Voltage Regulators in Series in Power Distribution System
Voltage Regulators in Series in Power Distribution System
(OP)
Hi. Can anyone comment on experience with using multiple Voltage Regulators in series on a distribution network, for example in maintain voltage on a long overhead line. Would there be issues with power factor towards the end of the line because of the impedance of the regulators in series? If so how is this overcome, it is my understanding that in the US for example where there are several miles of overhead line distribution they use many of these in succession to maintain the voltage at distribution level.
Thanks
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RE: Voltage Regulators in Series in Power Distribution System
RE: Voltage Regulators in Series in Power Distribution System
"They may use more than one of these in succession."
Bill
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"Why not the best?"
Jimmy Carter
RE: Voltage Regulators in Series in Power Distribution System
But the impedance of the regulator/s would be present if I had the equivalent model from source to load and via the return path, doesn't the inductance of the regulator (just coils same as a transformer) create a phase shift and hence affect the power factor?
Thanks
RE: Voltage Regulators in Series in Power Distribution System
RE: Voltage Regulators in Series in Power Distribution System
Interesting you say that. Last I checked a large inductance (ie a transformer) causes the current to lag the voltage.
Thanks
RE: Voltage Regulators in Series in Power Distribution System
RE: Voltage Regulators in Series in Power Distribution System
CR
"As iron sharpens iron, so one person sharpens another." [Proverbs 27:17, NIV]
RE: Voltage Regulators in Series in Power Distribution System
RE: Voltage Regulators in Series in Power Distribution System
CR
"As iron sharpens iron, so one person sharpens another." [Proverbs 27:17, NIV]
RE: Voltage Regulators in Series in Power Distribution System
I have seen three in a row, from distant memory it was a 180 km 22 kV line with a MW or two of total load.
The source power factor is changed only marginally, since the series impedance of regulators is small (zero at nominal tap, often only a percent or two on nameplate base at extreme tap) and the shunt impedance large relative to load impedance.
Utilities often have a rule specifying a maximum number in a row, but nobody has yet explained to me the basis for these rules.
Usually they are time-graded, so the more in a row, the slower the response and in extreme cases lamp flicker or step voltage change limits may impose a constraint on the number in series. Other than this it seems to be based around "That's the rule" with no technical justification.
John.
RE: Voltage Regulators in Series in Power Distribution System
This is no problem for single phase loads but reduces the available HP of three phase motors.
In extreme cases the motor current at no load may exceed rated full load current.
When regulators are in series, it is possible for one regulator the correct the neutral shift of another series regulator but the odds against this are overwhelming.
Bill
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"Why not the best?"
Jimmy Carter
RE: Voltage Regulators in Series in Power Distribution System