rectifying the problem, they will do whatever I'm willing to pay them to do. I suppose I'm up against the attitude "We got electricity - light on - no problem".

[electau]

Standard nominal voltage in Thailand is 220V single phase to neutral and 380V phase to phase. The variation % age ( + / -) is 7% of the nominal voltage in Bangkok and 10% outside Bangkok.

The voltage tap setting on the transformer may be at 0%, increasing this to the 2.5% or 5% position may rectify the voltage problem.

2.5% rise would bring the on load voltage up to 219V from 215, a 5% rise would achieve a rise to 226.

This is maybe what the PEA intend to do.

At 10% ( - /+ ) of 220 is 198V to 242V.

[Pib]

Based on three digitial multimeters I have, here at my western Bangkok moobaan the voltage runs in the 225-227V ballpark...and at my mother-in-law's home in a small village in a nearby province, her's runs around 227-230V. All home appliances at both homes work fine...can't attibute any home electronic failures to the voltage running up to 230V, but I also put whole house surge protectors at both homes to help protect from lightning and equipment induced surges...along with surge protected power strips at my home....as I did experience some failures during thunderstorms prior to installation of the surge protectors.

And I wouldn't be surprised if that welding equipment is not sending some healthy equipment-made surges/spikes down the line to the OP's home on top of dragging down the voltage. Supposedly, around 80% of surges experienced in a home are man-made/equipment-based (i.e., high power equipment like air cons, motors, microwave ovens, elevators, welding machines, etc., turning off and on) and the other 20% come from lightning-induced surges.

[Marvo]

Based on three digitial multimeters I have, here at my western Bangkok moobaan the voltage runs in the 225-227V ballpark...and at my mother-in-law's home in a small village in a nearby province, her's runs around 227-230V. All home appliances at both homes work fine...can't attibute any home electronic failures to the voltage running up to 230V, but I also put whole house surge protectors at both homes to help protect from lightning and equipment induced surges...along with surge protected power strips at my home....as I did experience some failures during thunderstorms prior to installation of the surge protectors.

And I wouldn't be surprised if that welding equipment is not sending some healthy equipment-made surges/spikes down the line to the OP's home on top of dragging down the voltage. Supposedly, around 80% of surges experienced in a home are man-made/equipment-based (i.e., high power equipment like air cons, motors, microwave ovens, elevators, welding machines, etc., turning off and on) and the other 20% come from lightning-induced surges.

Apparently the PEA propose fitting a "Precise" (trade name) capacitor on the pole outside the house. Maybe something like this as per the Precise website:

Any comments anyone? Will this address the "spiking" that Pib suggests may be an issue?

http://www.precise.c...citor&Itemid=11

[electau]

They appear to be power factor correction capacitors. thay are designed to correct the power fctor to closer to 0.9. this should improve your voltage. They are not designed for surge and spike protection.

[Pib]

They wouldn't help with surge protection.