Power Grid Voltage Fluctuations

Be more specific.

i have faced in our substation particularly on sundays when all other industries are shut down.At that time the voltage increses 415 to 450.What do u think

It is quite normal. On working days, when other loads are there in the industrial hub, there will be huge IR (Voltage) drop in the distribution lines feeding the hub. On Sundays/Holidays, when many industries lay off, the current on the distribution lines will be lesser and hence the IR drop will be lesser too. Hence, you will get an increased voltage.

It is same everywhere.

This is commonly called " The line's regulation"

The reason that voltage fluctuations on the grid occurs comes from two basic principles. First, your node on the grid is not near a voltage regulated supply node. It is only at one of these voltage regulated sub-stations that one should expect a consistent RMS voltage level. But even here, things happen. Next, while all metals conduct well at room temperature they all have some resistance. Copper has a resistivity (Ρ) of about 17 nano-ohms meters at room temperature, close to but not at zero. (To convert a copper wire length to resistance R=Ρ*l/A, with l ≡ wire length in meters and A ≡ cross sectional area of wire in meters^2.) So as loads and supplies change on the grid for any reason, fluctuations in the voltage will appear. A simple demonstration of this happens when a person uses a hair dryer in a bathroom lit by incandescent lights. When the hair dryer is turned on the lights in the bathroom typically dim. But if one could monitor safely the voltage at the supply transformer, no voltage drop would happen while a voltage drop occurred in your bathroom.

Totally normal as others have posted. A typical utility regulates the substation distribution bus voltage at plus or minus 5% of nominal. So a 120 volt service supplied by a transformer tapped to the substation bus will range from 114 to 126 volts. Do not confuse supply service voltage with utilization voltage. The utilization voltage is what you might expect at the outlet in your home or business. The service voltage is measured at the point of connection with the utility - generally at or near the revenue meter. For example, you may measure 120 volts at the meter but 114 volts at a receptacle in your house. The utility is responsible for supplying the 120 volt service voltage only.

Utilities may also regulate the voltage at the transmission level and use distribution line capacitors and distribution line voltage regulators to maintain acceptable customer voltage.

The service voltage will also fluctuate based on the system configuration, generation, system loads, etc.

As system load increases & therefore voltage drop increases, the bus voltage will be increased to compensate. Line capacitors may also be switched on to reduce the reactive load. Opposite is also true of course.

Yes You are right my friend.

Insufficient transmission line is a real trouble.

It feeds back and goes to avalanch effect as I will try to mention below:

If the active load is exceeding the calculation parameters of the transmission line, The result is voltage drop.

Voltage drop causes much current drawing for the motors.

Much current causes much voltage drop across the line.

And it feeds back itself.

This generally occurs here in the rapid enlarging suburbian industrial regions.

Load is rapidly enlarging to exceed the estimations of the transmission lines.

Kindest Regards.

Grid voltage fluctuations due to phase angle and frequency mismatch across all the generations and also for the transmission line faults.

DEAR MR. MANSURI,

POWER GRID GENERATED VOLTAGE & FREQUENCY AS PER NORMS ONLY BUT STATE ELECTRICITY BOARDS OR DISTRIBUTION NETWORK DRAWING MORE OR LESS POWER THAT'S WHY VOLTAGE UPDOWN IN CERTAIN LIMITS ALSO IN CASE OF OVERDRAWING OR IMMIDIATE LOAD SHUTDOWN FREQUENCY& VOLAGE UP/DOWN DRASTICALLY RESULT IN GIRD FAILURE.

REGARDS.

VIPIN NAGORI