Auto-Reclosing Scheme with Adaptive Dead Time Control Based on Synchro-Check Principle

Abstract

Series compensation plays important role in smart power grid to improve power transfer capacity and voltage profiles. Majority of faults occurring in the grid are transient in nature. However, the discrimination between transient fault and permanent fault are contemporary problems in the field of distance protection of transmission line. Advanced numerical relays implement auto-reclosing feature to detect the transient fault and regain the service continuity automatically when the transient fault is cleared. The research work outlined in this chapter presents an auto-reclosure scheme using synchronized voltage phasors across the breaker pole along with adaptive dead time control to enhance system stability. The developed auto-reclosing scheme provides adaptive dead time control for both uncompensated and series compensated transmission lines as compared to conventional schemes which normally respond with fix dead time control.

Appendix: System Parameters During Modeling in PSCAD

Generator G1 and G2

• Power rating: 100 MVA;

• Voltage rating: 13.8 kV;

• Phase angle: 0^o for G1 and variable for G2.

• Frequency = 50 Hz;

• Positive-sequence impedance = 0.871 + j9.96Ω.

Transmission Line Data

• Total length = 110 km;

• System voltage = 230 kV;

• Positive-sequence impedance = 0.0297 + j0.332 Ω/km;

• Zero-sequence impedance = 0.162 + j1.24 Ω/km.

Transformer Data

• 175 MVA, 13.8 kV/220 kV, DYng,

• 50 Hz three-phase transformer with leakage reactance of 12%.

System Parameters During Emulation of Laboratory Prototype:

Generator Data

• Power rating: 3.75 kVA;

• Voltage rating: 415 V;

• Frequency = 50 Hz; speed = 1500 rpm.

• Excitation voltage = 200 V, current = 1.7 A,

• Insulation class: B.

Transmission Line Data

• System voltage = 415 V;

• Variable rheostat = 0-–8 Ω, 12 A,

• Variable inductor = 0–20 Ω, 10 A.