Why does the supply voltage fluctuate when the load changes?

The main factor that causes voltage deviation is the system voltage loss caused by the reactive load of the system lagging. Therefore, when the load changes, the voltage loss in the system can be changed by adjusting the access capacity of the capacitor accordingly, thereby narrowing the range of voltage deviation to a certain extent.

In the three-phase four-wire system, if the three-phase load is unevenly distributed (phase line to neutral line), the zero sequence voltage will be generated, so that the zero point is shifted, the voltage of one phase decreases, and the voltage of the other phase increases, which increases the voltage deviation.

In a two-shift or two-shift plant (as is the case for a one-shift plant), the voltage is low during peak load during the day, so the transformer tap is adjusted"-5%"At this time, if the transformer of part of the load is cut off, the low-voltage contact line is used for power supply, and the voltage loss in the transformer and line is increased, and the excessive voltage of the electrical equipment can be reduced. There is no shortage of such examples in the survey. They cut off part of the transformer at light load, which not only reduces the no-load loss of the transformer, but also plays the role of voltage regulation.

In the design of the power supply and distribution system, the power supply of the shock load needs to reduce the grid voltage fluctuation and voltage flicker caused by the impact load, and the measures should be taken as follows:

First, the use of special line power supply.

2. When sharing the distribution line with other loads, reduce the impedance of the distribution line.

3. The impact load or shock load group with higher power and the load sensitive to voltage fluctuation and flicker are respectively supplied by different transformers.

4. For the furnace transformer of high-power electric arc furnace, the power supply is provided by the power grid with large short-circuit capacity.

To put it simply, when the load changes, the supply voltage fluctuates, which means that the power supply is insufficient.

For example, if a generator runs with a motor, when the generator load is fixed at 10kw and the motor needs 11kw, the voltage and frequency will drop until the speed of the motor is reduced to 10kw; Key Transport.

If the motor needs 9kw, then the motor will heat up, the voltage, and frequency will be too high, and the motor will still consume 10kw of power. In other words, power generation - electricity consumption is always how much is generated, or how much is used;

However, there is a problem of power quality, only according to the change of the electric load of the beam of the manuscript to reasonably adjust the power generation load, so that the voltage and frequency are maintained within a reasonable range of electric energy can be used, otherwise it will inevitably cause equipment damage and other problems.

Voltage. Voltage, also known as potential difference or potential difference, is a physical quantity that measures the energy difference between a unit electric charge in an electrostatic field due to different electric potentials.

1.Causes of voltage fluctuation and flicker (1) Electrical equipment has shock load or fluctuating load, such as electric arc furnace, steelmaking furnace, rolling mill, electric welding machine, rail transit, electrified railway, and short circuit test load. (2) The system has a short-circuit fault, causing power grid fluctuations and flicker.

3) The influence of the operation wave is generated when the system equipment is automatically switched, such as the automatic switching of the standby power supply, the automatic reclosing action, etc. (4) Grid voltage fluctuations caused by lightning strikes. 2.

The influence of voltage fluctuation and flickerVoltage flicker is mainly a parameter that characterizes the subjective perception of the human eye on the light flash. It is generally caused by switching action or a load change that is large enough compared to the short-circuit capacity of the system. Although some voltage fluctuations are within the normal voltage change limit, they may cause lighting flickering of about 10 Hz and interfere with the normal operation of voltage-sensitive electronic equipment and instruments such as computers.

Voltage fluctuations and flicker are mostly generated in the distribution system and transmitted to the user power supply on the low voltage side through the distribution transformer. The main cause of voltage fluctuations and flicker is industrial electrical loads, such as the operation of electric arc furnaces, welding machines, and capacitor switching, which can produce rapid voltage changes. Voltage fluctuations have similar physical causes to the generation of harmonics, such as the nonlinear nature of shock loads, regular or irregular opening and closing maneuvers, etc.

The nonlinear alternating load current causes voltage fluctuations in the grid impedance that is dependent on the frequency. The preferred solution for the influence of voltage fluctuation and flicker is to use power electronics technology to eliminate the flicker of the power supply with a fast reactive power compensator, so that the components of the voltage other than the power frequency are reduced.

There may be a variety of reasons for the frequent fluctuation of power station voltage sail tracks, and the following are some common reasons:1Load Variation:

When there is a sudden change in load, overload or underload, it can cause grid voltage fluctuations. 2.Power failure:

Faults in equipment such as generators or transformers can cause voltage fluctuations. For example, problems such as damaged generator cylinder heads, rotor imbalance, etc., can cause the AC voltage output of the generator to fluctuate. 3.

Impedance mismatch: If there is an impedance mismatch in the system, reflections and interferences may occur, causing voltage fluctuations. 4.

Failure of the regulated control system: If the regulated control system is not working properly, it can cause voltage fluctuations or destabilization in the system. These are just some of the common causes, but there are other factors that can also cause frequent voltage fluctuations in power stations.

In order to ensure the safety, stable operation and reliability of the equipment, please design, maintain and operate the power station reasonably. At the same time, troubleshooting and repair should be carried out in time when abnormal conditions occur to ensure stable voltage.

Good afternoon, dear, dear, dear, dear, dear, dear, dear,Load fluctuations:

Fluctuations in the load on the grid can lead to fluctuations in the output voltage of the generator, especially when the power station is hungry to rapidly increase or decrease the load in a short period of time. 2.Generator excitation failure:

Problems with the generator's excitation system can cause voltage fluctuations or instability, such as problems with the excitation power supply, regulator, or excitation windings. 3.Capacitor assembly damage:

Damage or failure of capacitor components can cause voltage fluctuations or even resonance in the power system. 4.Voltage Destroyer Regulator Failure:

A voltage regulator malfunctions or fails, causing the voltage to fluctuate or even become unstable. 5.Other equipment failures or abnormalities:

For example, faults in switching equipment, transformers, switches, etc., can also lead to voltage fluctuations or instability.