A synchronous condenser, also known as a synchronous compensator, is a specialized device used in power systems to provide reactive power support. Reactive power is essential for maintaining the voltage stability and transmission efficiency of the electrical grid. Synchronous condensers are particularly useful in situations where there is an imbalance between the reactive power supply and demand.
Here's how a synchronous condenser works in power systems:
Synchronous Machine: A synchronous condenser is essentially a synchronous machine that operates without a mechanical load. It looks similar to a synchronous generator, consisting of a rotor and a stator. However, unlike a generator, it is not connected to a turbine or any mechanical system.
No Mechanical Power Generation: A synchronous condenser does not generate real power (kW). Instead, it is purely used to provide or absorb reactive power (kVAr).
Operation as Capacitor or Inductor: A synchronous condenser can be operated in two modes: over-excited mode and under-excited mode. In over-excited mode, it acts as a capacitor, supplying reactive power to the grid. In this state, the field current (excitation) is increased, leading to an increased voltage on the stator terminals, creating leading reactive power. In under-excited mode, it acts as an inductor, absorbing reactive power from the grid. Here, the field current is decreased, which results in a lagging reactive power.
Voltage Regulation: One of the key benefits of a synchronous condenser is its ability to regulate voltage on the electrical grid. When the grid voltage is low, the synchronous condenser can supply reactive power and increase the voltage. Conversely, when the grid voltage is high, the condenser can absorb reactive power, helping to reduce the voltage.
Dynamic Response: Synchronous condensers have a fast response time, making them valuable for managing sudden changes in the system's reactive power requirements. They can quickly adjust their reactive power output to stabilize the grid voltage during events like faults or switching operations.
Supporting Grid Stability: By providing reactive power support and voltage regulation, synchronous condensers contribute to grid stability. They help prevent voltage collapses, voltage sags, and other voltage-related issues that can lead to power system instability.
Reactive Power Compensation: Synchronous condensers are strategically located at various points in the power grid to compensate for the reactive power demand and improve the overall power factor of the system.
In summary, synchronous condensers are valuable assets in power systems for maintaining voltage stability and improving power factor by supplying or absorbing reactive power as needed. Their ability to respond quickly to grid conditions makes them crucial in supporting the reliable and efficient operation of the electrical grid.