Power Factor Correction



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1-what is Power factor correction

Power factor correction is displayed by the PFC, the power factor adjustment of values smaller than 1 to values close to 1. High-voltage power factor correction also during the post in order to increase the conversion efficiency of voltage conversion and the electric energy consumption centers is done. In fact, with power factor correction costs to produce electric energy and also reduce the cost of the cable and power equipment. And thus the production and transport costs are reduced.

1-1-What do we need for power factor correction

In cases where the need for power factor correction are: 1. If the power factor of 0.85 is lower building electrical installations to electric power company paid the penalty area after holding capacitor for high power factor should be.2. If losses due to low power factor is high plants with a simple calculation we can see that the Deepwater holding capacitor short time and then compensate all costs is profit. 3. If additional time is part of the facility and reduce the amperage is desired. 4. If the new machines added to the network to full capacity.
Under normal conditions the electrical equipment (electric motors, welding machines, fluorescent tubes) in addition to the active power consumption W, reactive energy consumption will also Dasht.az Var physical point of view, reactive energy to function properly and to make the necessary equipment. In However, the sum of these two energy distribution networks delivered to the load capacitors and inductors the purpose choice and correct connection group (reactors) are unique to the time required reactive power can be provided.

2-A variety of methods power factor correction

The three main methods used for power factor correction: 1-The individual power factor correction2-group power factor correction 3-The central power factor correction

2-1-The individual power factor correction

The procedure for no-load transformers, devices with long cables and motors are used where a permanent job for each consumer individually calculated and install capacitors For this the advantages of the use of power factor regulators, accurate compensation , network discharge the burden of reactive and reduce the cost per Kylvvar capacitor. The disadvantage of this method is based on the simultaneous use of different consumer factor that increases the value of the capacitor installed in the network.

2-2-group power factor correction

In this way for a consumer who work together at the same time, a large capacitor is installed. Because this type of compensation is a special case of compensation position, the previous method has the advantage of reducing the number of capacitors in addition to the steps for installation, it is more economical cost.

2-3- The central power factor correction

The total capacitance at the input of the system and is divided into small steps. A regulator, power factor capacitor network control required to calculate and enter the network. This method can be used almost everywhere. Such compensation benefits include simple installation, simple controls, use of capacitors installed Byhnh and flexibility to changes in load and harmonic control network, with the addition of the reactor is capacitors. The main drawback of this method of compensation in the consumer network.

3-linear load power factor correction

This is usually done by feeding a certain amount of capacitor or inductor. For example, the effect of the induction motor can be counteracted by connecting capacitors in the installation time. Sometimes the capacitive mode tends network characteristics (such as cable lines) of inductors (which in this application is said to them reactor) is used to neutralize the effect of capacitive network; this is generally done in voltage substations. In electrical engineering applied to the synchronous machine in neutral mode synchronous condenser say that by changing the excitation current, the machine can act as an inductor or capacitor. Synchronous condensers used to regulate voltage transmission lines Mygyrnd.msla end instead of the capacitor and capacitor to create the effect of a synchronous motor can also be used in a state of high agitation. In this case, the reactive power generated in the synchronous motor depends on the flow rate will be stimulated. The advantage of using such capacitive loads can change power output according to the current drive.

4-The power factor correction non-linear loads

Non-linear loads in AC circuits caused by harmonic currents in the mainstream AC. The linear loads such as capacitors or inductors can not add to neutralize the impact of these charges, so you should use other methods such as the use of filters or active power factor correction systems to smooth out the effect of these charges in the mainstream of Jst.mytvan filter design that flows with a certain frequency (for example 50 or 60 Hz) pass. If you use filters non-linear loads such as linear loads on the circuit, and then the linear loads can be used for power factor correction. But these filters are not without limitations, for example, they need to intermediaries, high current, high-volume and high cost of them. To neutralize the effect of non-linear loads active power factor correction method can be used.

5-Active power factor correction

Active power factor correction (active PFC) power electronics system is the amount of current drawn by the load factor to bring more power to control. In most cases, active power factor correction system works such that by controlling the input current waveform to flow much closer to the voltage waveform. Active power factor correction system can act as a class or multi-class power factor to about 0. 99 close. Microprocessor regulator with voltage transformer and current status of the network connection by calculating the relationship between active power and reactive power factor regulator. It examines the main harmonic component of active and reactive currents using the FFT algorithm used to calculate the . So the measurement and precise control even if the current waveform distortion and contamination with higher-order harmonics done easily.

6- passive power factor correction

This method is a simple method for power factor correction in the linear load is usually done with use of capacitor banks. But this method is not effective as active power factor correction. Although this method because it simply Decreasing cost and widely used, but in this way and out the capacitors of the circuit caused by harmonic currents and the fault is one of the reasons that tend to use synchronous motors or active power factor correction is still there.

7-calculate the reactive power for power factor correction

The following method can be reactive power needed to reach the target power factor can be calculated