When the automatic power factor controller project is implemented, the power factor is automatically improved whenever it falls below a certain level. Electrical energy demand is steadily increasing every day. More and more loads with inductive characteristics are being applied in industry and household applications. These loads are the primary reason power systems have a low power factor.
Projects such as automatic power controllers can provide solutions to this problem. A low power factor unnecessarily burdens transmission lines and power systems. An improved power factor of a power system automatically can enhance power system efficiency. This article is all about automatic power factor controllers in detail.
Types of automatic power factor controller
There are power factor controllers available for mono-phase and three-phase networks. They come in 96mm-wide and 144mm-wide versions with only 62mm depths; these controllers are available in 4-6-8-12 steps versions, covering the entire traditional power factor industry.
In the panel-mounting version, a TTL port is included, while in the 96mm version, it is optional.
In addition to the Mod-bus RTU protocol for interfacing with complex systems, the 96mm version includes a proprietary communication protocol for local management.
Working of automatic power factor controller
Real power is defined as the difference between apparent power and absolute power. Unity is the best power factor. The best power factor is for pure resistive loads. However, such loads do not exist. Accordingly, we always try to keep the power factor close to unity. High reactive power is another reason for the low power factor. Inductive loads absorb reactive power, while capacitive loads generate reactive power.
Therefore, power factor correction circuits employ capacitor banks to improve power factors. The capacitor banks are connected parallel to the load, increasing the power factor. Instead of generating reactive power from generators or power systems, capacitors provide it locally to loads, thereby reducing the burden on the power system. The goal of automatic power factor controllers is to do just that.
Components of automatic power factor controller
APFC consists of these main components:
· The capacitor bank.
This is the main component of the APFC controller. The only thing it does is improve the power factor. When there is an inductive load in the electrical circuit, the power factor tends to lag, but when there is a capacitor bank, the power factor tends to be leading. Many capacitors in the capacitor bank are internally connected either in delta or start connections.
However, there are times when they are connected in a delta configuration. The capacitor banks are protected internally by various types of protective equipment, such as fuses and circuit breakers. Despite showing only three capacitor banks in the above block diagram, many capacitor banks are in use. Power factor is maintained by automatically connecting or disconnecting capacitor banks according to the APFC circuit.
· An embedded microcontroller
APFC controllers are controlled by microcontrollers, who are their brains. The power factor is analyzed to determine how much capacitor bank needs to be connected to the power line to improve the power factor. A signal is sent to the thyristor that determines whether to connect or disconnect the capacitor banks to the power line based on the current power factor level.
· Sensor/Transducer for Power Factor
Power factor sensors are combined with current transformers or current sensors. Power factor measuring is accomplished by connecting the microcontroller to the power line. The microcontroller uses this power factor sensor or transducer to measure current, voltage, and power factor.
· The thyristor
Thyristors are electronic switches. This is the connection between a capacitor bank and the main power line or circuit. When the microcontroller sends a pulse or signal to these thyristors, they connect or disconnect the capacitor banks from the main power supply. TRIACs are most commonly used because they can work with AC supplies. The microcontroller operates a thyristor according to the signals it receives.
Uses of automatic power factor controller
APFC uses capacitors controlled by contactors using an automatic power factor correction unit. A power factor regulator controls these contactors by measuring the power factor of an electrical network or an individual motor. Depending on the load and power factor of the network, only the necessary capacitors will be powered up, ensuring the power factor remains above a predetermined level. According to different resources, fixed capacitors are usually used in this application because they offer the most straightforward and cheapest way to correct the power factor.
Unlike reactive power factor loads, leading power factor loads are created with capacitive load banks. They are typical of specific electronic or nonlinear loads in the telecommunications, computer, and UPS industries. An automatic capacitor system should power multiple loads to ensure that a power factor capacitor of the correct value is always connected to the system. Consequently, the power factor compensation is created by using a microcontroller.
Benefits of automatic power factor controller
The following are some of the main advantages of APFC:
- Low reactive power consumption in power system
- Enhanced system efficiency and load efficiency
- Reduced household and commercial electricity bills
Drawbacks of APFC using Capacitor
- The service life of these devices varies from 8 to 10 years
- If the voltage is exceeded, they can be damaged
- Afterward, repairing them is not economically feasible
The power factor, which is determined by the proportion of real and perceived power, is monitored by an automatic power factor controller. We frequently place the power factor at or near unity. In power equipment, the automatic power controller is often used to raise the power factor if it drops below a predetermined threshold.
The power factor, which would be determined by the ratio of real and perceived energy, is monitored by an automatic power controller. We frequently set the power factor at or near unity. In power equipment, the power – factor regulator is used to raise the power factor if it drops below a predetermined threshold.