In this article from Electrosheil, we aim to discuss capacitor banks with you. Be sure to stay with this text to provide you with comprehensive information on this subject. You can also read the article on how capacitor bank testing should be done here.
What is a Capacitor Bank?
To begin, we need to familiarize ourselves with the concept of a capacitor bank. A capacitor bank refers to a collection of capacitors arranged next to each other and used to improve the power factor of the network.
Why a Capacitor Bank?
The significance of electricity in both large and small industries today is undeniable; therefore, efficient management and utilization are crucial.
The presence of reactive power in the system leads to a reduction in the effective power available in the network and a decrease in equipment performance, resulting in increased costs.
Therefore, to compensate for these costs and increase the available power in the equipment, it is necessary to use a capacitor bank in the electrical panel.
Motors, devices with winding coils, transformers, and any equipment that has a coil (winding) generate reactive power. Reactive power, like active power, is calculated in the joint billing. The capacitor bank prevents reactive power from entering the network.
In a three-phase electrical network, there are several types of consumable power:
1. Active Power (Real Power):
Active power, also known as real power, is the power consumed by devices for performing useful work.
2. Reactive Power:
Reactive power, also known as non-useful power, is another type of power consumed in the network. This non-useful power is generated due to the presence of inductive loads in the network.
Inductive loads cause displacement of voltage and current peaks in relation to each other. This displacement results in additional current consumption in the network, which, when examined on a large scale, can lead to damage to power generation facilities.
Considering the issues mentioned above, any three-phase subscriber with a current exceeding 50 amperes is required by the power management authority to install a capacitor panel to correct the power factor.
Typically, in addition to theoretical formulas for designing a capacitor bank and selecting capacitor coefficients, the formula of 2/1 of the total unit current is used. For example, if the nominal current of a production unit is 100 amperes, a capacitor bank of 50 kilovars is used for it.
Definition of Capacitor:
A capacitor consists of two metal or electrolytic plates separated by an insulator or dielectric. These plates have the ability to store electrical energy and correct the current phase shift concerning voltage while smoothing the voltage waveform.
Voltage Regulator:
A voltage regulator is an intelligent unit that, based on the consumed voltage and current, places the optimal capacitor in the circuit. For selecting capacitor steps, specific ratios like 1:2:2:2 or 1:2:4:8 are usually used (depending on the regulator brand in use, for example, for a 50-kilovar capacitor bank, two 5-kilovar capacitors, two 10-kilovar capacitors, and one 20-kilovar capacitor may be used).
Applications of Capacitor Banks:
Capacitor banks find applications in various sectors, including energy transmission networks, switching stations, distribution networks, industrial centers, and more. They are utilized to improve the power factor and compensate for reactive power in low-pressure distribution networks.
Operation of Automatic Capacitor Bank Panel:
These panels are used in low-pressure distribution networks to increase the power factor and compensate for reactive power. They operate by measuring the voltage and current waveforms, and their time difference, determining the required capacitance, and introducing it into the network.
Automatic capacitor bank panels have a regulator or power factor controller that measures the voltage and current waveforms, calculates the required capacitor values, and connects them to the network. Contactor switches controlled by the regulator are responsible for switching the capacitors in automatic panels. These automatic panels are commonly used in hospitals, factories, workshops, commercial and administrative complexes, hotels, and similar environments.
Types of Capacitors Used in Capacitor Bank Panels:
In capacitor bank panels, what type of capacitors is utilized? Some features that capacitor banks should possess include:
1. Tolerance for Alternating Exchanges:
Capacitors in a capacitor bank should tolerate alternating exchanges of high current and power between themselves and the coil.
2. Heat or Air Cooling Tolerance:
They should tolerate heat or air cooling.
3. Network Voltage Tolerance:
Capacitors should tolerate the voltage of the power grid. (The power grid may operate at low pressure with a voltage of 380 volts.)
4. High Initial Current Tolerance:
They should tolerate high initial currents received when connected to the power grid.
Important Note: Since the unit for reactive power is kilovar (kvar) and the capacitor’s role is to correct this power, the capacitors for power factor correction are specified in kilovars, not microfarads. Pay careful attention to this crucial point!
Advantages of Using Capacitor Banks:
1. Optimizing Network Power:
Capacitor banks optimize the power of the network.
2. Reducing System Losses Due to Joule Effect:
They reduce system losses due to the Joule effect.
3. Preventing Incurrence of Additional Costs:
Capacitor banks prevent the imposition of additional costs.
4. Increasing Available Power in the Network:
They increase the available power in the network by eliminating reactive power.
Loads in the Network:
1. Resistive Loads:
Resistive loads consist of pure resistances, and the phase voltage in this case is similar to the network voltage.
2. Inductive Loads:
Inductive loads include asynchronous motors, fluorescent lamps, etc. If we consider a pure inductive load, the phase voltage will always lag 90 degrees behind the network voltage.
3. Capacitive Loads:
In this case, the line is always equipped with a capacitor, such as a capacitor bank. If we consider a pure capacitive load, the phase voltage will always lead 90 degrees ahead of the network.
How to Determine the Appropriate Capacitor Bank Size:
The following methods are used to determine the appropriate size of the capacitor bank (kvar) for compensating reactive power in the system:
1. Analysis and Examination of Electricity Bills According to the Type of Subscription:
Analyzing and examining electricity bills based on the type of subscription.
2. Measurement of Reactive Power and Power Factor (cosφ):
Measuring reactive power and power factor using suitable control equipment or network measurement equipment for troubleshooting and investigating network phenomena.
3. Calculation of Required Active Power to Compensate for Reactive Power:
Calculating the active power required to compensate for reactive power for all equipment in the network, such as transformers, motors, and other motorized equipment, based on device manuals or information.
4. Calculation of Equipment That May Be Added to the Network in the Future:
Calculating equipment that may be added to the network later on.
These methods help determine the appropriate size of the capacitor bank for effectively compensating reactive power in the system.
Reasons for Using Capacitor Bank Panels:
The use of capacitor bank panels offers numerous advantages, making them economically efficient. Therefore, their installation in industrial environments is essential and necessary. Given that in industries, most loads are resistive-inductive, causing the emergence of reactive power in the electrical grid, the installation of capacitor banks becomes crucial. It’s worth mentioning that this property leads to various issues such as increased wire and cable cross-sections, elevated losses, and increased current. Hence, adding capacitors to the circuit is the best option to mitigate these problems.
In essence, elements composed of coil windings utilize reactive power in addition to active power. Today, with technological advancements, the use of such devices like coil windings, transformers, and motors has significantly proliferated across industries.
Considering the widespread use of consumers like elevators, fluorescent lights, transformers, pumps, various motors, etc., in workspaces and homes, the consumption of reactive power has notably increased. Therefore, the best way to reduce reactive power consumption and energy in these devices is to install parallel capacitors in the circuit. Additionally, the use of capacitor bank panels helps reduce voltage drops since capacitors neutralize the leading current of inductive elements, resulting in decreased current consumption, reduced losses in wires, and a decrease in voltage drops in the wires.
Other Benefits of Using Capacitor Bank Panels:
One significant advantage of using capacitor bank panels is a reduction of over half of the electricity bills. In the absence of capacitor bank panels, the reactive power meter of the power management will calculate not only the active meter but also the electricity cost separately. It can confidently be stated that if these panels are not used, the electricity cost will be almost twice as much, making it economically impractical for users.
Furthermore, another advantage of capacitor bank panels is their remarkable capability to significantly improve the power factor. It’s important to note that the power factor of an electrical device represents the amount of reactive energy the device utilizes. Capacitor bank panels, with their ability to regulate and maintain voltage, effectively prevent considerable damage to the intended devices.
We appreciate your companion with Electrosheil throughout the entirety of the capacitor bank panel article. For inquiries and orders regarding various industrial electrical equipment, feel free to contact our experts.