Power factor issues? What causes the power factor to be too low and why should the power factor be i

The calculation method in the electricity bill is as follows: first calculate the total active electricity in this month and subtract the total active code in the previous month to get the number of codes in this month, and then multiply it by the metering multiplier to calculate the total electricity number p in this month; In the same way, the reactive power Q1 and the reverse reactive power Q2 are calculated.

The power factor COS is calculated using the figure below, which is greater than the reward electricity fee, and the penalty is doubled if it is less than that.

The lower the power factor, the less electricity is used to do useful work, for example, the total amount of electricity transmitted from the outside is 100W, if the power factor is, then the amount of electricity used to do useful work is 90W, and the remaining 10W is used to do useless work, and these reactive power are generally consumed in some inductive electrical appliances.

Hope you understand.

Power factor = active power apparent power.

Apparent power = active power + reactive power.

The part of the electricity bill you need to pay is active power, which is the actual amount of electricity consumed by your unit's electrical equipment.

The maximum power that a power plant needs to be able to provide is the apparent power.

Why is the maximum power provided by a power plant not the same as the power you consume? It is because of the reactive power.

So what is reactive power? That is, every time your equipment works, due to the energy storage effect of the capacitors and inductors in it, the extra part of the power, this part of the power will be returned to the power plant, so you don't have to pay for it.

Why should we care about the power factor, because the higher the power factor, the smaller the reactive power, then the smaller the power generation capacity of the power plant can be then burned less coal, then it can be more environmentally friendly pf=Yes Your company is amazing!

What causes the power factor to be too low and why should the power factor be increased

Hello, the power factor is too low because of the large load of the power system, most of which are induction electric base machines. In normal operation, it is generally between, and the power factor of the gods is only when there is no load, and the power factor is not high when it is light load. The significance of increasing the power of the potato factor is:

The power factor is the ratio of useful work to apparent work in a circuit, usually denoted by the symbol cos. In AC circuits, there is a phase difference between current and voltage, which is due to the presence of elements such as inductance and capacitance in the circuit. When there is only pure resistance in the circuit, the phase difference between current and voltage is zero, the power factor is 1, and the circuit is most efficient.

However, when components such as inductors and capacitors are present in the circuit, the phase difference between the current and the voltage will lead to the separation of the useful and useless work in the circuit, thus reducing the utilization efficiency of the circuit.

The magnitude of the power factor reflects the efficiency of the useful work in the circuit. When the power factor is 1, the useful work and apparent work in the circuit are equal, and the utilization efficiency of the circuit is the highest. When the power factor is less than 1, the useless work in the circuit increases, and the utilization efficiency of the circuit decreases. At this time, the phase difference between the current and voltage in the circuit will also increase, resulting in an increase in the load of the power grid, affecting the stability and safety of the power grid.

In order to improve the utilization efficiency of the circuit and reduce the loss of useless work, some measures need to be taken to improve the power factor. Among them, the most common method is to use reactive power compensation devices, such as capacitors, inductors, etc. These devices can generate reactive power in the circuit as opposed to components such as inductors and capacitors, thereby canceling out the useless work in the circuit and improving the power factor.

In addition, high power factor electrical equipment, such as high power factor motors, high power factor lamps, etc., can also be used to improve the power factor of the circuit.

In short, the power factor is the ratio of the useful work and the apparent work in the circuit, which reflects the utilization efficiency of the useful work in the circuit. In order to improve the utilization efficiency of the circuit and reduce the loss of useless work, some measures need to be taken to improve the power factor, such as the use of reactive power compensation devices, electrical equipment with high power factors, etc. <>

1. The power factor is expressed by cos, cos = active power p apparent power s. The angle between voltage and current is called the power factor angle.

Power factor and power factor angle are different concepts.

2. The simplest explanation of the principle of capacitance compensation is: adding capacitive load to an inductive circuit, because the capacitive load can emit inductive reactive power, so after adding capacitor, the reactive power drawn by this circuit from the power supply will be reduced, and the power factor will be increased.

3. The so-called "light load" of transformers and motors means that the active power is very small, but the reactive power used to form the magnetic field is almost the same as the full load, that is to say, the active power is reactive power, so the power factor is very low.

1. In the power system, there are three kinds of power, active power P, reactive power Q and apparent power S.

The cosine of the phase difference ( ) between voltage and current is called the power factor, which is represented by the symbol cos, and numerically, the power factor is the ratio of the active power to the apparent power, i.e., cos = p s

The three power and power factor COS is a right-angled power triangle: the two right-angled sides are the active power p, the reactive power q, and the hypotenuse side is the apparent power s. At any time, these three kinds of power always exist at the same time, the active power p is the power of work and heating, the reactive power q is the power to establish the magnetic field and carry out electromagnetic conversion, and the apparent power s is the sum of the squares of the active power and the reactive power, that is, s = p + q s = (p + q ).

The power factor of the power system can only operate stably if it is less than 1, and the phase difference between voltage and current must be that the voltage is ahead of the current or the current lags behind the voltage. The angle formed by voltage and current is exactly the same as that of the power triangle.

2. Because cos = p s, the capacitance compensation is actually to compensate for reactive power, and the capacitance of the compensation is its own, which is not transmitted from the network, which reduces the reactive power of the network transmission, reduces the apparent power s, and improves the power factor.

3. Reactive power Q is the power to establish the magnetic field and carry out electromagnetic conversion, and the dosage is fixed, regardless of the size of the load. When there is light load or no load, the active power is reduced a lot, the reactive power is not reduced, the amount is still as much as the full load, and the power factor must be reduced of course.

Voltage lead current waveform diagram.

Power triangle.

Causes and hazards of low power factor.

Reason (1) A large number of induction motors or other inductive electrical equipment are used.

2) Inductive electrical equipment is not matched or used unreasonably, resulting in long-term light load or no-load operation of the equipment.

3) When fluorescent lamps and street lamps are used, there is no distribution capacitor.

4) The load rate and annual utilization hours of substation equipment are too low.

Hazard (1) increases the loss of the power supply line, and in order to reduce this loss, the cross-section of the power supply line must be increased, which in turn increases the investment.

2) Increase the voltage drop of the line and reduce the voltage quality.

3) Reduce the utilization rate of power generation and power supply equipment.

4) It has increased the electricity expenditure of enterprises and increased the cost.

The voltage corresponding to the usual alternating current is also alternating, taking the current and voltage of the sine wave as an example, which involves the phase problem, when the phase of the sine wave of the current and the voltage is different, the difference is a certain angle, and this is called a degree.

Speaking of power, the power classification in electricity mainly includes "active power", "reactive power", "apparent power", and "complex power".

Active power is the most common average power, because the AC current and voltage have a phase difference angle, as shown in the figure, assuming that the X axis based on U at this time, then the current should be orthogonally decomposed in the direct coordinate system, where the decomposition of the parallel X axis is ICOS The other Y-axis is perpendicular to the voltage U is ISIN. The decomposed x-axis component ICOS is multiplied by the voltage U to obtain the active power, that is, the active power is UICOS, and the vertical component UISIN is called the reactive power. From here, it is also easy to see the meaning of "active" and "reactive".

The definition of apparent power is UI

The power factor refers to cos, so the power factor = active depends on the relationship is obviously true, and this is also the angle between the AC voltage and the current.

So how did this horn come about? That is, why the phases of AC voltage and current may be different, and how is the current ahead voltage or voltage ahead current generated?

What we know is that the inductor and the capacitor have an energy storage effect in the circuit, the inductive element will make the current in the circuit be blocked, and the inductor has a hindering effect on the AC current, but it has no hindering effect on the voltage. This makes that in the AC circuit composed of inductive elements, "the AC voltage leads the AC current through the inductive element", and at this time, the voltage ahead current has a phase angle, and this angle is .

For the capacitive element, it has a hindrance effect on the AC voltage, but not on the current, so in the AC circuit composed of capacitive elements, "the AC current is ahead of the AC voltage through the capacitive element", at this time, the current ahead of the voltage is a phase angle, and this angle is .

It can be seen from the above description that the inductive element and the capacitive element are converted and stored by their respective effects on the current and voltage, so that the phase angle difference between the current and the voltage appears, and the active power and reactive power we mentioned before happen to be related to , with the difference of , the ratio of active power and reactive power is different, therefore, the setting of the parameters of the inductance and capacitive element can adjust the active power and reactive power output of the circuit. This is the principle of compensation using capacitance.

Now that the principle of angle generation is clear, then you can analyze the third problem yourself.

1》The power factor is less than 1, and the angle between voltage and current is that the voltage is ahead of the current (or the current lags behind the voltage).

2》When the capacitor is connected to the alternating voltage, the capacitor can be continuously charged and discharged, forming a continuous alternating current back and forth. The current is 90° ahead of the voltage (or the voltage lags behind the current); It compensates for the narrowing of the angle between the current lag and the voltage due to the J inductive load.

3》The motor is dependent on the reactive current excitation rotation, and the reactive excitation current consumed by the no-load or full-load operation is basically unchanged, and the active current consumed by the no-load operation is very small (only consumed in the iron and copper loss), and the active current consumed by the full-load operation is the rated value, so the power factor is low at light load.

Hehe. It is Yuliang that your reactive power compensation equipment is not operating properly.

Why Increase the Power Factor?

Let's talk about the power factor first.

Power factor is a data used to measure the power efficiency of electrical equipment (including generalized electrical equipment, such as transformers, transmission lines, etc.) of the power grid.

The formula for defining power factor: power factor, active power, apparent power.

Active power is the power consumed by the device and converted into other energy.

Reactive power is the amount of energy that keeps equipment running, but does not consume. It exists between the power grid and the equipment, and is an indispensable part of the energy of the power grid and equipment. However, if the reactive power is occupied too much by the equipment, it will cause the efficiency of the power grid to be low, and at the same time, a large amount of reactive power is transmitted back and forth in the power grid, which makes the line loss high and the waste is serious.

Therefore, in order to reduce the reactive power transmission of the power grid, the user is required to provide reactive power (compensation reactive power) to the equipment at the power consumption end to improve the power factor of the user.

The act of providing reactive power is reactive power compensation. The compensation equipment that provides reactive power is called: reactive power compensation device. For example, the ATBX local compensation box of Shenzhen Aote Electric Appliance Company is a very effective local compensation device.

1. The low power factor of the circuit is caused by too much inductive load in the system.

2. The power factor of the circuit is too low, which will cause the generator capacity to not be fully utilized, and cause excessive voltage and power loss due to excessive current of the transmission line, so it is of great economic significance to improve the power factor of the power system.

Hello netizens!

The power factor is too low because there is too much inductive load and the compensation capacitance is too small.

The purpose of increasing the power factor is to improve the working efficiency and service life of electrical appliances.

1. Power is equal to current multiplied by voltage multiplied by power factor (p=uicos), while current is equal to power divided by voltage divided by power factor (i=p u cos), obviously, the lower the cos, the greater the current. The power loss is equal to the square multiplied resistance of the current (p=i r), and when the current increases, the voltage loss and the electrical energy loss both increase. And because of the formula for calculating the resistance of the wire r (l s).

The cross-sectional area of the wire is inversely proportional to the resistance of the wire, increasing the cross-sectional area of the wire, reducing the resistance of the wire, and reducing the power loss by the power loss p=i r.

2. Voltage loss U = UI, the power factor is too low, the current increases, the voltage loss increases, the power supply voltage is reduced, and the power supply quality is poor.

3. The power generation and power supply equipment is designed according to the rated voltage, load, current, etc., and the current increases, and if it exceeds the rating, it is necessary to reduce the power to reduce the current and reduce the effective utilization rate.

4. The voltage is low, the current is large, and the meter is not slow, but the output of the electrical equipment is reduced, the work is reduced, and the production cost is increased.