In this note, we are going to learn about the KVAR Controller, also about its functions, working principle, and applications as well. Welcome to Poly Notes Hub, a leading destination for engineering notes for diploma and degree engineering students.
Author Name: Arun Paul.
What is KVAR Controller?
A KVAR (Kilovolt-Ampere Reactive) controller is a device used in electrical power systems to control and optimize power factor. The power factor is the ratio of real power (measured in kilowatts, kW) compared to estimated power (measured in kilovolt-amperes, kVA), which indicates how efficiently electrical power is used.
Key functions of Kilovolt-Ampere Reactive Controller –
- The KVAR controller improves the power system’s efficiency by minimizing the phase mismatch between voltage and current.
- It reduces reactive power (measured in KVAR), which does not do beneficial work but adds to the overall power flow in the system.
- Many utilities demand additional fees for a low power factor. These expenses can be reduced by using a KVAR controller to improve power factor.
- Optimizing the power factor might help to lower peak demand charges.
- Helps to keep voltage levels within the appropriate range, which improves power supply stability.
- Lower reactive power leads to fewer losses in transmission and distribution networks.
- By boosting power system efficiency, KVAR controllers contribute to reducing the overall energy consumption and carbon footprint.
Block Diagram of KVAR Controller
The function of Each Block –
- Transformer: Reduces the high voltage from the power lines to a level acceptable for use by the KVAR controller and other components. Offers electrical isolation and voltage transformation. This enables the safe monitoring and control of the power system.
- Current Transformer: Measures the current that flows through electricity cables. Reduces excessive current to a lower, safer level for metering and protection circuits. The CT transmits a proportionate current signal to the PF Controller for analysis.
- Potential Transformer: Measures the voltage across electricity lines. Steps down the high voltage to a level appropriate for metering and control circuits. The PT sends a proportional voltage signal to the PF controller.
- PF Controller: Analyzes current and voltage information to estimate the system’s power factor. The PF Controller estimates the reactive power (KVAR) required to restore the power factor to the specified level. This calculation determines how the Capacitor Bank is switched.
- Capacitor Bank: Offers reactive power adjustment. The PF Controller may switch numerous capacitors into and out of the circuit. By increasing capacitance, the Capacitor Bank compensates for the system’s inductive reactive power, boosting the power factor.
This method guarantees that the power factor remains within the specified range, lowering losses and increasing the efficiency of the electrical power system.
Types of KVAR Controller
There are two types of this controller –
- Fixed Capacitor Banks: A simple and cost-effective solution for rather stable load conditions.
- Automatic Power Factor Controllers (APFC): More advanced, capable of dynamically adapting to changing load conditions by switching capacitor banks on and off as needed.
KVAR Controller Working Principle
Below we describe its working in list format to understand clearly –
- Measurement: Continuously monitors the power factor by measuring both real and apparent power.
- Analysis: Analyzes the present power factor to calculate the necessary fix.
- Correction: Engages or disengages capacitors (or inductors) to alter the system’s reactive power, hence enhancing the power factor.
- Feedback Loop: Constantly changes based on real-time measurements to ensure the best power factor.
Applications of KVAR Controller
Below we listed some uses of this device –
- Used in factories and manufacturing plants with heavy inductive loads including motors, welders, and HVAC systems.
- Used in huge buildings with complex lighting and HVAC systems.
- Used to manage the electricity quality in the distribution network.