Generators absorb or supply reactive power to the grid depending on the operating conditions and the needs of the electrical system. Reactive power is essential for maintaining voltage levels within acceptable limits across the grid. Generators can absorb reactive power when the grid has excess reactive power and needs to lower voltage levels. Conversely, generators supply reactive power when the grid requires additional reactive power to raise voltage levels and support the transmission of active power over long distances or through networks with high impedance.
The grid needs reactive power primarily to maintain stable voltage levels across the transmission and distribution networks. Reactive power helps to manage the phase angle between voltage and current in AC systems, ensuring that the electrical equipment and loads receive adequate voltage to operate efficiently and reliably. Without sufficient reactive power, voltage levels can drop, leading to voltage instability, equipment malfunction, and potential grid instability. Therefore, by supplying or absorbing reactive power as needed, generators and other devices help maintain grid voltage within specified tolerances for optimal operation.
Reactive power can be delivered or absorbed depending on the requirements of the electrical system at any given time. Generators and other sources of reactive power can supply reactive power to the grid when there is a deficit, which typically occurs when there is a high demand for active power transmission or when voltage levels need to be maintained across long transmission lines. Conversely, when the grid has excess reactive power, generators may absorb reactive power to help stabilize voltage levels by lowering them to the desired range and preventing overvoltage conditions.
Various devices and components within the electrical grid can absorb reactive power to stabilize voltage levels and improve system efficiency. Capacitors are commonly used to absorb reactive power by generating reactive current that leads the voltage. This helps maintain voltage levels within acceptable limits. Inductive devices such as motors and transformers can also absorb reactive power due to their inherent inductance, which causes them to lag behind the voltage waveform in terms of current flow. By absorbing reactive power, these devices contribute to maintaining stable voltage levels and ensuring efficient power transmission and distribution.
Active power and reactive power are two fundamental components of electrical power in AC (alternating current) systems. Active power, measured in watts (W), represents the actual useful power that performs work, such as driving motors, heating elements, and lighting. It is the power that is transferred to the load and converted into useful energy. In contrast, reactive power, measured in volt-amperes reactive (VAR), represents the power that oscillates between the source and the load without performing any useful work. It is required to establish and maintain the magnetic fields in inductive devices and to maintain the voltage levels across the grid. Together, active power and reactive power make up the total apparent power, measured in volt-amperes (VA), which is the combination of real power (active power) and reactive power needed to meet the electrical demands of the grid and its consumers efficiently.