Reactive_Power_Injection_Methods in PSOC.pptx

Reacive power injection methods

1. Reactive Power Injection Methods in Power Systems

2. Introduction Reactive power is essential for voltage stability, power factor correction, and system security. Various devices and methods are used to inject or absorb reactive power in power systems.

3. Shunt Capacitor Banks Provide capacitive reactive power (Q = V^2 / Xc ). Used for power factor correction and local voltage support. Advantages: Low cost, simple, efficient. Limitations: Coarse control, switching transients.

4. Shunt Reactors Absorb reactive power during light load conditions. Prevent over-voltage in long transmission lines. Opposite function of capacitor banks.

5. Synchronous Machines & Condensers Generators: Reactive power controlled by excitation system. Over-excited → inject Q, Under-excited → absorb Q. Synchronous condensers: Provide inertia and fault current support. Advantages: Large dynamic capability. Limitations: High cost, maintenance required.

6. Static VAR Compensator (SVC) Composed of thyristor-controlled reactors (TCR) and thyristor-switched capacitors (TSC). Provides fast dynamic reactive power control. Advantages: Fast , moderate cost. Limitations: Generates harmonics, less effective at low voltages.

7. STATCOM Static Synchronous Compensator – VSC based device. Injects or absorbs reactive current rapidly by voltage control. Advantages: Very fast, effective at low voltages, compact. Limitations: High cost, thermal limits.

8. STATCOM

9. Series Compensation Methods Series capacitors reduce line reactance, improving voltage profile. TCSC/SSSC/UPFC provide dynamic and controllable compensation. Advantages: Increase power transfer, stability support. Limitations: Expensive, complex, protection challenges.

10. On-Load Tap Changers (OLTC) Adjust transformer turns ratio to control secondary voltage. Indirectly influences reactive power flow. Advantages: Widely used, effective for steady-state control. Limitations: Slow response, not suitable for fast transients.

11. Comparison of Methods Capacitors: Low cost, steady correction. SVC: Dynamic, moderate cost, needs filters. STATCOM: Fastest, effective under low voltage, costly. Synchronous condensers: Inertia + Q, costly. Series devices: Power flow control, complex. DER inverters: Distributed, fast, limited by rating.